Antimicrobial activity of antihypertensive food-derived peptides and selected alanine analogues.

PubMed

McClean, Stephen; Beggs, Louise B; Welch, Robert W

2014-03-01

This study evaluated four food-derived peptides with known antihypertensive activities for antimicrobial activity against pathogenic microorganisms, and assessed structure-function relationships using alanine analogues. The peptides (EVSLNSGYY, barley; PGTAVFK, soybean; TTMPLW, α-casein; VHLPP, α-zein) and the six alanine substitution peptides of PGTAVFK were synthesised, characterised and evaluated for antimicrobial activity using the bacteria, Escherichia coli, Staphylococcus aureus, and Micrococcus luteus and the yeast, Candida albicans. The peptides TTMPLW and PGTAVFK inhibited growth of all four microorganisms tested, with activities of a similar order of magnitude to ampicillin and ethanol controls. EVSLNSGYY inhibited the growth of the bacteria, but VHLPP showed no antimicrobial activity. The alanine analogue, PGAAVFK showed the highest overall antimicrobial activity and PGTAVFA showed no activity; overall, the activities of the analogues were consistent with their structures. Some peptides with antihypertensive activity also show antimicrobial activity, suggesting that food-derived peptides may exert beneficial effects via a number of mechanisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of the flora of northern Mexico for in vitro antimicrobial and antituberculosis activity.

PubMed

Molina-Salinas, G M; Pérez-López, A; Becerril-Montes, P; Salazar-Aranda, R; Said-Fernández, S; de Torres, N Waksman

2007-02-12

The aim of the present study was to evaluate the potential antimicrobial activity of 14 plants used in northeast México for the treatment of respiratory diseases, against drug-sensitive and drug-resistant strains of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae type b and Mycobacterium tuberculosis. Forty-eight organic and aqueous extracts were tested against these bacterial strains using a broth microdilution test. No aqueous extracts showed antimicrobial activity, whereas most of the organic extracts presented antimicrobial activity against at least one of the drug-resistant microorganisms tested. Methanol-based extracts from the roots and leaves of Leucophyllum frutescens and ethyl ether extract from the roots of Chrysanctinia mexicana showed the greatest antimicrobial activity against the drug-resistant strain of Mycobacterium tuberculosis; the minimal inhibitory concentration (MIC) were 62.5, 125 and 62.5 microg/mL, respectively; methanol-based extract from the leaves of Cordia boissieri showed the best antimicrobial activity against the drug-resistant strain of Staphylococcus aureus (MIC 250 microg/mL); the hexane-based extract from the fruits of Schinus molle showed considerable antimicrobial activity against the drug-resistant strain of Streptococcus pneumoniae (MIC 62.5 microg/mL). This study supports that selecting plants by ethnobotanical criteria enhances the possibility of finding species with activity against resistant microorganisms.

A novel direct contact method for the assessment of the antimicrobial activity of dental cements.

PubMed

Costa, E M; Silva, S; Madureira, A R; Cardelle-Cobas, A; Tavaria, F K; Pintado, M M

2013-06-01

Dental cements are a crucial part of the odontological treatment, however, due to the hazardous nature and reduced biological efficiency of some of the used materials, newer and safer alternatives are needed, particularly so those possessing higher antimicrobial activity than their traditional counterparts. The evaluation of the antimicrobial properties of solid and semi-solid antimicrobials, such as dental cements and gels, is challenging, particularly due to the low sensitivity of the current methods. Thus, the main aim of this study was the evaluation of the antimicrobial activity of a novel chitosan containing dental cement while simultaneous assessing/validating a new, more efficient, method for the evaluation of the antimicrobial activity of solid and gel like materials. The results obtained showed that the proposed method exhibited a higher sensitivity than the standard 96 well microtiter assay and allowed the determination of bactericidal activity. Additionally, it is interesting to note that the chitosan containing cement, which presented higher antimicrobial activity than the traditional zinc oxide/eugenol mix, was capable of inducing a viable count reduction above 5 log of CFU for all of the studied microorganisms. Copyright © 2013 Elsevier B.V. All rights reserved.

Structure-activity studies and therapeutic potential of host defense peptides of human thrombin.

PubMed

Kasetty, Gopinath; Papareddy, Praveen; Kalle, Martina; Rydengård, Victoria; Mörgelin, Matthias; Albiger, Barbara; Malmsten, Martin; Schmidtchen, Artur

2011-06-01

Peptides of the C-terminal region of human thrombin are released upon proteolysis and identified in human wounds. In this study, we wanted to investigate minimal determinants, as well as structural features, governing the antimicrobial and immunomodulating activity of this peptide region. Sequential amino acid deletions of the peptide GKYGFYTHVFRLKKWIQKVIDQFGE (GKY25), as well as substitutions at strategic and structurally relevant positions, were followed by analyses of antimicrobial activity against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive bacterium Staphylococcus aureus, and the fungus Candida albicans. Furthermore, peptide effects on lipopolysaccharide (LPS)-, lipoteichoic acid-, or zymosan-induced macrophage activation were studied. The thrombin-derived peptides displayed length- and sequence-dependent antimicrobial as well as immunomodulating effects. A peptide length of at least 20 amino acids was required for effective anti-inflammatory effects in macrophage models, as well as optimal antimicrobial activity as judged by MIC assays. However, shorter (>12 amino acids) variants also displayed significant antimicrobial effects. A central K14 residue was important for optimal antimicrobial activity. Finally, one peptide variant, GKYGFYTHVFRLKKWIQKVI (GKY20) exhibiting improved selectivity, i.e., low toxicity and a preserved antimicrobial as well as anti-inflammatory effect, showed efficiency in mouse models of LPS shock and P. aeruginosa sepsis. The work defines structure-activity relationships of C-terminal host defense peptides of thrombin and delineates a strategy for selecting peptide epitopes of therapeutic interest.

Comparison of Antimicrobial Efficacy of Triclosan- Containing, Herbal and Homeopathy Toothpastes- An Invitro Study

PubMed Central

Fawaz, Mohammed Alimullah; Narahari, Rao; Shahela, Tanveer; Syed, Afroz

2015-01-01

Background Use of antimicrobial agents is one of the important strategies to prevent oral diseases. These agents vary in their abilities to deliver preventive and therapeutic benefits. Objectives This invitro study was conducted to assess antimicrobial efficacy of different toothpastes against various oral pathogens. Materials and Methods A total of nine toothpastes in three groups were tested for their antimicrobial activity against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Streptococcus mutans (ATCC 0266P) and Candida albicans (Laboratory Strain) by modified agar well diffusion method. Statistical Analysis was performed using Minitab Software. A p-value of less than 0.05 was considered significant. Results Triclosan-based dental formulation with combination of fluoride (1000ppm) exhibited higher antimicrobial activity against test organisms than the combination of lower fluoride-concentration or sodium monofluorophosphate. Among herbal dentifrices, formulation containing Neem, Pudina, Long, Babool, Turmeric and Vajradanti showed significant antimicrobial activity against all the four tested microorganisms (p<0.05). However, against Streptococcus mutans, all three herbal products showed significant antimicrobial activity. Homeo products showed least antimicrobial activity on the tested strains. Formulation with kreosotum, Plantago major and calendula was significantly effective only against Streptococcus mutans. Conclusion In the present study, antimicrobial activity of the toothpaste containing both triclosan and fluoride (1000ppm) as active ingredients showed a significant difference (p< 0.05) against all four tested microflora compared to that of with lower fluoride-concentration or sodium monofluorophosphate. Of herbal groups, the only dentifrice containing several phytochemicals was found to be significantly effective and comparable to triclosan-fluoride (1000ppm) formulation. Thus, this herbal toothpaste can be used as alternative to triclosan-based formulations. However, these results might not be clinically useful unless tested invivo. PMID:26557516

Cyclodextrins: A Weapon in the Fight Against Antimicrobial Resistance

NASA Astrophysics Data System (ADS)

Wong, Chew Ee; Dolzhenko, Anton V.; Lee, Sui Mae; Young, David James

Antimicrobial resistance poses one of the most serious global challenges of our age. Cyclodextrins (CDs) are widely utilized excipients in formulations because of their solubilizing properties, low toxicity, and low inflammatory response. This review summarizes recent investigations of antimicrobial agents involving CDs and CD-based antimicrobial materials. CDs have been employed for antimicrobial applications either through formation of inclusion complexes or by chemical modification of their hydroxyl groups to tailor pharmaceutically active compounds. Applications of these CD inclusion complexes include drug delivery, antimicrobial coatings on materials (e.g., biomedical devices and implants) and antimicrobial dressings that help to prevent wound infections. There are relatively limited studies of chemically modified CDs with antimicrobial activity. The mechanism of action of antimicrobial CD inclusion complexes and derivatives needs further elucidation, but activity of CDs and their derivatives is often associated with their interaction with bacterial cell membranes.

Antimicrobial activity of Ulopterol isolated from Toddalia asiatica (L.) Lam.: a traditional medicinal plant.

PubMed

Karunai Raj, M; Balachandran, C; Duraipandiyan, V; Agastian, P; Ignacimuthu, S

2012-03-06

The leaves of Toddalia asiatica (L.) Lam. (Rutaceae) are widely used in folk medicine in India to treat various ailments like cough, malaria, indigestion, influenza lung diseases and rheumatism, fever, stomach ailments, cholera and diarrhea. In our earlier communication we have reported the antimicrobial study on the various extracts of the leaves and the isolation and identification of Flindersine, a quinolone alkaloid as the major active principle. In the present study, we report the antibacterial and antifungal activities of Ulopterol, a coumarin isolated as another major active antimicrobial principle. The leaves were successively extracted with hexane, chloroform, ethyl acetate, methanol and water. The extracts were studied for their antimicrobial activity against selected bacteria and fungi by using disc-diffusion method. The ethyl acetate extract which was found to possess highest antimicrobial activity was subjected to activity guided fractionation by column chromatography over silica gel. This resulted in the isolation of the coumarin, Ulopetrol, an active principle besides Flindersine which was reported by us earlier. The structure of the compound was elucidated using physical and spectroscopic data. Flindersine and Ulopterol were quantified by HPLC. Ulopterol showed activity against the bacteria viz. Staphylococcus epidermidis, Enterobacter aerogenes, Shigella flexneri, Klebsiella pneumoniae (ESBL-3967), Escherichia coli (ESBL-3984) and fungi viz. Aspergillus flavus, Candida krusei and Botrytis cinerea. Quantification by HPLC showed the content of Flindersine and Ulopterol to be 0.361% and 0.266% respectively on dry weight basis of the leaves. Ethyl acetate extract (successive extraction) contained Ulopterol, a coumarin, besides Flindersine, a quinolone alkaloid, as a major active principle in the antimicrobial studies. This is the first report of the antimicrobial activity of Ulopterol and also its first report from the plant. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Antimicrobial and Antibiofilm Activity of Human Milk Oligosaccharides against Streptococcus agalactiae, Staphylococcus aureus, and Acinetobacter baumannii.

PubMed

Ackerman, Dorothy L; Craft, Kelly M; Doster, Ryan S; Weitkamp, Jörn-Hendrik; Aronoff, David M; Gaddy, Jennifer A; Townsend, Steven D

2018-03-09

In a previous study, we reported that human milk oligosaccharides (HMOs) isolated from five donor milk samples possessed antimicrobial and antibiofilm activity against Streptococcus agalactiae, also known as Group B Streptococcus or GBS. Herein, we present a broader evaluation of the antimicrobial and antibiofilm activity by screening HMOs from 14 new donors against three strains of GBS and two of the ESKAPE pathogens of particular interest to child health, Staphylococcus aureus and Acinetobacter baumannii. Growth and biofilm assays showed that HMOs from these new donors possessed antimicrobial and antibiofilm activity against all three strains of GBS, antibiofilm activity against methicillin-resistant S. aureus strain USA300, and antimicrobial activity against A. baumannii strain ATCC 19606.

Antimicrobial activity of Austroeupatorium inulaefolium (H.B.K.) against intracellular and extracellular organisms.

PubMed

Bua, A; Usai, D; Donadu, M G; Delgado Ospina, J; Paparella, A; Chaves-Lopez, C; Serio, A; Rossi, C; Zanetti, S; Molicotti, P

2017-10-11

The antimicrobial activity of Austroeupatorium inulaefolium (H.B.K.) essential oil was studied in different pathogens species and its cytotoxicity activity was determinated on different cellular lines. Despite the good antibacterial activity of A. inulaefolium, it has been cytotoxic at low concentrations. Consequently it might be interesting to determine the antimicrobial activity and cytotoxicity of the major compounds of this essential oil.

[Studies on antimicrobial activity of extracts from thyme].

PubMed

Fan, M; Chen, J

2001-08-01

The extracts from thyme by water and ethanol, thyme essential oil, thymol and carvacrol were used as antimicrobial agents in this paper. The results show that all antimicrobial agents used have strong inhibition activity against Staphalococcus aureus, Bacillus subtilis, Escherichia coli.

Effects of antimicrobial treatment on fiberglass-acrylic filters.

PubMed

Cecchini, C; Verdenelli, M C; Orpianesi, C; Dadea, G M; Cresci, A

2004-01-01

The aims of the present study were to: (i) analyse a group of antimicrobial agents and to select the most active against test microbial strains; (ii) test the effect of the antimicrobial treatment on air filters in order to reduce microbial colonization. Different kinds of antimicrobial agents were analysed to assess their compatibility with the production process of air filter media. The minimal inhibitory concentration for each antimicrobial agent was determined against a defined list of microbial strains, and an antimicrobial activity assay of filter prototypes was developed to determine the most active agent among the compatible antimicrobials. Then, the most active was chosen and added directly to the filter during the production process. The microbial colonization of treated and untreated filter media was assessed at different working times for different incubation times by stereomicroscope and scanning electron microscope analysis. Some of the antimicrobial agents analysed were more active against microbial test strains and compatible with the production process of the filter media. Filter sections analysis of treated filter media showed a significantly lower microbial colonization than those untreated, a reduction of species both in density and varieties and of the presence of bacteria and fungal hyphae with reproductive structures. This study demonstrated the ability of antimicrobial treatments to inhibit the growth of micro-organisms in filter media and subsequently to increase indoor air quality (IAQ), highlighting the value of adding antimicrobials to filter media. To make a contribution to solving the problem of microbial contamination of air filters, by demonstrating the efficacy of incorporating antimicrobial agents in the filter media to improve IAQ and health.

[In vitro studies on antioxidant and antimicrobial activities of polysaccharide from Lycoris aurea].

PubMed

Ru, Qiao-Mei; Pei, Zhen-Ming; Zheng, Hai-Lei

2008-10-01

To study the preliminary antioxidant and antimicrobial activities of polysaccharide extracted from Lycoris aurea. The scavenging activities of the polysaccharide in vitro on superoxide radical (O2-*), hydroxyl radical (*OH), alkyl radical (R*) and hydrogen peroxide (H2O2) were investigated by modified chemical systems. Meanwhile, the antimicrobial activities were tested using paper-discagar diffusion method. In general, the antioxidant activities of the polysaccharide were lower compared with Vc. However, the scavenging effects to *OH and H2O2 were parallel to Vc. Meanwhile, polysaccharide from Lycoris aurea had strong antimicrobial activities against Micrococcus luteus, Bacillus pumilus and Staphylococcus aureus. The polysaccharide extracted from L. aurea can scavenge *OH and H2O2 effectively and inhibit Gram-positive bacterias.

Antimicrobial Activities of Clove and Thyme Extracts

PubMed Central

Nzeako, B C; Al-Kharousi, Zahra S N; Al-Mahrooqui, Zahra

2006-01-01

Objective: It has been postulated that geographical locations of the herbs affect the constituents of their essential oils and thus the degree of their antimicrobial action. This study examine two samples of clove obtained from Sri Lanka and Zanzibar and two samples of thyme from Iran and Oman to determine the antimicrobial potential of their extracted oils. Method: The active agents in each plant were extracted by steam distillation and by boiling. The antimicrobial activities of the extracts were determined at neat and by two-fold dilutions in well agar diffusion technique using Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Streptococcus pyogenes, Corynebacterium species, Salmonella species, Bacteroides fragilis and Candida albicans. Results: All oil extracts possessed antimicrobial activity against all bacteria and yeast tested. Their water extracts exhibited lower antimicrobial activity, though thyme aqueous extract was active only against S. aureus. The lowest concentration of antimicrobial activity (0.1% i.e., 1:1024) was obtained with thyme oil extract using Candida albicans. There was no significant difference in antimicrobial activity between clove obtained from Sri Lanka or Zanzibar or thyme obtained from Iran or Oman. Conclusion: Our experiment showed that the country of origin of the herbs has no effect on their antimicrobial activity. However, further work is necessary to ascertain why Candida albicans displayed remarkable degree of sensitivity with the extracts than all the other organisms test. PMID:21748125

Antimicrobial efficacy of 0·05% cetylpyridinium chloride mouthrinses.

PubMed

Sreenivasan, P K; Haraszthy, V I; Zambon, J J

2013-01-01

This study evaluated the antimicrobial activity of two commercially available 0·05% cetylpyridinium chloride (CPC) mouthrinses with or without alcohol and examined its antimicrobial activity on oral bacterial species including fresh clinical isolates compared to a chlorhexidine mouthrinse and a control fluoride mouthrinse without CPC. Two different approaches were used to evaluate antimicrobial activity. First, the minimum inhibitory concentration (MIC) was determined for each mouthrinse against a panel of 25 micro-organisms including species associated with dental caries, gingivitis and periodontitis. Second, supragingival dental plaque obtained from 15 adults was incubated with the four mouthrinses to evaluate antimicrobial activity on micro-organisms in oral biofilms. Both CPC mouthrinses exhibited lower MIC's, that is, greater antimicrobial activity, against oral Gram-negative bacteria especially periodontal pathogens and species implicated in halitosis such as Aggregatibacter actinomycemcomitans, Campylobacter rectus, Eikenella corrodens, Porphyromonas gingivalis, Prevotella intermedia and Solobacterium moorei than the control mouthrinse. Ex-vivo tests on supragingival plaque micro-organisms demonstrated significantly greater antimicrobial activity by the CPC mouthrinses (>90% killing, P < 0·001) and the chlorhexidine rinse (>98% killing, P < 0·05) compared to the control fluoride mouthrinse. Whilst the chlorhexidine mouthrinse was most effective, mouthrinses containing 0·05% CPC formulated with or without alcohol demonstrated broad-spectrum antimicrobial activity against both laboratory strains and supragingival plaque bacteria compared to a control mouthrinse without CPC. These in vitro and ex-vivo studies provide a biological rationale for previous clinical studies demonstrating the efficacy of CPC mouthrinses in reducing supragingival plaque and plaque-associated gingivitis. © 2012 The Society for Applied Microbiology.

Synthesis and biological activity of lipophilic analogs of the cationic antimicrobial active peptide anoplin.

PubMed

Chionis, Kostas; Krikorian, Dimitrios; Koukkou, Anna-Irini; Sakarellos-Daitsiotis, Maria; Panou-Pomonis, Eugenia

2016-11-01

Anoplin is a short natural cationic antimicrobial peptide which is derived from the venom sac of the solitary wasp, Anoplius samariensis. Due to its short sequence G 1 LLKR 5 IKT 8 LL-NH 2 , it is ideal for research tests. In this study, novel analogs of anoplin were prepared and examined for their antimicrobial, hemolytic activity, and proteolytic stability. Specific substitutions were introduced in amino acids Gly 1 , Arg 5 , and Thr 8 and lipophilic groups with different lengths in the N-terminus in order to investigate how these modifications affect their antimicrobial activity. These cationic analogs exhibited higher antimicrobial activity than the native peptide; they are also nontoxic at their minimum inhibitory concentration (MIC) values and resistant to enzymatic degradation. The substituted peptide GLLKF 5 IKK 8 LL-NH 2 exhibited high activity against Gram-negative bacterium Zymomonas mobilis (MIC = 7 µg/ml), and the insertion of octanoic, decanoic, and dodecanoic acid residues in its N-terminus increased the antimicrobial activity against Gram-positive and Gram-negative bacteria (MIC = 5 µg/ml). The conformational characteristics of the peptide analogs were studied by circular dichroism. Structure activity studies revealed that the substitution of specific amino acids and the incorporation of lipophilic groups enhanced the amphipathic α-helical conformation inducing better antimicrobial effects. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Bioprospecting saline gradient of a Wildlife Sanctuary for bacterial diversity and antimicrobial activities.

PubMed

DeLuca, Mara; King, Riley; Morsy, Mustafa

2017-08-11

Antibiotic-resistant bacteria are becoming a global crisis, causing death of thousands of people and significant economic impact. The discovery of novel antibiotics is crucial to saving lives and reducing healthcare costs. To address the antibiotic-resistant crisis, in collaboration the Small World Initiative, which aims to crowdsource novel antibiotic discovery, this study aimed to identify antimicrobial producing bacteria and bacterial diversity in the soil of the Stimpson Wildlife Sanctuary, an inland area with a soil salt gradient. Approximately 4500 bacterial colonies were screened for antimicrobial activity and roughly 100 bacteria were identified as antimicrobial producers, which belong to Entrococcaceae (74%), Yersiniaceae (19%), and unidentified families (7%). Several bacterial isolates showed production of broad spectrum inhibitory compounds, while others were more specific to certain pathogens. The data obtained from the current study provide a resource for further characterization of the soil bacteria with antimicrobial activity, with an aim to discover novel ones. The study showed no correlation between soil salt level and the presence of bacteria with antimicrobial activities. However, most of the identified antimicrobial producing bacteria do not belong to actinomycetes, the most common phyla of antibiotic producing bacteria and this could potentially lead to the discovery of novel antibiotics.

Molecular dynamics simulation studies and in vitro site directed mutagenesis of avian beta-defensin Apl_AvBD2

PubMed Central

2010-01-01

Background Defensins comprise a group of antimicrobial peptides, widely recognized as important elements of the innate immune system in both animals and plants. Cationicity, rather than the secondary structure, is believed to be the major factor defining the antimicrobial activity of defensins. To test this hypothesis and to improve the activity of the newly identified avian β-defensin Apl_AvBD2 by enhancing the cationicity, we performed in silico site directed mutagenesis, keeping the predicted secondary structure intact. Molecular dynamics (MD) simulation studies were done to predict the activity. Mutant proteins were made by in vitro site directed mutagenesis and recombinant protein expression, and tested for antimicrobial activity to confirm the results obtained in MD simulation analysis. Results MD simulation revealed subtle, but critical, structural variations between the wild type Apl_AvBD2 and the more cationic in silico mutants, which were not detected in the initial structural prediction by homology modelling. The C-terminal cationic 'claw' region, important in antimicrobial activity, which was intact in the wild type, showed changes in shape and orientation in all the mutant peptides. Mutant peptides also showed increased solvent accessible surface area and more number of hydrogen bonds with the surrounding water molecules. In functional studies, the Escherichia coli expressed, purified recombinant mutant proteins showed total loss of antimicrobial activity compared to the wild type protein. Conclusion The study revealed that cationicity alone is not the determining factor in the microbicidal activity of antimicrobial peptides. Factors affecting the molecular dynamics such as hydrophobicity, electrostatic interactions and the potential for oligomerization may also play fundamental roles. It points to the usefulness of MD simulation studies in successful engineering of antimicrobial peptides for improved activity and other desirable functions. PMID:20122244

Investigation of cream and ointment on antimicrobial activity of Mangifera indica extract.

PubMed

Awad El-Gied, Amgad A; Abdelkareem, Abdelkareem M; Hamedelniel, Elnazeer I

2015-01-01

Medicinal plants have curative properties due to the presence of various complex chemical substance of different composition, which are found as secondary plant metabolites in one or more parts of these plants. Mangifera indica Linn (MI L.) is a species of mango in the Anacardiaceae family. Phytoconstituents in the seed extracts may be responsible for the antimicrobial activity of the plant. The purpose of the study was to formulate and evaluate the antimicrobial herbal ointment and cream from extracts of the seeds of mango (MI L.) The formulated ointments containing oleaginous-based showed the best formulation compared to the emulsion water in oil type, the ointment and cream bases in different concentration 1%, 5% and 10%. The formulated ointment and cream of MI L. were subjected to evaluation of Uniformity of Weight, measurement of pH, viscosity, Spreadability, Acute skin irritation study, stability study and antimicrobial activity. Our study shows that MI has high potential as an antimicrobial agent when formulated as ointment and creams for topical use. Thus, the present study concludes that the formulated formulations of the MI are safe and efficient carriers, with potent antimicrobial activity.

Investigation of cream and ointment on antimicrobial activity of Mangifera indica extract

PubMed Central

Awad El-Gied, Amgad A.; Abdelkareem, Abdelkareem M.; Hamedelniel, Elnazeer I.

2015-01-01

Medicinal plants have curative properties due to the presence of various complex chemical substance of different composition, which are found as secondary plant metabolites in one or more parts of these plants. Mangifera indica Linn (MI L.) is a species of mango in the Anacardiaceae family. Phytoconstituents in the seed extracts may be responsible for the antimicrobial activity of the plant. The purpose of the study was to formulate and evaluate the antimicrobial herbal ointment and cream from extracts of the seeds of mango (MI L.) The formulated ointments containing oleaginous-based showed the best formulation compared to the emulsion water in oil type, the ointment and cream bases in different concentration 1%, 5% and 10%. The formulated ointment and cream of MI L. were subjected to evaluation of Uniformity of Weight, measurement of pH, viscosity, Spreadability, Acute skin irritation study, stability study and antimicrobial activity. Our study shows that MI has high potential as an antimicrobial agent when formulated as ointment and creams for topical use. Thus, the present study concludes that the formulated formulations of the MI are safe and efficient carriers, with potent antimicrobial activity. PMID:25878974

Antimicrobial activity of ProRoot MTA in contact with blood

PubMed Central

Farrugia, C.; Baca, P.; Camilleri, J.; Arias Moliz, M. T.

2017-01-01

Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess whether antimicrobial properties of the Portland cement-based dental cements such as mineral trioxide aggregate (MTA) are also affected by contact with blood present in clinical situations. ProRoot MTA, a Portland cement-based dental cement was characterized following contact with water, or heparinized blood after 1 day and 7 days aging. The antimicrobial activity under the mentioned conditions was assessed using 3 antimicrobial tests: agar diffusion test, direct contact test and intratubular infection test. MTA in contact with blood was severely discoloured, exhibited an additional phosphorus peak in elemental analysis, no calcium hydroxide peaks and no areas of bacterial inhibition growth in the agar diffusion test were demonstrated. ProRoot MTA showed limited antimicrobial activity, in both the direct contact test and intratubular infection test. When aged in water ProRoot MTA showed higher antimicrobial activity than when aged in blood. Antimicrobial activity reduced significantly after 7 days. Further assessment is required to investigate behaviour in clinical situations. PMID:28128328

Potential antimicrobial agents from triazole-functionalized 2H-benzo[b][1,4]oxazin-3(4H)-ones.

PubMed

Bollu, Rajitha; Banu, Saleha; Bantu, Rajashaker; Reddy, A Gopi; Nagarapu, Lingaiah; Sirisha, K; Kumar, C Ganesh; Gunda, Shravan Kumar; Shaik, Kamal

2017-12-01

A series of substituted triazole functionalized 2H-benzo[b][1,4]oxazin-3(4H)-ones were synthesized by employing click chemistry and further characterized based on 1 H NMR, 13 C NMR, IR and mass spectral studies. All the synthesized derivatives were screened for their in vitro antimicrobial activities. Further, molecular docking studies were accomplished to explore the binding interactions between 1,2,3-triazol-4-yl-2H-benzo[b][1,4]oxazin-3(4H)-one and the active site of Staphylococcus aureus (CrtM) dehydrosqualene synthase (PDB ID: 2ZCS). These docking studies revealed that the synthesized derivatives showed high binding energies and strong H-bond interactions with the dehydrosqualene synthase validating the observed antimicrobial activity data. Based on antimicrobial activity and docking studies, the compounds 9c, 9d and 9e were identified as promising antimicrobial leads. Copyright © 2017 Elsevier Ltd. All rights reserved.

In-vitro antimicrobial activity and identification of bioactive components using GC-MS of commercially available essential oils in Saudi Arabia.

PubMed

Ashraf, Syed Amir; Al-Shammari, Eyad; Hussain, Talib; Tajuddin, Shaikh; Panda, Bibhu Prasad

2017-11-01

This study was designed to evaluate antimicrobial activity and chemical composition of four different plant essential oils i.e. Ginger oil (GiO), Black seed oil (BSO), Oregano oil (OO) and Rose oil (RO) against different bacterial and fungal strains. Anti-microbial activities of selected essential oils were determined by the microbiological technique using Agar well diffusion assay. After in vitro study, most of the essential oils showed antimicrobial activity against all the selected pathogens. Among all the tested oils, GiO showed strong antimicrobial activity. GiO showed highest antimicrobial activity against Shigella (119.79%), Enteococcus hirae (110.61%) and Escherichia coli (106.02%), when compared with the tetracycline (50 µg/mL) activity. However, Antifungal activity of GiO was found to be present against Candida albicans and Aspergilluas flavus , when compared with clotrimazole (50 µg/mL) activity. Among all the selected bacteria, BSO showed maximum antimicrobial activity against the E. coli followed by Citrobacter freundii. Moreover, BSO had highest zone of inhibition against the C. ablicans (33.58%). OO indicated that, Shigella had the highest sensitivity (12.6 ± 0.58, 131.25%), followed by E. hirae (19.1 ± 0.61, 96.46%) and Salmonella typhi (15.2 ± 0.27, 83.06%) when compared with tetracycline activity. OO showed poor sensitivity against all the selected fungal strains. Furthermore, Gas Chromatography analysis revealed that, Gingerol (10.86%) was the chief chemical constituents found in GiO followed by α -Sesquiphellandrene (6.29%), Zingiberene (5.88%). While, BSO, OO and RO had higher percentage of p-Cymene (6.90%), Carvacrol (15.87%) and Citronellol (8.07%) respectively. The results exhibited that the essential oils used for this study was the richest source for antimicrobial activity which indicates the presence of broad spectrum antimicrobial compounds in these essential oils. Hence, essential oils and their components can be recommended for therapeutic purposes as source of an alternative medicine.

The antimicrobial action of resveratrol against Listeria monocytogenes in food-based models and its antibiofilm properties.

PubMed

Ferreira, Susana; Domingues, Fernanda

2016-10-01

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural phytoalexin synthesized by plants in response to stress. This compound has several beneficial documented properties, namely anti-inflammatory, antioxidant, neuroprotective and antimicrobial activities. In this study the antimicrobial activity of resveratrol against Listeria monocytogenes and Listeria innocua was investigated. Resveratrol had a minimum inhibitory concentration of 200 µg mL(-1) for the tested strains, with time-kill curves demonstrating bacteriostatic activity. Inhibition of biofilm formation was also assessed, with resveratrol strongly inhibiting biofilm formation by both species even at subinhibitory concentrations. Overall, resveratrol showed antimicrobial properties on planktonic cells and on biofilm formation ability. Considering the potential use of resveratrol as a food preservative, the antimicrobial efficacy of resveratrol in food was studied in milk, lettuce leaf model and chicken juice. Resveratrol retained greater efficacy in both lettuce leaf model and chicken juice, but milk had a negative impact on its antilisterial activity, indicating a possible reduction of resveratrol availability in milk. This study reinforces resveratrol as an antimicrobial agent, pointing out its antibiofilm activity and its potential use as preservative in some food matrices. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Synthesis, antimicrobial activity and advances in structure-activity relationships (SARs) of novel tri-substituted thiazole derivatives.

PubMed

Reddy, Guda Mallikarjuna; Garcia, Jarem Raul; Reddy, Vemulapati Hanuman; de Andrade, Ageo Meier; Camilo, Alexandre; Pontes Ribeiro, Renan Augusto; de Lazaro, Sergio Ricardo

2016-11-10

Trisubstituted thiazoles were synthesized and studied for their antimicrobial activity and supported by theoretical calculations. In addition, MIC, MBC and MFC were also tested. Moreover, the present study was analyzed to scrutinize comprehensive structure-activity relationships. In fact, LUMO orbital energy and orbital orientation was reliable to explain their antibacterial and antifungal assay. Amongst the tested compounds, tri-methyl-substituted thiazole compound showed higher antimicrobial activity and low MIC value due to highest LUMO energy. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Spectrum of antimicrobial activity associated with ionic colloidal silver.

PubMed

Morrill, Kira; May, Kathleen; Leek, Daniel; Langland, Nicole; Jeane, La Deana; Ventura, Jose; Skubisz, Corey; Scherer, Sean; Lopez, Eric; Crocker, Ephraim; Peters, Rachel; Oertle, John; Nguyen, Krystine; Just, Scott; Orian, Michael; Humphrey, Meaghan; Payne, David; Jacobs, Bertram; Waters, Robert; Langland, Jeffrey

2013-03-01

Silver has historically and extensively been used as a broad-spectrum antimicrobial agent. However, the Food and Drug Administration currently does not recognize colloidal silver as a safe and effective antimicrobial agent. The goal of this study was to further evaluate the antimicrobial efficacy of colloidal silver. Several strains of bacteria, fungi, and viruses were grown under multicycle growth conditions in the presence or absence of ionic colloidal silver in order to assess the antimicrobial activity. For bacteria grown under aerobic or anaerobic conditions, significant growth inhibition was observed, although multiple treatments were typically required. For fungal cultures, the effects of ionic colloidal silver varied significantly between different genera. No viral growth inhibition was observed with any strains tested. The study data support ionic colloidal silver as a broad-spectrum antimicrobial agent against aerobic and anaerobic bacteria, while having a more limited and specific spectrum of activity against fungi.

Extraction, Antimicrobial, and Antioxidant Activities of Crude Polysaccharides from the Wood Ear Medicinal Mushroom Auricularia auricula-judae (Higher Basidiomycetes).

PubMed

Cai, Ming; Lin, Yang; Luo, Yin-long; Liang, Han-hua; Sun, Pei-long

2015-01-01

In this study, crude polysaccharides of culinary-medicinal mushroom Auricularia auricular-judae were extracted by hot water extraction and alcohol precipitation, and their antimicrobial and antioxidant activities were investigated. An optimum extraction condition was obtained at a ratio of liquid to solid 70 mL/g, temperature 90°C, time 4 h and extraction number 4. Accordingly, the best yield of crude polysaccharides was 6.89% with 76.12% in purity. Some bacteria and fungi were used for antimicrobial studies. It was found that crude A. auricula-judae had great antimicrobial activities against Escherichia coli and Staphylococcus aureus, but no activities on the others. The inhibitory diameters of antimicrobial zones for the two were 5.55 ± 0.182 and 9.84 ± 0.076 mm, respectively. Moreover, crude A. auricula-judae had significant antioxidant activities in scavenging free radicals, reducing power assays, and Fe2+ chelating ability assay. Results revealed that crude A. auricula-judae has a great potential as antimicrobial and antioxidant, and it can be a supplementary food for human health.

Phytochemical screening and in vitro antimicrobial activity of Thymus lanceolatus Desf. from Algeria

PubMed Central

Benbelaïd, Fethi; Khadir, Abdelmounaïm; Abdoune, Mohamed Amine; Bendahou, Mourad

2013-01-01

Objective To investigate the antimicrobial activity of an endemic Thyme, Thymus lanceolatus (T. lanceolatus), against a large number of pathogens. Methods Four solvent extracts were evaluated for antimicrobial activity using disc diffusion method and MIC determination on twenty-one strains. Results T. lanceolatus extracts showed a broad-spectrum antimicrobial activity, especially ethanol extract with inhibition zone diameters ranging from 14 to 32 mm, and MIC values from 0.052 to 0.500 mg/mL. Chloroform extract was more active against Gram-positive bacteria, since it has an inhibitory potency on Staphylococcus aureus and Enterococcus faecalis at only 31 µg/mL. While, hexane and water extracts were less effective since they were inactive against several strains. Conclusions The findings of this study indicate that T. lanceolatus has a strong antimicrobial potential, which justifies its use in folk medicine for treatment of infectious diseases. Since this species is poorly investigated, further refined studies on it pure secondary metabolites are needed and very important, in the perspective to identify new antimicrobial molecules from this endemic plant.

Antimicrobial activity of fractions and subfractions of Elaeagia utilis against microorganisms of importance in dental caries.

PubMed

Aldana, Jennyfer; Téllez, Nohemí; Gamboa, Fredy

2013-01-01

Dental caries is a multifactorial infectious disease that leads to the destruction of dental hard tissue. The main goal of research into medicinal plants is to seek compounds with antimicrobial activity for subsequent use in prevention strategies and control of infectious diseases. The aim of this study was to evaluate the antimicrobial activity of fractions and subfractions obtained from Elaeagia utilis against Streptococcus mutans, Streptococcus sobrinus and Lactobacillus acidophilus. The plant material was collected in the town of Alban (Cundinamarca, Colombia), which is located at an altitude of 2245 meters above sea level. Two extracts were obtained by cold maceration of E. utilis leaves in (a) petroleum ether extract and (b) ethanol extract. Fractions were obtained from the petroleum ether extract by column vacuum chromatography, and from the ethanol extract by continuous liquid/liquid partitioning. The antimicrobial activity of fractions and subfractions was evaluated by the well diffusion method. At a concentration of 10 mg/well, several fractions from both extracts showed antimicrobial activity against S. mutans, S. sobrinus and L. acidophilus. Among the ethanol extract fractions, the dichloromethane fraction had notably greater antimicrobial activity. It was sub-partitioned, yielding three subfractions with inhibitory activity, of which the most active was MeOH: H2O (Bp) with minimum inhibitory concentration 0.1 mg/well on the 3 study bacteria. Terpenes, sesquiterpenlactones and simple phenolic compounds were identified in it. In conclusion, this study shows the antimicrobial potential of fractions and subfractions obtained from extracts of E. utilis leaves against bacteria that are important in dental caries.

Food-grade antimicrobials potentiate the antibacterial activity of 1,2-hexanediol.

PubMed

Yogiara; Hwang, S J; Park, S; Hwang, J-K; Pan, J-G

2015-05-01

Preservative agents determining the shelf life of cosmetic products must have effective antimicrobial activity while meeting safety requirements for topical use. In this study, we determined the antimicrobial activity of 1,2-hexanediol against several Gram-positive and Gram-negative bacteria. Antimicrobial susceptibility tests have shown that 1,2-hexanediol exhibits broad-spectrum activity against Gram-positive and Gram-negative bacteria with MICs of 0·5-2% (v/v). The bactericidal concentration of 1,2-hexanediol was ranging from 1 to 2 × MIC as demonstrated by time-kill curve assay. A membrane depolarization assay showed that 1,2-hexanediol disrupted the cytoplasmic membrane potential. A checkerboard assay indicated that the effective concentration of 1,2-hexanediol was reduced up to 0·25-0·5 × MIC when combined with macelignan and octyl gallate against Gram-positive bacteria. However, this combination was not effective against Gram-negative bacteria. A turbidity reduction assay demonstrated that the combination of a high concentration of 1,2-hexanediol with food-grade antimicrobial compounds could trigger lytic activity towards Bacillus cereus cells. The remaining cell turbidity was 24·6 and 22·2% when 2% of 1,2-hexanediol was combined with 8 mg l(-1) octyl gallate or with 32 mg l(-1) macelignan respectively. This study showed that food-grade antimicrobial compounds may be used in combination with 1,2-hexanediol to increase its efficacy as a preservative agent in cosmetics. The antimicrobial activity of 1,2-hexanediol against Gram-positive and Gram-negative bacteria was potentiated with food-grade antimicrobials including xanthorrhizol, macelignan, panduratin A and octyl gallate, which have already been reported to display anti-inflammatory and other beneficial activities related to cosmetics. Therefore, the combination of 1,2-hexanediol and these food-grade antimicrobial agents would have benefits not only for increasing the antimicrobial activity but also in cosmetics use. © 2015 The Society for Applied Microbiology.

Improving the water solubility and antimicrobial activity of silymarin by nanoencapsulation.

PubMed

Lee, Ji-Soo; Hong, Da Young; Kim, Eun Suh; Lee, Hyeon Gyu

2017-06-01

The aims of this study were to improve the water solubility and antimicrobial activity of milk thistle silymarin by nanoencapsulation and to assess the functions of silymarin nanoparticle-containing film as an antimicrobial food-packaging agent. Silymarin nanoparticles were prepared using water-soluble chitosan (WCS) and poly-γ-glutamic acid (γ-PGA). As the WCS and silymarin concentrations increased, particle size and polydispersity index (PDI) significantly increased. Nanoencapsulation significantly improved the water solubility of silymarin 7.7-fold. Antimicrobial activity of silymarin was effectively improved when silymarin was entrapped within the nanocapsule compared to when it was not entrapped. Films incorporating silymarin nanoparticles had better antimicrobial activity than films incorporating free silymarin. The results suggest that silymarin nanoparticles have applications in antimicrobial food additives and food packing. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrocarbon-stapled lipopeptides exhibit selective antimicrobial activity.

PubMed

Jenner, Zachary B; Crittenden, Christopher M; Gonzalez, Martín; Brodbelt, Jennifer S; Bruns, Kerry A

2017-05-01

Antimicrobial peptides (AMPs) occur widely in nature and have been studied for their therapeutic potential. AMPs are of interest due to the large number of possible chemical structural combinations using natural and unnatural amino acids, with varying effects on their biological activities. Using physicochemical properties from known naturally occurring amphipathic cationic AMPs, several hydrocarbon-stapled lipopeptides (HSLPs) were designed, synthesized, and tested for antimicrobial properties. Peptides were chemically modified by N-terminal acylation, C-terminal amidation, and some were hydrocarbon stapled by intramolecular olefin metathesis. The effects of peptide length, amphipathic character, and stapling on antimicrobial activity were tested against Escherichia coli, three species of Gram-positive bacteria (Staphylococcus aureus, Bacillus megaterium, and Enterococcus faecalis), and two strains of Candida albicans. Peptides were shown to disrupt liposomes of different phospholipid composition, as measured by leakage of a fluorescent compound from vesicles. Peptides with (S)-2-(4'-pentenyl)-alanine substituted for l-alanine in a reference peptide showed a marked increase in antimicrobial activity, hemolysis, and membrane disruption. Stapled peptides exhibited slightly higher antimicrobial potency; those with greatest hydrophobic character showed the greatest hemolysis and liposome leakage, but lower antimicrobial activity. The results support a model of HSLPs as membrane-disruptive AMPs with potent antimicrobial activity and relatively low hemolytic potential at biologically active peptide concentrations. © 2017 Wiley Periodicals, Inc.

Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity

NASA Astrophysics Data System (ADS)

Jiang, Linhai; Xu, Dawei; Sellati, Timothy J.; Dong, He

2015-11-01

Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05233e

Comparative evaluation of the antimicrobial efficacy of four chewing sticks commonly used in South India: an in vitro study.

PubMed

Elangovan, Arun; Muranga, Jayanthi; Joseph, Elizabeth

2012-01-01

The use of chewing sticks has been well documented since ancient times in India. Chewing sticks are a good alternative to the toothbrush for maintaining oral hygiene. The present study was designed and conducted to compare and evaluate the antimicrobial effects of the aqueous extracts of neem, miswak, mango, and banyan chewing sticks against two bacterial species considered the most important in the initiation and progression of dental caries, namely Streptococcus mutans and Lactobacillus acidophilus, respectively. Twigs of the above mentioned chewing sticks were sun dried and powdered, and sterile aqueous solutions of 10%, 25% and 50% concentrations were prepared. Culture plates for S mutans and L acidophilus were prepared and the growth was transferred to nutrient agar and Mueller-Hinton agar; antimicrobial activity of the extracts was tested after 72 h, using the disc diffusion method. Normal saline was used as control. The antimicrobial activity of neem, miswak, and mango extracts increased as their concentrations increased. Both banyan extract and saline showed no antimicrobial activity against the organisms tested. Based on the zones of inhibition, aqueous extracts of neem showed the most antimicrobial activity against S mutans, while miswak extracts showed superior antimicrobial activity against L acidophilus. We recommend further phytochemical and pharmacological studies to discover newer nonsynthetic tooth pastes and mouthwashes.

Efficacy of antimicrobial agents incorporated in orthodontic bonding systems: a systematic review and meta-analysis.

PubMed

de Almeida, C M; da Rosa, W L O; Meereis, C T W; de Almeida, S M; Ribeiro, J S; da Silva, A F; Lund, Rafael Guerra

2018-06-01

The purpose of this study was to evaluate the efficacy of orthodontic bonding systems containing different antimicrobial agents, as well as the influence of antimicrobial agent incorporation in the bonding properties of these materials. Eight databases were searched: PubMed (Medline), Web of Science, Scopus, Lilacs, Ibecs, BBO, Scielo and Google Scholar. Any study that evaluated antimicrobial activity in experimental or commercial orthodontic bonding systems was included. Data were tabulated independently and in duplicated by two authors on pre-designed data collection form. The global analysis was carried out using a random-effects model, and pooled-effect estimates were obtained by comparing the standardised mean difference of each antimicrobial orthodontic adhesive with the respective control group. A p-value < .05 was considered as statistically significant. Thirty-two studies were included in the qualitative analysis; of these, 22 studies were included in the meta-analysis. Antimicrobial agents such as silver nanoparticles, benzalkonium chloride, chlorhexidine, triclosan, cetylpyridinium chloride, Galla chinensis extract, acid ursolic, dimethylaminododecyl methacrylate, dimethylaminohexadecyl methacrylate, 2-methacryloyloxyethyl phosphorylcholine, 1,3,5-triacryloylhexahydro-1,3,5-triazine, zinc oxide and titanium oxide have been incorporated into orthodontic bonding systems. The antimicrobial agent incorporation in orthodontic bonding systems showed higher antimicrobial activity than the control group in agar diffusion (overall standardised mean difference: 3.71; 95% CI 2.98 to 4.43) and optical density tests (0.41; 95% CI -0.05 to 0.86) (p < .05). However, for biofilm, the materials did not present antimicrobial activity (6.78; 95% CI 4.78 to 8.77). Regarding bond strength, the global analysis showed antimicrobial orthodontic bonding systems were statistically similar to the control. Although there is evidence of antibacterial activity from in vitro studies, clinical and long-term studies are still necessary to confirm the effectiveness of antibacterial orthodontic bonding systems in preventing caries disease.

The in vitro antimicrobial activity of natural infant fluoride-free toothpastes on oral micro-organisms.

PubMed

Carvalho, Fabíola G; Negrini, Thais De Cássia; Sacramento, Luis Victor S; Hebling, Josimeri; Spolidorio, Denise M P; Duque, Cristiane

2011-01-01

The objective of this study was to evaluate the antimicrobial activity of six toothpastes for infants: 3 fluoride-free experimental toothpastes--cashew-based, mango-based and without plant extract and fluoride compared with 2 commercially fluoride-free toothpastes and 1 fluoridated toothpastes. Six toothpastes for infants were evaluated in this study: (1) experimental cashew-based toothpaste; (2) experimental mango-based toothpaste; (3) experimental toothpaste without plant extract and fluoride (negative control); (4) First Teeth brand toothpaste; (5) Weleda brand toothpaste; and (6) Tandy brand toothpaste (positive control). The antimicrobial activity was recorded against Streptococcus mutans, Streptococcus sobrinus, Lactobacillus acidophilus, and Candida albicans using the agar plate diffusion test. First Teeth, Weleda, mango-based toothpaste, and toothpaste without plant extract presented no antimicrobial effect against any of the tested micro-organisms. Cashew toothpaste had antimicrobial activity against S mutans, S sobrinus, and L acidophilus, but it showed no antimicrobial activity against C albicans. There was no statistical difference between the inhibition halo of cashew and Tandy toothpastes against S mutans and L acidophilus. Cashew fluoride-free toothpaste had inhibitory activity against Streptococcus mutans and Lactobacillus acidophilus, and these results were similar to those obtained for fluoridated toothpaste.

Pharmacokinetic parameters explain the therapeutic activity of antimicrobial agents in a silkworm infection model.

PubMed

Paudel, Atmika; Panthee, Suresh; Urai, Makoto; Hamamoto, Hiroshi; Ohwada, Tomohiko; Sekimizu, Kazuhisa

2018-01-25

Poor pharmacokinetic parameters are a major reason for the lack of therapeutic activity of some drug candidates. Determining the pharmacokinetic parameters of drug candidates at an early stage of development requires an inexpensive animal model with few associated ethical issues. In this study, we used the silkworm infection model to perform structure-activity relationship studies of an antimicrobial agent, GPI0039, a novel nitrofuran dichloro-benzyl ester, and successfully identified compound 5, a nitrothiophene dichloro-benzyl ester, as a potent antimicrobial agent with superior therapeutic activity in the silkworm infection model. Further, we compared the pharmacokinetic parameters of compound 5 with a nitrothiophene benzyl ester lacking chlorine, compound 7, that exerted similar antimicrobial activity but had less therapeutic activity in silkworms, and examined the metabolism of these antimicrobial agents in human liver fractions in vitro. Compound 5 had appropriate pharmacokinetic parameters, such as an adequate half-life, slow clearance, large area under the curve, low volume of distribution, and long mean residence time, compared with compound 7, and was slowly metabolized by human liver fractions. These findings suggest that the therapeutic effectiveness of an antimicrobial agent in the silkworms reflects appropriate pharmacokinetic properties.

Crude Extract from Ziziphus Jujuba Fruits, a Weapon against Pediatric Infectious Disease

PubMed Central

Daneshmand, F; Zare-Zardini, H; Tolueinia, B; Hasani, Z; Ghanbari, T

2013-01-01

Background Pediatric infectious disease is one of the main problems in cancerous children that treat by chemotherapy drugs. Thus, study in this regard is necessary. The aim of this study was to evaluate antimicrobial properties of ethanolic extract of Ziziphus Jujuba fruits against different infectious pathogens. Materials and Methods This study is descriptive. In vitro antimicrobial activity of extract was assessed on gram negative and gram positive bacteria as well as fungi. The antimicrobial activity was tested by Radial Diffusion Assay (RDA) and Minimal Inhibitory Concentration (MIC) methods. Results The results showed a wide antimicrobial activity of the extract against the microbes studied. Escherichia coli was the most susceptible to the extracts among tested microorganisms for which the MIC was 0.65±0.22 mg/ml. Amongst the bacterial strains investigated, Staphylococcus aureus was the most resistant strain with MIC of 2.26±0.68 mg/ml. The ethanolic extract also showed antimicrobial activity on the fungi studied as no growth was observed in 2.35±0.38 and 2.86±0.7 mg/ml concentration for Candida albicans and Aspergillus fumigatus, respectively. The results of qualitive and quantitative test are well indicative of the extract effective activity against the microbes mentioned. Conclusion Confirming the potential antimicrobial activities of crude extract of Ziziphus Jujuba fruits, this study suggested that ethanolic extracts of this plant is appropriate candidate for treatment of microbial infections, especially pediatric infectious diseases. PMID:24575267

Phytochemical analysis, antimicrobial, antioxidant activities and total phenols of Ferulago carduchorum in two vegetative stages (flower and fruit).

PubMed

Golfakhrabadi, Fereshteh; Shams Ardekani, Mohammad Reza; Saeidnia, Soodabeh; Yousefbeyk, Fatemeh; Jamalifar, Hossein; Ramezani, Nasrin; Akbarzadeh, Tahmineh; Khanavi, Mahnaz

2016-03-01

Ferulago carduchorum (Apiaceae family) is an endemic plant of Iran. The crude extract and four fractions of aerial parts of F. carduchorum in two vegetative stages (flower and fruit) were studied for their total phenolic contents, antimicrobial and antioxidant activities using folin-ciocalteu assay, micro dilution method and DPPH assay, respectively. The results indicated that the best antioxidant activity was determined in flower crude extract (IC50=0.44 mg/mL). The flower ethyl acetate fraction (FLE) showed better antimicrobial and antifungal activities than other fractions. So, FLE was selected for phytochemical investigations, resulting in isolation of a flavonoid (hesperetin). Hesperetin showed antimicrobial activity. The results showed that the antimicrobial and antioxidant effects during the flowering are obviously more than the fruit season.

Anti-Bacterial and Anti-Fungal Activity of Xanthones Obtained via Semi-Synthetic Modification of α-Mangostin from Garcinia mangostana.

PubMed

Narasimhan, Srinivasan; Maheshwaran, Shanmugam; Abu-Yousef, Imad A; Majdalawieh, Amin F; Rethavathi, Janarthanam; Das, Prince Edwin; Poltronieri, Palmiro

2017-02-12

The microbial contamination in food packaging has been a major concern that has paved the way to search for novel, natural anti-microbial agents, such as modified α-mangostin. In the present study, twelve synthetic analogs were obtained through semi-synthetic modification of α-mangostin by Ritter reaction, reduction by palladium-carbon (Pd-C), alkylation, and acetylation. The evaluation of the anti-microbial potential of the synthetic analogs showed higher bactericidal activity than the parent molecule. The anti-microbial studies proved that I E showed high anti-bacterial activity whereas I I showed the highest anti-fungal activity. Due to their microbicidal potential, modified α-mangostin derivatives could be utilized as active anti-microbial agents in materials for the biomedical and food industry.

Discovery of novel histidine-derived lipo-amino acids: applied in the synthesis of ultra-short antimicrobial peptidomimetics having potent antimicrobial activity, salt resistance and protease stability.

PubMed

Ahn, Mija; Murugan, Ravichandran N; Jacob, Binu; Hyun, Jae-Kyung; Cheong, Chaejoon; Hwang, Eunha; Park, Hyo-Nam; Seo, Ji-Hyung; Srinivasrao, G; Lee, Kyung S; Shin, Song Yub; Bang, Jeong Kyu

2013-10-01

Here we report for the first time the synthesis of Histidine (His) derived lipo-amino acids having pendant lipid tails at N(τ)- and N(π)-positions on imidazole group of His and applied it into synthesis of lipo-peptides. The attachment of His-derived lipo-amino acid into the very short inactive cationic peptides endows potent antimicrobial activity against Gram-positive and Gram-negative bacteria without hemolytic activity. Furthermore, our designed His-derived lipo-peptidomimetics (HDLPs) consisting of two or three residues displayed strong anti-MRSA activity and protease stability as well as retained potent antimicrobial activity under high salt concentration. Our results demonstrate that the novel lipo-amino acid is highly flexible to synthesize and carry out the extensive structure-activity relationship (SAR) on lipo-antimicrobial peptidomimetics and represents a unique amenable platform for modifying parameters important for antimicrobial activity. Through this study, we proved that the discovery of His-derived lipo-amino acid and the corresponding HDLPs are an excellent candidate as a lead compound for the development of novel antimicrobial agents. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Antimicrobial Activity of Seven Essential Oils From Iranian Aromatic Plants Against Common Causes of Oral Infections

PubMed Central

Zomorodian, Kamiar; Ghadiri, Pooria; Saharkhiz, Mohammad Jamal; Moein, Mohammad Reza; Mehriar, Peiman; Bahrani, Farideh; Golzar, Tahereh; Pakshir, Keyvan; Fani, Mohammad Mehdi

2015-01-01

Background: Over the past two decades, there has been a growing trend in using oral hygienic products originating from natural resources such as essential oils (EOs) and plant extracts. Seven aromatic plants used in this study are among popular traditional Iranian medicinal plants with potential application in modern medicine as anti-oral infectious diseases. Objectives: This study was conducted to determine the chemical composition and antimicrobial activities of essential oils from seven medicinal plants against pathogens causing oral infections. Materials and Methods: The chemical compositions of EOs distilled from seven plants were analyzed by gas chromatography/mass spectrometry (GC/MS). These plants included Satureja khuzestanica, S. bachtiarica, Ocimum sanctum, Artemisia sieberi, Zataria multiflora, Carum copticum and Oliveria decumbens. The antimicrobial activity of the essential oils was evaluated by broth micro-dilution in 96 well plates as recommended by the Clinical and Laboratory Standards Institute (CLSI) methods. Results: The tested EOs inhibited the growth of examined oral pathogens at concentrations of 0.015-16 µL/mL. Among the examined oral pathogens, Enterococcus faecalis had the highest Minimum Inhibitory Concentrations (MICs) and Minimum Microbicidal Concentrations (MMCs). Of the examined EOs, S. khuzestanica, Z. multiflora and S. bachtiarica, showed the highest antimicrobial activities, respectively, while Artemisia sieberi exhibited the lowest antimicrobial activity. Conclusions: The excellent antimicrobial activities of the tested EOs might be due to their major phenolic or alcoholic monoterpenes with known antimicrobial activities. Hence, these EOs can be possibly used as an antimicrobial agent in treatment and control of oral pathogens. PMID:25793100

Antimicrobial activity and hydrophobicity of edible whey protein isolate films formulated with nisin and/or glucose oxidase.

PubMed

Murillo-Martínez, María M; Tello-Solís, Salvador R; García-Sánchez, Miguel A; Ponce-Alquicira, Edith

2013-04-01

The use of edible antimicrobial films has been reported as a means to improve food shelf life through gradual releasing of antimicrobial compounds on the food surface. This work reports the study on the incorporation of 2 antimicrobial agents, nisin (N), and/or glucose oxidase (GO), into the matrix of Whey protein isolate (WPI) films at pH 5.5 and 8.5. The antimicrobial activity of the edible films was evaluated against Listeria innocua (ATCC 33090), Brochothrix thermosphacta (NCIB10018), Escherichia coli (JMP101), and Enterococcus faecalis (MXVK22). In addition, the antimicrobial activity was related to the hydrophobicity and water solubility of the WPI films. The greatest antibacterial activity was observed in WPI films containing only GO. The combined addition of N and GO resulted in films with lower antimicrobial activity than films with N or GO alone. In most cases, a pH effect was observed as greater antimicrobial response at pH 5.5 as well as higher film matrix hydrophobicity. WPI films supplemented with GO can be used in coating systems suitable for food preservation. © 2013 Institute of Food Technologists®

Effect of ripening inhibitor type on formation, stability, and antimicrobial activity of thyme oil nanoemulsion.

PubMed

Ryu, Victor; McClements, David J; Corradini, Maria G; McLandsborough, Lynne

2018-04-15

The objective of this research was to study the impact of ripening inhibitor level and type on the formation, stability, and activity of antimicrobial thyme oil nanoemulsions formed by spontaneous emulsification. Oil-in-water antimicrobial nanoemulsions (10 wt%) were formed by titrating a mixture of essential oil, ripening inhibitor, and surfactant (Tween 80) into 5 mM sodium citrate buffer (pH 3.5). Stable nanoemulsions containing small droplets (d < 70 nm) were formed. The antimicrobial activity of the nanoemulsions decreased with increasing ripening inhibitor concentration which was attributed to a reduction in the amount of hydrophobic antimicrobial constituents transferred to the separated hydrophobic domain, mimicking bacterial cell membranes, by using dialysis and chromatography. The antimicrobial activity of the nanoemulsions also depended on the nature of the ripening inhibitor used: palm ≈ corn > canola > coconut which also depended on their ability to transfer hydrophobic antimicrobial constituents to the separated hydrophobic domain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of mixed antimicrobial agents and flavors in active packaging films.

PubMed

Gutiérrez, Laura; Escudero, Ana; Batlle, Ramón; Nerín, Cristina

2009-09-23

Active packaging is an emerging food technology to improve the quality and safety of food products. Many works have been developed to study the antimicrobial activity of essential oils. Essential oils have been traditionally used as flavorings in food, so they have an important odor impact but they have as well antimicrobial properties that could be used to protect the food. Recent developments in antimicrobial active packaging showed the efficiency of essential oils versus bread and bakery products among other applications. However, one of the main problems to face is the odor and taste they could provide to the packaged food. Using some aromas to mask the odor could be a good approach. That is why the main objective of this paper is to develop an antimicrobial packaging material based on the combination of the most active compounds of essential oils (hydrocinnamaldehyde, oregano essential oil, cinnamaldehyde, thymol, and carvacrol) together with some aromas commonly used in the food industry. A study of the concentration required to get the antimicrobial properties, the organoleptic compatibility with typical aroma present in many food systems (vanilla, banana, and strawberry), and the right combination of both systems has been carried out. Antimicrobial tests of both the mentioned aromas, the main components of some essential oils, and the combination of both groups were carried out against bacteria (Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Salmonella choleraesuis, Yersinia enterocolitica, Escherichia coli), yeasts (Candida albicans, Debaryomyces hansenii, Zygosaccharomyces rouxii), and molds (Botrytis cinerae, Aspergillus flavus, Penicillium roqueforti, Eurotium repens, Penicillium islandicum, Penicillium commune, Penicillium nalgiovensis). The sensory properties of the combinations were evaluated with a triangular test and classification was by an order test; the odor threshold of the aroma compounds was also studied. The results reveal that none of the aromas had antimicrobial properties. The most antimicrobial compounds are thymol, carvacrol, and cinnamaldehyde, but none of them could be combined with banana aroma, whereas only thymol with strawberry aroma gave the right combined organoleptic profile. All of the antimicrobials under study could be combined with vanilla aroma, providing both antimicrobial property and the odor expected.

Antimicrobial activity of Nigerian medicinal plants

PubMed Central

Anyanwu, Madubuike Umunna; Okoye, Rosemary Chinazam

2017-01-01

Antimicrobial resistance (AMR) is currently one of the major threats facing mankind. The emergence and rapid spread of multi- and pan-drug-resistant organisms (such as vancomycin-, methicillin-, extended-spectrum β-lactam-, carbapenem- and colistin-resistant organisms) has put the world in a dilemma. The health and economic burden associated with AMR on a global scale are dreadful. Available antimicrobials have been misused and are almost ineffective with some of these drugs associated with dangerous side effects in some individuals. Development of new, effective, and safe antimicrobials is one of the ways by which AMR burden can be reduced. The rate at which microorganisms develop AMR mechanisms outpaces the rate at which new antimicrobials are being developed. Medicinal plants are potential sources of new antimicrobial molecules. There is renewed interest in antimicrobial activities of phytochemicals. Nigeria boasts of a huge heritage of medicinal plants and there is avalanche of researches that have been undertaken to screen antimicrobial activities of these plants. Scientific compilation of these studies could provide useful information on the antimicrobial properties of the plants. This information can be useful in the development of new antimicrobial drugs. This paper reviews antimicrobial researches that have been undertaken on Nigerian medicinal plants. PMID:28512606

Physics and chemistry of antimicrobial behavior of ion-exchanged silver in glass.

PubMed

Borrelli, N F; Senaratne, W; Wei, Y; Petzold, O

2015-02-04

The results of a comprehensive study involving the antimicrobial activity in a silver ion-exchanged glass are presented. The study includes the glass composition, the method of incorporating silver into the glass, the effective concentration of the silver available at the glass surface, and the effect of the ambient environment. A quantitative kinetic model that includes the above factors in predicting the antimicrobial activity is proposed. Finally, experimental data demonstrating antibacterial activity against Staphylococcus aureus with correlation to the predicted model is shown.

Diversity, Antimicrobial Action and Structure-Activity Relationship of Buffalo Cathelicidins

PubMed Central

Brahma, Biswajit; Patra, Mahesh Chandra; Karri, Satyanagalakshmi; Chopra, Meenu; Mishra, Purusottam; De, Bidhan Chandra; Kumar, Sushil; Mahanty, Sourav; Thakur, Kiran; Poluri, Krishna Mohan; Datta, Tirtha Kumar; De, Sachinandan

2015-01-01

Cathelicidins are an ancient class of antimicrobial peptides (AMPs) with broad spectrum bactericidal activities. In this study, we investigated the diversity and biological activity of cathelicidins of buffalo, a species known for its disease resistance. A series of new homologs of cathelicidin4 (CATHL4), which were structurally diverse in their antimicrobial domain, was identified in buffalo. AMPs of newly identified buffalo CATHL4s (buCATHL4s) displayed potent antimicrobial activity against selected Gram positive (G+) and Gram negative (G-) bacteria. These peptides were prompt to disrupt the membrane integrity of bacteria and induced specific changes such as blebing, budding, and pore like structure formation on bacterial membrane. The peptides assumed different secondary structure conformations in aqueous and membrane-mimicking environments. Simulation studies suggested that the amphipathic design of buCATHL4 was crucial for water permeation following membrane disruption. A great diversity, broad-spectrum antimicrobial action, and ability to induce an inflammatory response indicated the pleiotropic role of cathelicidins in innate immunity of buffalo. This study suggests short buffalo cathelicidin peptides with potent bactericidal properties and low cytotoxicity have potential translational applications for the development of novel antibiotics and antimicrobial peptidomimetics. PMID:26675301

Antimicrobial Activity of Serbian Propolis Evaluated by Means of MIC, HPTLC, Bioautography and Chemometrics

PubMed Central

Trifković, Jelena; Berić, Tanja; Vovk, Irena; Milojković-Opsenica, Dušanka; Stanković, Slaviša

2016-01-01

New information has come to light about the biological activity of propolis and the quality of natural products which requires a rapid and reliable assessment method such as High Performance Thin-Layer Chromatography (HPTLC) fingerprinting. This study investigates chromatographic and chemometric approaches for determining the antimicrobial activity of propolis of Serbian origin against various bacterial species. A linear multivariate calibration technique, using Partial Least Squares, was used to extract the relevant information from the chromatographic fingerprints, i.e. to indicate peaks which represent phenolic compounds that are potentially responsible for the antimicrobial capacity of the samples. In addition, direct bioautography was performed to localize the antibacterial activity on chromatograms. The biological activity of the propolis samples against various bacterial species was determined by a minimum inhibitory concentration assay, confirming their affiliation with the European poplar type of propolis and revealing the existence of two types (blue and orange) according to botanical origin. The strongest antibacterial activity was exhibited by sample 26 against Staphylococcus aureus, with a MIC value of 0.5 mg/mL, and Listeria monocytogenes, with a MIC as low as 0.1 mg/mL, which was also the lowest effective concentration observed in our study. Generally, the orange type of propolis shows higher antimicrobial activity compared to the blue type. PLS modelling was performed on the HPTLC data set and the resulting models might qualitatively indicate compounds that play an important role in the activity exhibited by the propolis samples. The most relevant peaks influencing the antimicrobial activity of propolis against all bacterial strains were phenolic compounds at RF values of 0.37, 0.40, 0.45, 0.51, 0.60 and 0.70. The knowledge gained through this study could be important for attributing the antimicrobial activity of propolis to specific chemical compounds, as well as the verification of HPTLC fingerprinting as a reliable method for the identification of compounds that are potentially responsible for antimicrobial activity. This is the first report on the activity of Serbian propolis as determined by several combined methods, including the modelling of antimicrobial activity by HPTLC fingerprinting. PMID:27272728

Antimicrobial activities of natural antimicrobial compounds against susceptible and antibiotic-resistant pathogens in the absence and presence of food

USDA-ARS?s Scientific Manuscript database

In an effort to improve microbial food safety, we are studying the antimicrobial activities of different classes of natural compounds including plant essential oils, apple, grape, olive, and tea extracts, bioactive components, and seashell-derived chitosans against multiple foodborne pathogens in cu...

ANTIMICROBIAL ACTION OF THE LEAF EXTRACT OF MORINGA OLEIFERA LAM.

PubMed Central

Pal, Saroj K.; Mukherjee, Pulok K.; Saha, Kakali; Pal, M.; Saha, B.P.

1995-01-01

The ethnolic extract of the leaves of Moringa oleifera Lam. (Fam. Moringaceae) was tested for antimicrobial activities against Gram Positive – Bacillus cereus, Bacillus subtilis Staphylococcus aureus, Sarcina lutea: Gram negative – Escherichia coli and Acid fast Mycobacterium phlei. Significant antimicrobial activity of the extract was found in this study. PMID:22556699

Development of antimicrobial films for microbiological control of packaged salad.

PubMed

Muriel-Galet, Virginia; Cerisuelo, Josep P; López-Carballo, Gracia; Lara, Marta; Gavara, Rafael; Hernández-Muñoz, Pilar

2012-07-02

The aim of the present work was to characterize the antimicrobial efficiency of films consisting of PP/EVOH structures with oregano essential oil and citral. Both substances are known for their antimicrobial activity based on their interaction with the cell membrane. The films developed were used to pack minimally processed salads, combining modified atmosphere technology to extend shelf-life and active packaging technology to reduce possible microbiological risks. The antimicrobial activity of the films against the pathogenic microorganisms Escherichia coli, Salmonella enterica and Listeria monocytogenes and natural microflora was investigated "in vitro" and also on the food itself. The effect of release of the antimicrobial agent on the sensory characteristics of the salad was also studied. The results showed that antimicrobial activity reduced spoilage flora on the salad as well as inhibited the growth of pathogens in contaminated salads. This effect was greater against Gram-negative bacteria. Sensory studies showed that the package that was most effective and most accepted by customers was the one containing 5% oregano essential oil. Copyright © 2012 Elsevier B.V. All rights reserved.

Antimicrobial effectiveness of oregano and sage essential oils incorporated into whey protein films or cellulose-based filter paper.

PubMed

Royo, Maite; Fernández-Pan, Idoya; Maté, Juan I

2010-07-01

In this study the antimicrobial effectiveness of oregano and sage essential oils (EOs) incorporated into two different matrices, whey protein isolate (WPI) and cellulose-based filter paper, was analysed. Antimicrobial properties of WPI-based films containing oregano and sage EOs were tested against Listeria innocua, Staphylococcus aureus and Salmonella enteritidis. Oregano EO showed antimicrobial activity against all three micro-organisms. The highest inhibition zones were against L. innocua. However, sage EO did not show antimicrobial activity against any of the micro-organisms. Antimicrobial activity was confirmed for both EOs using cellulose-based filter paper as supporting matrix, although it was significantly more intense for oregano EO. Inhibition surfaces were significantly greater when compared with those of the WPI films. This finding is likely due to the higher porosity and diffusivity of the active compounds in the filter paper. The interactions between the EOs and the films have a critical effect on the diffusivity of the active compounds and therefore on the final antimicrobial activity. As a result, to obtain active edible films, it is necessary to find the equilibrium point between the nature and concentration of the active compounds in the EO and the formulation of the film.

Progress in antimicrobial activities of chitin, chitosan and its oligosaccharides: a systematic study needs for food applications.

PubMed

Dutta, J; Tripathi, S; Dutta, P K

2012-02-01

In recent years, active biomolecules such as chitosan and its derivatives are undergoing a significant and very fast development in food application area. Due to recent outbreaks of contaminations associated with food products, there have been growing concerns regarding the negative environmental impact of packaging materials of antimicrobial biofilms, which have been studied. Chitosan has a great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, nontoxicity and versatile chemical and physical properties. It can be formed into fibers, films, gels, sponges, beads or nanoparticles. Chitosan films have been used as a packaging material for the quality preservation of a variety of foods. Chitosan has high antimicrobial activities against a wide variety of pathogenic and spoilage microorganisms, including fungi, and Gram-positive and Gram-negative bacteria. A tremendous effort has been made over the past decade to develop and test films with antimicrobial properties to improve food safety and shelf-life. This review highlights the preparation, mechanism, antimicrobial activity, optimization of biocide properties of chitosan films and applications including biocatalysts for the improvement of quality and shelf-life of foods.

Preliminary phytochemical and antibacterial screening of Sesuvium portulacastrum in the United Arab Emirates.

PubMed

Al-Azzawi, Amad; Alguboori, Alyaa; Hachim, Mahmoud Y; Najat, M; Al Shaimaa, A; Sad, Maryam

2012-10-01

The present study describes the phytochemical profile and antimicrobial activity of Sesuvium portulacastrum. Three extracts of S. portulacastrum obtained by extraction in aqueous, ethanolic and dichloromethane solvents, respectively, were compared for their antimicrobial activity and ethanolic extract further subjected to gas chromatography-mass spectrometry (GC-MS) analysis to find out the nature of the compounds responsible for the antimicrobial activity. The antibacterial activities were assessed by measuring the diameter of the inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Compared to the aqueous and dichloromethane extract, the ethanolic extract showed better antimicrobial activity against Staphylococcus aureus and E. coli, indicating its potential application related to noscomial infections. GC-MS results revealed 22, 23-Dihydrostigmasterol, Benzoic acid, 3,4,5-trihydroxy-(Gallic acid), (2R,3R)-(-)-Epicatechin and Capsaicin in the ethanolic extract to be the molecules responsible for the antimicrobial activity of S. portulacastrum. To the best of our knowledge, this is the first report on analysis of antimicrobial components from S. portulacastrum in United Arab Emirates (UAE), and our results confer the utility of this plant extract in developing a novel broad spectrum antimicrobial agent.

A study on the antimicrobial efficacy of RF oxygen plasma and neem extract treated cotton fabrics

NASA Astrophysics Data System (ADS)

Vaideki, K.; Jayakumar, S.; Thilagavathi, G.; Rajendran, R.

2007-06-01

The paper deals with a thorough investigation on the antimicrobial activity of RF oxygen plasma and Azadirachtin (neem extract) treated cotton fabric. The hydrophilicity of cotton fabric was found to improve when treated with RF oxygen plasma. The process parameters such as electrode gap, time of exposure and oxygen pressure have been varied to study their effect on improving the hydrophilicity of the cotton fabric. The static immersion test has been carried out to assess the hydrophilicity of the oxygen plasma treated samples and the process parameters were optimized based on these test results. The formation of carbonyl group during surface modification in the plasma treated sample was analysed using FTIR studies. The surface morphology has been studied using SEM micrographs. The antimicrobial activity was imparted to the RF oxygen plasma treated samples using methanolic extract of neem leaves containing Azadirachtin. The antimicrobial activity of these samples has been analysed and compared with the activity of the cotton fabric treated with neem extract alone. The investigation reveals that the surface modification due to RF oxygen plasma was found to increase the hydrophilicity and hence the antimicrobial activity of the cotton fabric when treated with Azadirachtin.

Antimicrobial peptides: a review of how peptide structure impacts antimicrobial activity

NASA Astrophysics Data System (ADS)

Soares, Jason W.; Mello, Charlene M.

2004-03-01

Antimicrobial peptides (AMPs) have been discovered in insects, mammals, reptiles, and plants to protect against microbial infection. Many of these peptides have been isolated and studied exhaustively to decipher the molecular mechanisms that impart protection against infectious bacteria, fungi, and viruses. Unfortunately, the molecular mechanisms are still being debated within the scientific community but valuable clues have been obtained through structure/function relationship studies1. Biophysical studies have revealed that cecropins, isolated from insects and pigs, exhibit random structure in solution but undergo a conformational change to an amphipathic α-helix upon interaction with a membrane surface2. The lack of secondary structure in solution results in an extremely durable peptide able to survive exposure to high temperatures, organic solvents and incorporation into fibers and films without compromising antibacterial activity. Studies to better understand the antimicrobial action of cecropins and other AMPs have provided insight into the importance of peptide sequence and structure in antimicrobial activities. Therefore, enhancing our knowledge of how peptide structure imparts function may result in customized peptide sequences tailored for specific applications such as targeted cell delivery systems, novel antibiotics and food preservation additives. This review will summarize the current state of knowledge with respect to cell binding and antimicrobial activity of AMPs focusing primarily upon cecropins.

Antibiotic Screening of Urine Culture for Internal Quality Audit at Amrita Hospital, Kochi.

PubMed

Suresh, Aswathy; Gopinathan, Anusha; Dinesh, Kavitha R; Kumar, Anil

2017-07-01

Urine antimicrobial activity is a seldom analysed laboratory test which greatly impacts the quantification of urine specimens. Presence of antimicrobial activity in the urine reduces the bacterial load in these specimens. Hence, the chances of erroneously reporting insignificant bacteriuria can be reduced on analysis of the antimicrobial activity in urine. The aim of the study was to measure the antimicrobial activity of urine samples obtained from patients in a tertiary care hospital. A total of 100 urine specimens were collected from the study group. Tests like wet mount, Gram staining and culture were performed. Antimicrobial susceptibility testing was done on the bacteria isolated from each specimen. The urine specimens were reported as significant bacteriuria (>105 Colony Forming Unit (CFU)/ml) and insignificant bacteriuria (<105 CFU/ml - clean catch midstream urine; <102 CFU/ml - catheterized urine sample) according to the CFU/ml. Staphylococcus aureus ATCC ® 25923 ™ and Escherichia coli ATCC ® 25922 ™ were used to identify the presence of antimicrobial activity in the urine sample by Urine Anti-Bacterial substance Assay (UABA). McNemar test was used for statistical analysis using Statistical Package for the Social Sciences (SPSS) version 21.0. On analysis of the antimicrobial activity of urine sample with the prior antibiotic history of the patients, 17 were true positives and 43 were true negatives. Twenty six of samples with UABA positivity were culture negative and 28 samples with UABA positivity were culture positive. Sensitivity and specificity of the test was 85% and 53.8% respectively. Accuracy of the test was 60%. The p-value of UABA was <0.001. Enterobacteriaceae was the most common bacterial family isolated from the urine specimens. A total of 85% patients responded to treatment. Presence of antimicrobial activity in urine has a great impact on the interpretation of urine culture reports. Identification of urine antimicrobial activity helps in evaluating the quantification of bacterial growth reported in urine culture. It facilitates speedy recovery of patients by early administration of antibiotics.

Studies on tridecaptin B(1), a lipopeptide with activity against multidrug resistant Gram-negative bacteria.

PubMed

Cochrane, Stephen A; Lohans, Christopher T; van Belkum, Marco J; Bels, Manon A; Vederas, John C

2015-06-07

Previously other groups had reported that Paenibacillus polymyxa NRRL B-30507 produces SRCAM 37, a type IIA bacteriocin with antimicrobial activity against Campylobacter jejuni. Genome sequencing and isolation of antimicrobial compounds from this P. polymyxa strain show that the antimicrobial activity is due to polymyxins and tridecaptin B1. The complete structural assignment, synthesis, and antimicrobial profile of tridecaptin B1 is reported, as well as the putative gene cluster responsible for its biosynthesis. This peptide displays strong activity against multidrug resistant Gram-negative bacteria, a finding that is timely to the current problem of antibiotic resistance.

Metal-chelating active packaging film enhances lysozyme inhibition of Listeria monocytogenes.

PubMed

Roman, Maxine J; Decker, Eric A; Goddard, Julie M

2014-07-01

Several studies have demonstrated that metal chelators enhance the antimicrobial activity of lysozyme. This study examined the effect of metal-chelating active packaging film on the antimicrobial activity of lysozyme against Listeria monocytogenes. Polypropylene films were surface modified by photoinitiated graft polymerization of acrylic acid (PP-g-PAA) from the food contact surface of the films to impart chelating activity based on electrostatic interactions. PP-g-PAA exhibited a carboxylic acid density of 113 ± 5.4 nmol cm(-2) and an iron chelating activity of 53.7 ± 9.8 nmol cm(-2). The antimicrobial interaction of lysozyme and PP-g-PAA depended on growth media composition. PP-g-PAA hindered lysozyme activity at low ionic strength (2.48-log increase at 64.4 mM total ionic strength) and enhanced lysozyme activity at moderate ionic strength (5.22-log reduction at 120 mM total ionic strength). These data support the hypothesis that at neutral pH, synergy between carboxylate metal-chelating films (pKa(bulk) 6.45) and lysozyme (pI 11.35) is optimal in solutions of moderate to high ionic strength to minimize undesirable charge interactions, such as lysozyme absorption onto film. These findings suggest that active packaging, which chelates metal ions based on ligand-specific interactions, in contrast to electrostatic interactions, may improve antimicrobial synergy. This work demonstrates the potential application of metal-chelating active packaging films to enhance the antimicrobial activity of membrane-disrupting antimicrobials, such as lysozyme.

Antimicrobial and free radical scavenging activities of five Palestinian medicinal plants.

PubMed

Qabaha, Khaled Ibraheem

2013-01-01

Extracts from five indigenous Palestinian medicinal plants including Rosmarinus officinalis, Pisidium guajava, Punica granatum peel, grape seeds and Teucrium polium were investigated for antimicrobial and free radical scavenging activities against eight microorganisms, using well diffusion method. The microorganisms included six bacterial isolates (i.e. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginos, Klebsiella pneumonia, Bacillus subtilis and Micrococcus luteus) and two fungal isolates (i.e. Candida albicans and Aspergillus niger). A standard antioxidant assay was performed on the plant extracts to assess their capability in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH). Of the five tested plant extract, only Rosmarinus offcinalis extract contained significant antimicrobial activity against all eight microbial isolates including Pseudomonas aeruginosa. Extracts from other four plants exhibited a variable antimicrobial activity against all microorganisms, except Pseudomonas aeruginosa. Significant antioxidant activity was detected in all plant extracts. However, extracts from Pisidium guajava leaves contained significantly higher antioxidant activity compared to the other extracts tested. The antimicrobial and scavenging activities detected in this in vitro study in extracts from the five Palestinian medicinal plants suggest that further study is needed to identify active compounds to target diseases caused by a wide-spectrum pathogens.

Activity of 10 antimicrobial agents against intracellular Rhodococcus equi.

PubMed

Giguère, Steeve; Berghaus, Londa J; Lee, Elise A

2015-08-05

Studies with facultative intracellular bacterial pathogens have shown that evaluation of the bactericidal activity of antimicrobial agents against intracellular bacteria is more closely associated with in vivo efficacy than traditional in vitro susceptibility testing. The objective of this study was to determine the relative activity of 10 antimicrobial agents against intracellular Rhodococcus equi. Equine monocyte-derived macrophages were infected with virulent R. equi and exposed to erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, gentamicin, enrofloxacin, vancomycin, imipenem, or doxycycline at concentrations achievable in plasma at clinically recommended dosages in foals. The number of intracellular R. equi was determined 48h after infection by counting colony forming units (CFUs). The number of R. equi CFUs in untreated control wells were significantly higher than those of monolayers treated with antimicrobial agents. Numbers of R. equi were significantly lower in monolayers treated with enrofloxacin followed by those treated with gentamicin, and vancomycin, when compared to monolayers treated with other antimicrobial agents. Numbers of R. equi in monolayers treated with doxycycline were significantly higher than those of monolayers treated with other antimicrobial agents. Differences in R. equi CFUs between monolayers treated with other antimicrobial agents were not statistically significant. Enrofloxacin, gentamicin, and vancomycin are the most active drugs in equine monocyte-derived macrophages infected with R. equi. Additional studies will be needed to determine if these findings correlate with in vivo efficacy. Copyright © 2015 Elsevier B.V. All rights reserved.

Antimicrobial activity of chemomechanical gingival retraction products.

PubMed

Hsu, Belinda; Lee, Stephanie; Schwass, Donald; Tompkins, Geoffrey

2017-07-01

Application of astringent hemostatic agents is the most widely used technique for gingival retraction, and a variety of products are offered commercially. However, these products may have additional unintended yet clinically beneficial properties. The authors assessed the antimicrobial activities of marketed retraction products against plaque-associated bacteria in both planktonic and biofilm assays, in vitro. The authors assessed hemostatic solutions, gels, pellets, retraction cords, pastes, and their listed active agents against a collection of microorganisms by means of conventional agar diffusion and minimum bacteriostatic and bactericidal concentration determinations. The authors then tested the most active products against monospecies biofilms grown on hydroxyapatite disks. All of the tested retraction products exhibited some antimicrobial activity. The results of the most active products were comparable with those of a marketed mouthwash. The listed retraction-active agents displayed relatively little activity when tested in pure form. At 10% dilution, some products evidenced inhibitory activity against most tested bacteria within 3 minutes of exposure, whereas others displayed variable effects after 10 minutes. The most active agents reduced, but did not completely prevent, the metabolic activity of a monospecies biofilm. Commercial gingival retraction products exhibit antimicrobial effects to various degrees in vitro. Some products display rapid bactericidal activity. The antimicrobial activity is not owing to the retraction-active agents. Biofilm bacteria are less sensitive to the antimicrobial effects of the agents. The rapidity of killing by some hemostatic agents suggests an antimicrobial effect that may be efficacious during clinical placement. The results of this in vitro study suggest that clinicians should be aware of the potential antimicrobial effects of some hemostatic agents, but more research is needed to confirm these observations in clinical use. Copyright © 2017 American Dental Association. Published by Elsevier Inc. All rights reserved.

Antimicrobial activity of endophytic fungi from olive tree leaves.

PubMed

Malhadas, Cynthia; Malheiro, Ricardo; Pereira, José Alberto; de Pinho, Paula Guedes; Baptista, Paula

2017-03-01

In this study, the antimicrobial potential of three fungal endophytes from leaves of Olea europaea L. was evaluated and the host plant extract effect in the antimicrobial activity was examined. The volatile compounds produced by endophytes were identified by GC/MS and further correlated with the antimicrobial activity. In potato dextrose agar, both Penicillium commune and Penicillium canescens were the most effective inhibiting Gram-positive and -negative bacteria (up to 2.7-fold compared to 30 µg/mL chloramphenicol), whereas Alternaria alternata was most effective inhibiting yeasts (up to 8.0-fold compared to 25 μg/mL fluconazole). The presence of aqueous leaf extract in culture medium showed to induce or repress the antimicrobial activity, depending on the endophytic species. In the next step, various organic extracts from both A. alternata mycelium and cultured broth were prepared; being ethyl acetate extracts displayed the widest spectrum of anti-microorganisms at a minimum inhibitory concentration ≤0.095 mg/mL. The volatile composition of the fungi that displayed the highest (A. alternata) and the lowest (P. canescens) antimicrobial activity against yeasts revealed the presence of six volatiles, being the most abundant components (3-methyl-1-butanol and phenylethyl alcohol) ascribed with antimicrobial potentialities. Overall the results highlighted for the first time the antimicrobial potential of endophytic fungi from O. europaea and the possibility to be exploited for their antimicrobial agents.

Antagonistic interactions and production of halocin antimicrobial peptides among extremely halophilic prokaryotes isolated from the solar saltern of Sfax, Tunisia.

PubMed

Ghanmi, Fadoua; Carré-Mlouka, Alyssa; Vandervennet, Manon; Boujelben, Ines; Frikha, Doniez; Ayadi, Habib; Peduzzi, Jean; Rebuffat, Sylvie; Maalej, Sami

2016-05-01

Thirty-five extremely halophilic microbial strains isolated from crystallizer (TS18) and non-crystallizer (M1) ponds in the Sfax solar saltern in Tunisia were examined for their ability to exert antimicrobial activity. Antagonistic assays resulted in the selection of eleven strains that displayed such antimicrobial activity and they were further characterized. Three cases of cross-domain inhibition (archaea/bacteria or bacteria/archaea) were observed. Four archaeal strains exerted antimicrobial activity against several other strains. Three strains, for which several lines of evidence suggested the antimicrobial activity was, at least in part, due to peptide/protein agents (Halobacterium salinarum ETD5, Hbt. salinarum ETD8, and Haloterrigena thermotolerans SS1R12), were studied further. Optimal culture conditions for growth and antimicrobial production were determined. Using DNA amplification with specific primers, sequencing and RT-PCR analysis, Hbt. salinarum ETD5 and Hbt. salinarum ETD8 were shown to encode and express halocin S8, a hydrophobic antimicrobial peptide targeting halophilic archaea. Although the gene encoding halocin H4 was amplified from the genome of Htg. thermotolerans SS1R12, no transcript could be detected and the antimicrobial activity was most likely due to multiple antimicrobial compounds. This is also the first report that points to four different strains isolated from different geographical locations with the capacity to produce identical halocin S8 proteins.

Nanoparticles for antimicrobial purposes in Endodontics: A systematic review of in vitro studies.

PubMed

Samiei, Mohammad; Farjami, Afsaneh; Dizaj, Solmaz Maleki; Lotfipour, Farzaneh

2016-01-01

Antimicrobial nanoparticles with enhanced physiochemical properties have attracted attention as modern antimicrobials, especially in the complicated oral cavity environment. The goal of the present article is to review the current state of nanoparticles used for antimicrobial purposes in root canal infections. A review was conducted in electronic databases using MeSH keywords to identify relevant published literature in English. The analysis and eligibility criteria were documented according to the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA-guidelines). No restrictions on publication date were imposed. Data regarding root canal disinfections, general antimicrobial mechanisms of nanoparticles, type of nanoparticles as antimicrobial agent and antimicrobial effect of nanoparticles in endodontics were collected and subjected to descriptive data analysis. The literature search in electronic databases according to the inclusion criteria provided 83 titles and abstracts. Among them 15 papers were related to antimicrobial effect of nanoparticles in Endodontics. Silver nanoparticles with sustainable activity were the most studied agent for its antimicrobial behavior in root canal infection. Aided polymeric nanoparticles with photo or ultrasound, glass bioactive nanoparticles as well as Calcium derivative based nanoparticles, with improved activity in comparison with the non-nano counterparts, are of importance in infection control of dental root canal. Bioactive Non-organic nanoparticles with structural capabilities present enhanced antimicrobial activity in root canal infections. All included studies showed an enhanced or at least equal effect of nanoparticulate systems to combat dental root canal infections compared to conventional antimicrobial procedures. However, it is crucial to understand their shortcomings and their probable cellular effects and toxicity as well as environmental effects. Copyright © 2015 Elsevier B.V. All rights reserved.

Antioxidant and antimicrobial activities of solvent fractions of Vernonia cinerea (L.) Less leaf extract.

PubMed

Sonibare, Mubo A; Aremu, Oluwafunmilola T; Okorie, Patricia N

2016-06-01

Vernonia cinerea (L.) Less is used in folk medicine as a remedy for various diseases. The present study reports antioxidant and antimicrobial activities of solvent fractions of Vernonia cinerea. The antioxidant properties of solvent fractions of V. cinerea were evaluated by determining radicals scavenging activity, total flavonoid and phenolic contents measured with the 2,2-diphenyl-1-picryl hydrazyl (DPPH) test, the aluminum chloride and the Folin-ciocalteau methods, respectively. Antimicrobial activities were tested against human pathogenic microorganisms using agar diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each active extract were determined. The ethyl acetate fraction having the IC50 value of 6.50 µg/mL demonstrated comparable DPPH radical-scavenging activity with standard antioxidants, gallic acid and quercetin included in the study. All fractions displayed moderate antimicrobial potential against the tested pathogens with the zone of inhibition that ranged from 9.0 to 13.5 mm. The MIC (1.56 mg/mL) and MBC (3.13 mg/mL) indicated highest susceptibility of Candida albicans in all fractions. The results of this study showed that the solvent fractions of V. cinerea possess antioxidant and antimicrobial activities, hence justifying the folkloric use of the plant for the treatment of various ailments in traditional medicine.

5-Nitroimidazole-derived Schiff bases and their copper(II) complexes exhibit potent antimicrobial activity against pathogenic anaerobic bacteria.

PubMed

Oliveira, Alexandre A; Oliveira, Ana P A; Franco, Lucas L; Ferencs, Micael O; Ferreira, João F G; Bachi, Sofia M P S; Speziali, Nivaldo L; Farias, Luiz M; Magalhães, Paula P; Beraldo, Heloisa

2018-05-07

In the present work a family of novel secnidazole-derived Schiff base compounds and their copper(II) complexes were synthesized. The antimicrobial activities of the compounds were evaluated against clinically important anaerobic bacterial strains. The compounds exhibited in vitro antibacterial activity against Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides vulgatus, Bacteroides ovatus, Parabacteroides distasonis and Fusubacterium nucleatum pathogenic anaerobic bacteria. Upon coordination to copper(II) the antibacterial activity significantly increased in several cases. Some derivatives were even more active than the antimicrobial drugs secnidazole and metronidazole. Therefore, the compounds under study are suitable for in vivo evaluation and the microorganisms should be classified as susceptible to them. Electrochemical studies on the reduction of the nitro group revealed that the compounds show comparable reduction potentials, which are in the same range of the bio-reducible drugs secnidazole and benznidazole. The nitro group reduction potential is more favorable for the copper(II) complexes than for the starting ligands. Hence, the antimicrobial activities of the compounds under study might in part be related to intracellular bio-reduction activation. Considering the increasing resistance rates of anaerobic bacteria against a wide range of antimicrobial drugs, the present work constitutes an important contribution to the development of new antibacterial drug candidates.

In Vitro Antimicrobial Potential of the Lichen Parmotrema sp. Extracts against Various Pathogens.

PubMed

Chauhan, Ritika; Abraham, Jayanthi

2013-07-01

The ongoing increasing antibiotic resistance is one of the biggest challenges faced by global public health. The perennial need for new antimicrobials against a background of increasing antibiotic resistance in pathogenic and opportunistic microorganisms obliges the scientific community to constantly develop new drugs and antimicrobial agents. Lichens are known prolific sources of natural antimicrobial drugs and biologically active natural products. This study was aimed to explore in vitro antimicrobial activity of lichen Parmotrema sp. The methanol and aqueous extracts of lichen Parmotrema sp. was extracted using Soxhlet extractor. Antibiotic assessment of methanol and aqueous extracts was done against eight bacterial (Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Salmonella sp., Shigella sp., Enterococci faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae,) clinical pathogens and five plant pathogenic fungal strains (Aspergillus terreus strain JAS1, Scedosporium sp. JAS1, Ganoderma sp. JAS4, Candida tropicalis and Fusarium sp.) by Kirby-Bauer method. The methanol lichen Parmotrema sp. extract inhibited all the test organisms. The highest antibacterial activity was found against Pseudomonas aeruginosa and Staphylococcus aureus. The weakest activity was manifested in Salmonella sp. and Scedosporium sp. JAS1. Strong antifungal effect was found against Ganoderma sp. JAS4 and Fusarium sp. The aqueous lichen Parmotrema sp. extract revealed neither antibacterial nor antifungal activity. The present study shows that tested lichen Parmotrema sp. extracts demonstrated a strong antimicrobial effect. That suggests the active components from methanol extracts of the investigated lichen Parmotrema sp. can be used as natural antimicrobial agent against pathogens.

Evaluation of the antimicrobial activities of chlorhexidine gluconate, sodium hypochlorite and octenidine hydrochloride in vitro.

PubMed

Tirali, Resmiye E; Bodur, Haluk; Sipahi, Bilge; Sungurtekin, Elif

2013-04-01

The objective of this study was to compare the antimicrobial activity of sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX) and octenidine hydrochloride (OCT) in different concentrations against endodontic pathogens in vitro. Agar diffusion procedure was used to determine the antimicrobial activity of the tested materials. Enterococcus faecalis, Candida albicans and the mixture of these were used for this study. In the agar diffusion test, 5.25% NaOCl exhibited better antimicrobial effect than the other concentrations of NaOCl for all strains. All concentrations of OCT were effective against C. albicans and E. faecalis. Some 0.2% CHX was ineffective on all microorganisms. Antibacterial effectiveness of all experimental solutions decreased on the mixture of all strains. Decreasing concentrations of NaOCl resulted in significantly reduced antimicrobial effect. © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

Highly Stable Graphene-Based Nanocomposite (GO-PEI-Ag) with Broad-Spectrum, Long-Term Antimicrobial Activity and Antibiofilm Effects.

PubMed

Zhao, Rongtao; Kong, Wen; Sun, Mingxuan; Yang, Yi; Liu, Wanying; Lv, Min; Song, Shiping; Wang, Lihua; Song, Hongbin; Hao, Rongzhang

2018-05-30

Various silver nanoparticle (AgNP)-decorated graphene oxide (GO) nanocomposites (GO-Ag) have received increasing attention owing to their antimicrobial activity and biocompatibility; however, their aggregation in physiological solutions and the generally complex synthesis methods warrant improvement. This study aimed to synthesize a polyethyleneimine (PEI)-modified and AgNP-decorated GO nanocomposite (GO-PEI-Ag) through a facile approach through microwave irradiation without any extra reductants and surfactants; its antimicrobial activity was investigated on Gram-negative/-positive bacteria (including drug-resistant bacteria) and fungi. Compared with GO-Ag, GO-PEI-Ag acquired excellent stability in physiological solutions and electropositivity, showing substantially higher antimicrobial efficacy. Moreover, GO-PEI-Ag exhibited particularly excellent long-term effects, presenting no obvious decline in antimicrobial activity after 1 week storage in physiological saline and repeated use for three times and the lasting inhibition of bacterial growth in nutrient-rich culture medium. In contrast, GO-Ag exhibited a >60% decline in antimicrobial activity after storage. Importantly, GO-PEI-Ag effectively eliminated adhered bacteria, thereby preventing biofilm formation. The primary antimicrobial mechanisms of GO-PEI-Ag were evidenced as physical damage to the pathogen structure, causing cytoplasmic leakage. Hence, stable GO-PEI-Ag with robust, long-term antimicrobial activity holds promise in combating public-health threats posed by drug-resistant bacteria and biofilms.

New milk protein-derived peptides with potential antimicrobial activity: an approach based on bioinformatic studies.

PubMed

Dziuba, Bartłomiej; Dziuba, Marta

2014-08-20

New peptides with potential antimicrobial activity, encrypted in milk protein sequences, were searched for with the use of bioinformatic tools. The major milk proteins were hydrolyzed in silico by 28 enzymes. The obtained peptides were characterized by the following parameters: molecular weight, isoelectric point, composition and number of amino acid residues, net charge at pH 7.0, aliphatic index, instability index, Boman index, and GRAVY index, and compared with those calculated for known 416 antimicrobial peptides including 59 antimicrobial peptides (AMPs) from milk proteins listed in the BIOPEP database. A simple analysis of physico-chemical properties and the values of biological activity indicators were insufficient to select potentially antimicrobial peptides released in silico from milk proteins by proteolytic enzymes. The final selection was made based on the results of multidimensional statistical analysis such as support vector machines (SVM), random forest (RF), artificial neural networks (ANN) and discriminant analysis (DA) available in the Collection of Anti-Microbial Peptides (CAMP database). Eleven new peptides with potential antimicrobial activity were selected from all peptides released during in silico proteolysis of milk proteins.

New Milk Protein-Derived Peptides with Potential Antimicrobial Activity: An Approach Based on Bioinformatic Studies

PubMed Central

Dziuba, Bartłomiej; Dziuba, Marta

2014-01-01

New peptides with potential antimicrobial activity, encrypted in milk protein sequences, were searched for with the use of bioinformatic tools. The major milk proteins were hydrolyzed in silico by 28 enzymes. The obtained peptides were characterized by the following parameters: molecular weight, isoelectric point, composition and number of amino acid residues, net charge at pH 7.0, aliphatic index, instability index, Boman index, and GRAVY index, and compared with those calculated for known 416 antimicrobial peptides including 59 antimicrobial peptides (AMPs) from milk proteins listed in the BIOPEP database. A simple analysis of physico-chemical properties and the values of biological activity indicators were insufficient to select potentially antimicrobial peptides released in silico from milk proteins by proteolytic enzymes. The final selection was made based on the results of multidimensional statistical analysis such as support vector machines (SVM), random forest (RF), artificial neural networks (ANN) and discriminant analysis (DA) available in the Collection of Anti-Microbial Peptides (CAMP database). Eleven new peptides with potential antimicrobial activity were selected from all peptides released during in silico proteolysis of milk proteins. PMID:25141106

[Isolation and antimicrobial activities of actinomycetes from vermicompost].

PubMed

Wang, Xue-jun; Yan, Shuang-lin; Min, Chang-li; Yang, Yan

2015-02-01

In this paper, actinomycetes were isolated from vermicompost by tablet coating method. Antimicrobial activities of actinomycetes were measured by the agar block method. Strains with high activity were identified based on morphology and biochemical characteristics, as well as 16S rDNA gene sequence analysis. The results showed that 26 strains of actinomycetes were isolated, 16 of them had antimicrobial activities to the test strains which accounts for 61.54% of all strains. Among the 16 strains, the strain QYF12 and QYF22 had higher antimicrobial activity to Micrococcus luteus, with a formed inhibition zone of 27 mm and 31 mm, respectively. While the strain QYF26 had higher antimicrobial activity to Bacillus subtilis, and the inhibition zone diameter was 21 mm. Based on the identification of strains with high activity, the strain QYF12 was identified as Streptomyces chartreusis, the strain QYF22 was S. ossamyceticus and the strain QYF26 was S. gancidicus. This study provided a theoretical basis for further separate antibacterial product used for biological control.

Antimicrobial activity of human pancreatic juice and its interaction with antibiotics.

PubMed Central

Minelli, E B; Benini, A; Bassi, C; Abbas, H; Falconi, M; Locatelli, F; de Marco, R; Pederzoli, P

1996-01-01

Pancreatic juice (PJ) should be a factor of variability in the antimicrobial activity of antibiotics eliminated by the pancreas during pancreatic infections. We studied its effects on the activity of antimicrobial drugs with different mechanisms of action. Samples of pure PJ were collected from 16 patients with stabilized external pancreatic fistulas. The antimicrobial activity of the juice at different concentrations (from 1.25 to 100%) alone and in combination with mezlocillin, imipenem, ceftriaxone, gentamicin, ofloxacin, and ciprofloxacin was studied by a microbiological method (continuous turbidimetric recording of bacterial growth). The human PJ showed dose-dependent antimicrobial activity that increased directly with the concentration. The activity of the antibiotics at bactericidal concentrations were not modified by the PJ, while the combination with subinhibitory concentrations produced the following variable and different effects: (i) additivity with mezlocillin, ceftriaxone, gentamicin, and ciprofloxacin and autonomy (no interaction) with imipenem and ofloxacin against Providencia rettgeri and (ii) additivity with ceftriaxone, ofloxacin, gentamicin, imipenem, and mezlocillin and autonomy with ciprofloxacin against Escherichia coli. In the presence of PJ, fluoroquinolones showed constant positive effects, while beta-lactams showed more variable antimicrobial activity. Antibiotic concentrations and PJ pharmacodynamics are the main factors determining the final effect of the interaction in vitro. These results may be useful in choosing antibiotics for the treatment of pancreatic infections when they are supplemented with the pharmacokinetic data for each drug. PMID:8878588

Antimicrobial Activity of Lippia Species from the Brazilian Semiarid Region Traditionally Used as Antiseptic and Anti-Infective Agents

PubMed Central

Pinto, Cristiana da Purificação; Rodrigues, Velize Dias; Pinto, Fernanda da Purificação; Pinto, Renata da Purificação; Uetanabaro, Ana Paula Trovatti; Pinheiro, Carla Santos Ribeiro; Gadea, Suzana Ferreira Magalhães; Silva, Tânia Regina dos Santos; Lucchese, Angélica Maria

2013-01-01

Lippia origanoides Kunth, Lippia alnifolia Schauer, and Lippia thymoides Martius and Schauer are shrubs used in the traditional Brazilian medicine as antiseptics, as well as in the treatment of infectious diseases. This study was designed to investigate the antibacterial and antifungal activities of the methanolic extracts of these species, as new potential sources of antimicrobial drugs. The antimicrobial activity of methanolic extracts was investigated against resistant yeasts and bacteria by agar disk diffusion. Then, the MIC determination of the most active species and its fractions in hexane, dichloromethane, ethyl acetate, and water was performed. By the agar diffusion assay, all species were active against at least two microorganisms, giving evidence to support their use in the popular medicine. L. origanoides leaves exhibited the widest antimicrobial action, inhibiting the growth of two Gram-positive bacteria and two yeasts; this activity was also confirmed by the MIC evaluation. The fractionation of L. origanoides crude extracts improved the activity in spectrum and intensity. The results obtained in this study indicate that L. origanoides may be a promising alternative in the treatment of bacterial and fungal infections and in the seeking of new antimicrobial drugs. PMID:24109492

Organogel-nanoemulsion containing nisin and D-limonene and its antimicrobial activity

PubMed Central

Bei, Weiya; Zhou, Yan; Xing, Xuya; Zahi, Mohamed Reda; Li, Yuan; Yuan, Qipeng; Liang, Hao

2015-01-01

The aim of this study was to investigate a novel delivery system containing D-limonene and nisin by food organogel-nanoemulsion and study its effect on the antimicrobial activity. Organogel-nanoemulsion containing with D-limonene and nisin or without nisin was prepared by a homogenization method. Factors that may affect the droplet size and stability of organogel-nanoemulsion such as pressure and surfactant to oil ratio (SOR) were studied. The average droplet size decreased with pressure, and the organogel-nanoemulsion could achieve good stability at low SOR. Positive effects and outstanding antimicrobial activities of organogel-nanoemulsion containing with D-limonene and nisin were confirmed by minimal inhibitory concentrations comparison, growth curves of bacteria, scanning electron microscopy and determination of cell constituents’ release. Furthermore, the organogel-nanoemulsion applied as food preservative in milk also shown excellent antimicrobial performance. Overall, the research described in the current article show that organogel-nanoemulsion containing with D-limonene and nisin may be an effective antimicrobial system for the production and preservation of food. PMID:26441935

Antimicrobial Properties of Biofunctionalized Silver Nanoparticles on Clinical Isolates of Streptococcus mutans and Its Serotypes

PubMed Central

Martínez-Robles, Ángel Manuel; Loyola-Rodríguez, Juan Pablo; Zavala-Alonso, Norma Verónica; Martinez-Martinez, Rita Elizabeth; Ruiz, Facundo; Lara-Castro, René Homero; Donohué-Cornejo, Alejandro; Reyes-López, Simón Yobanny; Espinosa-Cristóbal, León Francisco

2016-01-01

(1) Background: Streptococcus mutans (S. mutans) is the principal pathogen involved in the formation of dental caries. Other systemic diseases have also been associated with specific S. mutans serotypes (c, e, f, and k). Silver nanoparticles (SNP) have been demonstrated to have good antibacterial effects against S. mutans; therefore, limited studies have evaluated the antimicrobial activity of biofunctionalized SNP on S. mutans serotypes. The purpose of this work was to prepare and characterize coated SNP using two different organic components and to evaluate the antimicrobial activity of SNP in clinical isolates of S. mutans strains and serotypes; (2) Methods: SNP with bovine serum albumin (BSA) or chitosan (CS) coatings were prepared and the physical, chemical and microbiological properties of SNP were evaluated; (3) Results: Both types of coated SNP showed antimicrobial activity against S. mutans bacteria and serotypes. Better inhibition was associated with smaller particles and BSA coatings; however, no significant differences were found between the different serotypes, indicating a similar sensitivity to the coated SNP; (4) Conclusion: This study concludes that BSA and CS coated SNP had good antimicrobial activity against S. mutans strains and the four serotypes, and this study suggest the widespread use of SNP as an antimicrobial agent for the inhibition of S. mutans bacteria. PMID:28335264

Antimicrobial Properties of Biofunctionalized Silver Nanoparticles on Clinical Isolates of Streptococcus mutans and Its Serotypes.

PubMed

Martínez-Robles, Ángel Manuel; Loyola-Rodríguez, Juan Pablo; Zavala-Alonso, Norma Verónica; Martinez-Martinez, Rita Elizabeth; Ruiz, Facundo; Lara-Castro, René Homero; Donohué-Cornejo, Alejandro; Reyes-López, Simón Yobanny; Espinosa-Cristóbal, León Francisco

2016-07-22

(1) Background: Streptococcus mutans ( S. mutans ) is the principal pathogen involved in the formation of dental caries. Other systemic diseases have also been associated with specific S. mutans serotypes ( c , e , f , and k ). Silver nanoparticles (SNP) have been demonstrated to have good antibacterial effects against S. mutans ; therefore, limited studies have evaluated the antimicrobial activity of biofunctionalized SNP on S. mutans serotypes. The purpose of this work was to prepare and characterize coated SNP using two different organic components and to evaluate the antimicrobial activity of SNP in clinical isolates of S. mutans strains and serotypes; (2) Methods: SNP with bovine serum albumin (BSA) or chitosan (CS) coatings were prepared and the physical, chemical and microbiological properties of SNP were evaluated; (3) Results: Both types of coated SNP showed antimicrobial activity against S. mutans bacteria and serotypes. Better inhibition was associated with smaller particles and BSA coatings; however, no significant differences were found between the different serotypes, indicating a similar sensitivity to the coated SNP; (4) Conclusion: This study concludes that BSA and CS coated SNP had good antimicrobial activity against S. mutans strains and the four serotypes, and this study suggest the widespread use of SNP as an antimicrobial agent for the inhibition of S. mutans bacteria.

Antimicrobial activity and safety evaluation of Enterococcus faecium KQ 2.6 isolated from peacock feces.

PubMed

Zheng, Wei; Zhang, Yu; Lu, Hui-Min; Li, Dan-Ting; Zhang, Zhi-Liang; Tang, Zhen-Xing; Shi, Lu-E

2015-05-12

The objective of this paper was to study antimicrobial activity and safety of Enterococcus faecium KQ 2.6 (E. faecium KQ 2.6) isolated from peacock feces. Agar well diffusion method was adopted in antimicrobial activity assay. Disk diffusion test was used to determine the antibiotic resistance. The identification and virulence potential of E. faecium KQ 2.6 were investigated using PCR amplification. The results indicated that cell free supernatant (CFS) of the strain had the good antimicrobial activity against selected gram-positive and gram-negative bacteria. The biochemical characteristics of antimicrobial substances were investigated. The results indicated that the antimicrobial substances were still active after treatment with catalase and proteinase, respectively. Moreover, the stability of antimicrobial substances did not change after heat treatment at 40, 50, 60, 70 and 80°C for 30 min, respectively. The activity of antimicrobial substances remained stable at 4 and -20°C after long time storage. The antimicrobial activity of CFS was compared with that of the buffer with similar strength and pH. The inhibitory zone of the buffer was apparently smaller than that of CFS, which meant that the acid in CFS was not the only factor that was contributed to antibacterial activity of CFS. The antibiotic resistance and virulence potential were evaluated using disk diffusion test and PCR amplification. The results showed that E. faecium KQ 2.6 did not harbor any tested virulence genes such as gelE, esp, asa1, cylA, efaA and hyl. It was susceptible to most of tested antibiotics except for vancomycin and polymyxin B. E. faecium KQ 2.6 may be used as bio-preservative cultures for the production of fermented foods.

Incorporation of nisin in poly (ethylene-co-vinyl acetate) films by melt processing: a study on the antimicrobial properties.

PubMed

Scaffaro, Roberto; Botta, Luigi; Marineo, Sandra; Puglia, Anna Maria

2011-07-01

Both industry and academia have shown a growing interest in materials with antimicrobial properties suitable for food packaging applications. In this study, we prepared and characterized thin films of ethylene-co-vinyl acetate (EVA) copolymer with antimicrobial properties. The films were prepared with a film blowing process by incorporating a nisin preparation as an antimicrobial agent in the melt. Two grades of EVA containing 14 and 28% (wt/wt) vinyl acetate (EVA 14 and EVA 28, respectively) and two commercial formulations of nisin with different nominal activities were used. The effect of the nisin concentration also was evaluated. The films with the highest antimicrobial activity were those formulated with nisin at the highest activity and EVA with the highest content of vinyl acetate. The use of the commercial formulation of nisin with high activity in the EVA films allowed reduction in the amount of nisin needed to provide antimicrobial properties. Consequently, the mechanical properties of these films were only slightly inferior to those of the pure polymers. In contrast, films prepared by incorporating more of the nisin with lower activity had poor mechanical properties. The effect of different processing temperatures used in the preparation of the films on the antimicrobial properties of the films also was evaluated. The materials displayed antimicrobial properties even when they were prepared at temperatures as high as 160 °C, probably because of the very short processing time (60 to 90 s) required for preparation. Copyright ©, International Association for Food Protection

Efficacy of newly formulated ointment containing 20% active antimicrobial honey in treatment of burn wound infections.

PubMed

Tasleem, Samiyah; Naqvi, Syed Baqir Shyum; Khan, Saadat Ali; Hashmi, Khursheed

2013-01-01

Honey has been familiar to possess antimicrobial potential to clear infection against burn wound infecting bacteria since ancient times. The objective of the study was to evaluate the efficacy of the newly formulated honey ointment during the treatment of burn wound infections. The Experimental (Non comparative) study was conducted at outpatient department of Dermatology, Fauji Foundation Hospital, Rawalpindi from November 2009 to October 2010. The antimicrobial activity of different Pakistani floral sources (Acacia nilotica species indica, Zizyphus, Helianthus annuus and Carisa opaca) honey samples were investigated by disc diffusion method against freshly isolated burn wounds infecting bacteria. Ointment containing 20% active antimicrobial honey was formulated as a sovereign remedy. A total number of twenty patients with second degree of burn wounds on different parts of the body were studied. A thin layer of honey ointment on gauze was applied to the wounds two to three times a day up to the complete healing. During microbiological study, Pakistani honey samples were discovered to exhibit a very promising antimicrobial activity against all the wound infecting microorganisms tested. Clinical trials demonstrated that the topical application of honey ointment have significant control of infections arising form pathogenic bacteria and up to 100% healing results were observed in all burn wound cases within mean healing time for the duration of 8.15 (3-18) days time period. Newly formulated ointment containing 20% active antimicrobial honey is more effective and low-cost alternative preparation for the treatment of burn wound infections.

In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum.

PubMed

Ahmad, Sohail; AbdEl-Salam, Naser M; Ullah, Riaz

2016-01-01

The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm). Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25-225 μg/mL). Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines.

Probiotic Potential of Lactobacillus Strains with Antimicrobial Activity against Some Human Pathogenic Strains

PubMed Central

Shokryazdan, Parisa; Sieo, Chin Chin; Kalavathy, Ramasamy; Liang, Juan Boo; Alitheen, Noorjahan Banu; Faseleh Jahromi, Mohammad; Ho, Yin Wan

2014-01-01

The objective of this study was to isolate, identify, and characterize some lactic acid bacterial strains from human milk, infant feces, and fermented grapes and dates, as potential probiotics with antimicrobial activity against some human pathogenic strains. One hundred and forty bacterial strains were isolated and, after initial identification and a preliminary screening for acid and bile tolerance, nine of the best isolates were selected and further identified using 16 S rRNA gene sequences. The nine selected isolates were then characterized in vitro for their probiotic characteristics and their antimicrobial activities against some human pathogens. Results showed that all nine isolates belonged to the genus Lactobacillus. They were able to tolerate pH 3 for 3 h, 0.3% bile salts for 4 h, and 1.9 mg/mL pancreatic enzymes for 3 h. They exhibited good ability to attach to intestinal epithelial cells and were not resistant to the tested antibiotics. They also showed good antimicrobial activities against the tested pathogenic strains of humans, and most of them exhibited stronger antimicrobial activity than the reference strain L. casei Shirota. Thus, the nine Lactobacillus strains could be considered as potential antimicrobial probiotic strains against human pathogens and should be further studied for their human health benefits. PMID:25105147

Design of novel analogues of short antimicrobial peptide anoplin with improved antimicrobial activity.

PubMed

Wang, Yang; Chen, Jianbo; Zheng, Xin; Yang, Xiaoli; Ma, Panpan; Cai, Ying; Zhang, Bangzhi; Chen, Yuan

2014-12-01

Currently, novel antibiotics are urgently required to combat the emergence of drug-resistant bacteria. Antimicrobial peptides with membrane-lytic mechanism of action have attracted considerable interest. Anoplin, a natural α-helical amphiphilic antimicrobial peptide, is an ideal research template because of its short sequence. In this study, we designed and synthesized a group of analogues of anoplin. Among these analogues, anoplin-4 composed of D-amino acids displayed the highest antimicrobial activity due to increased charge, hydrophobicity and amphiphilicity. Gratifyingly, anoplin-4 showed low toxicity to host cells, indicating high bacterial selectivity. Furthermore, the mortality rate of mice infected with Escherichia coli was significantly reduced by anoplin-4 treatment relative to anoplin. In conclusion, anoplin-4 is a novel anoplin analogue with high antimicrobial activity and enzymatic stability, which may represent a potent agent for the treatment of infection. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

Prospective Source of Antimicrobial Compounds From Pigment Produced by Bacteria associated with Brown Alga ( Phaeophyceae ) Isolated from Karimunjawa island, Indonesia

NASA Astrophysics Data System (ADS)

Lunggani, A. T.; Darmanto, Y. S.; Radjasa, O. K.; Sabdono, A.

2018-02-01

Brown algae or Phaeophyceae characterized by their natural pigments that differ from other important algal classes. Several publications proves that brown algae - associated bacteria have great potential in developing marine pharmaceutical industry since they are capable to synthesized numerous bioactive metabolite compounds. However the potency of marine pigmented microbes associated with brown alga to produce natural pigments and antimicrobials has been less studied. Marine pigmented bacteria associated with brown algae collected from Karimunjawa Island were successfully isolated and screened for antimicrobial activity. The aim of this research was evaluated of the antimicrobial activity of pigments extracted from culturable marine pigmented bacteria on some pathogenic bacteria and yeast. The results showed that all isolates had antimicrobial activity and could be prospectively developed as antimicrobial agent producing pigments. The 6 marine pigmented bacteria was identified to genus level as Pseudoalteromonas, Sphingomonas, Serratia, Paracoccus, Vibrio.

Archetypal tryptophan-rich antimicrobial peptides: properties and applications.

PubMed

Shagaghi, Nadin; Palombo, Enzo A; Clayton, Andrew H A; Bhave, Mrinal

2016-02-01

Drug-resistant microorganisms ('superbugs') present a serious challenge to the success of antimicrobial treatments. Subsequently, there is a crucial need for novel bio-control agents. Many antimicrobial peptides (AMPs) show a broad-spectrum activity against bacteria, fungi or viruses and are strong candidates to complement or substitute current antimicrobial agents. Some AMPs are also effective against protozoa or cancer cells. The tryptophan (Trp)-rich peptides (TRPs) are a subset of AMPs that display potent antimicrobial activity, credited to the unique biochemical properties of tryptophan that allow it to insert into biological membranes. Further, many Trp-rich AMPs cross bacterial membranes without compromising their integrity and act intracellularly, suggesting interactions with nucleic acids and enzymes. In this work, we overview some archetypal TRPs derived from natural sources, i.e., indolicidin, tritrpticin and lactoferricin, summarising their biochemical properties, structures, antimicrobial activities, mechanistic studies and potential applications.

[Antimicrobial properties of antiseptic composite with prolonged action].

PubMed

Paliĭ, G K; Nazarchuk, A A; Paliĭ, D V; Nazarchuk, G G; Gonchar, O O; Sukhliak, V V; Trofimenko, Iu Iu; Zadereĭ, N V; Stukan, O K

2013-01-01

Antimicrobial properties of a composite based on decamethoxine and modified polysaccharides (carboxymethylamylum, oxyethyl-cellulose) were studied. The composite was shown to have high antimicrobial activity against grampositive and gramnegative bacteria under different conditions of the experiment.

Influence of ball milling on the particle size and antimicrobial properties of Tridax procumbens leaf nanoparticles.

PubMed

Karthik, Subramani; Suriyaprabha, Rangaraj; Balu, Kolathupalayam Shanmugam; Manivasakan, Palanisamy; Rajendran, Venkatachalam

2017-02-01

The herbal nanoparticles were prepared from shade dried Tridax procumbens plant leaves employing ball milling technique using different process parameters, like ball ratio/size and milling time. The obtained nanoparticles were comprehensively characterised using X-ray diffraction, Fourier transform infrared spectroscopy, UV-visible spectroscopy, dynamic light scattering, scanning electron microscopy and antimicrobial analysis techniques. The crystallinity of the nanoparticles was retained without altering even though the particle size changes due to milling periods. The antibacterial activities of the prepared herbal nanoparticles against Staphylococcus aureus and Escherichia coli were explored to understand the influence of particle size on antimicrobial activities and their functional properties. The increase in ball ratio and milling time periods leads to a decrease in nanoparticle size from 114 to 45 nm which in turn increases the antimicrobial activities. The above study confirms that antimicrobial activity relies on nanoparticle size. The observed knowledge on influence of particle size on antimicrobial activities will help to optimise the production of potential herbal nanoparticles for different biomedical applications.

On the Functional Overlap between Complement and Anti-Microbial Peptides.

PubMed

Zimmer, Jana; Hobkirk, James; Mohamed, Fatima; Browning, Michael J; Stover, Cordula M

2014-01-01

Intriguingly, activated complement and anti-microbial peptides share certain functionalities; lytic, phagocytic, and chemo-attractant activities and each may, in addition, exert cell instructive roles. Each has been shown to have distinct LPS detoxifying activity and may play a role in the development of endotoxin tolerance. In search of the origin of complement, a functional homolog of complement C3 involved in opsonization has been identified in horseshoe crabs. Horseshoe crabs possess anti-microbial peptides able to bind to acyl chains or phosphate groups/saccharides of endotoxin, LPS. Complement activity as a whole is detectable in marine invertebrates. These are also a source of anti-microbial peptides with potential pharmaceutical applicability. Investigating the locality for the production of complement pathway proteins and their role in modulating cellular immune responses are emerging fields. The significance of local synthesis of complement components is becoming clearer from in vivo studies of parenchymatous disease involving specifically generated, complement-deficient mouse lines. Complement C3 is a central component of complement activation. Its provision by cells of the myeloid lineage varies. Their effector functions in turn are increased in the presence of anti-microbial peptides. This may point to a potentiating range of activities, which should serve the maintenance of health but may also cause disease. Because of the therapeutic implications, this review will consider closely studies dealing with complement activation and anti-microbial peptide activity in acute inflammation (e.g., dialysis-related peritonitis, appendicitis, and ischemia).

Analysis of essential oils from Voacanga africana seeds at different hydrodistillation extraction stages: chemical composition, antioxidant activity and antimicrobial activity.

PubMed

Liu, Xiong; Yang, Dongliang; Liu, Jiajia; Ren, Na

2015-01-01

In this study, essential oils from Voacanga africana seeds at different extraction stages were investigated. In the chemical composition analysis, 27 compounds representing 86.69-95.03% of the total essential oils were identified and quantified. The main constituents in essential oils were terpenoids, alcohols and fatty acids accounting for 15.03-24.36%, 21.57-34.43% and 33.06-57.37%, respectively. Moreover, the analysis also revealed that essential oils from different extraction stages possessed different chemical compositions. In the antioxidant evaluation, all analysed oils showed similar antioxidant behaviours, and the concentrations of essential oils providing 50% inhibition of DPPH-scavenging activity (IC50) were about 25 mg/mL. In the antimicrobial experiments, essential oils from different extraction stages exhibited different antimicrobial activities. The antimicrobial activity of oils was affected by extraction stages. By controlling extraction stages, it is promising to obtain essential oils with desired antimicrobial activities.

The role of diallyl sulfides and dipropyl sulfides in the in vitro antimicrobial activity of the essential oil of garlic, Allium sativum L., and leek, Allium porrum L.

PubMed

Casella, Sergio; Leonardi, Michele; Melai, Bernardo; Fratini, Filippo; Pistelli, Luisa

2013-03-01

The in vitro antibacterial activity of essential oils (EOs) obtained from fresh bulbs of garlic, Allium sativum L., and leek, Allium porrum L. ( Alliaceae), was studied. A. sativum (garlic) EO showed a good antimicrobial activity against Staphylococcus aureus (inhibition zone 14.8 mm), Pseudomonas aeruginosa (inhibition zone 21.1 mm), and Escherichia coli (inhibition zone 11.0 mm), whereas the EO of A. porrum (leek) had no antimicrobial activity. The main constituents of the garlic EO were diallyl monosulfide, diallyl disulfide (DADS), diallyl trisulfide, and diallyl tetrasulfide. The EO of A. porrum was characterized by the presence of dipropyl disulfide (DPDS), dipropyl trisulfide, and dipropyl tetrasulfide. The antimicrobial activities of the DADS and DPDS were also studied. The results obtained suggest that the presence of the allyl group is fundamental for the antimicrobial activity of these sulfide derivatives when they are present in Allium or in other species (DADS inhibition zone on S. aureus 15.9 mm, P. aeruginosa 21.9 mm, E. coli 11.4 mm). Copyright © 2012 John Wiley & Sons, Ltd.

External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials

PubMed Central

Halawani, Omar; Pearson, Bria; Mathews, Stephanie; López-Uribe, Margarita M.; Dunn, Robert R.; Smith, Adrian A.

2018-01-01

Social insects live in dense groups with a high probability of disease transmission and have therefore faced strong pressures to develop defences against pathogens. For this reason, social insects have been hypothesized to invest in antimicrobial secretions as a mechanism of external immunity to prevent the spread of disease. However, empirical studies linking the evolution of sociality with increased investment in antimicrobials have been relatively few. Here we quantify the strength of antimicrobial secretions among 20 ant species that cover a broad spectrum of ant diversity and colony sizes. We extracted external compounds from ant workers to test whether they inhibited the growth of the bacterium Staphylococcus epidermidis. Because all ant species are highly social, we predicted that all species would exhibit some antimicrobial activity and that species that form the largest colonies would exhibit the strongest antimicrobial response. Our comparative approach revealed that strong surface antimicrobials are common to particular ant clades, but 40% of species exhibited no antimicrobial activity at all. We also found no correlation between antimicrobial activity and colony size. Rather than relying on antimicrobial secretions as external immunity to control pathogen spread, many ant species have probably developed alternative strategies to defend against disease pressure. PMID:29515850

In vitro Antimicrobial Activity of Traditional Plant Used in Mestizo Shamanism from the Peruvian Amazon in Case of Infectious Diseases

PubMed Central

Roumy, Vincent; Gutierrez-Choquevilca, Andréa-Luz; Lopez Mesia, Jean Pierre; Ruiz, Lastenia; Ruiz Macedo, Juan Celidonio; Abedini, Amin; Landoulsi, Ameni; Samaillie, Jennifer; Hennebelle, Thierry; Rivière, Céline; Neut, Christel

2015-01-01

Context: Our survey was performed near Iquitos (Peruvian Amazon) and its surroundings and leads us to consider Mestizo ethnomedical practices. The plant species reported here are traditionally used for ailments related to microbial infections. Inhabitants of various ethnic origins were interviewed, and 52 selected plants extracts were evaluated for their antimicrobial properties against a panel of 36 sensitive and multi-resistant bacteria or yeast. The study aimed at providing information on antimicrobial plant extract activities and the ethnomedical context of Mestizo riverine populations from Loreto (Peru). Material and Method: The minimum inhibitory concentrations (MICs) of the plant crude extracts were carried out using the agar dilution method and ranged between 0.075 and 5.0 mg/ml. Results: Of the 40 plants analyzed, 9 species showed MIC ≤0.3 mg/ml (Anacardium occidentale, Couroupita guianensis, Croton lechleri, Davilla rugosa, Erythrina amazonica, Jacaranda copaia subsp. Spectabilis, Oenocarpus bataua, Peperomia macrostachya, and Phyllanthus urinaria) for one or several of the 36 microorganisms and only 6 drug extracts were inactive. Among the 40 plants, 13 were evaluated for the first time for an antibacterial activity. Conclusion: This evaluation of the antimicrobial activity of 40 plants using an approved standard methodology allowed comparing those activities against various microbes to establish antimicrobial spectra of standardized plant extracts, and give support to the traditional use of these plants. It may also help discovering new chemical classes of antimicrobial agents that could serve against multi-resistant bacteria. SUMMARY This study leads us to consider Mestizo ethnomedical practices near Iquitos (Peruvian Amazon) and its surroundings. The plant species reported here are traditionally used for ailments related to microbial infections. 52 selected plants extracts were evaluated for their antimicrobial properties against a panel of 36 sensitive and multi resistant bacteria or yeast. The study aimed at providing information on antimicrobial plant extract activities and the ethnomedical context of Mestizo riverine populations from Loreto. PMID:27013805

In vitro Antimicrobial Activity of Traditional Plant Used in Mestizo Shamanism from the Peruvian Amazon in Case of Infectious Diseases.

PubMed

Roumy, Vincent; Gutierrez-Choquevilca, Andréa-Luz; Lopez Mesia, Jean Pierre; Ruiz, Lastenia; Ruiz Macedo, Juan Celidonio; Abedini, Amin; Landoulsi, Ameni; Samaillie, Jennifer; Hennebelle, Thierry; Rivière, Céline; Neut, Christel

2015-10-01

Our survey was performed near Iquitos (Peruvian Amazon) and its surroundings and leads us to consider Mestizo ethnomedical practices. The plant species reported here are traditionally used for ailments related to microbial infections. Inhabitants of various ethnic origins were interviewed, and 52 selected plants extracts were evaluated for their antimicrobial properties against a panel of 36 sensitive and multi-resistant bacteria or yeast. The study aimed at providing information on antimicrobial plant extract activities and the ethnomedical context of Mestizo riverine populations from Loreto (Peru). The minimum inhibitory concentrations (MICs) of the plant crude extracts were carried out using the agar dilution method and ranged between 0.075 and 5.0 mg/ml. Of the 40 plants analyzed, 9 species showed MIC ≤0.3 mg/ml (Anacardium occidentale, Couroupita guianensis, Croton lechleri, Davilla rugosa, Erythrina amazonica, Jacaranda copaia subsp. Spectabilis, Oenocarpus bataua, Peperomia macrostachya, and Phyllanthus urinaria) for one or several of the 36 microorganisms and only 6 drug extracts were inactive. Among the 40 plants, 13 were evaluated for the first time for an antibacterial activity. This evaluation of the antimicrobial activity of 40 plants using an approved standard methodology allowed comparing those activities against various microbes to establish antimicrobial spectra of standardized plant extracts, and give support to the traditional use of these plants. It may also help discovering new chemical classes of antimicrobial agents that could serve against multi-resistant bacteria. This study leads us to consider Mestizo ethnomedical practices near Iquitos (Peruvian Amazon) and its surroundings. The plant species reported here are traditionally used for ailments related to microbial infections. 52 selected plants extracts were evaluated for their antimicrobial properties against a panel of 36 sensitive and multi resistant bacteria or yeast. The study aimed at providing information on antimicrobial plant extract activities and the ethnomedical context of Mestizo riverine populations from Loreto.

Discovery of novel antimicrobial peptides: A transcriptomic study of the sea anemone Cnidopus japonicus.

PubMed

Grafskaia, Ekaterina N; Polina, Nadezhda F; Babenko, Vladislav V; Kharlampieva, Daria D; Bobrovsky, Pavel A; Manuvera, Valentin A; Farafonova, Tatyana E; Anikanov, Nikolay A; Lazarev, Vassili N

2018-04-01

As essential conservative component of the innate immune systems of living organisms, antimicrobial peptides (AMPs) could complement pharmaceuticals that increasingly fail to combat various pathogens exhibiting increased resistance to microbial antibiotics. Among the properties of AMPs that suggest their potential as therapeutic agents, diverse peptides in the venoms of various predators demonstrate antimicrobial activity and kill a wide range of microorganisms. To identify potent AMPs, the study reported here involved a transcriptomic profiling of the tentacle secretion of the sea anemone Cnidopus japonicus. An in silico search algorithm designed to discover toxin-like proteins containing AMPs was developed based on the evaluation of the properties and structural peculiarities of amino acid sequences. The algorithm revealed new proteins of the anemone containing antimicrobial candidate sequences, and 10 AMPs verified using high-throughput proteomics were synthesized. The antimicrobial activity of the candidate molecules was experimentally estimated against Gram-positive and -negative bacteria. Ultimately, three peptides exhibited antimicrobial activity against bacterial strains, which suggests that the method can be applied to reveal new AMPs in the venoms of other predators as well.

In vitro investigation of antimicrobial activities of ethnomedicinal plants against dental caries pathogens.

PubMed

Besra, Mamta; Kumar, Vipin

2018-05-01

The study aimed to evaluate the antimicrobial activity of medicinal plant extracts against the bacterial pathogens prominent in dental caries. A total of 20 plant species (herbs, shrubs and trees) belonging to 18 genera and 15 families were documented for dental caries. Antimicrobial activity of solvent extracts and essential oil from plants were determined by zone of inhibition on the growth of Streptococcus mutans (MTCC 497) and Lactobacillus acidophilus (MTCC 10307) using the agar well diffusion method. The results of in vitro antimicrobial assay prove that methanol is more successful in the extraction of phytochemicals from plant samples than aqueous solvent, as methanol extracts show higher antimicrobial activity than aqueous extracts against both the test pathogens. Methanol extracts of Nigella sativa, Psidium guajava and Syzygium aromaticum were the most effective among all 20 plant samples and have potent inhibitory activity against both dental caries pathogens with minimum inhibitory concentration of 0.2 mg mL - 1 . N. sativa seed methanol extract was more effective with 22.3 mm zone of inhibition at 0.2 mg mL - 1 against S. mutans (MTCC 497), while L. acidophilus (MTCC 10307) was more sensitive to S. aromaticum bud methanol extract at 11.3 mm zone of inhibition at concentration 0.1 mg mL - 1 . Essential oil extracted from plants also possesses strong antimicrobial activity for both test pathogens, with a minimum inhibitory concentration range of 0.05-0.16 mg mL - 1 . Syzygium aromaticum bud essential oil at 0.05 mg mL - 1 was most active against S. mutans (MTCC 497). Plant extracts viewing antimicrobial activity with minimum inhibitory concentration show the efficacy of the plant products that could be considered as a good indicator of prospective plants for discovering new antimicrobial agents against dental caries pathogens. The findings of this study provide a lead to further polyherbal formulations for the treatment of dental caries malaise.

Purification and characterization of ribosomal proteins L27 and L30 having antimicrobial activity produced by the Lactobacillus salivarius SGL 03.

PubMed

Pidutti, P; Federici, F; Brandi, J; Manna, L; Rizzi, E; Marini, U; Cecconi, D

2018-02-01

The aim of this study was to investigate the antimicrobial potential of proteins secreted by a new strain of Lactobacillus salivarius. The secretome of L. salivarius SGL 03 strain was analysed by gel-assisted fractionation and MS/MS to identify low-molecular-mass proteins. This strategy allowed us to identify 10 secreted proteins. Then, a combination of heterologous expression and agar well diffusion was used to characterize them as to their antimicrobial activity, mechanisms of action and stability. Our findings indicate that L27 and L30 proteins of the 50S ribosomal subunit have antimicrobial activity against Streptococcus pyogenes, Streptococcus uberis and Enterococcus faecium. In addition, both proteins are bactericidal against S. pyogenes and maintain their antimicrobial activity after different protease treatments, at acidic pH, after heat treatment, and if stored in a refrigerated ambient at least at 4°C. The overall results demonstrated that the L27 and L30 ribosomal proteins are of interest as new antimicrobial molecules to prevent the growth of S. pyogenes, S. uberis and E. faecium. Our results provide the first insight into the extra-ribosomal activity of L27 and L30 secreted proteins of L. salivarius. This study demonstrated the capacity of L. salivarius SGL 03 to produce antimicrobial molecules and suggested this strain as a promising probiotic candidate. © 2017 The Society for Applied Microbiology.

High-density antimicrobial peptide coating with broad activity and low cytotoxicity against human cells.

PubMed

Rai, Akhilesh; Pinto, Sandra; Evangelista, Marta B; Gil, Helena; Kallip, Silvar; Ferreira, Mario G S; Ferreira, Lino

2016-03-01

Medical device-associated infections are a multi-billion dollar burden for the worldwide healthcare systems. The modification of medical devices with non-leaching coatings capable of killing microorganisms on contact is one of the strategies being investigated to prevent microorganism colonization. Here we developed a robust antimicrobial coating based on the chemical immobilization of the antimicrobial peptide (AMP), cecropin-melittin (CM), on gold nanoparticles coated surfaces. The concentration of AMP immobilized (110 μg/cm(2)) was higher than most of the studies reported so far (<10 μg/cm(2)). This translated onto a coating with high antimicrobial activity against Gram positive and negative bacteria sp., as well as multi-drug resistant bacteria. Studies with E. coli reporter bacteria showed that these coatings induced the permeability of the outer membrane of bacteria in less than 5 min and the inner membrane in approximately 20 min. Importantly, the antimicrobial properties of the coating are maintained in the presence of 20% (v/v) human serum, and have low probability to induce bacteria resistance. We further show that coatings have low toxicity against human endothelial and fibroblast cells and is hemocompatible since it does not induce platelet and complement activation. The antimicrobial coating described here may be promising to prevent medical device-associated infections. In recent years, antimicrobial peptides (AMPs) have been chemically immobilized on surfaces of medical devices to render them with antimicrobial properties. Surfaces having immobilized cationic peptides are susceptible to be adsorbed by plasma proteins with the subsequent loss of antimicrobial activity. Furthermore, with the exception of very few studies that have determined the cytotoxicity of surfaces in mammalian cells, the effect of the immobilized AMP on human cells is relatively unknown. Here we report a coating based on cecropin-melittin peptide (CM) that maintains its antimicrobial activity against Gram-positive and negative bacteria including multi-drugs resistance bacteria in the presence of serum and has relatively low cytotoxicity against human cells. The reported coatings may be translated on to variety of substrates (glass and titanium) and medical devices to prevent device-associated microbial infection. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect of Encapsulation on Antimicrobial Activity of
Herbal Extracts with Lysozyme

PubMed Central

Matouskova, Petra; Bokrova, Jitka; Benesova, Pavla

2016-01-01

Summary Resistance of microorganisms to antibiotics has increased. The use of natural components with antimicrobial properties can be of great significance to reduce this problem. The presented work is focused on the study of the effect of encapsulation of selected plant and animal antimicrobial substances (herbs, spices, lysozyme and nisin) on their activity and stability. Antimicrobial components were packaged into liposomes and polysaccharide particles (alginate, chitosan and starch). Antimicrobial activity was tested against two Gram-positive (Bacillus subtilis and Micrococcus luteus) and two Gram-negative (Escherichia coli and Serratia marcescens) bacteria. Encapsulation was successful in all types of polysaccharide particles and liposomes. The prepared particles exhibited very good long-term stability, especially in aqueous conditions. Antimicrobial activity was retained in all types of particles. Liposomes with encapsulated herb and spice extracts exhibited very good inhibitory effect against all tested bacterial strains. Most of herbal extracts had very good antimicrobial effect against the tested Gram-negative bacterial strains, while Gram-positive bacteria were more sensitive to lysozyme particles. Thus, particles with co-encapsulated herbs and lysozyme are more active against different types of bacteria, and more stable and more effective during long-term storage. Particles with encapsulated mixture of selected plant extracts and lysozyme could be used as complex antimicrobial preparation with controlled release in the production of food and food supplements, pharmaceutical and cosmetic industries. PMID:27956862

Retention of antimicrobial activity in plaque and saliva following mouthrinse use in vivo.

PubMed

Otten, M P T; Busscher, H J; van der Mei, H C; Abbas, F; van Hoogmoed, C G

2010-01-01

The aim of this study was to determine the contribution of plaque and saliva towards the prolonged activity, also called substantivity, of three antimicrobial mouthrinses (Listerine®, Meridol®, Crest Pro Health®), used in combination with a toothpaste (Prodent Coolmint®). Volunteers brushed for 4 weeks with a toothpaste without antimicrobial claims, while during the last 2 weeks half of the volunteers used an antimicrobial mouthrinse in addition to brushing. At the end of the experimental period, plaque and saliva samples were collected 6 h after oral hygiene, and bacterial concentrations and viabilities were determined. The contribution of plaque and saliva towards substantivity was assessed by combining plaque obtained after mechanical cleaning only with plaque and saliva obtained after additional use of an antimicrobial rinse. Subsequently, resulting viabilities of the combined plaques were determined. The viabilities of plaque samples after additional rinsing with mouthrinses were lower than of plaque obtained after mechanical cleaning only, regardless of the rinse involved. Moreover, plaque collected 6 h after rinsing with antimicrobial mouthrinses contained a surplus of antimicrobial activity. Only Listerine showed decreased viability in saliva, but none of the mouthrinses showed any residual antimicrobial activity in saliva. The findings indicate that plaque left behind after mechanical cleaning contributes to the prolonged substantivity of antimicrobial mouthrinses. Copyright © 2010 S. Karger AG, Basel.

Methylsulfonyl benzothiazoles (MSBT) derivatives: Search for new potential antimicrobial and anticancer agents.

PubMed

Lad, Nitin P; Manohar, Yogesh; Mascarenhas, Malcolm; Pandit, Yashwant B; Kulkarni, Mahesh R; Sharma, Rajiv; Salkar, Kavita; Suthar, Ashish; Pandit, Shivaji S

2017-03-01

A series of novel 4 and 5-substituted methylsulfonyl benzothiazole (MSBT) compounds having amide, alkoxy, sulfonamide, nitro and amine functionality were synthesized from sequential reactions on 5-ethoxy-2-(methylsulfonyl)benzo[d]thiazole such as nitration, reduction, sulfonation, dealkylation, etc. All synthesized compounds were screened against antimicrobial and selected screened for anticancer activity. Antimicrobial activities studies reveled that among all compounds screened, out of MSBT-07, MSBT-11, MSBT-12, MSBT-14, MSBT-19, and MSBT-27 were found to have promising antimicrobial activity at MIC range of 4-50μg/ml against selected bacterial as well as fungal species. Compounds having good antimicrobial activity were screened for cervical cancer (HeLA cell lines). Of these MSBT-07 and MSBT-12 significantly reduced the cell growth. Consequently their calculated GI 50 values were found to be 0.1 or <0.1μM. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antimicrobial Polymeric Materials with Quaternary Ammonium and Phosphonium Salts

PubMed Central

Xue, Yan; Xiao, Huining; Zhang, Yi

2015-01-01

Polymeric materials containing quaternary ammonium and/or phosphonium salts have been extensively studied and applied to a variety of antimicrobial-relevant areas. With various architectures, polymeric quaternary ammonium/phosphonium salts were prepared using different approaches, exhibiting different antimicrobial activities and potential applications. This review focuses on the state of the art of antimicrobial polymers with quaternary ammonium/phosphonium salts. In particular, it discusses the structure and synthesis method, mechanisms of antimicrobial action, and the comparison of antimicrobial performance between these two kinds of polymers. PMID:25667977

Dimers of coumarin-1,2,3-triazole hybrids bearing alkyl spacer: Design, microwave-assisted synthesis, molecular docking and evaluation as antimycobacterial and antimicrobial agents

NASA Astrophysics Data System (ADS)

Ashok, Dongamanti; Gundu, Srinivas; Aamate, Vikas Kumar; Devulapally, Mohan Gandhi; Bathini, Raju; Manga, Vijjulatha

2018-04-01

The present study demonstrated the synthesis of new series of coumarin-1,2,3-triazole hybrids under microwave irradiation method. Several dimers of coumarin based 1,2,3-triazole derivatives were synthesized and their antimycobacterial and antimicrobial activities were investigated. The antimycobacterial activity screening results revealed that compounds 6i and 6j were the most active against Mycobacterium tuberculosis H37Rv strain. The active compounds were further evaluated for cytotoxicity with HEK cell lines and exhibited less % of inhibition. The same synthetic hybrids were evaluated for their antimicrobial activity against various bacterial strains and fungal strains and compounds 6e, 6h, 6i and 6j were found to be the most promising antimicrobial potent molecules. Furthermore, the active compounds against Mycobacterium tuberculosis were evaluated for their molecular docking studies against pantothenate synthetase (PS) enzyme of MTB and the docking results are in well agreement with the antitubercular evaluation results.

Human β-defensin 4 with non-native disulfide bridges exhibit antimicrobial activity.

PubMed

Sharma, Himanshu; Nagaraj, Ramakrishnan

2015-01-01

Human defensins play multiple roles in innate immunity including direct antimicrobial killing and immunomodulatory activity. They have three disulfide bridges which contribute to the stability of three anti-parallel β-strands. The exact role of disulfide bridges and canonical β-structure in the antimicrobial action is not yet fully understood. In this study, we have explored the antimicrobial activity of human β-defensin 4 (HBD4) analogs that differ in the number and connectivity of disulfide bridges. The cysteine framework was similar to the disulfide bridges present in μ-conotoxins, an unrelated class of peptide toxins. All the analogs possessed enhanced antimicrobial potency as compared to native HBD4. Among the analogs, the single disulfide bridged peptide showed maximum potency. However, there were no marked differences in the secondary structure of the analogs. Subtle variations were observed in the localization and membrane interaction of the analogs with bacteria and Candida albicans, suggesting a role for disulfide bridges in modulating their antimicrobial action. All analogs accumulated in the cytosol where they can bind to anionic molecules such as nucleic acids which would affect several cellular processes leading to cell death. Our study strongly suggests that native disulfide bridges or the canonical β-strands in defensins have not evolved for maximal activity but they play important roles in determining their antimicrobial potency.

Human β-Defensin 4 with Non-Native Disulfide Bridges Exhibit Antimicrobial Activity

PubMed Central

Sharma, Himanshu; Nagaraj, Ramakrishnan

2015-01-01

Human defensins play multiple roles in innate immunity including direct antimicrobial killing and immunomodulatory activity. They have three disulfide bridges which contribute to the stability of three anti-parallel β-strands. The exact role of disulfide bridges and canonical β-structure in the antimicrobial action is not yet fully understood. In this study, we have explored the antimicrobial activity of human β-defensin 4 (HBD4) analogs that differ in the number and connectivity of disulfide bridges. The cysteine framework was similar to the disulfide bridges present in μ-conotoxins, an unrelated class of peptide toxins. All the analogs possessed enhanced antimicrobial potency as compared to native HBD4. Among the analogs, the single disulfide bridged peptide showed maximum potency. However, there were no marked differences in the secondary structure of the analogs. Subtle variations were observed in the localization and membrane interaction of the analogs with bacteria and Candida albicans, suggesting a role for disulfide bridges in modulating their antimicrobial action. All analogs accumulated in the cytosol where they can bind to anionic molecules such as nucleic acids which would affect several cellular processes leading to cell death. Our study strongly suggests that native disulfide bridges or the canonical β-strands in defensins have not evolved for maximal activity but they play important roles in determining their antimicrobial potency. PMID:25785690

Bovine and human lactoferricin peptides: chimeras and new cyclic analogs.

PubMed

Arias, Mauricio; McDonald, Lindsey J; Haney, Evan F; Nazmi, Kamran; Bolscher, Jan G M; Vogel, Hans J

2014-10-01

Lactoferrin (LF) is an important antimicrobial and immune regulatory protein present in neutrophils and most exocrine secretions of mammals. The antimicrobial activity of LF has been related to the presence of an antimicrobial peptide sequence, called lactoferricin (LFcin), located in the N-terminal region of the protein. The antimicrobial activity of bovine LFcin is considerably stronger than the human version. In this work, chimera peptides combining segments of bovine and human LFcin were generated in order to study their antimicrobial activity and mechanism of action. In addition, the relevance of the conserved disulfide bridge and the resulting cyclic structure of both LFcins were analyzed by using "click chemistry" and sortase A-catalyzed cyclization of the peptides. The N-terminal region of bovine LFcin (residues 17-25 of bovine LF) proved to be very important for the antimicrobial activity of the chimera peptides against E. coli, when combined with the C-terminal region of human LFcin. Similarly the cyclic bovine LFcin analogs generated by "click chemistry" and sortase A preserved the antimicrobial activity of the original peptide, showing the significance of these two techniques in the design of cyclic antimicrobial peptides. The mechanism of action of bovine LFcin and its active derived peptides was strongly correlated with membrane leakage in E. coli and up to some extent with the ability to induce vesicle aggregation. This mechanism was also preserved under conditions of high ionic strength (150 mM NaCl) illustrating the importance of these peptides in a more physiologically relevant system.

C-terminal Lysine-Linked Magainin 2 with Increased Activity Against Multidrug-Resistant Bacteria.

PubMed

Lorenzón, Esteban N; Santos-Filho, Norival A; Ramos, Matheus A S; Bauab, Tais M; Camargo, Ilana L B C; Cilli, Eduardo M

2016-01-01

Due to the growing problem of antibiotic-resistant microorganisms, the development of novel antimicrobial agents is a very important challenge. Dimerization of cationic antimicrobial peptides (cAMPs) is a potential strategy for enhancing antimicrobial activity. Here, we studied the effects of magainin 2 (MG2) dimerization on its structure and biological activity. Lysine and glutamic acid were used to synthesize the C- and N-terminal dimers of MG2, respectively, in order to evaluate the impact of linker position used to obtain the dimers. Both MG2 and its dimeric versions showed a random coil structure in aqueous solution. However, in the presence of a structure-inducing solvent or a membrane mimetic, all peptides acquired helical structure. N-terminal dimerization did not affect the biological activity of the peptide. On the other hand, the C-terminal dimer, (MG2)2K, showed antimicrobial activity 8-16 times higher than that of MG2, and the time required to kill Escherichia coli was lower. The enhanced antimicrobial activity was related to membrane permeabilization. (MG2)2K was also more active against multidrug-resistant bacteria of clinical origin. Overall, the results presented here demonstrate that C-terminal lysine-linked dimerization improve the activity of MG2, and (MG2)2K can be considered as a potential antimicrobial agent.

Comparative Analysis of the Antimicrobial Activities of Plant Defensin-Like and Ultrashort Peptides against Food-Spoiling Bacteria.

PubMed

Kraszewska, Joanna; Beckett, Michael C; James, Tharappel C; Bond, Ursula

2016-07-15

Antimicrobial peptides offer potential as novel therapeutics to combat food spoilage and poisoning caused by pathogenic and nonpathogenic bacteria. Our previous studies identified the peptide human beta-defensin 3 (HBD3) as a potent antimicrobial agent against a wide range of beer-spoiling bacteria. Thus, HBD3 is an excellent candidate for development as an additive to prevent food and beverage spoilage. To expand the repertoire of peptides with antimicrobial activity against bacteria associated with food spoilage and/or food poisoning, we carried out an in silico discovery pipeline to identify peptides with structure and activity similar to those of HBD3, focusing on peptides of plant origin. Using a standardized assay, we compared the antimicrobial activities of nine defensin-like plant peptides to the activity of HBD3. Only two of the peptides, fabatin-2 and Cp-thionin-2, displayed antimicrobial activity; however, the peptides differed from HBD3 in being sensitive to salt and were thermostable. We also compared the activities of several ultrashort peptides to that of HBD3. One of the peptides, the synthetic tetrapeptide O3TR, displayed biphasic antimicrobial activity but had a narrower host range than HBD3. Finally, to determine if the peptides might act in concert to improve antimicrobial activity, we compared the activities of the peptides in pairwise combinations. The plant defensin-like peptides fabatin-2 and Cp-thionin-2 displayed a synergistic effect with HBD3, while O3TR was antagonistic. Thus, some plant defensin-like peptides are effective antimicrobials and may act in concert with HBD3 to control bacteria associated with food spoilage and food poisoning. Food spoilage and food poisoning caused by bacteria can have major health and economic implications for human society. With the rise in resistance to conventional antibiotics, there is a need to identify new antimicrobials to combat these outbreaks in our food supply. Here we screened plant peptide databases to identify peptides that share structural similarity with the human defensin peptide HBD3, which has known antimicrobial activity against food-spoiling bacteria. We show that two of the plant peptides display antimicrobial activity against bacteria associated with food spoilage. When combined with HBD3, the peptides are highly effective. We also analyzed the activity of an easily made ultrashort synthetic peptide, O3TR. We show that this small peptide also displays antimicrobial activity against food-spoiling bacteria but is not as effective as HBD3 or the plant peptides. The plant peptides identified are good candidates for development as natural additives to prevent food spoilage. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

[Study on the chemical components, antimicrobial and antitumor activities of the essential oil from the leaves of Zanthoxylum avicennae].

PubMed

Zhang, Da-Shuai; Zhong, Qiong-Xin; Song, Xin-Ming; Liu, Wen-Jie; Wang, Jing; Zhang, Qiong-Yu

2012-08-01

To study the chemical constituents, antimicrobial activity and antitumor activity of the essential oil from Zanthoxylum avicennae. The essential oil from the leaves of Zanthoxylum avicennae was extracted by steam distillation. The components of the essential oil were separated and identified by GC-MS. 72 components were identified and accounted for 98.15% of the all peak area. The essential oil exhibited strong antitumor activity against K-562 human tumor cell lines with IC50 of 1.76 microg/mL. It also exhibited moderate antimicrobial activity against three bacteria. The essential oil of Zanthoxylum avicennae contains various active constituents. This result provides scientific reference for the pharmacological further research of Zanthoxylum avicennae.

Efficacy of Antimicrobial Agents for Food Contact Applications: Biological Activity, Incorporation into Packaging, and Assessment Methods: A Review.

PubMed

Mousavi Khaneghah, Amin; Hashemi, Seyed Mohammad Bagher; Eş, Ismail; Fracassetti, Daniela; Limbo, Sara

2018-07-01

Interest in the utilization of antimicrobial active packaging for food products has increased in recent years. Antimicrobial active packaging involves the incorporation of antimicrobial compounds into packaging materials, with the aim of maintaining or extending food quality and shelf life. Plant extracts, essential oils, organic acids, bacteriocins, inorganic substances, enzymes, and proteins are used as antimicrobial agents in active packaging. Evaluation of the antimicrobial activity of packaging materials using different methods has become a critical issue for both food safety and the commercial utilization of such packaging technology. This article reviews the different types of antimicrobial agents used for active food packaging materials, the main incorporation techniques, and the assessment methods used to examine the antimicrobial activity of packaging materials, taking into account their safety as food contact materials.

Antimicrobial activity of southern African medicinal plants with dermatological relevance: From an ethnopharmacological screening approach, to combination studies and the isolation of a bioactive compound.

PubMed

Mabona, Unathi; Viljoen, Alvaro; Shikanga, Emmanual; Marston, Andrew; Van Vuuren, Sandy

2013-06-21

Ethnobotanical reports on more than 100 southern African medicinal plants with dermatological relevance have been highlighted, yet there is still limited scientific data to support claims for their antimicrobial effectiveness against skin pathogens. Guided by ethnobotanical data, this paper explores the antimicrobial efficacies of southern African medicinal plants used to treat skin ailments. To investigate the antimicrobial properties of southern African medicinal plants against dermatologically relevant pathogens. The study also aimed at providing a scientific rationale for the traditional use of plant combinations to treat skin diseases and the isolation of the bio-active compound from the most active species, Aristea ecklonii (Iridaceae). Organic and aqueous extracts (132) were prepared from 47 plant species and screened for antimicrobial properties against dermatologically relevant pathogens using the micro-titre plate dilution method. Four different plant combinations were investigated for interactive properties and the sum of the fractional inhibitory concentration (ƩFIC) calculated. Isobolograms were used to further investigate the antimicrobial interactive properties of Pentanisia prunelloides combined with Elephantorrhiza elephantina at varied ratios. A bioactivity-guided fractionation process was adopted to fractionate the organic leaf extract of Aristea ecklonii. Plants demonstrating notable broad-spectrum activities (MIC values ≤1.00mg/ml) against the tested pathogens included extracts from Aristea ecklonii, Chenopodium ambrosioides, Diospyros mespiliformis, Elephantorrhiza elephantina, Eucalyptus camaldulensis, Gunnera perpensa, Harpephyllum caffrum, Hypericum perforatum, Melianthus comosus, Terminalia sericea and Warburgia salutaris. The organic extract of Elephantorrhiza elephantina, a plant reportedly used to treat acne vulgaris, demonstrated noteworthy antimicrobial activity (MIC value of 0.05mg/ml) against Propionibacterium acnes. Similarly, Diospyros mespiliformis reported for its traditional use to treat ringworm, also displayed noteworthy antimicrobial activity against Trichophyton mentagrophytes (MIC 0.10mg/ml) and Microsporum canis (MIC 0.50mg/ml). The aqueous root extracts of Pentanisia prunelloides combined (1:1) with Elephantorrhiza elephantina displayed synergistic interactions (ƩFIC values 0.31-0.38) against Staphylococcus aureus, gentamycin-methicillin resistant Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans. Fractionation of Aristea ecklonii resulted in the isolation of the known bio-active compound, plumbagin, displaying noteworthy antimicrobial activity (MIC range between 2.00μg/ml and 16.00μg/ml). Most of the plant extracts demonstrated pathogen specific antimicrobial effects with a few exhibiting broad-spectrum activities. Positive antimicrobial effects noted for plants such as Elephantorrhiza elephantina and Diospyros mespiliformis used for acne vulgaris and ringworm infections, respectively, give some validation to their reported traditiona l uses. Synergistic interactions noted for Pentanisia prunelloides combined with Elephantorrhiza elephantina validate an enhanced antimicrobial effect when used in combination. Noteworthy antimicrobial activities (MIC range between 2.00μg/ml and 16.00μg/ml) were observed for plumbagin isolated from Aristea ecklonii. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Antimicrobial activity of spices.

PubMed

Arora, D S; Kaur, J

1999-08-01

Spices have been shown to possess medicinal value, in particular, antimicrobial activity. This study compares the sensitivity of some human pathogenic bacteria and yeasts to various spice extracts and commonly employed chemotherapeutic substances. Of the different spices tested only garlic and clove were found to possess antimicrobial activity. The bactericidal effect of garlic extract was apparent within 1 h of incubation and 93% killing of Staphylococcus epidermidis and Salmonella typhi was achieved within 3 h. Yeasts were totally killed in 1 h by garlic extract but in 5 h with clove. Some bacteria showing resistance to certain antibiotics were sensitive to extracts of both garlic and clove. Greater anti-candidal activity was shown by garlic than by nystatin. Spices might have a great potential to be used as antimicrobial agents.

[Antibacterial activity of copper salts against microorganisms isolated from chronic infected wounds].

PubMed

Febré, Naldy; Silva, Viviana; Báez, Andrea; Palza, Humberto; Delgado, Katherine; Aburto, Isabel; Silva, Victor

2016-12-01

The antimicrobial activity of copper (Cu+2) is recognized and used as an antimicrobial agent. To evaluate the antimicrobial activity of copper against microorganisms obtained from chronic cutaneous wound infections. Five chemical products that contained copper particles in their composition were tested (zeolite, silica, acetate, nitrate and nanoparticle of copper). The antimicrobial activity against antibiotic resistant strains usually isolated from chronic cutaneous wound infections was determined for two of the products with better performance in copper release. The minimal inhibitory and minimal bactericidal concentrations of copper acetate and nitrate were similar, fluctuating between 400-2,000 µg/ml. The studied copper salts show great potential to be used to control both gram positive and gram negative, antibiotic resistant bacteria isolated from wound infections.

[The study of antimicrobial properties of silver nanoparticles in the form of a colloidal solution in the matrix of finely dispersed silica].

PubMed

Korchak, G I; Surmasheva, E V; Mikhienkova, A I; Nikonova, N A; Romanenko, L I; Oliĭnyk, Z A; Gorval', A K; Rosada, M A

2012-01-01

In the experimental study obtained with chemical method colloid solution of nanoparticles (NPs) of silver (Ag) and a composite on his base in the matrix of finely dispersed silica with particle size of 8-12 nm and NPs concentration in basic solution of 0,0016% (0,016 mg/cm3) were established to exhibit high antimicrobial activity against the test organisms: E. coli, P. aeruginosa, S. Aureus and C. Albicans, which depended on a set of factors. Antibacterial properties of tissue impregnated with Ag-NPs were studied. As stabilizing substances a mixture of surface-active substance sodium dodecyl sulfate and polymer polyvinylpyrrolidone was used Before the beginning of the study effective neutralizer was tailored. Times of preservation of antimicrobial activity of test samples have been established, and also their stability throughout long term of supervision (24 months) has been shown. Effect of organic pollution on antimicrobal activity of the samples has been studied. Based on obtained results the algorithm of the study of antimicrobial properties of nanopreparations has been elaborated.

An endogenous ribonuclease inhibitor regulates the antimicrobial activity of ribonuclease 7 in the human urinary tract

PubMed Central

Spencer, John David; Schwaderer, Andrew L.; Eichler, Tad; Wang, Huanyu; Kline, Jennifer; Justice, Sheryl S.; Cohen, Daniel M.; Hains, David S.

2013-01-01

Recent studies stress the importance of antimicrobial peptides in protecting the urinary tract from infection. Previously, we have shown that ribonuclease 7 (RNase 7) is a potent antimicrobial peptide that has broad-spectrum antimicrobial activity against uropathogenic bacteria. The urothelium of the lower urinary tract and intercalated cells of the kidney produce RNase 7 but regulation of its antimicrobial activity has not been well defined. Here we characterize the expression of an endogenous inhibitor, ribonuclease inhibitor (RI), in the urinary tract and evaluate its effect on RNase 7’s antimicrobial activity. Using RNA isolated from non-infected human bladder and kidney tissue, quantitative real-time PCR showed that RNH1, the gene encoding RI, is constitutively expressed throughout the urinary tract. With pyelonephritis, RNH1 expression and RI peptide production significantly decrease. Immunostaining localized RI production to the umbrella cells of the bladder and intercalated cells of the renal collecting tubule. In vitro assays showed that RI bound to RNase 7 and suppressed its antimicrobial activity by blocking its ability to bind the cell wall of uropathogenic bacteria. Thus, these results demonstrate a new immunomodulatory role for RI and identified a unique regulatory pathway that may affect how RNase 7 maintains urinary tract sterility. PMID:24107847

Total antioxidant activity and antimicrobial potency of the essential oil and oleoresin of Zingiber officinale Roscoe

PubMed Central

Bellik, Yuva

2014-01-01

Objective To compare in vitro antioxidant and antimicrobial activities of the essential oil and oleoresin of Zingiber officinale Roscoe. Methods The antioxidant activity was evaluated based on the ability of the ginger extracts to scavenge ABTS°+ free radical. The antimicrobial activity was studied by the disc diffusion method and minimal inhibitory concentration was determined by using the agar incorporation method. Results Ginger extracts exerted significant antioxidant activity and dose-depend effect. In general, oleoresin showed higher antioxidant activity [IC50=(1.820±0.034) mg/mL] when compared to the essential oil [IC50=(110.14±8.44) mg/mL]. In terms of antimicrobial activity, ginger compounds were more effective against Escherichia coli, Bacillus subtilis and Staphylococcus aureus, and less effective against Bacillus cereus. Aspergillus niger was least, whereas, Penicillium spp. was higher sensitive to the ginger extracts; minimal inhibitory concentrations of the oleoresin and essential oil were 2 mg/mL and 869.2 mg/mL, respectively. Moreover, the studied extracts showed an important antifungal activity against Candida albicans. Conclusions The study confirms the wide application of ginger oleoresin and essential oil in the treatment of many bacterial and fungal diseases.

Antifungal and antibacterial activity of marine microorganisms.

PubMed

El Amraoui, B; El Amraoui, M; Cohen, N; Fassouane, A

2014-03-01

In order to explore marine microorganisms with pharmaceutical potential, marine bacteria, collected from different coastal areas of the Moroccan Atlantic Ocean, were previously isolated from seawater, sediment, marine invertebrates and seaweeds. The antimicrobial activities of these microorganisms were investigated against the pathogens involved in human pathologies. Whole cultures of 34 marine microorganisms were screened for antimicrobial activities using the method of agar diffusion against three Gram-positive bacteria, two Gram-negative bacteria, and against yeast. The results showed that among the 34 isolates studied, 28 (82%) strains have antimicrobial activity against at least one pathogen studied, 11 (32%) strains have antifungal activity and 24 (76%) strains are active against Gram-positive bacteria, while 21 (62%) strains are active against Gram-negative bacteria. Among isolates having antimicrobial activity, 14 were identified and were assigned to the genera Acinetobacter, Aeromonas, Alcaligenes, Bacillus, Chromobacterium, Enterococcus, Pantoea and Pseudomonas. Due to a competitive role for space and nutrient, the marine microorganisms can produce antibiotic substance; therefore, these marine microorganisms were expected to be potential resources of natural antibiotic products. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

GC-MS analysis and antimicrobial activity determination of Citrus medica L. var proper leaf essential oil from South Sulawesi against skin pathogen microorganism

NASA Astrophysics Data System (ADS)

Aliyah; Himawan, A.; Rante, H.; Mufidah; Ningsih, D. R.

2017-11-01

A research about Citrus medica L. var sarcodactylis had been conducted and it showed a significant antimicrobial activity, thus drive our curiosity to investigate the other variety from the same species, Citrus medica L. var proper. This research focuses in chemical compound study and antimicrobial activity screening against Staphylococcus aureus, Propionibacterium acne, and Candida albicans of Citrus medica L. var Proper leaves’ essential oil. The essential oil is distillated from fresh leaves by hydrodestillation. The chemical compound was analysed using GC-MS instrument while the antimicrobial activity was tested using disk diffusion method. The results showed that the major component of the essential oil was Z-citral, citral and limonene compounds. The antimicrobial activity test results against the test microorganism are 9.15±0.15 mm, 11.15±1.3 mm and 8.02±0.48 mm, consecutively, for Staphylococcus aureus, Propionibacterium acne and Candida albicans.

Antimicrobial and physical properties of chitosan films incorporated with turmeric extract.

PubMed

Kalaycıoğlu, Zeynep; Torlak, Emrah; Akın-Evingür, Gülşen; Özen, İlhan; Erim, F Bedia

2017-08-01

In this study, the effects of turmeric extract incorporation on the antibacterial and physical properties of the chitosan films were evaluated. Turmeric containing chitosan-based film was produced with casting procedure and cross-linked with sodium sulfate. Mechanical, optical, thermal properties, and water vapor permeability of the films were studied. The addition of turmeric to chitosan film significantly increased the tensile strength of the film and improved the ultraviolet-visible light barrier of the film. Infrared spectroscopy analysis suggested an interaction between the phenolic compounds of the extract and amin group of chitosan. Antimicrobial activity of the chitosan films was studied against Salmonella and Staphylococcus aureus by plate count agar technique and a better antimicrobial activity was observed with turmeric incorporation. Turmeric incorporated chitosan films with enhanced antimicrobial activity and film stiffness can be suggested as a promising application for food packaging. Copyright © 2017 Elsevier B.V. All rights reserved.

Antimicrobial activity of highly stable silver nanoparticles embedded in agar-agar matrix as a thin film.

PubMed

Ghosh, S; Kaushik, R; Nagalakshmi, K; Hoti, S L; Menezes, G A; Harish, B N; Vasan, H N

2010-10-13

Highly stable silver nanoparticles (Ag NPs) in agar-agar (Ag/agar) as inorganic-organic hybrid were obtained as free-standing film by in situ reduction of silver nitrate by ethanol. The antimicrobial activity of Ag/agar film on Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans) was evaluated in a nutrient broth and also in saline solution. In particular, films were repeatedly tested for antimicrobial activity after recycling. UV-vis absorption and TEM studies were carried out on films at different stages and morphological studies on microbes were carried out by SEM. Results showed spherical Ag NPs of size 15-25 nm, having sharp surface plasmon resonance (SPR) band. The antimicrobial activity of Ag/agar film was found to be in the order, C. albicans>E. coli>S. aureus, and antimicrobial activity against C. albicans was almost maintained even after the third cycle. Whereas, in case of E. coli and S. aureus there was a sharp decline in antimicrobial activity after the second cycle. Agglomeration of Ag NPs in Ag/agar film on exposure to microbes was observed by TEM studies. Cytotoxic experiments carried out on HeLa cells showed a threshold Ag NPs concentration of 60 μg/mL, much higher than the minimum inhibition concentration of Ag NPs (25.8 μg/mL) for E. coli. The mechanical strength of the film determined by nanoindentation technique showed almost retention of the strength even after repeated cycle. Copyright © 2010 Elsevier Ltd. All rights reserved.

Eggshell bacterial load is related to antimicrobial properties of feathers lining barn swallow nests.

PubMed

Peralta-Sánchez, Juan Manuel; Soler, Juan José; Martín-Platero, Antonio Manuel; Knight, Rob; Martínez-Bueno, Manuel; Møller, Anders Pape

2014-02-01

The use of feathers to line bird's nests has traditionally been interpreted as having a thermoregulatory function. Feather-degrading bacteria growing on feathers lining nests may have antimicrobial properties, which may provide an additional benefit to lining nests with feathers. We test the hypothesis that the production of antimicrobial substances by feather bacteria affects the microbiological environment of the nest, and therefore the bacterial density on eggshells and, indirectly, hatching success. These effects would be expected to differ between nests lined with pigmented and white feathers, because bacteria grow differently on feathers of different colors. We experimentally manipulated the composition of pigmented and unpigmented feathers in nests of the barn swallow (Hirundo rustica) and studied the antimicrobial properties against the keratin-degrading bacterium Bacillus licheniformis of bacteria isolated from feathers of each color. Analyzed feathers were collected at the end of the incubation period, and antimicrobial activity was defined as the proportion of bacteria from the feathers that produce antibacterial substances effective against B. licheniformis. Our experimental manipulation affected antimicrobial activity, which was higher in nests with only white feathers at the beginning of incubation. Moreover, white feathers showed higher antimicrobial activity than black ones. Interestingly, antimicrobial activity in feathers of one of the colors correlated negatively with bacterial density on feather of the opposite color. Finally, antimicrobial activity of white feathers was negatively related to eggshell bacterial load. These results suggest that antimicrobial properties of feathers in general and of white feathers in particular affect the bacterial environment in nests. This environment in turn affects the bacterial load on eggshells, which may affect hatching success.

Antimicrobial activity in the common seawhip, Leptogorgia virgulata (Cnidaria: Gorgonaceae).

PubMed

Shapo, Jacqueline L; Moeller, Peter D; Galloway, Sylvia B

2007-09-01

Antimicrobial activity was examined in the gorgonian Leptogorgia virgulata (common seawhip) from South Carolina waters. Extraction and assay protocols were developed to identify antimicrobial activity in crude extracts of L. virgulata. Detection was determined by liquid growth inhibition assays using Escherichia coli BL21, Vibrio harveyii, Micrococcus luteus, and a Bacillus sp. isolate. This represents the first report of antimicrobial activity in L. virgulata, a temperate/sub-tropical coral of the western Atlantic Ocean. Results from growth inhibition assays guided a fractionation scheme to identify active compounds. Reverse-phase HPLC, HPLC-mass spectrometry, and 1H and 13C NMR spectroscopy were used to isolate, purify, and characterize metabolites in antimicrobial fractions of L. virgulata. Corroborative HPLC-MS/NMR evidence validated the presence of homarine and a homarine analog, well-known emetic metabolites previously isolated from L. virgulata, in coral extracts. In subsequent assays, partially-purified L. virgulata fractions collected from HPLC-MS fractionation were shown to contain antimicrobial activity using M. luteus and V. harveyii. This study provides evidence that homarine is an active constituent of the innate immune system in L. virgulata. We speculate it may act synergistically with cofactors and/or congeners in this octocoral to mount a response to microbial invasion and disease.

Evaluation of antimicrobial activity and bronchodialator effect of a polyherbal drug-Shrishadi.

PubMed

Kajaria, Divya Kumari; Gangwar, Mayank; Kumar, Dharmendra; Kumar Sharma, Amit; Tilak, Ragini; Nath, Gopal; Tripathi, Yamini Bhusan; Tripathi, J S; Tiwari, S K

2012-11-01

To investigate antimicrobial and bronchodialator effect of hydroalcholic extract of polyherbal drug Shirishadi containing Shirisha (Albezzia lebbeck), Nagarmotha (Cyprus rotandus) & Kantakari (Solanum xanthocarpum). Antimicrobial activity was evaluated by disc diffusion method and MIC, MBC, MFC were calculated by micro dilution method. Hydroalcholic extract of this preparation was investigated for its phytochemical analysis, phenol and flavonoid were determined by spectrophotometric method and in vivo bronchodilator effect was analysed by convulsion time. The phytochemical tests revealed presence of alkaloids, anthraquinones, carbohydrates, flavonoids, saponins and tannins. The antimicrobial result showed the MIC of 6.25 mg/mL against Staphylococcus aureus and 12.5 mg/mL for Escherichia coli and 12.5 mg/mL against remaining bacteria tested, with strong antifungal activity. The maximum inhibition zone is found against Pseudomonas aeruginosa with MIC 16 mg/mL. Drug showed significant bronchodilator effect with 27.86% & 36.13% increase in preconvulsion time of guinea pigs pretreated with 100 & 200 mg/kg body weight of extract. The study reveals that the extracts possess antibacterial activity and antifungal activity in a dose dependent manner. This antimicrobial property may be due to presence of several saponins, further studies are highly needed for the drug development.

Facile one-pot multicomponent synthesis and molecular docking studies of steroidal oxazole/thiazole derivatives with effective antimicrobial, antibiofilm and hemolytic properties.

PubMed

Ansari, Anam; Ali, Abad; Asif, Mohd; Rauf, Mohd Ahmar; Owais, Mohammad; Shamsuzzaman

2018-06-01

A series of steroidal oxazole and thiazole derivatives have been synthesized employing thiosemicarbazide/semicarbazide hydrochloride and ethyl 2-chloroacetoacetate with a simple and facile one-pot multicomponent reaction pathway. The antimicrobial activity of newly synthesized compounds were evaluated against four bacterial strains namely Gram-negative (Escherichia coliand Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) in addition to pathogenic fungi (Candida albicans and Cryptococcus neoformans). Bioactivity assay manifested that most of the compounds exhibited good antimicrobial activity. To provide additional insight into antimicrobial activity, the compounds were also tested for their antibiofilm activity against S. aureus biofilm. Moreover, molecular docking study shows binding of compounds with amino acid residues of DNA gyrase and glucosamine-6-phosphate synthase (promising antimicrobial target) through hydrogen bonding interactions. Hemolytic activity have been also investigated to ascertain the effect of compounds over RBC lysis and results indicate good prospects for biocompatibility. The expedient synthesis of steroidal heterocycles, effective antibacterial and antifungal behavior against various clinically relevant human pathogens, promising biocompatibility offer opportunities for further modification and potential applications as therapeutic agents. Copyright © 2018 Elsevier Inc. All rights reserved.

Anti-microbial screening and cytotoxic activity of aerial part of Thymelaea hirsuta L. essential oil growing in south-west Tunisia.

PubMed

Felhi, Samir; Chaaibia, Mouna; Bakari, Sana; Mansour, Riadh Ben; Békir, Ahmed; Gharsallah, Néji; Kadri, Adel

2017-01-01

This study aimed to investigate the antimicrobial and cytotoxic activities of essential oil isolated by the hydro-distillation of aerial parts of Thymelaea hirsuta. The antimicrobial activity of the oil was evaluated against eight bacterial and three fungal pathogenic strains. The results revealed that the essential oil exhibited a moderate-to-potent anti-microbial activity against all the microorganisms tested. Gram-positive bacteria were noted to be more sensitive to the oil than gram-negative bacteria and yeasts. In vitro cytotoxicity evaluation against HeLa cell lines showed that the essential oil exhibited moderate cytotoxicity on human tumor cells, with a high IC 50 value of 175μg/mL. To the author's knowledge, this is the first study reporting on the antimicrobial and cytotoxic activities of Thymelaea hirsuta essential oil. Overall, the results indicate that the T. hirsuta essential oil has a number of attractive properties that might open new promising opportunities for the control or prevention of a wide range of microbial infections and cancers and can facilitate the use of essential oils as natural preservatives against spoilage microorganisms in food systems.

Conformational study of melectin and antapin antimicrobial peptides in model membrane environments

NASA Astrophysics Data System (ADS)

Kocourková, Lucie; Novotná, Pavlína; Čujová, Sabína; Čeřovský, Václav; Urbanová, Marie; Setnička, Vladimír

2017-01-01

Antimicrobial peptides have long been considered as promising compounds against drug-resistant pathogens. In this work, we studied the secondary structure of antimicrobial peptides melectin and antapin using electronic (ECD) and vibrational circular dichroism (VCD) spectroscopies that are sensitive to peptide secondary structures. The results from quantitative ECD spectral evaluation by Dichroweb and CDNN program and from the qualitative evaluation of the VCD spectra were compared. The antimicrobial activity of the selected peptides depends on their ability to adopt an amphipathic α-helical conformation on the surface of the bacterial membrane. Hence, solutions of different zwitterionic and negatively charged liposomes and micelles were used to mimic the eukaryotic and bacterial biological membranes. The results show a significant content of α-helical conformation in the solutions of negatively charged liposomes mimicking the bacterial membrane, thus correlating with the antimicrobial activity of the studied peptides. On the other hand in the solutions of zwitterionic liposomes used as models of the eukaryotic membranes, the fraction of α-helical conformation was lower, which corresponds with their moderate hemolytic activity.

Expression of a bioactive bacteriophage endolysin in Nicotiana benthamiana plants

USDA-ARS?s Scientific Manuscript database

The emergence and spread of antibiotic-resistant pathogens has led to an increased interest in alternative antimicrobial treatments, such as bacteriophage, bacteriophage-encoded peptidoglycan hydrolases (endolysins) and antimicrobial peptides. In our study, the antimicrobial activity of the CP933 en...

[Study on the Chinese herbal formula for treatment of vaginitis and the antimicrobial activity in murine models].

PubMed

Fu, Ting-ting; Wu, Jian-yuan; Wang, Li; Ma, Yao; Wang, Ying; Liu, Ying; Ding, Hong

2006-09-01

To study on the various proportions of Radix Sophorae Flavescentis, Cortex Phellodendri, Fructus Cnidii and pericarp of Zanthoxylum bungeanum Maxim in the formulas, whose antimicrobial effects on E. coli, S. aureus, P. aeruginosa and C. albicans under different pH values were compared in vitro. According to Chinese ancient proved recipe, the K-B method and plate diluting method were adopted to measure antimicrobial activity, and orthogonal design to ascertain the herbal formula in vitro. Finally, murine models were established to test the antimicrobial activity in vivo through vaginal membrane irritancy experiment, negative rate of pathogeny and pathological grade of vaginal membrane. The results suggested that formulas with different proportions of the herbs had diverse antimicrobial activities, and the effect was shown to be most obvious when one milliliter drug contains 100 microl Fructus Cnidii-pericarp of Zanthoxylum bungeanum (2:1) co-extracted volatile oil and 50 microl Radix Sophorae Flavescentis and Cortex Phenodendri ethanol extraction respectively under pH6. The antimicrobial effect of the formula, which hardly had any membrane irritancy, was better than Jie Eryin in vitro and vivo. The fromula has few components and better effect, and adaptation to the pH value of vaginitis. It is a promising alternative for gynecological diseases.

Antimicrobial Activity and Modulatory Effect of Essential Oil from the Leaf of Rhaphiodon echinus (Nees & Mart) Schauer on Some Antimicrobial Drugs.

PubMed

Duarte, Antonia Eliene; de Menezes, Irwin Rose Alencar; Bezerra Morais Braga, Maria Flaviana; Leite, Nadghia Figueiredo; Barros, Luiz Marivando; Waczuk, Emily Pansera; Pessoa da Silva, Maria Arlene; Boligon, Aline; Teixeira Rocha, João Batista; Souza, Diogo Onofre; Kamdem, Jean Paul; Melo Coutinho, Henrique Douglas; Escobar Burger, Marilise

2016-06-08

Rhaphiodon echinus is a weed plant used in the Brazilian folk medicinal for the treatment of infectious diseases. In this study, the essential oil of R. echinus leaf was investigated for its antimicrobial properties. The chemical constituents of the essential oil were characterized by GC-MS. The antimicrobial properties were determined by studying by the microdilution method the effect of the oil alone, and in combination with antifungal or antibiotic drugs against the fungi Candida albicans, Candida krusei and Candida tropicalis and the microbes Escherichia coli, Staphylococcus aureus and Pseudomonas. In addition, the iron (II) chelation potential of the oil was determined. The results showed the presence of β-caryophyllene and bicyclogermacrene in major compounds, and revealed a low antifungal and antibacterial activity of the essential oil, but a strong modulatory effect on antimicrobial drugs when associated with the oil. The essential oil showed iron (II) chelation activity. The GC-MS characterization revealed the presence of monoterpenes and sesquiterpenes in the essential oil and metal chelation potential, which may be responsible in part for the modulatory effect of the oil. These findings suggest that essential oil of R. echinus is a natural product capable of enhancing the antibacterial and antifungal activity of antimicrobial drugs.

Effect of surface properties of NiFe2O4 nanoparticles synthesized by dc thermal plasma route on antimicrobial activity

NASA Astrophysics Data System (ADS)

Bhosale, S. V.; Ekambe, P. S.; Bhoraskar, S. V.; Mathe, V. L.

2018-05-01

The present work reports the role of surface properties of NiFe2O4 nanoparticles on the antimicrobial activity. The NiFe2O4 nanoparticles were synthesized by gas phase condensation and chemical co-precipitation route. These nanoparticles were extensively investigated using X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and electro-kinetic property measurements. The HRTEM was used to analyze surface morphology of nickel ferrite nanoparticles obtained by two different routes. Electro-kinetic properties of the nanoparticles under investigation were recorded, analyzed and correlated with the antimicrobial properties. It was observed that nickel ferrite nanoparticles synthesized by thermal plasma route (NFOTP) formed highly stable colloidal solution as compared to chemically synthesized (NFOCP), as the later tends to agglomerate due to low surface charge. The antimicrobial activity of NiFe2O4 nanoparticles were investigated on two Gram positive bacteria Staphylococcus aureus and Streptococcus pyogenes, two Gram negative bacteria Escherichia coli and Salmonella typhimurium and one fungal species Candida albicans. It was noted that the surface properties of NiFe2O4 particles have revealing effect on the antimicrobial activity. The NFOTP nanoparticles showed significant activity for gram negative E. coli bacteria however no activity was observed for other bacteria's and fungi under study. Moreover NFOCP particles did not show any significant activity for both bacteria's and fungi. Further, antimicrobial activity of nickel ferrite nanoparticles were studied even for different concentration to obtain the minimum inhibition concentration (MIC).

Black cobra (Naja naja karachiensis) lysates exhibit broad-spectrum antimicrobial activities

PubMed Central

Sagheer, Mehwish; Siddiqui, Ruqaiyyah; Iqbal, Junaid; Khan, Naveed Ahmed

2014-01-01

It is hypothesized that animals living in polluted environments possess antimicrobials to counter pathogenic microbes. The fact that snakes feed on germ-infested rodents suggests that they encounter pathogenic microbes and likely possess antimicrobials. The venom is used only to paralyze the rodent, but the ability of snakes to counter potential infections in the gut due to disease-ridden rodents requires robust action of the immune system against a broad range of pathogens. To test this hypothesis, crude lysates of different organs of Naja naja karachiensis (black cobra) were tested for antimicrobial properties. The antimicrobial activities of extracts were tested against selected bacterial pathogens (neuropathogenic Escherichia coli K1, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Streptococcus pneumonia), protist (Acanthamoeba castellanii), and filamentous fungus (Fusarium solani). The findings revealed that plasma and various organ extracts of N. n. karachiensis exhibited antimicrobial activity against E. coli K1, MRSA, P. aeruginosa, S. pneumoniae, A. castellanii, and F. solani in a concentration-dependent manner. The results of this study are promising for the development of new antimicrobials. PMID:24625321

An in vitro antibacterial study of savory essential oil and geraniol in combination with standard antimicrobials.

PubMed

Miladinović, Dragoljub L; Ilić, Budimir S; Kocić, Branislava D; Miladinović, Marija D

2014-11-01

The chemical composition and antibacterial activity of Satureja kitaibelii Wierzb. ex Heuff. (savory) essential oil were examined, as well as the association between it and standard antimicrobials: tetracycline and chloramphenicol. The antibacterial activities of geraniol, the main constituent of S. kitaibelii oil, individually and in combination with standard antimicrobials were also determined. The interactions of the essential oil and geraniol with antimicrobials toward five selected strains were evaluated using the microdilution checkerboard assay in combination with chemometric methods. Oxygenated monoterpenes were the most abundant compound class in the oil (59.7%), with geraniol (50.4%) as the major compound. The essential oil exhibited in vitro antibacterial activity against all tested bacterial strains, but the activities were lower than those of the standard antimicrobials. The combinations savory oil-chloramphenicol, savory oil-tetracycline and geraniol-chloramphenicol produced predominantly synergistic interactions (FIC indices in the range 0.21-0.87) and substantial reductions in the MIC values of antimicrobials against Gram-negative bacteria, the pharmacological treatment of which is very difficult nowadays. In the PCA and HCA analyses these combinations form a separate group.

Mushrooms as possible antioxidant and antimicrobial agents.

PubMed

Kosanić, Marijana; Ranković, Branislav; Dašić, Marko

2012-01-01

The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 μg/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 μg/mL), BHA (IC50 = 6.42 μg/mL) and α-tocopherol (IC50 = 62.43 μg/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases.

Antimicrobial activity of fractions and compounds from Calophyllumbrasiliense (Clusiaceae/Guttiferae).

PubMed

Pretto, Juliana B; Cechinel-Filho, Valdir; Noldin, Vânia F; Sartori, Mara R K; Isaias, Daniela E B; Cruz, Alexandre Bella

2004-01-01

Calophyllum brasiliense (Clusiaceae/Guttiferae) is a native Brazilian medicinal plant traditionally used against several diseases, including infectious pathologies. Crude methanolic extracts (CME) and two fractions, denoted non-polar (soluble in chloroform) and polar (nonsoluble in chloroform), were prepared from different parts of the plant (roots, stems, leaves, flowers and fruits) and studied. The following compounds were isolated and tested against pathogenic bacteria and yeasts by determination of the minimal inhibitory concentration (MIC): brasiliensic acid (1), gallic acid (2), epicatechin (3), protocatechuic acid (4), friedelin (5) and 1,5-dihydroxyxanthone (6). The results indicated that all the parts of the plant exhibited antimicrobial activity against Gram-positive bacteria, which are selectively inhibited by components of C. brasiliense. No activity was observed against Gram-negative bacteria and yeasts tested. Regarding the isolated compounds, substance 4 showed antimicrobial activity against all the tested microorganisms, whereas compound 6 exhibited antimicrobial activity only against Gram-positive bacteria. The results from the current study confirm and justify the popular use of this plant to treat infectious processes.

Structure-activity relationships of an antimicrobial peptide plantaricin s from two-peptide class IIb bacteriocins.

PubMed

Soliman, Wael; Wang, Liru; Bhattacharjee, Subir; Kaur, Kamaljit

2011-04-14

Class IIb bacteriocins are ribosomally synthesized antimicrobial peptides comprising two different peptides synergistically acting in equal amounts for optimal potency. In this study, we demonstrate for the first time potent (nanomolar) antimicrobial activity of a representative class IIb bacteriocin, plantaricin S (Pls), against four pathogenic gram-positive bacteria, including Listeria monocytogenes. The structure-activity relationships for Pls were studied using activity assays, circular dichroism (CD), and molecular dynamics (MD) simulations. The two Pls peptides and five Pls derived fragments were synthesized. The CD spectra of the Pls and selected fragments revealed helical conformations in aqueous 2,2,2-trifluoroethanol. The MD simulations showed that when the two Pls peptides are in antiparallel orientation, the helical regions interact and align, mediated by strong attraction between conserved GxxxG/AxxxA motifs. The results strongly correlate with the antimicrobial activity suggesting that helix-helix alignment of the two Pls peptides and interaction between the conserved motifs are crucial for interaction with the target cell membrane.

Comparative study of volatile oil content and antimicrobial activity of pecan cultivars growing in Egypt.

PubMed

El Hawary, Seham S; Zaghloul, Soumaya S; El Halawany, Ali M; El Bishbishy, Mahitab H

2013-11-01

The volatile oils obtained from the leaves of four pecan cultivars growing in Egypt were evaluated for their chemical composition and antimicrobial activity. The selected cultivars (cv.) were Carya illinoinensis (Wangneh.) K. Koch. cv. Wichita, C. illinoinensis cv. Western Schley, C. illinoinensis cv. Cherokee, and C. illinoinensis cv. Sioux. The gas chromatography-mass spectrometry analyses revealed that the volatile oils from samples of the different cultivars differ in composition and percentage of their components. β-Curcumene was found as the major constituent of the cv. Wichita oil, whereas germacrene D was the major component of cv. Sioux, cv. Cherokee, and cv. Western Schley. The antimicrobial activity was assayed using the Kirby-Bauer Method by measuring the zone of inhibition of growth. All volatile oils displayed an antimicrobial activity against the tested bacterial strains. On the other hand, only the volatile oil of cv. Wichita showed an antifungal effect on Aspergillus flavus. This work has identified candidates of volatile oils for future in vivo studies to develop antibiotic substitutes for the diminution of human and animal pathogenic bacteria. Nevertheless, the variations of the volatile oil components and antimicrobial potencies of the different studied cultivars, necessitate identifying the cultivars used in future studies.

Antimicrobial activity of natural products from the flora of Northern Ontario, Canada.

PubMed

Vandal, Janique; Abou-Zaid, Mamdouh M; Ferroni, Garry; Leduc, Leo G

2015-06-01

The number of multidrug resistant (MDR) microorganisms is increasing and the antimicrobial resistance expressed by these pathogens is generating a rising global health crisis. In fact, there are only a few antimicrobial agents left that can be used against MDR bacteria and fungi. In this study, the antimicrobial activities of selected natural products from the flora of Northern Ontario against selected microorganisms are reported. Plants were collected from Sault Ste. Marie, Ontario, Canada, and ethanol extracts were prepared using EtOH:H2O (1:1, v/v). Fungal cultures used in this study were Candida albicans ATCC 10231 and Schizosaccharomyces octosporus. Bacterial cultures employed included Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Mycobacterium phlei ATCC 11758, and Streptococcus lactis ATCC 19435. The microplate resazurin assay was used to screen for antimicrobial activity. Extracts of four plant species Chimaphila umbellata L. (Pyrolaceae), Betula papyrifera Marshall (Betulaceae), Rhus typhina L. (Anacardiaceae), and Fraxinus pennsylvanica Marshall (Oleaceae), and six compounds (gallic acid, ethyl gallate, caffeic acid, sinapic acid, gentisic acid, and chlorogenic acid) demonstrated antibacterial or antifungal activities with MICs ranging from 62.5 to 1000 µg/mL, respectively, for a chemical fraction of an extract from Betula papyrifera against the bacterium S. aureus. The present study has shown that certain plant extracts and select fractions and standard chemical compounds exhibit antimicrobial effects. Prince's Pine, Chimaphila umbellate, White Birch, Betula papyrifera, Staghorn Sumac, Rhus typhina, and Green Ash, Fraxinus pennsylvanica were the principal extracts exhibiting notable antibacterial and/or antifungal activities; while gallic acid, ethyl gallate, and caffeic acid demonstrated antibacterial activities and sinapic acid, gentisic acid, and chlorogenic acid demonstrated antifungal activities.

Antimicrobial activity of traditional medicinal plants from Ankober District, North Shewa Zone, Amhara Region, Ethiopia.

PubMed

Lulekal, E; Rondevaldova, J; Bernaskova, E; Cepkova, J; Asfaw, Z; Kelbessa, E; Kokoska, L; Van Damme, P

2014-05-01

Traditional medicinal plants have long been used in Ethiopia to treat human and livestock ailments. Despite a well-documented rich tradition of medicinal plant use in the country, their direct antimicrobial effects are still poorly known. To investigate the antimicrobial activity of 19 medicinal plant species that were selected based on the ethnobotanical information on their traditional use to treat infectious diseases in Ankober District. About 23 different ethanol extracts of plants obtained by maceration of various parts of 19 medicinal plant species were studied for potential antimicrobial activity using a broth microdilution method against Bacillus cereus, Bacteroides fragilis, Candida albicans, Clostridium perfringens, Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella enteritidis, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. Plant extracts from Embelia schimperi Vatke (Myrsinaceae) showed the strongest antibacterial activity with a minimum inhibitory concentration (MIC) value of 64 µg/ml against B. cereus, L. monocytogenes, and S. pyogenes. Growth inhibitory activities were also observed for extracts of Ocimum lamiifolium Hochst. (Lamiaceae) against S. pyogenes, and those of Rubus steudneri Schweinf. (Rosaceae) against S. epidermidis at an MIC value of 128 µg/ml. Generally, 74% of ethanol extracts (17 extracts) showed antimicrobial activity against one or more of the microbial strains tested at an MIC value of 512 µg/ml or below. Results confirm the antimicrobial role of traditional medicinal plants of Ankober and warrant further investigations on promising medicinal plant species so as to isolate and characterise chemicals responsible for the observed strong antimicrobial activities.

Natural sorbents modified by divalent Cu2+- and Zn2+- ions and their corresponding antimicrobial activity.

PubMed

Đolić, Maja B; Rajaković-Ognjanović, Vladana N; Štrbac, Svetlana B; Dimitrijević, Suzana I; Mitrić, Miodrag N; Onjia, Antonije E; Rajaković, Ljubinka V

2017-10-25

The objective of this study was to investigate the modification of materials used in wastewater treatment for possible antimicrobial application(s). Granulated activated carbon (GAC) and natural clinoptilolite (CLI) were activated using Cu 2+ - and Zn 2+ - ions and the disinfection ability of the resulting materials was tested. Studies of the sorption and desorption kinetics were performed in order to determine and clarify the antimicrobial activity of the metal-activated sorbents. The exact sorption capacities of the selected sorbents, GAC and CLI, activated through use of Cu 2+ - ions, were 15.90 and 3.60mg/g, respectively, while for the materials activated by Zn 2+ - ions, the corresponding capacities were 14.00 and 4.72mg/g,. The desorption rates were 2 and 3 orders of magnitude lower than their sorption efficacy for the Cu 2+ -, and Zn 2+ -activated sorbents, respectively. The intermediate sorption capacity and low desorption rate indicated that the overall antimicrobial activity of the metal-modified sorbents was a result of metal ions immobilized onto surface sites. The effect of antimicrobial activity of free ions desorbed from the metal-activated surface may thus be disregarded. The antimicrobial activities of Cu/GAC, Zn/GAC, Cu/CLI and Zn/CLI were also tested against Escherichia coli, Staphylococcus aureus, and Candida albicans. After 15min exposure, the highest levels of cell inactivation were obtained through the Cu/CLI and the Cu/GAC against E. coli, 100.0 and 98.24%, respectively. However, for S. aureus and yeast cell inactivation, all Cu 2+ - and Zn 2+ -activated sorbents proved to be unsatisfactory. A characterization of the sorbents was performed by X-ray diffraction (XRD), X-ray photo electron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM). A concentration of the adsorbed and released ions was determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and mass spectrometry (ICP-MS). The results showed that the antimicrobial performance of the activated sorbents depended on the surface characteristics of the material, which itself designates the distribution and the bioavailability of the activating agent. Copyright © 2017 Elsevier B.V. All rights reserved.

In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum

PubMed Central

2016-01-01

The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm). Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25–225 μg/mL). Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines. PMID:27597961

In vitro antimicrobial activities of cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene against Mycoplasma hominis clinical isolates.

PubMed

Sleha, Radek; Mosio, Petra; Vydrzalova, Marketa; Jantovska, Alexandra; Bostikova, Vanda; Mazurova, Jaroslava

2014-06-01

The aim of this study was to evaluate the antimicrobial effects of five natural substances against 50 clinical isolates of Mycoplasma hominis. The in vitro activity of selected natural compounds, cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene, was investigated against 50 M. hominis isolates cultivated from cervical swabs by the broth dilution method. All showed valuable antimicrobial activity against the tested isolates. Oil from the bark of Cinnamomum zeylanicum (MBC90 = 500 µg/mL) however was found to be the most effective. Carvacrol (MBC90 = 600 µg/mL) and eugenol (MBC90 = 1000 µg/mL) also possessed strong antimycoplasmal activity. The results indicate that cinnamon bark oil, carvacrol and eugenol have strong antimycoplasmal activity and the potential for use as antimicrobial agents in the treatment of mycoplasmal infections.

Lactobacillus plantarum as a Probiotic Potential from Kouzeh Cheese (Traditional Iranian Cheese) and Its Antimicrobial Activity.

PubMed

Jabbari, Vahid; Khiabani, Mahmoud Sowti; Mokarram, Reza Rezaei; Hassanzadeh, Azad Mohammad; Ahmadi, Elham; Gharenaghadeh, Sasan; Karimi, Nayyer; Kafil, Hossein Samadi

2017-06-01

The aim of this study is to isolate and identify Lactobacillus plantarum isolates from traditional cheese, Kouzeh, and evaluate their antimicrobial activity against some food pathogens. In total, 56 lactic acid bacteria were isolated by morphological and biochemical methods, 12 of which were identified as Lactobacillus plantarum by biochemical method and 11 were confirmed by molecular method. For analyzing the antimicrobial activity of these isolates properly, diffusion method was performed. The isolates were identified by 318 bp band dedicated for L. plantarum. The isolated L. plantarum represented an inhibitory activity against four of the pathogenic bacteria and showed different inhibition halos against each other. The larger halos were observed against Staphylococcus aureus and Staphylococcus epidermidis (15 ± 0.3 and 14.8 ± 0.7 mm, respectively). The inhibition halo of Escherichia coli was smaller than that of other pathogen and some L. plantarum did not show any inhibitory activity against E. coli, which were resistant to antimicrobial compounds produced by L. plantarum. The isolated L. plantarum isolates with the antimicrobial activity in this study had strong probiotic properties. These results indicated the nutritional value of Kouzeh cheese and usage of the isolated isolates as probiotic strains.

Antibacterial activity of peritoneal exudate in patients treated with 2 g cefotiam for surgical anti-microbial prophylaxis.

PubMed

Miglioli, P A; Schoeffel, U; Gabroska, E; Allerberger, F

1998-01-01

The objective of this study was to investigate the presence of antibacterial activity in peritoneal exudate (PE) of patients treated with cefotiam (CFT). CFT (2 g) was administered as a 'single-shot' antimicrobial prophylaxis to 6 patients at the beginning of colorectal resection. Samples of PE were collected from each patient on days 1, 2 and 3 after surgery. CFT was detectable in the samples of day 1 for 5 of the 6 patients. The influence of PE on antibacterial activity of the antimicrobial drug was evaluated carrying out the MICs of CFT against Escherichia coli K-12, E. coli (ATCC 10798), Klebsiella pneumoniae (ATCC 1003), Proteus rettgeri (Sanelli) and Staphylococcus aureus (ATCC 29213) with and without the addition of PE. The presence of PE enhanced the antimicrobial activity of CFT against gram-negative strains, but not against S. aureus (ATCC 29213). These results suggest the presence of substances in PE that possess endogenous antibacterial activity. Thus, antimicrobial activity in PE cannot be predicted by evaluating pathogen sensitivity in vitro only.

Anticancer and enhanced antimicrobial activity of biosynthesizd silver nanoparticles against clinical pathogens

NASA Astrophysics Data System (ADS)

Rajeshkumar, Shanmugam; Malarkodi, Chelladurai; Vanaja, Mahendran; Annadurai, Gurusamy

2016-07-01

The present investigation shows the biosynthesis of eco-friendly silver nanoparticles using culture supernatant of Enterococcus sp. and study the effect of enhanced antimicrobial activity, anticancer activity against pathogenic bacteria, fungi and cancer cell lines. Silver nanoparticles was synthesized by adding 1 mM silver nitrate into the 100 ml of 24 h freshly prepared culture supernatant of Enterococcus sp. and were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Selected Area Diffraction X-Ray (SAED), Energy Dispersive X Ray (EDX) and Fourier Transform Infra red Spectroscopy (FT-IR). The synthesized silver nanoparticles were impregnated with commercial antibiotics for evaluation of enhanced antimicrobial activity. Further these synthesized silver nanoparticles were assessed for its anticancer activity against cancer cell lines. In this study crystalline structured nanoparticles with spherical in the size ranges from 10 to 80 nm and it shows excellent enhanced antimicrobial activity than the commercial antibiotics. The in vitro assay of silver nanoparticles on anticancer have great potential to inhibit the cell viability. Amide linkages and carboxylate groups of proteins from Enterococcus sp. may bind with silver ions and convert into nanoparticles. The activities of commercial antibiotics were enhanced by coating silver nanoparticles shows significant improved antimicrobial activity. Silver nanoparticles have the great potential to inhibit the cell viability of liver cancer cells lines (HepG2) and lung cancer cell lines (A549).

Isolation and characterization of antimicrobial compounds in plant extracts against multidrug-resistant Acinetobacter baumannii.

PubMed

Miyasaki, Yoko; Rabenstein, John D; Rhea, Joshua; Crouch, Marie-Laure; Mocek, Ulla M; Kittell, Patricia Emmett; Morgan, Margie A; Nichols, Wesley Stephen; Van Benschoten, M M; Hardy, William David; Liu, George Y

2013-01-01

The number of fully active antibiotic options that treat nosocomial infections due to multidrug-resistant Acinetobacter baumannii (A. baumannii) is extremely limited. Magnolia officinalis, Mahonia bealei, Rabdosia rubescens, Rosa rugosa, Rubus chingii, Scutellaria baicalensis, and Terminalia chebula plant extracts were previously shown to have growth inhibitory activity against a multidrug-resistant clinical strain of A. baumannii. In this study, the compounds responsible for their antimicrobial activity were identified by fractionating each plant extract using high performance liquid chromatography, and determining the antimicrobial activity of each fraction against A. baumannii. The chemical structures of the fractions inhibiting >40% of the bacterial growth were elucidated by liquid chromatography/mass spectrometry analysis and nuclear magnetic resonance spectroscopy. The six most active compounds were identified as: ellagic acid in Rosa rugosa; norwogonin in Scutellaria baicalensis; and chebulagic acid, chebulinic acid, corilagin, and terchebulin in Terminalia chebula. The most potent compound was identified as norwogonin with a minimum inhibitory concentration of 128 µg/mL, and minimum bactericidal concentration of 256 µg/mL against clinically relevant strains of A. baumannii. Combination studies of norwogonin with ten anti-Gram negative bacterial agents demonstrated that norwogonin did not enhance the antimicrobial activity of the synthetic antibiotics chosen for this study. In conclusion, of all identified antimicrobial compounds, norwogonin was the most potent against multidrug-resistant A. baumannii strains. Further studies are warranted to ascertain the prophylactic and therapeutic potential of norwogonin for infections due to multidrug-resistant A. baumannii.

How gamma-rays and electron-beam irradiation would affect the antimicrobial activity of differently processed wild mushroom extracts?

PubMed

Alves, M J; Fernandes, Â; Barreira, J C M; Lourenço, I; Fernandes, D; Moura, A; Ribeiro, A R; Salgado, J; Antonio, A; Ferreira, I C F R

2015-03-01

The effects of irradiation (gamma-rays and electron-beams), up to 10 kGy, in the antimicrobial activity of mushroom species (Boletus edulis, Hydnum repandum, Macrolepiota procera and Russula delica) differently processed (fresh, dried, freeze) were evaluated. Clinical isolates with different resistance profiles from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal, were used as target micro-organisms. The mushrooms antimicrobial activity did not suffer significant changes that might compromise applying irradiation as a possible mushroom conservation technology. Two kGy dose (independently of using gamma-rays or electron-beams) seemed to be the most suitable choice to irradiate mushrooms. This study provides important results in antimicrobial activity of extracts prepared from irradiated mushroom species. © 2014 The Society for Applied Microbiology.

Isolation and characterization of Bacillus sp. GFP-2, a novel Bacillus strain with antimicrobial activities, from Whitespotted bamboo shark intestine.

PubMed

Wu, Jia; Xu, Guoqiang; Jin, Yangyang; Sun, Cong; Zhou, Li; Lin, Guodong; Xu, Rong; Wei, Ling; Fei, Hui; Wang, Dan; Chen, Jianqing; Lv, Zhengbing; Liu, Kuancheng

2018-05-22

The abuse of antibiotics and following rapidly increasing of antibiotic-resistant pathogens is the serious threat to our society. Natural products from microorganism are regarded as the important substitution antimicrobial agents of antibiotics. We isolated a new strain, Bacillus sp. GFP-2, from the Chiloscyllium plagiosum (Whitespotted bamboo shark) intestine, which showed great inhibitory effects on the growth of both Gram-positive and Gram-negative bacteria. Additionally, the growth of salmon was effectively promoted when fed with inactivated strain GFP-2 as the inhibition agent of pathogenic bacteria. The genes encoding antimicrobial peptides like LCI, YFGAP and hGAPDH and gene clusters for secondary metabolites and bacteriocins, such as difficidin, bacillibactin, bacilysin, surfactin, butirosin, macrolactin, bacillaene, fengycin, lanthipeptides and LCI, were predicted in the genome of Bacillus sp. GFP-2, which might be expressed and contribute to the antimicrobial activities of this strain. The gene encoding β-1,3-1,4-glucanase was successfully cloned from the genome and this protein was detected in the culture supernatant of Bacillus sp. GFP-2 by the antibody produced in rabbit immunized with the recombinant β-1,3-1,4-glucanase, indicating that this strain could express β-1,3-1,4-glucanase, which might partially contribute to its antimicrobial activities. This study can enhance a better understanding of the mechanism of antimicrobial activities in genus Bacillus and provide a useful material for the biotechnology study in antimicrobial agent development.

Identification of milk proteins enhancing the antimicrobial activity of lactoferrin and lactoferricin.

PubMed

Murata, M; Wakabayashi, H; Yamauchi, K; Abe, F

2013-08-01

Lactoferrin (LF) is known as an iron-binding antimicrobial protein present in exocrine secretions such as milk and releases the potent antimicrobial peptide lactoferricin (LFcin) by hydrolysis with pepsin. The antimicrobial activity of LF and LFcin has been studied well; however, their cooperative action with other milk proteins remains to be elucidated. In this study, we identified milk proteins enhancing the antimicrobial activity of bovine LF and LFcin against gram-negative bacteria, gram-positive bacteria, and fungi. As the target fraction, we isolated a minor milk protein fraction around 15 kDa, which was identified as bovine RNase 5 (angiogenin-1), RNase 4, and angiogenin-2 by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. As these proteins are collectively known as the RNase A family, we referred to the target protein fraction as milk RNase of 15 kDa (MR15). The number of colony-forming units of Escherichia coli and other pathogenic microorganisms with the addition of MR15 to LF (MR15:LF ratio=16:1,000) was dramatically lowered than that with LF alone. On the other hand, MR15 itself did not show any reductions in the number of colony-forming units at the concentrations tested. Similarly, the antimicrobial activities of LFcin against various microorganisms were significantly enhanced by the addition of MR15. These results suggest that LF and MR15 may be concomitantly acting antimicrobial agents in milk. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Phytochemical and antimicrobial study of an antidiabetic plant: Scoparia dulcis L.

PubMed

Latha, M; Ramkumar, K M; Pari, L; Damodaran, P N; Rajeshkannan, V; Suresh, T

2006-01-01

The antimicrobial and antifungal effects of different concentrations of chloroform/methanol fractions of Scoparia dulcis were investigated. The isolated fractions were tested against different bacteria like Salmonella typhii, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Proteus vulgaris and fungal strains such as Alternaria macrospora, Candida albicans, Aspergillus niger, and Fusarium oxysporum. The isolated fractions exhibited significant antimicrobial and antifungal activity against all the tested organisms compared with respective reference drugs. The isolated fractions of S. dulcis showed properties like antimicrobial and antifungal activities that will enable researchers in turn to look for application-oriented principles.

[The structure and antimicrobial activity of the partial degradation products of the antibiotic eremomycin].

PubMed

Berdnikova, T F; Lomakina, N N; Olsuf'eva, E N; Aleksandrova, L G; Potapova, N P; Rozynov, B V; Malkova, I V; Orlova, G I

1991-06-01

Antimicrobial activity of partial degradation products of eremomycin, a new glycopeptide antibiotic, was studied. The products formed by eremomycin deglycosylation (deseremosaminyl eremomycin, eremosaminyl aglycone and aglycone) and elimination of the chlorine atom from the molecule aglycone moiety (dechloroeremomycin). The spectral data in favour of the compounds structure are presented. It was found that partial degradation led to a decrease in the antimicrobial activity of the antibiotic. Dechloreremomycin had the highest activity among the products. Its MIC for the methicillin-resistant strains of Staphylococcus aureus was only twice as low as that of the initial antibiotic.

Pyrazole derived ultra-short antimicrobial peptidomimetics with potent anti-biofilm activity.

PubMed

Ahn, Mija; Gunasekaran, Pethaiah; Rajasekaran, Ganesan; Kim, Eun Young; Lee, Soo-Jae; Bang, Geul; Cho, Kun; Hyun, Jae-Kyung; Lee, Hyun-Ju; Jeon, Young Ho; Kim, Nam-Hyung; Ryu, Eun Kyoung; Shin, Song Yub; Bang, Jeong Kyu

2017-01-05

In this study, we report on the first chemical synthesis of ultra-short pyrazole-arginine based antimicrobial peptidomimetics derived from the newly synthesized N-alkyl/aryl pyrazole amino acids. Through the systematic tuning of hydrophobicity, charge, and peptide length, we identified the shortest peptide Py11 with the most potent antimicrobial activity. Py11 displayed greater antimicrobial activity against antibiotic-resistant bacteria, including MRSA, MDRPA, and VREF, which was approximately 2-4 times higher than that of melittin. Besides its higher selectivity (therapeutic index) toward bacterial cells than LL-37, Py11 showed highly increased proteolytic stability against trypsin digestion and maintained its antimicrobial activity in the presence of physiological salts. Interestingly, Py11 exhibited higher anti-biofilm activity against MDRPA compared to LL-37. The results from fluorescence spectroscopy and transmission electron microscopy (TEM) suggested that Py11 kills bacterial cells possibly by integrity disruption damaging the cell membrane, leading to the cytosol leakage and eventual cell lysis. Furthermore, Py11 displayed significant anti-inflammatory (endotoxin-neutralizing) activity by inhibiting LPS-induced production of nitric oxide (NO) and TNF-α. Collectively, our results suggest that Py11 may serve as a model compound for the design of antimicrobial and antisepsis agents. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Antimicrobial impact of the components of essential oil of Litsea cubeba from Taiwan and antimicrobial activity of the oil in food systems.

PubMed

Liu, Tai-Ti; Yang, Tsung-Shi

2012-05-01

Using natural additives to preserve foods has become popular due to consumer demands for nature and safety. Antimicrobial activity is one of the most important properties in many plant essential oils (EOs). The antimicrobial activity of the essential oil of Litsea cubeba (LC-EO) from Taiwan and the antimicrobial impact of individual volatile components in the oil on pathogens or spoilage microorganisms: Vibrio parahaemolyticus, Listeria monocytogenes, Lactobacillus plantarum, and Hansenula anomala in vitro, and the antimicrobial activity of the LC-EO against these organisms in food systems were studied. The "antimicrobial impact" (AI) is a new term that combines the effects of minimal microbicidal concentration (MMC) and quantity of an antimicrobial substance. The AI can quantitatively reflect the relative importance of individual components of the EO on the entire antimicrobial activity of the EO. The MMCs of the LC-EO against V. parahaemolyticus, L. monocytogenes, L. plantarum, and H. anomala were determined as 750, 750, 1500, and 375 μg/g, respectively in vitro. The MMCs of the LC-EO were 3000, 6000, and 12,000 μg/g for L. monocytogenes in tofu stored at 4 °C, 25 °C, and 37 °C, respectively. The temperature affected the bacterial growth which consequently influenced the MMCs of the LC-EO. The MMCs of the LC-EO were 3000, 6000, and 375 μg/g for Vibrio spp. in oysters, L. plantarum in orange-milk beverage, and H. anomala in soy sauce, respectively. Except for soy sauce, the food systems exhibited marked matrix effects on diminishing the antimicrobial activity of the LC-EO. Averagely, citral accounted for ca 70% of the total AI value for all the tested organisms, and the rest of the AI value of the LC-EO was determined by all the tested compounds (ca 4%) and the unidentified compounds (ca 26%). Copyright © 2012 Elsevier B.V. All rights reserved.

Antimicrobial activity of 9-O-acyl- and 9-O-benzoyl-substituted berberrubines.

PubMed

Hong, S W; Kim, S H; Jeun, J A; Lee, S J; Kim, S U; Kim, J H

2000-05-01

In the course of a structure-activity relationship study on berberrubine derivatives, a series of compounds bearing 9-O-acyl-(4-6) and 9-O-benzoyl- (7) substituents was synthesized with the expectation of increasing the antimicrobial activity. One of the berberrubine derivatives, 9-lauroylberberrubine chloride was the most active against Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Bacillus subtilis as well as the Gram-negative bacterium Klebsiella pneumoniae in comparison to berberine, the currently used antibiotic in clinic. This result suggested that the presence of lipophilic substituents of certain structures and sizes might be crucial for the optimal antimicrobial activity.

Contact Active Antimicrobial Coatings Prepared by Polymer Blending.

PubMed

Cuervo-Rodríguez, Rocío; López-Fabal, Fátima; Gómez-Garcés, José L; Muñoz-Bonilla, Alexandra; Fernández-García, Marta

2017-11-01

Herein, contact active antimicrobial films are prepared by simply blending cationic amphiphilic block copolymers with commercial polystyrene (PS). The copolymers are prepared by combining atom transfer radical polymerization and "click chemistry." A variety of copolymers are synthesized, and composed of a PS segment and an antimicrobial block bearing flexible side chain with thiazole and triazole groups, 4-(1-(2-(4-methylthiazol-5-yl)ethyl)-1H-1,2,3-triazol-4-yl) butyl methacrylate (TTBM). The length of the TTBM block is varied as well as the alkylating agent. Different films are prepared from N,N-dimethylformamide solution, containing variable PS-b-PTTBM/PS ratio: from 0 to 100 wt%. Remarkably, the blend films, especially those with 30 and 50 wt% of copolymers, exhibit excellent antimicrobial activities against Gram-positive, Gram-negative bacteria and fungi, even higher than films prepared exclusively from the cationic copolymers. Blends composed of 50 wt% of the copolymers present a more than 99.999% killing efficiency against the studied microorganisms. The better activity found in blends can be due to the higher roughness, which increases the surface area and consequently the contact with the microorganisms. These results demonstrate that the use of blends implies a reduction of the content of antimicrobial agent and also enhances the antimicrobial activity, providing new insights for the better designing of antimicrobial coatings. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Euterpe oleracea pulp extract: Chemical analyses, antibiofilm activity against Staphylococcus aureus, cytotoxicity and interference on the activity of antimicrobial drugs.

PubMed

Dias-Souza, Marcus Vinícius; Dos Santos, Renan Martins; Cerávolo, Isabela Penna; Cosenza, Gustavo; Ferreira Marçal, Pedro Henrique; Figueiredo, Flávio Jr Barbosa

2018-01-01

Euterpe oleracea (Açaí) fruit are widely consumed at the Brazilian Amazon region, and biological potentials such as immunomodulatory and antioxidant have been described for its extracts. However, its antimicrobial properties remain poorly investigated. Here, the antimicrobial and antibiofilm activities of the methanolic extract of an artisanally-manufactured açaí pulp (MEAP) were evaluated against clinical isolates of Staphylococcus aureus. Besides, MEAP interference on the activity of antimicrobial drugs of clinical relevance was explored, and its cytotoxicity against hepatocellular carcinoma cells (HepG2) was investigated. Biochemical and physicochemical properties of the pulp were investigated, and the presence of polyphenols on the extract was confirmed. For the first time, we report that the methanolic extract of açaí pulp is effective against planktonic cells and biofilms of S. aureus, and also decreased the proliferation of HepG2 cells. Statistically significant synergism was observed when the extract was combined to the tested antimicrobials except for erythromycin, and all biochemical and physicochemical parameters ranged within the accepted values established by the Brazilian legislation. Our data open doors for more studies on the antimicrobial activity of phytomolecules isolated from Euterpe oleracea extracts, and also for its combined use with antimicrobial drugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative Study of Surface-Active Properties and Antimicrobial Activities of Disaccharide Monoesters

PubMed Central

Zhang, Xi; Song, Fei; Taxipalati, Maierhaba; Wei, Wei; Feng, Fengqin

2014-01-01

The objective of this research was to determine the effect of sugar or fatty acid in sugar ester compounds on the surface-active properties and antimicrobial activities of these compounds. Disaccharides of medium-chain fatty acid monoesters were synthesized through transesterifications by immobilized lipase (Lipozyme TLIM) to yield nine monoesters for subsequent study. Their antimicrobial activities were investigated using three pathogenic microorganisms: Staphylococcus aureus, Escherichia coli O157:H7 and Candida albicans. Their surface-active properties including air–water surface tension, critical micelle concentration, and foaming and emulsion power and stability were also studied. The results showed that all of the tested monoesters were more effective against Staphylococcus aureus (Gram-positive bacterium) than against Escherichia coli O157:H7 (Gram-negative bacterium). The results demonstrated that the carbon chain length was the most important factor influencing the surface properties, whereas degree of esterification and hydrophilic groups showed little effect. PMID:25531369

The effect of standard heat and filtration processing procedures on antimicrobial activity and hydrogen peroxide levels in honey.

PubMed

Chen, Cuilan; Campbell, Leona T; Blair, Shona E; Carter, Dee A

2012-01-01

There is increasing interest in the antimicrobial properties of honey. In most honey types, antimicrobial activity is due to the generation of hydrogen peroxide (H(2)O(2)), but this can vary greatly among samples. Honey is a complex product and other components may modulate activity, which can be further affected by commercial processing procedures. In this study we examined honey derived from three native Australian floral sources that had previously been associated with H(2)O(2)-dependent activity. Antibacterial activity was seen in four red stringybark samples only, and ranged from 12 to 21.1% phenol equivalence against Staphylococcus aureus. Antifungal activity ranged from MIC values of 19-38.3% (w/v) against Candida albicans, and all samples were significantly more active than an osmotically equivalent sugar solution. All honey samples were provided unprocessed and following commercial processing. Processing was usually detrimental to antimicrobial activity, but occasionally the reverse was seen and activity increased. H(2)O(2) levels varied from 0 to 1017 μM, and although samples with no H(2)O(2) had little or no antimicrobial activity, some samples had relatively high H(2)O(2) levels yet no antimicrobial activity. In samples where H(2)O(2) was detected, the correlation with antibacterial activity was greater in the processed than in the unprocessed samples, suggesting other factors present in the honey influence this activity and are sensitive to heat treatment. Antifungal activity did not correlate with the level of H(2)O(2) in honey samples, and overall it appeared that H(2)O(2) alone was not sufficient to inhibit C. albicans. We conclude that floral source and H(2)O(2) levels are not reliable predictors of the antimicrobial activity of honey, which currently can only be assessed by standardized antimicrobial testing. Heat processing should be reduced where possible, and honey destined for medicinal use should be retested post-processing to ensure that activity levels have not changed.

The effect of standard heat and filtration processing procedures on antimicrobial activity and hydrogen peroxide levels in honey

PubMed Central

Chen, Cuilan; Campbell, Leona T.; Blair, Shona E.; Carter, Dee A.

2012-01-01

There is increasing interest in the antimicrobial properties of honey. In most honey types, antimicrobial activity is due to the generation of hydrogen peroxide (H2O2), but this can vary greatly among samples. Honey is a complex product and other components may modulate activity, which can be further affected by commercial processing procedures. In this study we examined honey derived from three native Australian floral sources that had previously been associated with H2O2-dependent activity. Antibacterial activity was seen in four red stringybark samples only, and ranged from 12 to 21.1% phenol equivalence against Staphylococcus aureus. Antifungal activity ranged from MIC values of 19–38.3% (w/v) against Candida albicans, and all samples were significantly more active than an osmotically equivalent sugar solution. All honey samples were provided unprocessed and following commercial processing. Processing was usually detrimental to antimicrobial activity, but occasionally the reverse was seen and activity increased. H2O2 levels varied from 0 to 1017 μM, and although samples with no H2O2 had little or no antimicrobial activity, some samples had relatively high H2O2 levels yet no antimicrobial activity. In samples where H2O2 was detected, the correlation with antibacterial activity was greater in the processed than in the unprocessed samples, suggesting other factors present in the honey influence this activity and are sensitive to heat treatment. Antifungal activity did not correlate with the level of H2O2 in honey samples, and overall it appeared that H2O2 alone was not sufficient to inhibit C. albicans. We conclude that floral source and H2O2 levels are not reliable predictors of the antimicrobial activity of honey, which currently can only be assessed by standardized antimicrobial testing. Heat processing should be reduced where possible, and honey destined for medicinal use should be retested post-processing to ensure that activity levels have not changed. PMID:22866051

Caseins from bovine colostrum and milk strongly bind piscidin-1, an antimicrobial peptide from fish.

PubMed

Kütt, Mary-Liis; Stagsted, Jan

2014-09-01

A model system of bovine colostrum and piscidin, a fish-derived antimicrobial peptide, was developed to study potential interactions of antimicrobial peptides in colostrum. We did not detect any antimicrobial activity of colostrum using the radial plate diffusion assay; in fact colostrum completely abrogated activity of added piscidin. This could not be explained by degradation of piscidin by colostrum, which was less than ten percent. We found that colostrum even protected piscidin against degradation by added proteases. We further observed that colostrum and milk rapidly quenched the fluorescence of fluorescein-piscidin but not that of fluorescein. This effect was not seen with BSA and the specific quenching of fluorescein-piscidin by colostrum was saturably inhibited with unlabeled piscidin. Size exclusion chromatography indicated that fluorescein-piscidin bound to casein micelles with no apparent binding to IgG or whey proteins. Further, addition of pure caseins was able to quench fluorescence of fluorescein-piscidin and to inhibit the antimicrobial activity of piscidin. The interaction between caseins and piscidin could be dissociated by guanidine hydrochloride and recovered piscidin had antimicrobial activity against bacteria. Based on our results we propose that caseins could be carriers for antimicrobial peptides in colostrum and milk. Copyright © 2014 Elsevier B.V. All rights reserved.

Investigation on the effect of RF air plasma and neem leaf extract treatment on the surface modification and antimicrobial activity of cotton fabric

NASA Astrophysics Data System (ADS)

Vaideki, K.; Jayakumar, S.; Rajendran, R.; Thilagavathi, G.

2008-02-01

A thorough investigation on the antimicrobial activity of RF air plasma and azadirachtin (neem leaf extract) treated cotton fabric has been dealt with in this paper. The cotton fabric was given a RF air plasma treatment to improve its hydrophilicity. The process parameters such as electrode gap, time of exposure and RF power have been varied to study their effect in improving the hydrophilicity of the cotton fabric and they were optimized based on the static immersion test results. The neem leaf extract (azadirachtin) was applied on fabric samples to impart antimicrobial activity. The antimicrobial efficacy of the samples have been analysed and compared with the efficacy of the cotton fabric treated with the antimicrobial finish alone. The investigation reveals that the RF air plasma has modified the surface of the fabric, which in turn increased the antimicrobial activity of the fabric when treated with azadirachtin. The surface modification due to RF air plasma treatment has been analysed by comparing the FTIR spectra of the untreated and plasma treated samples. The molecular interaction between the fabric, azadirachtin and citric acid which was used as a cross linking agent to increase the durability of the antimicrobial finish has also been analysed using FTIR spectra.

Development and evaluation of antimicrobial activated carbon fiber filters using Sophora flavescens nanoparticles.

PubMed

Sim, Kyoung Mi; Kim, Kyung Hwan; Hwang, Gi Byoung; Seo, SungChul; Bae, Gwi-Nam; Jung, Jae Hee

2014-09-15

Activated carbon fiber (ACF) filters have a wide range of applications, including air purification, dehumidification, and water purification, due to their large specific surface area, high adsorption capacity and rate, and specific surface reactivity. However, when airborne microorganisms such as bacteria and fungi adhere to the carbon substrate, ACF filters can become a source of microbial contamination, and their filter efficacy declines. Antimicrobial treatments are a promising means of preventing ACF bio-contamination. In this study, we demonstrate the use of Sophora flavescens in antimicrobial nanoparticles coated onto ACF filters. The particles were prepared using an aerosol process consisting of nebulization-thermal drying and particle deposition. The extract from S. flavescens is an effective, natural antimicrobial agent that exhibits antibacterial activity against various pathogens. The efficiency of Staphylococcus epidermidis inactivation increased with the concentration of S. flavescens nanoparticles in the ACF filter coating. The gas adsorption efficiency of the coated antimicrobial ACF filters was also evaluated using toluene. The toluene-removal capacity of the ACF filters remained unchanged while the antimicrobial activity was over 90% for some nanoparticle concentrations. Our results provide a scientific basis for controlling both bioaerosol and gaseous pollutants using antimicrobial ACF filters coated with S. flavescens nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

Antimicrobial activity of tempeh gembus hydrolyzate

NASA Astrophysics Data System (ADS)

Noviana, A.; Dieny, F. F.; Rustanti, N.; Anjani, G.; Afifah, D. N.

2018-02-01

Tropical disease can be prevented by consumming fermented foods that have antimicrobial activity. One of them is tempeh gembus that has short shelf life. It can be overcome by processing it into hydrolyzate. This study aimed to determine antimicrobial activity of tempeh gembus hydrolyzate. Tempeh gembus was made of local soybean from Grobogan. They were added 5,000 ppm, 8,000 ppm, and 10,000 ppm of bromelain enzyme (TGH BE). Antimicrobial effects of TGH BE were tested against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Steptococcus mutans. Antimicrobial test was carried out using Kirby-Bauer Disc Diffussion method. Soluble protein test used Bradford method. The largest inhibition zone against S. aureus and S. mutans were shown by TGH BE 8,000 ppm, 0.89±0.53 mm and 2.40±0.72 mm. The largest inhibition zone of B. subtilis, 7.33±2,25 mm, was shown by TGH BE 5,000 ppm. There wasn’t antimicrobial effect of TGH BE against E. coli. There weren’t significant differences of soluble protein (P=0.293) and the inhibition zones againt S. aureus (P = 0.967), E. coli (P = 1.000), B. subtilis (P = 0.645), S. mutans (P=0.817) of all treatments. There were antimicrobial activities of TGH BE against S. aureus, B. subtilis, and S. mutans.

Antimicrobial activity and safety evaluation of peptides isolated from the hemoglobin of chickens.

PubMed

Hu, Fengjiao; Wu, Qiaoxing; Song, Shuang; She, Ruiping; Zhao, Yue; Yang, Yifei; Zhang, Meikun; Du, Fang; Soomro, Majid Hussain; Shi, Ruihan

2016-12-05

Hemoglobin is a rich source of biological peptides. As a byproduct and even wastewater of poultry-slaughtering facilities, chicken blood is one of the most abundant source of hemoglobin. In this study, the chicken hemoglobin antimicrobial peptides (CHAP) were isolated and the antimicrobial and bactericidal activities were tested by the agarose diffusion assay, minimum inhibitory concentration (MIC) analysis, minimal bactericidal concentration (MBC) analysis, and time-dependent inhibitory and bactericidal assays. The results demonstrated that CHAP had potent and rapid antimicrobial activity against 19 bacterial strains, including 9 multidrug-resistant bacterial strains. Bacterial biofilm and NaCl permeability assays, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were further performed to detect the mechanism of its antimicrobial effect. Additionally, CHAP showed low hemolytic activity, embryo toxicity, and high stability in different temperatures and animal plasma. CHAP may have great potential for expanding production and development value in animal medication, the breeding industry and environment protection.

Synthesis, characterization and anti-microbial evaluation of Cu(II), Ni(II), Pt(II) and Pd(II) sulfonylhydrazone complexes; 2D-QSAR analysis of Ni(II) complexes of sulfonylhydrazone derivatives

NASA Astrophysics Data System (ADS)

Özbek, Neslihan; Alyar, Saliha; Alyar, Hamit; Şahin, Ertan; Karacan, Nurcan

2013-05-01

Copper(II), nickel(II), platinum(II) and palladium(II) complexes with 2-hydroxy-1-naphthaldehyde-N-methylpropanesulfonylhydrazone (nafpsmh) derived from propanesulfonic acid-1-methylhydrazide (psmh) were synthesized, their structure were identified, and antimicrobial activity of the compounds was screened against three Gram-positive and three Gram-negative bacteria. The results of antimicrobial studies indicate that Pt(II) and Pd(II) complexes showed the most activity against all bacteria. The crystal structure of 2-hydroxy-1-naphthaldehyde-N-methylpropanesulfonylhydrazone (nafpsmh) was also investigated by X-ray analysis. A series of Ni(II) sulfonyl hydrazone complexes (1-33) was synthesized and tested in vitro against Escherichia coli and Staphylococcus aureus. Their antimicrobial activities were used in the QSAR analysis. Four-parameter QSAR models revealed that nucleophilic reaction index for Ni and O atoms, and HOMO-LUMO energy gap play key roles in the antimicrobial activity.

A vapour phase assay for evaluating the antimicrobial activities of essential oils against bovine respiratory bacterial pathogens.

PubMed

Amat, S; Baines, D; Alexander, T W

2017-12-01

The objectives of this study were to develop a new assay for the evaluation of the antimicrobial activities of essential oils (EOs) in vapour phase and to demonstrate the antimicrobial activities of commercial EOs against BRPs. To achieve the first objective, a microtube cap containing 100 μl of EO was embedded in an agar plate. An agar plug (diameter 13 mm) inoculated with a bacterial suspension containing10 8  CFU per ml was then placed over the cap and incubated at 37°C for 24 h. Subsequently, bacteria were recovered from the agar plug by immersion in 5 ml of broth for 10 min, followed by vortexing for 30 s, and the broths were then plated for enumeration. To demonstrate the usefulness of the assay, nine commercial EOs derived from the following specific plants: ajowan, carrot seed, cinnamon leaf, citronella, fennel, ginger grass, lavender, rosemary and thyme were first evaluated for their vapour phase antimicrobial activities against Mannheimia haemolytica serotype 1. Selected EOs were further tested against Pasteurella multocida and Histophilus somni. The EOs of ajowan, thyme and cinnamon leaf completely or partially inhibited BRPs growth. This new assay provided reproducible results on the vapour phase antimicrobial activities of EOs against BRPs. These results support further study of EOs as a potential mitigation strategy against BRPs. In this study, we present a new vapour phase assay for evaluating the antimicrobial activities of essential oils (EO) against bovine respiratory pathogens (BRPs). Using this assay, we identified EOs, such as ajowan, thyme and cinnamon leaf, that can effectively inhibit growth of the BRPs Mannheimia haemolytica serotype 1, Pasteurella multocida and Histophilus somni. This is the first study to demonstrate the vapour phase antimicrobial activity of EOs against BRPs. © 2017 Her Majesty the Queen in Right of Canada. © 2017 The Society for Applied Microbiology Reproduced with the permission of the Minister of the Department of Agriculture and Agri-Food Canada.

Antimicrobial and water-triggered release characteristics of a copper sulfate-polyvinyl acetate adhesive composite

NASA Astrophysics Data System (ADS)

De Jesus, A. P. O.; Roxas-Villanueva, R. M. L.; Herrera, M. U.

2017-05-01

Water-triggered release of antimicrobial solutions is advantageous in inhibiting the growth of bacteria and fungi in moist and wet environments. In this study, we fabricated a composite, by mixing polyvinyl acetate adhesive with copper sulfate solution, which exhibits antimicrobial activities against bacteria. Polyvinyl acetate adhesive serves as the binder and water soluble substance while copper sulfate serves as the antimicrobial agent. The composite was coated in an acetate film and air-dried. To monitor the rate of release of copper ions, the composite was submerged in water and the conductivity was measured. The conductivity saturation time was determined. The composite showed antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive).

Dissection of the antimicrobial and hemolytic activity of Cap18: Generation of Cap18 derivatives with enhanced specificity.

PubMed

Ebbensgaard, Anna; Mordhorst, Hanne; Overgaard, Michael Toft; Aarestrup, Frank Møller; Hansen, Egon Bech

2018-01-01

Due to the rapid emergence of resistance to classical antibiotics, novel antimicrobial compounds are needed. It is desirable to selectively kill pathogenic bacteria without targeting other beneficial bacteria in order to prevent the negative clinical consequences caused by many broad-spectrum antibiotics as well as reducing the development of antibiotic resistance. Antimicrobial peptides (AMPs) represent an alternative to classical antibiotics and it has been previously demonstrated that Cap18 has high antimicrobial activity against a broad range of bacterial species. In this study we report the design of a positional scanning library consisting of 696 Cap18 derivatives and the subsequent screening for antimicrobial activity against Y. ruckeri, A. salmonicida, S. Typhimurium and L. lactis as well as for hemolytic activity measuring the hemoglobin release of horse erythrocytes. We show that the hydrophobic face of Cap18, in particular I13, L17 and I24, is essential for its antimicrobial activity against S. Typhimurium, Y. ruckeri, A. salmonicida, E. coli, P. aeruginosa, L. lactis, L. monocytogenes and E. faecalis. In particular, Cap18 derivatives harboring a I13D, L17D, L17P, I24D or I24N substitution lost their antimicrobial activity against any of the tested bacterial strains. In addition, we were able to generate species-specific Cap18 derivatives by particular amino acid substitutions either in the hydrophobic face at positions L6, L17, I20, and I27, or in the hydrophilic face at positions K16 and K18. Finally, our data showed the proline residue at position 29 to be essential for the inherent low hemolytic activity of Cap18 and that substitution of the residues K16, K23, or G21 by any hydrophobic residues enhances the hemolytic activity. This study demonstrates the potential of generating species-specific AMPs for the selective elimination of bacterial pathogens.

Covalent Dimer Species of β-Defensin Defr1 Display Potent Antimicrobial Activity against Multidrug-Resistant Bacterial Pathogens▿

PubMed Central

Taylor, Karen; McCullough, Bryan; Clarke, David J.; Langley, Ross J.; Pechenick, Tali; Hill, Adrian; Campopiano, Dominic J.; Barran, Perdita E.; Dorin, Julia R.; Govan, John R. W.

2007-01-01

Beta defensins comprise a family of cationic, cysteine-rich antimicrobial peptides, predominantly expressed at epithelial surfaces. Previously we identified a unique five-cysteine defensin-related peptide (Defr1) that, when synthesized, is a mixture of dimeric isoforms and exhibits potent antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa. Here we report that Defr1 displays antimicrobial activity against an extended panel of multidrug-resistant nosocomial pathogens for which antimicrobial treatment is limited or nonexistent. Defr1 fractions were collected by high-pressure liquid chromatography and analyzed by gel electrophoresis and mass spectrometry. Antimicrobial activity was initially investigated with the type strain Pseudomonas aeruginosa PAO1. All fractions tested displayed equivalent, potent antimicrobial activity levels comparable with that of the unfractionated Defr1. However, use of an oxidized, monomeric six-cysteine analogue (Defr1 Y5C), or of reduced Defr1, gave diminished antimicrobial activity. These results suggest that the covalent dimer structure of Defr1 is crucial to antimicrobial activity; this hypothesis was confirmed by investigation of a synthetic one-cysteine variant (Defr1-1cys). This gave an activity profile similar to that of synthetic Defr1 but only in an oxidized, dimeric form. Thus, we have shown that covalent, dimeric molecules based on the Defr1 β-defensin sequence demonstrate antimicrobial activity even in the absence of the canonical cysteine motif. PMID:17353239

Optimized dispersion of ZnO nanoparticles and antimicrobial activity against foodborne pathogens and spoilage microorganisms

NASA Astrophysics Data System (ADS)

Espitia, Paula Judith Perez; Soares, Nilda de Fátima Ferreira; Teófilo, Reinaldo F.; Vitor, Débora M.; Coimbra, Jane Sélia dos Reis; de Andrade, Nélio José; de Sousa, Frederico B.; Sinisterra, Rubén D.; Medeiros, Eber Antonio Alves

2013-01-01

Single primary nanoparticles of zinc oxide (nanoZnO) tend to form particle collectives, resulting in loss of antimicrobial activity. This work studied the effects of probe sonication conditions: power, time, and the presence of a dispersing agent (Na4P2O7), on the size of nanoZnO particles. NanoZnO dispersion was optimized by response surface methodology (RSM) and characterized by the zeta potential (ZP) technique. NanoZnO antimicrobial activity was investigated at different concentrations (1, 5, and 10 % w/w) against four foodborne pathogens and four spoilage microorganisms. The presence of the dispersing agent had a significant effect on the size of dispersed nanoZnO. Minimum size after sonication was 238 nm. An optimal dispersion condition was achieved at 200 W for 45 min of sonication in the presence of the dispersing agent. ZP analysis indicated that the ZnO nanoparticle surface charge was altered by the addition of the dispersing agent and changes in pH. At tested concentrations and optimal dispersion, nanoZnO had no antimicrobial activity against Pseudomonas aeruginosa, Lactobacillus plantarum, and Listeria monocytogenes. However, it did have antimicrobial activity against Escherichia coli, Salmonella choleraesuis, Staphylococcus aureus, Saccharomyces cerevisiae, and Aspergillus niger. Based on the exhibited antimicrobial activity of optimized nanoZnO against some foodborne pathogens and spoilage microorganisms, nanoZnO is a promising antimicrobial for food preservation with potential application for incorporation in polymers intended as food-contact surfaces.

Essential oil of the leaves of Ricinus communis L.: in vitro cytotoxicity and antimicrobial properties.

PubMed

Zarai, Zied; Ben Chobba, Ines; Ben Mansour, Riadh; Békir, Ahmed; Gharsallah, Néji; Kadri, Adel

2012-08-13

The aim of the present study was to appraise the antimicrobial activity of Ricinus communis L. essential oil against different pathogenic microorganisms and the cytotoxic activity against HeLa cell lines. The agar disk diffusion method was used to study the antibacterial activity of Ricinus communis L. essential oil against 12 bacterial and 4 fungi strains. The disc diameters of zone of inhibition (DD), the minimum inhibitory concentrations (MIC) and the concentration inhibiting 50% (IC50) were investigated to characterize the antimicrobial activities of this essential oil. The in vitro cytotoxicity of Ricinus communis L. essential oil was examined using a modified MTT assay; the viability and the IC50 were used to evaluate this test. The essential oil from the leaves of Ricinus communis L. was analyzed by GC-MS and bioassays were carried out. Five constituents of the oil were identified by GC-MS. The antimicrobial activity of the oil was investigated in order to evaluate its efficacy against twelve bacteria and four fungi species, using disc diffusion and minimum inhibitory concentration methods. The essential oil showed strong antimicrobial activity against all microorganisms tested with higher sensitivity for Bacillus subtilis, Staphylococcus aureus and Enterobacter cloacae. The cytotoxic and apoptotic effects of the essential oil on HeLa cell lines were examined by MTT assay. The cytotoxicity of the oil was quite strong with IC50 values less than 2.63 mg/ml for both cell lines. The present study showed the potential antimicrobial and anticarcinogenic properties of the essential oil of Ricinus communis L., indicating the possibilities of its potential use in the formula of natural remedies for the topical treatment of infections.

Anti-Inflammatory and Antimicrobial Properties of Flavonoids from Heliotropium subulatum Exudate.

PubMed

Singh, Bharat; Sharma, Ram A

2015-01-01

Heliotropium subulatum is an erect or procumbent perennial herb; leaves contain foliar trichomes and its resinous exudate is used in traditional medicine. The anti-inflammatory activity of dichloromethane fraction and isolated flavonoids was evaluated by using carrageenan and CFA-induced paw oedema models. Similarly, the disc diffusion and microdilution methods were used for the assessment of antimicrobial activity. Five isolated flavonoids were investigated for their antiinflammatory and antimicrobial activities. Eriodictyol demonstrated maximum anti-inflammatory activity (53.09%) at 30.0 mg/kg dose on 6(th) h and similarly, it inhibited the CFA-induced arthritis swelling (41.84%) with 30.0 mg/kg dose on 8(th) day respectively. As per disc diffusion and microdilution methods used for antimicrobial activity determination, the pinocembrin was found to be most active against Staphylococcus aureus (IZ=27±0.7 mm, 08 μg/ml dose) and Candida albicans (IZ=17±0.9 mm; 12 μg/ml dose). These investigated results revealed that the eriodictyol and pinocembrin showed significant anti-inflammatory and antimicrobial activities. Further studies which aimed to investigate the mechanism of action of these isolated flavonoids in the treatment of inflammations and various types of infections have been initiated.

The Genus Artemisia: A 2012–2017 Literature Review on Chemical Composition, Antimicrobial, Insecticidal and Antioxidant Activities of Essential Oils

PubMed Central

Singh, Pooja

2017-01-01

Essential oils of aromatic and medicinal plants generally have a diverse range of activities because they possess several active constituents that work through several modes of action. The genus Artemisia includes the largest genus of family Asteraceae has several medicinal uses in human and plant diseases aliments. Extensive investigations on essential oil composition, antimicrobial, insecticidal and antioxidant studies have been conducted for various species of this genus. In this review, we have compiled data of recent literature (2012–2017) on essential oil composition, antimicrobial, insecticidal and antioxidant activities of different species of the genus Artemisia. Regarding the antimicrobial and insecticidal properties we have only described here efficacy of essential oils against plant pathogens and insect pests. The literature revealed that 1, 8-cineole, beta-pinene, thujone, artemisia ketone, camphor, caryophyllene, camphene and germacrene D are the major components in most of the essential oils of this plant species. Oils from different species of genus Artemisia exhibited strong antimicrobial activity against plant pathogens and insecticidal activity against insect pests. However, only few species have been explored for antioxidant activity. PMID:28930281

Tolerance of dormant and active cells in Pseudomonas aeruginosa PA01 biofilm to antimicrobial agents.

PubMed

Kim, Jaeeun; Hahn, Ji-Sook; Franklin, Michael J; Stewart, Philip S; Yoon, Jeyong

2009-01-01

The aim of the study was to determine the susceptibility of active and dormant cell populations from Pseudomonas aeruginosa biofilms to non-antibiotic antimicrobial agents such as chlorine, hydrogen peroxide and silver ions in comparison with antibiotics. Active cells in colony biofilm were differentially labelled by induction of a green fluorescent protein (GFP). Active and dormant cells were sorted in phosphate buffered solution by flow cytometry. Reductions in viability were determined with plate counts. The spatial pattern of metabolic activity in colony biofilm was verified, and the active and dormant cells were successfully sorted according to the GFP intensity. Active cells had bigger cell size and higher intracellular density than dormant cells. While dormant cells were more tolerant to tobramycin and silver ions, active cells were more tolerant to chlorine. Metabolically active cells contain denser intracellular components that can react with highly reactive oxidants such as chlorine, thereby reducing the available concentrations of chlorine. In contrast, the concentrations of silver ions and hydrogen peroxide were constant during treatment. Aerobically grown stationary cells were significantly more tolerant to chlorine unlike other antimicrobial agents. Chlorine was more effective in inactivation of metabolically inactive dormant cells and also more effective under anaerobic conditions. The high oxidative reactivity and rapid decay of chlorine might influence the different antimicrobial actions of chlorine compared with antibiotics. This study contributes to understanding the effects of dormancy and the presence of oxygen on the susceptibility of P. aeruginosa biofilm to a wide range of antimicrobial agents.

Antimicrobial activity of filamentous fungi isolated from highly antibiotic-contaminated river sediment

PubMed Central

Svahn, K. Stefan; Göransson, Ulf; El-Seedi, Hesham; Bohlin, Lars; Larsson, D.G. Joakim; Olsen, Björn; Chryssanthou, Erja

2012-01-01

Background Filamentous fungi are well known for their production of substances with antimicrobial activities, several of which have formed the basis for the development of new clinically important antimicrobial agents. Recently, environments polluted with extraordinarily high levels of antibiotics have been documented, leading to strong selection pressure on local sentinel bacterial communities. In such microbial ecosystems, where multidrug-resistant bacteria are likely to thrive, it is possible that certain fungal antibiotics have become less efficient, thus encouraging alternative strategies for fungi to compete with bacteria. Methods In this study, sediment of a highly antibiotic-contaminated Indian river was sampled in order to investigate the presence of cultivable filamentous fungi and their ability to produce substances with antimicrobial activity. Results Sixty one strains of filamentous fungi, predominantly various Aspergillus spp. were identified. The majority of the Aspergillus strains displayed antimicrobial activity against methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase-producing Escherichia coli, vancomycin-resistant Enterococcus faecalis and Candida albicans. Bioassay-guided isolation of the secondary metabolites of A. fumigatus led to the identification of gliotoxin. Conclusion This study demonstrated proof of principle of using bioassay-guided isolation for finding bioactive molecules. PMID:22957125

Royal Jelly: An ancient remedy with remarkable antibacterial properties.

PubMed

Fratini, Filippo; Cilia, Giovanni; Mancini, Simone; Felicioli, Antonio

2016-11-01

Royal Jelly (RJ), a honeybee hypopharyngeal gland secretion of young nurse and an exclusive nourishment for bee queen, has been used since ancient times for care and human health and it is still very important in traditional and folkloristic medicine, especially in Asia within the apitherapy. Recently, RJ and its protein and lipid components have been subjected to several investigations on their antimicrobial activity due to extensive traditional uses and for a future application in medicine. Antimicrobial activities of crude Royal Jelly, Royalisin, 10-hydroxy-2-decenoic acid, Jelleines, Major Royal Jelly Proteins against different bacteria have been reported. All these beehive products showed antimicrobial activities that lead their potential employment in several fields as natural additives. RJ and its derived compounds show a highest activity especially against Gram positive bacteria. The purpose of this Review is to summarize the results of antimicrobial studies of Royal Jelly following the timescale of the researches. From the first scientific applications to the isolation of the single components in order to better understand its application in the past years and propose an employment in future studies as a natural antimicrobial agent. Copyright © 2016 Elsevier GmbH. All rights reserved.

Anion effects on anti-microbial activity of poly[1-vinyl-3-(2-sulfoethyl imidazolium betaine)].

PubMed

Garg, Godawari; Chauhan, Ghanshyam S; Gupta, Reena; Ahn, J-H

2010-04-01

Recent investigations in the anti-microbial properties of the functional polymers are predominantly focused on the structure of the cationic moieties. In the present study, we investigated that the nature of the anion present in polysulfobetaines affects activity against certain microorganisms and their anti-microbial properties have been rationalized in terms of the structure-activity relationship. Vinyl imidazolium-based polysulfobetaines were prepared by the quaternization of poly(N-vinyl imidazole) with sodium salt of 2-bromo ethanesulfonic acid. The bromide counter anion of the resulting polymer was exchanged with different anions to generate a series of polymers. These were characterized by FTIR, DSC, XRD, SEM, elemental analysis (C, H, N and S) and viscosity measurements. The anti-microbial activity studies were carried against three fungi (Aspergillus niger, Byssochlamys fulva and Mucor circenelliods) and two bacteria (Bacillus coagulans BTS-3 and Pseudomonas aeruginosa BTS-2). The nature of the anion affects the structure of polysulfobetaine by realignment of polymer chains. The anion-dependent anti-microbial properties of polysulfobetaines result from the interaction of the microbes at the polymer interface. Copyright 2009 Elsevier Inc. All rights reserved.

Potential of Piper betle extracts on inhibition of oral pathogens.

PubMed

Phumat, Pimpak; Khongkhunthian, Sakornrat; Wanachantararak, Phenphichar; Okonogi, Siriporn

2017-01-01

In the present study, antimicrobial activity of Piper betle crude ethanol extract against 4 strains of oral pathogens; Candida albicans DMST 8684, C. albicans DMST 5815, Streptococcus gordonii DMST 38731 and Streptococcus mutans DMST 18777 was compared with other medicinal plants. P. betle showed the strongest antimicrobial activity against all tested strains. Fractionated extracts of P. betle using hexane, ethyl acetate, and ethanol, respectively, were subjected to antimicrobial assay. The result revealed that the fractionated extract from ethyl acetate (F-EtOAc) possessed the strongest antimicrobial activity against all tested strains. Its inhibition zones against those pathogens were 23.00 ± 0.00, 24.33 ± 0.58, 12.50 ± 0.70 and 11.00 ± 0.00 mm, respectively and its minimum inhibitory concentrations were 0.50, 1.00, 0.50 and 1.00 mg/mL, respectively. Interestingly, the minimum concentration to completely kill those pathogens was the same for all strains and found to be 2.00 mg/mL. Killing kinetic study revealed that the activity of F-EtOAc was dose dependent. HPLC chromatograms of P. betle extracts were compared with its antimicrobial activity. An obvious peak at a retention time of 4.11 min was found to be a major component of F-EtOAc whereas it was a minor compound in the other extracts. This peak was considered to be an active compound of P. betle as it was consistent with the antimicrobial activity of F-EtOAc, the most potential extract against the tested pathogens. It is suggested that F-EtOAc is a promising extract of P. betle for inhibition of oral pathogens. Separation and structure elucidation of the active compound of this extract will be further investigated.

Antimicrobial and antiplasmid activities of essential oils.

PubMed

Schelz, Zsuzsanna; Molnar, Joseph; Hohmann, Judit

2006-06-01

The antimicrobial and antiplasmid activities of essential oils (orange oil, eucalyptus oil, fennel oil, geranium oil, juniper oil, peppermint oil, rosemary oil, purified turpentine oil, thyme oil, Australian tea tree oil) and of menthol, the main component of peppermint oil, were investigated. The antimicrobial activities were determined on the Gram (+) Staphylococcus epidermidis and the Gram (-) Escherichia coli F'lac K12 LE140, and on two yeast Saccharomyces cerevisiae 0425 delta/1 and 0425 52C strains. The antiplasmid activities were investigated on E. coli F'lac bacterial strain. Each of the oils exhibited antimicrobial activity and three of them antiplasmid action. The interaction of peppermint oil and menthol with the antibiotics was studied on the same bacterial strain with the checkerboard method. Peppermint oil and menthol displayed additive synergy with oxytetracycline. A new mechanism of plasmid curing was established for one of the oil components.

Expression of recombinant Arabian camel lactoferricin-related peptide in Pichia pastoris and its antimicrobial identification.

PubMed

Chahardooli, Mahmood; Niazi, Ali; Aram, Farzaneh; Sohrabi, Seyyed Mohsen

2016-01-30

Lactoferricin (LFcin) is a strong cationic peptide released from the N-terminus of lactoferrin by gastric pepsin digestion. LFcin has some important properties, including high antimicrobial activity. To date, lactoferricins have been isolated and characterised from various animal species, but not from camel. The aim of this study was to characterise and express recombinant camel lactoferricin (LFcinC) in Pichia pastoris and investigate its antimicrobial activity. After methanol induction, LFcinC was expressed and secreted into a culture broth medium and the results determined by concentrated supernatant culture medium showed high antimicrobial activity against the following microorganisms: Escherichia coli PTCC 1330 (ATCC 8739), Staphylococcus aureus PTCC 1112 (ATCC 6538), Pseudomonas aeruginosa PTCC 1074 (ATCC 9027), Bacillus subtilis PTCC 1023 (ATCC 6633), and Candida albicans PTCC 5027 (ATCC 10231). Thermal stability was clarified with antibacterial activity against Escherichia coli PTCC 1330 (ATCC 8739). Results confirmed that camel lactoferricin had suitable antimicrobial activity and its production by Pichia pastoris can be used for recombinant production. © 2015 Society of Chemical Industry.

Antioxidant and antimicrobial activity of natural phenolic extract from defatted soybean flour by-product for stone fruit postharvest application.

PubMed

Villalobos, María del Carmen; Serradilla, Manuel Joaquín; Martín, Alberto; Ordiales, Elena; Ruiz-Moyano, Santiago; Córdoba, María de Guía

2016-04-01

Fresh fruit is highly perishable during storage and transport, so there has been growing interest in finding safe and natural antimicrobial compounds as a control tool. Phenolic compounds are secondary metabolites naturally present in vegetable material and have been associated with antimicrobial and antioxidant properties. Therefore, the aim of this study was to investigate the antioxidant capacity and potential antimicrobial effect of phenolic extract obtained from defatted soybean flour against selected pathogenic bacteria and microorganisms responsible of fruit decay. Analysis of phenolic composition by HPLC-MS showed the presence of a wide range of compounds, with isoflavones and phenolic acids the main polyphenols identified. Furthermore, the phenolic extract had important antioxidant activity by two different assays. Related to antimicrobial activity, in vitro experiments demonstrated that phenolic extract displayed a high activity against the main foodborne pathogens, while a moderate inhibition was found against five spoilage yeasts and Monilia laxa and a scarce effect for Penicillium glabrum, Cladosporium uredinicola and Botrytis cinerea. Interestingly these compounds considerably inhibited the mycelial growth of Monilia laxa, in both in vitro and in vivo experiments. The results of the present study revealed that defatted soybean flour is an important source of phenolic compounds with remarkable antimicrobial and antioxidant activity, suggesting the possibility of using them as natural additives in postharvest treatments to extend the shelf life of fruit. © 2015 Society of Chemical Industry.

Mushrooms as Possible Antioxidant and Antimicrobial Agents

PubMed Central

Kosanić, Marijana; Ranković, Branislav; Dašić, Marko

2012-01-01

The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 μg/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 μg/mL), BHA (IC50 = 6.42 μg/mL) and α-tocopherol (IC50 = 62.43 μg/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases. PMID:24250542

Phytochemical, antimicrobial, and antioxidant activities of different citrus juice concentrates.

PubMed

Oikeh, Ehigbai I; Omoregie, Ehimwenma S; Oviasogie, Faith E; Oriakhi, Kelly

2016-01-01

The search for new antimicrobial compounds is ongoing. Its importance cannot be overemphasized in an era of emerging resistant pathogenic organisms. This study therefore investigated the phytochemical composition and antioxidant and antimicrobial activities of different citrus juice concentrates. Fruit juices of Citrus tangerine (tangerine), Citrus paradisi (grape), Citrus limon (lemon), and Citrus aurantifolia (lime) were evaluated. Antimicrobial activities against five bacterial and three fungal strains were evaluated. The results revealed the presence of alkaloids, flavonoids, steroids, terpenoids, saponins, cardiac glycosides, and reducing sugars in all the juice concentrates. DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacities varied with tangerine and grape juices having better scavenging capacities than lemon and lime juices. Grape juice was observed to have a significantly higher (P < 0.05) ferric-reducing antioxidant potential (FRAP) value (364.2 ± 10.25 μmol/L Fe(II)/g of the extract) than the reference antioxidant, ascorbic acid (312.88 ± 5.61 μmol/L). Antimicrobial studies revealed differential antimicrobial activities against different microbial strains. Zones of inhibition ranging from 4 to 26 mm were observed for the antibacterial tests with 0-24 mm for antifungal test. Minimum inhibitory concentrations (MIC) and minimum bacteriostatic concentrations (MBC) for concentrates against bacterial strains ranged from 12.5 to 200 μg/mL. Lemon and lime juice concentrates had lower MIC and MBC values with orange and tangerine having the highest values. Minimum fungicidal concentrations ranged from 50 to 200 μg/mL. The results of this study suggest that these juice concentrates may have beneficial antimicrobial roles that can be exploited in controlling unwanted microbial growth.

Discovery of antimicrobial compounds targeting bacterial type FAD synthetases.

PubMed

Sebastián, María; Anoz-Carbonell, Ernesto; Gracia, Begoña; Cossio, Pilar; Aínsa, José Antonio; Lans, Isaías; Medina, Milagros

2018-12-01

The increase of bacterial strains resistant to most of the available antibiotics shows a need to explore novel antibacterial targets to discover antimicrobial drugs. Bifunctional bacterial FAD synthetases (FADSs) synthesise the flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These cofactors act in vital processes as part of flavoproteins, making FADS an essential enzyme. Bacterial FADSs are potential antibacterial targets because of differences to mammalian enzymes, particularly at the FAD producing site. We have optimised an activity-based high throughput screening assay targeting Corynebacterium ammoniagenes FADS (CaFADS) that identifies inhibitors of its different activities. We selected the three best high-performing inhibitors of the FMN:adenylyltransferase activity (FMNAT) and studied their inhibition mechanisms and binding properties. The specificity of the CaFADS hits was evaluated by studying also their effect on the Streptococcus pneumoniae FADS activities, envisaging differences that can be used to discover species-specific antibacterial drugs. The antimicrobial effect of these compounds was also evaluated on C. ammoniagenes, S. pneumoniae, and Mycobacterium tuberculosis cultures, finding hits with favourable antimicrobial properties.

Essential oil constituents and antimicrobial activity of Pycnocycla bashagardiana Mozaff. from Iran.

PubMed

Alizadeh, Ardalan; Abdollahzadeh, Hamid

2017-09-01

Pycnocycla bashagardiana is a rare endemic and endangered species that has been used in folkloric medicine in Southern Iran. This study aimed to evaluate the essential oil constituents and antimicrobial activity of wild and cultivated p. bashagardiana. The aerial parts of wild and cultivated plants were collected from two provinces of Iran. The essential oil was isolated by hydrodistillation and analyzed by a combination of capillary GC and GC-MS. The main components in wild plants were myristicin (39.12%), (E)-β-ocimene (21.97%), sabinene (15.0%) and cis-iso-miristicin (2.67%) and in cultivated plants, (E)-β-ocimene (55.40%), myristicin (18.27%), (Z)-β-ocimene (12.47%) and cis-iso-miristicin (2.94%) were the main constituents in essential oil. The in vitro antimicrobial activity of the essential oil of P. bashagardiana were studied against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Candida albicans for the first time. The results showed that the oil exhibited strong antimicrobial activity against all the tested pathogens.

Evaluation of antimicrobial activity and bronchodialator effect of a polyherbal drug-Shrishadi

PubMed Central

Kajaria, Divya Kumari; Gangwar, Mayank; Kumar, Dharmendra; Kumar Sharma, Amit; Tilak, Ragini; Nath, Gopal; Tripathi, Yamini Bhusan; Tripathi, JS; Tiwari, SK

2012-01-01

Objective To investigate antimicrobial and bronchodialator effect of hydroalcholic extract of polyherbal drug Shirishadi containing Shirisha (Albezzia lebbeck), Nagarmotha (Cyprus rotandus) & Kantakari (Solanum xanthocarpum). Methods Antimicrobial activity was evaluated by disc diffusion method and MIC, MBC, MFC were calculated by micro dilution method. Hydroalcholic extract of this preparation was investigated for its phytochemical analysis, phenol and flavonoid were determined by spectrophotometric method and in vivo bronchodilator effect was analysed by convulsion time. Results The phytochemical tests revealed presence of alkaloids, anthraquinones, carbohydrates, flavonoids, saponins and tannins. The antimicrobial result showed the MIC of 6.25 mg/mL against Staphylococcus aureus and 12.5 mg/mL for Escherichia coli and 12.5 mg/mL against remaining bacteria tested, with strong antifungal activity. The maximum inhibition zone is found against Pseudomonas aeruginosa with MIC 16 mg/mL. Drug showed significant bronchodilator effect with 27.86% & 36.13% increase in preconvulsion time of guinea pigs pretreated with 100 & 200 mg/kg body weight of extract. Conclusions The study reveals that the extracts possess antibacterial activity and antifungal activity in a dose dependent manner. This antimicrobial property may be due to presence of several saponins, further studies are highly needed for the drug development. PMID:23569869

Growth Media Affect Assessment of Antimicrobial Activity of Plant-Derived Polyphenols.

PubMed

Xu, Xin; Ou, Zhen M; Wu, Christine D

2018-01-01

This study aimed to investigate the effects of different microbial growth media on the laboratory assessment of antimicrobial activity of natural polyphenolic compounds. The inhibition of the tea polyphenol EGCG on growth of selected oral microorganisms was evaluated in complex media and a protein-free chemically defined medium (CDM). Other antimicrobial agents (polyphenolic grape seed extract, plant alkaloid berberine, methyl salicylate, and chlorhexidine gluconate) were also tested in the study. The presence of proteins and their effects on the antimicrobial activity of EGCG were investigated by the addition of BSA to the CDM. The MICs of EGCG against test oral microorganisms were 4 to 64 times higher in complex media than in CDM. The polyphenolic grape seed extract exhibited similar discrepancies. However, the MICs of the nonpolyphenolic compounds (berberine, methyl salicylate, and chlorhexidine) were not significantly different between the two growth media. The MIC of EGCG against S. mutans UA159 in CDM with added BSA was 16 times higher than that in CDM alone. Therefore, nonproteinaceous CDM should be used to avoid interference of proteins with the active ingredients when testing the antimicrobial activity of plant-derived polyphenolic compounds against microorganisms. This will also minimize the discrepancies noted in results obtained by different investigators.

Quantitative analysis of catechins in Saraca asoca and correlation with antimicrobial activity

PubMed Central

Shirolkar, Amey; Gahlaut, Anjum; Chhillar, Anil K.; Dabur, Rajesh

2013-01-01

Herbal medicines are highly complex and have unknown mechanisms in diseases treatment. Saraca asoca (Roxb.), De. Wild has been recommended to treat gynecological disorders and used in several commercial polyherbal formulations. In present study, efforts have been made to explore antimicrobial activity and its co-relation with the distributions of catechins in the organs of S. asoca using targeted MS/MS. Eight extracts (cold and hot water) from four different organs of S. asoca and two drugs were prepared and antimicrobial activity was assessed by microbroth dilution assay. Quantitative and qualitative analysis of catechins in crude extracts was done by using targeted and auto-MS/MS and correlated with antimicrobial activity. (+)-Catechin and (+)-epicatechin and their biosynthesis related compound were found to be up-regulated in regenerated bark and leaves extracts. (−)-Epigallocatechin was found to be significantly higher in bark water extract as compared to others but showed low antimicrobial activity. Result showed down-regulation of (−)-epigallocatechin and up-regulation of (+)-catechin and (+)-epicatechin in the regenerated bark and leaves of S. asoca. It might be the contributing factor in the antimicrobial activity of regenerated bark and leaves of the plant. The concentration of (+)-epicatechin in processed drugs (Ashokarishta) from Baidyanath was found to be seven times higher than that of Dabur Pvt. Ltd., but no antimicrobial activity was observed, indicating the variations among the plant based drugs. This will be helpful in rational use of S. asoca parts. Furthermore, the analytical method developed is sensitive, repeatable and reliable; therefore, it is suitable for quality control of herbal drugs. PMID:29403849

Guanidino groups greatly enhance the action of antimicrobial peptidomimetics against bacterial cytoplasmic membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreev, Konstantin; Bianchi, Christopher; Laursen, Jonas S.

Antimicrobial peptides or their synthetic mimics are a promising class of potential new antibiotics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanismof antimicrobial α-peptide–β-peptoid chimeras. Langmuirmonolayers composed of 1,2-dipalmitoylsn- glycero-3-phosphatidylglycerol (DPPG) were used to model cytoplasmic membranes of both Gram-positive and Gram-negative bacteria,while lipopolysaccharide Kdo2-lipid Amonolayersweremimicking the outer membrane of Gram-negative species.We report the results of themeasurements using an array of techniques, including high-resolution synchrotron surface X-ray scattering, epifluorescence microscopy, and in vitro antimicrobial activity to study the molecularmechanisms of peptidomimetic interaction with bacterialmembranes.We found guanidinomore » group-containing chimeras to exhibit greater disruptive activity on DPPGmonolayers than the amino group-containing analogues. However, this effect was not observed for lipopolysaccharidemonolayerswhere the difference was negligible. Furthermore, the addition of the nitrobenzoxadiazole fluorophore did not reduce the insertion activity of these antimicrobials into both model membrane systems examined, which may be useful for future cellular localization studies.« less

Guanidino Groups Greatly Enhance the Action of Antimicrobial Peptidomimetics Against Bacterial Cytoplasmic Membranes

PubMed Central

Laursen, Jonas S.; Citterio, Linda; Hein-Kristensen, Line; Gram, Lone; Kuzmenko, Ivan; Olsen, Christian A.; Gidalevitz, David

2014-01-01

A promising class of potential new antibiotics are the antimicrobial peptides or their synthetic mimics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanism of antimicrobial α-peptide–β-peptoid chimeras. Two separate Langmuir monolayers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylglycerol (DPPG) and lipopolysaccharide Kdo2-lipid A were applied to model the outer membranes of Gram-positive and Gram-negative bacteria, respectively. We report the results of the measurements using an array of techniques, including high-resolution synchrotron surface X-ray scattering, epifluorescence microscopy, and in vitro antimicrobial activity to study the molecular mechanisms of peptidomimetic interaction with bacterial membranes. We found guanidino group-containing chimeras to exhibit greater disruptive activity on DPPG monolayers than the amino group-containing analogues. However, this effect was not observed for lipopolysaccharide monolayers where the difference was negligible. Furthermore, the addition of the nitrobenzoxadiazole fluorophore did not reduce the insertion activity of these antimicrobials into both model membrane systems examined, which may be useful for future cellular localization studies. PMID:24878450

Synthesis and structure-activity relationships of novel cationic lipids with anti-inflammatory and antimicrobial activities.

PubMed

Myint, Melissa; Bucki, Robert; Janmey, Paul A; Diamond, Scott L

2015-07-15

Certain membrane-active cationic steroids are known to also possess both anti-inflammatory and antimicrobial properties. This combined functionality is particularly relevant for potential therapies of infections associated with elevated tissue damage, for example, cystic fibrosis airway disease, a condition characterized by chronic bacterial infections and ongoing inflammation. In this study, six novel cationic glucocorticoids were synthesized using beclomethasone, budesonide, and flumethasone. Products were either monosubstituted or disubstituted, containing one or two steroidal groups, respectively. In vitro evaluation of biological activities demonstrated dual anti-inflammatory and antimicrobial properties with limited cytotoxicity for all synthesized compounds. Budesonide-derived compounds showed the highest degree of both glucocorticoid and antimicrobial properties within their respective mono- and disubstituted categories. Structure-activity analyses revealed that activity was generally related to the potency of the parent glucocorticoid. Taken together, these data indicate that these types of dual acting cationic lipids can be synthesized with the appropriate starting steroid to tailor activities as desired. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of antimicrobial agents on bond strength of orthodontic adhesives: a meta-analysis of in vitro studies.

PubMed

Altmann, A S P; Collares, F M; Leitune, V C B; Samuel, S M W

2016-02-01

Antimicrobial orthodontic adhesives aim to reduce white spot lesions' incidence in orthodontic patients, but they should not jeopardizing its properties. Systematic review and meta-analysis were performed to answer the question whether the association of antimicrobial agents with orthodontic adhesives compromises its mechanical properties and whether there is a superior antimicrobial agent. PubMed and Scopus databases. In vitro studies comparing shear bond strength of conventional photo-activated orthodontic adhesives to antimicrobial photo-activated orthodontic adhesives were considered eligible. Search terms included the following: orthodontics, orthodontic, antimicrobial, antibacterial, bactericidal, adhesive, resin, resin composite, bonding agent, bonding system, and bond strength. The searches yielded 494 citations, which turned into 467 after duplicates were discarded. Titles and abstracts were read and 13 publications were selected for full-text reading. Twelve studies were included in the meta-analysis. The global analysis showed no statistically significant difference between control and experimental groups. In the subgroup analysis, only the chlorhexidine subgroup showed a statistically significant difference, where the control groups had higher bond strength than the experimental groups. Many studies on in vitro orthodontic bond strength fail to report test conditions that could affect their outcomes. The pooled in vitro data suggest that adding an antimicrobial agent to an orthodontic adhesive system does not influence bond strength to enamel. It is not possible to state which antimicrobial agent is better to be associated. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Antimicrobial and anti-adherence activity of various combinations of coffee-chicory solutions on Streptococcus mutans: An in-vitro study

PubMed Central

Sharma, Rama; Reddy, Vamsi Krishna L; Prashant, GM; Ojha, Vivek; Kumar, Naveen PG

2014-01-01

Context: Several studies have demonstrated the activity of natural plants on the dental biofilm and caries development. But few studies on the antimicrobial activity of coffee-based solutions were found in the literature. Further there was no study available to check the antimicrobial effect of coffee solutions with different percentages of chicory in it. Aims: To evaluate the antimicrobial activity of different combinations of coffee-chicory solutions and their anti-adherence effect on Streptococcus mutans to glass surface. Materials and Methods: Test solutions were prepared. For antimicrobial activity testing, tubes containing test solution and culture medium were inoculated with a suspension of S. mutans followed by plating on Brain Heart Infusion (BHI) agar. S. mutans adherence to glass in presence of the different test solutions was also tested. The number of adhered bacteria (CFU/mL) was determined by plating method. Statistical Analysis: Statistical significance was measured using one way ANOVA followed by Tukey's post hoc test. P value < 0.05 was considered statistically significant. Results: Pure chicory had shown significantly less bacterial count compared to all other groups. Groups IV and V had shown significant reduction in bacterial counts over the period of 4 hrs. Regarding anti-adherence effect, group I-IV had shown significantly less adherence of bacteria to glass surface. Conclusions: Chicory exerted antibacterial effect against S. mutans while coffee reduced significantly the adherence of S. mutans to the glass surface. PMID:25328299

Fungi treated with small chemicals exhibit increased antimicrobial activity against facultative bacterial and yeast pathogens.

PubMed

Zutz, Christoph; Bandian, Dragana; Neumayer, Bernhard; Speringer, Franz; Gorfer, Markus; Wagner, Martin; Strauss, Joseph; Rychli, Kathrin

2014-01-01

For decades, fungi have been the main source for the discovery of novel antimicrobial drugs. Recent sequencing efforts revealed a still high number of so far unknown "cryptic" secondary metabolites. The production of these metabolites is presumably epigenetically silenced under standard laboratory conditions. In this study, we investigated the effect of six small mass chemicals, of which some are known to act as epigenetic modulators, on the production of antimicrobial compounds in 54 spore forming fungi. The antimicrobial effect of fungal samples was tested against clinically facultative pathogens and multiresistant clinical isolates. In total, 30 samples of treated fungi belonging to six different genera reduced significantly growth of different test organisms compared to the untreated fungal sample (growth log reduction 0.3-4.3). For instance, the pellet of Penicillium restrictum grown in the presence of butyrate revealed significant higher antimicrobial activity against Staphylococcus (S.) aureus and multiresistant S. aureus strains and displayed no cytotoxicity against human cells, thus making it an ideal candidate for antimicrobial compound discovery. Our study shows that every presumable fungus, even well described fungi, has the potential to produce novel antimicrobial compounds and that our approach is capable of rapidly filling the pipeline for yet undiscovered antimicrobial substances.

Fungi Treated with Small Chemicals Exhibit Increased Antimicrobial Activity against Facultative Bacterial and Yeast Pathogens

PubMed Central

Zutz, Christoph; Bandian, Dragana; Neumayer, Bernhard; Speringer, Franz; Wagner, Martin; Strauss, Joseph

2014-01-01

For decades, fungi have been the main source for the discovery of novel antimicrobial drugs. Recent sequencing efforts revealed a still high number of so far unknown “cryptic” secondary metabolites. The production of these metabolites is presumably epigenetically silenced under standard laboratory conditions. In this study, we investigated the effect of six small mass chemicals, of which some are known to act as epigenetic modulators, on the production of antimicrobial compounds in 54 spore forming fungi. The antimicrobial effect of fungal samples was tested against clinically facultative pathogens and multiresistant clinical isolates. In total, 30 samples of treated fungi belonging to six different genera reduced significantly growth of different test organisms compared to the untreated fungal sample (growth log reduction 0.3–4.3). For instance, the pellet of Penicillium restrictum grown in the presence of butyrate revealed significant higher antimicrobial activity against Staphylococcus (S.) aureus and multiresistant S. aureus strains and displayed no cytotoxicity against human cells, thus making it an ideal candidate for antimicrobial compound discovery. Our study shows that every presumable fungus, even well described fungi, has the potential to produce novel antimicrobial compounds and that our approach is capable of rapidly filling the pipeline for yet undiscovered antimicrobial substances. PMID:25121102

Characterisation of antimicrobial extracts from dandelion root (Taraxacum officinale) using LC-SPE-NMR.

PubMed

Kenny, O; Brunton, N P; Walsh, D; Hewage, C M; McLoughlin, P; Smyth, T J

2015-04-01

Plant extracts have traditionally been used as sources of natural antimicrobial compounds, although in many cases, the compounds responsible for their antimicrobial efficacy have not been identified. In this study, crude and dialysed extracts from dandelion root (Taraxacum officinale) were evaluated for their antimicrobial properties against Gram positive and Gram negative bacterial strains. The methanol hydrophobic crude extract (DRE3) demonstrated the strongest inhibition of microbial growth against Staphylococcus aureus, methicillin-resistant S. aureus and Bacillus cereus strains. Normal phase (NP) fractionation of DRE3 resulted in two fractions (NPF4 and NPF5) with enhanced antimicrobial activity. Further NP fractionation of NPF4 resulted in two fractions (NPF403 and NPF406) with increased antimicrobial activity. Further isolation and characterisation of compounds in NPF406 using liquid chromatography solid phase extraction nuclear magnetic resonance LC-SPE-NMR resulted in the identification of 9-hydroxyoctadecatrienoic acid and 9-hydroxyoctadecadienoic acid, while the phenolic compounds vanillin, coniferaldehyde and p-methoxyphenylglyoxylic acid were also identified respectively. The molecular mass of these compounds was confirmed by LC mass spectroscopy (MS)/MS. In summary, the antimicrobial efficacy of dandelion root extracts demonstrated in this study support the use of dandelion root as a source of natural antimicrobial compounds. Copyright © 2015 John Wiley & Sons, Ltd.

Antimicrobial Effect of Jasminum grandiflorum L. and Hibiscus rosa-sinensis L. Extracts Against Pathogenic Oral Microorganisms--An In Vitro Comparative Study.

PubMed

Nagarajappa, Ramesh; Batra, Mehak; Sharda, Archana J; Asawa, Kailash; Sanadhya, Sudhanshu; Daryani, Hemasha; Ramesh, Gayathri

2015-01-01

To assess and compare the antimicrobial potential and determine the minimum inhibitory concentration (MIC) of Jasminum grandiflorum and Hibiscus rosa-sinensis extracts as potential anti-pathogenic agents in dental caries. Aqueous and ethanol (cold and hot) extracts prepared from leaves of Jasminum grandiflorum and Hibiscus rosa-sinensis were screened for in vitro antimicrobial activity against Streptococcus mutans and Lactobacillus acidophilus using the agar well diffusion method. The lowest concentration of every extract considered as the minimum inhibitory concentration (MIC) was determined for both test organisms. Statistical analysis was performed with one-way analysis of variance (ANOVA). At lower concentrations, hot ethanol Jasminum grandiflorum (10 μg/ml) and Hibiscus rosa-sinensis (25 μg/ml) extracts were found to have statistically significant (P≤0.05) antimicrobial activity against S. mutans and L. acidophilus with MIC values of 6.25 μg/ml and 25 μg/ml, respectively. A proportional increase in their antimicrobial activity (zone of inhibition) was observed. Both extracts were found to be antimicrobially active and contain compounds with therapeutic potential. Nevertheless, clinical trials on the effect of these plants are essential before advocating large-scale therapy.

Antimicrobial resistance of Listeria spp. recovered from processed bison.

PubMed

Li, Q; Sherwood, J S; Logue, C M

2007-01-01

The current study examined the antimicrobial susceptibility of 86 Listeria spp. isolated from processed bison carcasses. Susceptibility to 25 antimicrobial agents was determined using E-test and National Antimicrobial Resistance Monitoring System (NARMS) panels. Most Listeria isolates (88-98%) exhibited resistance to bacitracin, oxacillin, cefotaxime, and fosfomycin. Resistance to tetracycline (18.6%) was also common. Of the 16 tetracycline-resistant Listeria isolates, 15 carried tetM and 2 contained integrase of Tn1545 transposons. Rifampicin and trimethoprim-sulfamethoxazole were the most active antimicrobial agents against Listeria spp., with a MIC(90) of 0.38 microg ml(-1). Ampicillin, erythromycin, penicillin, gentamicin, and tobramycin also exhibited good activity against Listeria spp., with MIC(90) not exceeding 1 microg ml(-1). Differences in resistance among Listeria spp. was displayed, as Listeria innocua strains were more resistant than other Listeria species. The study showed that Listeria monocytogenes strains from bison were susceptible to the antibiotics most commonly used to treat human listeriosis. However, the presence of antimicrobial resistance in L. innocua indicates the potential for transfer of resistance and a conjugative transposon to L. monocytogenes. The findings of our study will provide useful information for the development of public health policy in the use of antimicrobials in food animal production.

Guanidino groups greatly enhance the action of antimicrobial peptidomimetics against bacterial cytoplasmic membranes

DOE PAGES

Andreev, Konstantin; Bianchi, Christopher; Laursen, Jonas S.; ...

2014-05-28

In this study, antimicrobial peptides or their synthetic mimics are a promising class of potential new antibiotics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanism of antimicrobial α-peptide–β-peptoid chimeras. Langmuir monolayers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylglycerol (DPPG) were used to model cytoplasmic membranes of both Gram-positive and Gram-negative bacteria, while lipopolysaccharide Kdo2-lipid A monolayers were mimicking the outer membrane of Gram-negative species. We report the results of the measurements using an array of techniques, including high-resolution synchrotron surface X-ray scattering, epifluorescence microscopy, and in vitro antimicrobial activity tomore » study the molecular mechanisms of peptidomimetic interaction with bacterial membranes. We found guanidino group-containing chimeras to exhibit greater disruptive activity on DPPG monolayers than the amino group-containing analogues. However, this effect was not observed for lipopolysaccharide monolayers where the difference was negligible. Furthermore, the addition of the nitrobenzoxadiazole fluorophore did not reduce the insertion activity of these antimicrobials into both model membrane systems examined, which may be useful for future cellular localization studies.« less

Guanidino groups greatly enhance the action of antimicrobial peptidomimetics against bacterial cytoplasmic membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreev, Konstantin; Bianchi, Christopher; Laursen, Jonas S.

In this study, antimicrobial peptides or their synthetic mimics are a promising class of potential new antibiotics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanism of antimicrobial α-peptide–β-peptoid chimeras. Langmuir monolayers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylglycerol (DPPG) were used to model cytoplasmic membranes of both Gram-positive and Gram-negative bacteria, while lipopolysaccharide Kdo2-lipid A monolayers were mimicking the outer membrane of Gram-negative species. We report the results of the measurements using an array of techniques, including high-resolution synchrotron surface X-ray scattering, epifluorescence microscopy, and in vitro antimicrobial activity tomore » study the molecular mechanisms of peptidomimetic interaction with bacterial membranes. We found guanidino group-containing chimeras to exhibit greater disruptive activity on DPPG monolayers than the amino group-containing analogues. However, this effect was not observed for lipopolysaccharide monolayers where the difference was negligible. Furthermore, the addition of the nitrobenzoxadiazole fluorophore did not reduce the insertion activity of these antimicrobials into both model membrane systems examined, which may be useful for future cellular localization studies.« less

Development and Sequential Analysis of a New Multi-Agent, Anti-Acne Formulation Based on Plant-Derived Antimicrobial and Anti-Inflammatory Compounds.

PubMed

Saviuc, Crina; Ciubucă, Bianca; Dincă, Gabriela; Bleotu, Coralia; Drumea, Veronica; Chifiriuc, Mariana-Carmen; Popa, Marcela; Gradisteanu Pircalabioru, Gratiela; Marutescu, Luminita; Lazăr, Veronica

2017-01-17

The antibacterial and anti-inflammatory potential of natural, plant-derived compounds has been reported in many studies. Emerging evidence indicates that plant-derived essential oils and/or their major compounds may represent a plausible alternative treatment for acne, a prevalent skin disorder in both adolescent and adult populations. Therefore, the purpose of this study was to develop and subsequently analyze the antimicrobial activity of a new multi-agent, synergic formulation based on plant-derived antimicrobial compounds (i.e., eugenol, β-pinene, eucalyptol, and limonene) and anti-inflammatory agents for potential use in the topical treatment of acne and other skin infections. The optimal antimicrobial combinations selected in this study were eugenol/β-pinene/salicylic acid and eugenol/β-pinene/2-phenoxyethanol/potassium sorbate. The possible mechanisms of action revealed by flow cytometry were cellular permeabilization and inhibition of efflux pumps activity induced by concentrations corresponding to sub-minimal inhibitory (sub-MIC) values. The most active antimicrobial combination represented by salycilic acid/eugenol/β-pinene/2-phenoxyethanol/potassium sorbate was included in a cream base, which demonstrated thermodynamic stability and optimum microbiological characteristics.

In vitro antimicrobial activity of five essential oils on multidrug resistant Gram-negative clinical isolates.

PubMed

Sakkas, Hercules; Gousia, Panagiota; Economou, Vangelis; Sakkas, Vassilios; Petsios, Stefanos; Papadopoulou, Chrissanthy

2016-01-01

The emergence of drug-resistant pathogens has drawn attention on medicinal plants for potential antimicrobial properties. The objective of the present study was the investigation of the antimicrobial activity of five plant essential oils on multidrug resistant Gram-negative bacteria. Basil, chamomile blue, origanum, thyme, and tea tree oil were tested against clinical isolates of Acinetobacter baumannii (n = 6), Escherichia coli (n = 4), Klebsiella pneumoniae (n = 7), and Pseudomonas aeruginosa (n = 5) using the broth macrodilution method. The tested essential oils produced variable antibacterial effect, while Chamomile blue oil demonstrated no antibacterial activity. Origanum, Thyme, and Basil oils were ineffective on P. aeruginosa isolates. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values ranged from 0.12% to 1.50% (v/v) for tea tree oil, 0.25-4% (v/v) for origanum and thyme oil, 0.50% to >4% for basil oil and >4% for chamomile blue oil. Compared to literature data on reference strains, the reported MIC values were different by 2SD, denoting less successful antimicrobial activity against multidrug resistant isolates. The antimicrobial activities of the essential oils are influenced by the strain origin (wild, reference, drug sensitive, or resistant) and it should be taken into consideration whenever investigating the plants' potential for developing new antimicrobials.

Lipopolysaccharide induces amyloid formation of antimicrobial peptide HAL-2.

PubMed

Wang, Jiarong; Li, Yan; Wang, Xiaoming; Chen, Wei; Sun, Hongbin; Wang, Junfeng

2014-11-01

Lipopolysaccharide (LPS), the important component of the outer membrane of Gram-negative bacteria, contributes to the integrity of the outer membrane and protects the cell against bactericidal agents, including antimicrobial peptides. However, the mechanisms of interaction between antimicrobial peptides and LPS are not clearly understood. Halictines-2 (HAL-2), one of the novel antimicrobial peptides, was isolated from the venom of the eusocial bee Halictus sexcinctus. HAL-2 has exhibited potent antimicrobial activity against Gram-positive and Gram-negative bacteria and even against cancer cells. Here, we studied the interactions between HAL-2 and LPS to elucidate the antibacterial mechanism of HAL-2 in vitro. Our results show that HAL-2 adopts a significant degree of β-strand structure in the presence of LPS. LPS is capable of inducing HAL-2 amyloid formation, which may play a vital role in its antimicrobial activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Update on Monoterpenes as Antimicrobial Agents: A Particular Focus on p-Cymene

PubMed Central

Marchese, Anna; Arciola, Carla Renata; Barbieri, Ramona; Silva, Ana Sanches; Nabavi, Seyed Fazel; Tsetegho Sokeng, Arold Jorel; Izadi, Morteza; Jafari, Nematollah Jonaidi; Suntar, Ipek; Nabavi, Seyed Mohammad

2017-01-01

p-Cymene [1-methyl-4-(1-methylethyl)-benzene] is a monoterpene found in over 100 plant species used for medicine and food purposes. It shows a range of biological activity including antioxidant, anti-inflammatory, antinociceptive, anxiolytic, anticancer and antimicrobial effects. This last property has been widely investigated due to the urgent need for new substances with antimicrobial properties, to be used to treat communicable diseases whose diffusion in developed countries has been facilitated by globalization and the evolution of antimicrobial resistance. This review summarizes available scientific data, as reported by the most recent studies describing the antimicrobial activity of p-cymene either alone, or as the main component of plant extracts, as well as addressing the mechanisms of action of cymenes as antimicrobial agents. While p-cymene is one of the major constituents of extracts and essential oils used in traditional medicines as antimicrobial agents, but considering the limited data on its in vivo efficacy and safety, further studies are required to reach a definitive recommendation on the use and beneficial effects of p-cymene in human healthcare and in biomedical applications as a promising candidate to functionalize biomaterials and nanomaterials. PMID:28809799

Artepillin C and phenolic compounds responsible for antimicrobial and antioxidant activity of green propolis and Baccharis dracunculifolia DC.

PubMed

Veiga, R S; De Mendonça, S; Mendes, P B; Paulino, N; Mimica, M J; Lagareiro Netto, A A; Lira, I S; López, B G-C; Negrão, V; Marcucci, M C

2017-04-01

This study investigates the antimicrobial activity in Staphylococcus aureus isolates (methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA)) and antioxidant activity of green propolis, Baccharis dracunculifolia DC extracts and Artepillin C™. The amount of Artepillin C in different extracts was determined by high performance liquid chromatography analysis. Minimum inhibitory concentration 90 (MIC90) was determined using 40 isolates of S. aureus inoculated in Müeller-Hinton agar culture medium containing the green propolis and B. dracunculifolia DC extracts. PVEE (green propolis ethanolic extract) and BDEH (B. dracunculifolia hexanic extract) showed the greatest antimicrobial activity with MIC90 values of 246·3 and 295·5 μg ml -1 respectively. Green propolis ethanolic and hexanic extracts (PVEE and PVEH respectively) showed the greatest antioxidant activity assessed by DPPH (1,1-diphenyl-2-picryl hydrazyl radical) with IC 50 values of 13·09 and 95·86 μg ml -1 respectively. Green propolis ethanolic displays better antimicrobial and antioxidant activities compared to other extracts. These activities may be related to the presence of Artepillin C in synergism with the other constituents of the extracts. In this study, the antimicrobial activity of the extracts of green propolis and B. dracunculifolia DC demonstrated in MRSA and MSSA clinical isolates indicated that they can be important tools to treat infections caused by these bacteria. © 2017 The Society for Applied Microbiology.

A comparative study of the antioxidant, antimicrobial, cytotoxic and thrombolytic potential of the fruits and leaves of Spondias dulcis

PubMed Central

Islam, Shawkat Md. Aminul; Ahmed, Kh Tanvir; Manik, Mohammad Kawsar; Wahid, Md. Arif; Kamal, Chowdhury Shafayat Ibne

2013-01-01

Objective To investigate the antioxidant, antimicrobial, cytotoxic and thrombolytic property of the fruits and leaves of Spondias dulcis (S. dulcis). Methods Methanolic extracts of fruits and leaves of S. dulcis were partitioned with chloroform and dichloromethane. The antioxidant potential of the crude extract and partitioned fractions were evaluated in terms of total phenolic content, total flavonoid content, DPPH radical scavenging potential, reducing potential and total antioxidant capacity by specific standard procedures. The antimicrobial activity was evaluated using disc diffusion method. The cytotoxicity was evaluated by using brine shrimp lethality bioassay and compared with vincristine sulfate. The thrombolytic activity was compared with streptokinase. Results The methanolic fruit extract exhibited the highest phenolic content, flavonoid content and antioxidant capacity, among the other extracts, with the highest DPPH radical scavenging activity at a concentration of 10 µg/mL (IC50: 1.91 µg/mL) and maximum reducing power at a concentration of 100 µg/mL (EC50: 3.58 µg/mL). Though all extract showed moderate antimicrobial activity against the bacterial strains, weak or no activity against fungus. The range of LC50 value of all extracts was 1.335-14.057 µg/mL which was far lower than the cut off index for cytotoxicity. All extracts exhibited statistically significant (P<0.001) thrombolytic activity. Conclusions Our study suggested that S. dulcis exhibits antimicrobial activities against a wide variety of strains while it possesses significant antioxidant, cytotoxic and thrombolytic activity. PMID:23998007

A comparative study of the antioxidant, antimicrobial, cytotoxic and thrombolytic potential of the fruits and leaves of Spondias dulcis.

PubMed

Islam, Shawkat Md Aminul; Ahmed, Kh Tanvir; Manik, Mohammad Kawsar; Wahid, Md Arif; Kamal, Chowdhury Shafayat Ibne

2013-09-01

To investigate the antioxidant, antimicrobial, cytotoxic and thrombolytic property of the fruits and leaves of Spondias dulcis (S. dulcis). Methanolic extracts of fruits and leaves of S. dulcis were partitioned with chloroform and dichloromethane. The antioxidant potential of the crude extract and partitioned fractions were evaluated in terms of total phenolic content, total flavonoid content, DPPH radical scavenging potential, reducing potential and total antioxidant capacity by specific standard procedures. The antimicrobial activity was evaluated using disc diffusion method. The cytotoxicity was evaluated by using brine shrimp lethality bioassay and compared with vincristine sulfate. The thrombolytic activity was compared with streptokinase. The methanolic fruit extract exhibited the highest phenolic content, flavonoid content and antioxidant capacity, among the other extracts, with the highest DPPH radical scavenging activity at a concentration of 10 µg/mL (IC50: 1.91 µg/mL) and maximum reducing power at a concentration of 100 µg/mL (EC50: 3.58 µg/mL). Though all extract showed moderate antimicrobial activity against the bacterial strains, weak or no activity against fungus. The range of LC50 value of all extracts was 1.335-14.057 µg/mL which was far lower than the cut off index for cytotoxicity. All extracts exhibited statistically significant (P<0.001) thrombolytic activity. Our study suggested that S. dulcis exhibits antimicrobial activities against a wide variety of strains while it possesses significant antioxidant, cytotoxic and thrombolytic activity.

The in vitro antimicrobial evaluation of commercially essential oils and their combinations against acne.

PubMed

Orchard, A; van Vuuren, S F; Viljoen, A; Kamatou, Guy

2018-03-24

The study investigated the efficacy of commercial essential oil combinations against the two pathogens responsible for acne with the aim to identify synergy and favourable oils to possibly use in a blend. Antimicrobial activity was assessed using the minimum inhibitory concentration (MIC) assay against Staphylococcus epidermidis (ATCC 2223) and Propionibacterium acnes (ATCC 11827), and the fractional inhibitory concentration index (ΣFIC) was calculated. Combinations displaying synergistic interactions were further investigated at varied ratios and the results plotted on isobolograms. From the 408 combinations investigated, 167 combinations were identified as displaying noteworthy antimicrobial activity (MIC value ≤ 1.00 mg ml -1 ). Thirteen synergistic interactions were observed against S. epidermidis and three synergistic combinations were observed against P. acnes. It was found that not one of the synergistic interactions identified were based on the combinations recommended in the layman's aroma-therapeutic literature. Synergy was evident rather from leads based on antimicrobial activity from previous studies, thus emphasising the importance of scientific validation. Leptospermum scoparium J.R.Forst. and G.Forst (manuka) was the essential oil mostly involved in synergistic interactions (four) against S. epidermidis. Cananga odorata (Lam.) Hook.f. and Thomson (ylang ylang) essential oil was also frequently involved in synergy where synergistic interactions could be observed against both pathogens. The combination with the lowest MIC value against both acne pathogens was and Vetiveria zizanioides Stapf (vetiver) with Cinnamomum verum J.Presl (cinnamon bark) (MIC values 0.19-0.25 mg ml -1 ). Pogostemon patchouli Benth. (patchouli), V. zizanioides, C. verum and Santalum spp. (sandalwood) could be identified as the oils that contributed the most noteworthy antimicrobial activity towards the combinations. The different chemotypes of the essential oils used in the combinations predominantly resulted in similar antimicrobial activity. The investigated essential oil combinations resulted in at least 50% of the combinations displaying noteworthy antimicrobial activity. Most of the synergistic interactions do not necessarily correspond to the recommended aroma-therapeutic literature, which highlights a need for scientific validation of essential oil antimicrobial activity. No antagonism was observed. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Antimalarial and antimicrobial activities of 8-Aminoquinoline-Uracils metal complexes

PubMed Central

Phopin, Kamonrat; Sinthupoom, Nujarin; Treeratanapiboon, Lertyot; Kunwittaya, Sarun; Prachayasittikul, Supaluk; Ruchirawat, Somsak; Prachayasittikul, Virapong

2016-01-01

8-Aminoquinoline (8AQ) derivatives have been reported to have antimalarial, anticancer, and antioxidant activities. This study investigated the potency of 8AQ-5-substituted (iodo and nitro) uracils metal (Mn, Cu, Ni) complexes (1-6) as antimalarial and antimicrobial agents. Interestingly, all of these metal complexes (1-6) showed fair antimalarial activities. Moreover, Cu complexes 2 (8AQ-Cu-5Iu) and 5 (8AQ-Cu-5Nu) exerted antimicrobial activities against Gram-negative bacteria including P. shigelloides and S. dysenteriae. The results reveal application of 8AQ and its metal complexes as potential compounds to be further developed as novel antimalarial and antibacterial agents. PMID:27103894

Antimalarial and antimicrobial activities of 8-Aminoquinoline-Uracils metal complexes.

PubMed

Phopin, Kamonrat; Sinthupoom, Nujarin; Treeratanapiboon, Lertyot; Kunwittaya, Sarun; Prachayasittikul, Supaluk; Ruchirawat, Somsak; Prachayasittikul, Virapong

2016-01-01

8-Aminoquinoline (8AQ) derivatives have been reported to have antimalarial, anticancer, and antioxidant activities. This study investigated the potency of 8AQ-5-substituted (iodo and nitro) uracils metal (Mn, Cu, Ni) complexes (1-6) as antimalarial and antimicrobial agents. Interestingly, all of these metal complexes (1-6) showed fair antimalarial activities. Moreover, Cu complexes 2 (8AQ-Cu-5Iu) and 5 (8AQ-Cu-5Nu) exerted antimicrobial activities against Gram-negative bacteria including P. shigelloides and S. dysenteriae. The results reveal application of 8AQ and its metal complexes as potential compounds to be further developed as novel antimalarial and antibacterial agents.

Screening of selected single and polyherbal Ayurvedic medicines for Antibacterial and Antifungal activity

PubMed Central

Kekuda, T.R Prashith; Kavya, R; Shrungashree, R.M; Suchitra, S.V

2010-01-01

The present study deals with antimicrobial activity of ayurvedic drugs containing single herb (Amalaki Choorna and Yastimadhu Choorna) and combination of herbs (DN-90 and Asanadi Kwatha Choorna). Disc diffusion method was used to assess antibacterial activity and antifungal activity was tested using Poison food technique. Absence of bacterial growth around the discs impregnated with the aqueous extracts of drugs and reduction of fungal growth in poisoned plates indicated antimicrobial activity. Further, the results of antibacterial activity of Amalaki choorna were comparable with standard drug Streptomycin. Asanadi Kwatha Choorna inhibited bacteria to more extent than Yastimadhu choorna and DN-90. Among fungi tested, more antifungal activity was observed against Mucor sp. The antimicrobial activity of drugs tested could be due to active principles present in them. PMID:22557355

The antimicrobial and antiadhesion activities of micellar solutions of surfactin, CTAB and CPCl with terpinen-4-ol: applications to control oral pathogens.

PubMed

Bucci, Andreia R; Marcelino, Larissa; Mendes, Renata K; Etchegaray, Augusto

2018-06-06

The oral pathogen Streptococcus mutans is involved in tooth decay by a process that initiates with biofilm adhesion and caries development. The presence of other microbes such as Candida albicans may worsen the demineralization process. Since both microbes are virulent to the host and will proliferate under specific host immune deficiencies and systemic diseases, it is important to study antimicrobial substances and their effects on both pathogens. There are several antiseptic agents used to reduce plaque biofilm and its outcome (dental caries and/or periodontal disease). However, some of these have undesired effects. In the current study we investigated the antimicrobial and anti-adhesion properties of micellar solutions of surfactants and the plant natural product terpinen-4-ol (TP). The results revealed an increase in antimicrobial properties of the synthetic surfactants, cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CTAB), when mixed with TP. In addition, although surfactin, a biosurfactant, has little antimicrobial activity, it was demonstrated that it enhanced the effect of TP both as antimicrobial and anti-adhesion compound. Surfactin and the synthetic surfactants promote the antimicrobial activity of TP against S. mutans, the causal agent of tooth decay, suggesting specificity for membrane interactions that may be facilitated by surfactants. This is the first report on the successful use of surfactin in association with TP to inhibit the growth and adhesion of microbial pathogens. Surfactin has other beneficial properties besides being biodegradable, it has antiviral and anti-mycoplasma activities in addition to adjuvant properties and encapsulating capacity at low concentration.

New insights on antimicrobial efficacy of copper surfaces in the healthcare environment: a systematic review.

PubMed

Chyderiotis, S; Legeay, C; Verjat-Trannoy, D; Le Gallou, F; Astagneau, P; Lepelletier, D

2018-03-29

Hospital-acquired infections (HAIs) are a major public health issue. The potential of antimicrobial copper surfaces in reducing HAIs' rates is of interest but remains unclear. We conducted a systematic review of studies assessing the activity of copper surfaces (colony-forming unit (CFU)/surface, both in vitro and in situ) as well as clinical studies. In vitro study protocols were analysed through a tailored checklist developed specifically for this review, in situ studies and non-randomized clinical studies were assessed using the ORION (Outbreak Reports and Intervention studies Of Nosocomial infection) checklist and randomized clinical studies using the CONSORT guidelines. The search was conducted using PubMed database with the keywords 'copper' and 'surfaces' and 'healthcare associated infections' or 'antimicrobial'. References from relevant articles, including reviews, were assessed and added when appropriate. Articles were added until 30 August 2016. Overall, 20 articles were selected for review including 10 in vitro, eight in situ and two clinical studies. Copper surfaces were found to have variable antimicrobial activity both in vitro and in situ, although the heterogeneity in the designs and the reporting of the results prevented conclusions from being drawn regarding their spectrum and activity/time compared to controls. Copper effect on HAIs incidence remains unclear because of the limited published data and the lack of robust designs. Most studies have potential conflicts of interest with copper industries. Copper surfaces have demonstrated an antimicrobial activity but the implications of this activity in healthcare settings are still unclear. No clear effect on healthcare associated infections has been demonstrated yet. Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Antibacterial and anti-inflammatory activity of a temporin B peptide analogue on an in vitro model of cystic fibrosis.

PubMed

Bezzerri, Valentino; Avitabile, Concetta; Dechecchi, Maria Cristina; Lampronti, Ilaria; Borgatti, Monica; Montagner, Giulia; Cabrini, Giulio; Gambari, Roberto; Romanelli, Alessandra

2014-10-01

Natural peptides with antimicrobial properties are deeply investigated as tools to fight bacteria resistant to common antibiotics. Small peptides, as those belonging to the temporin family, are very attractive because their activity can easily be tuned after small modification to their primary sequence. Structure-activity studies previously reported by us allowed the identification of one peptide, analogue of temporin B, TB_KKG6A, showing, unlike temporin B, antimicrobial activity against both Gram-positive and Gram-negative bacteria. In this paper, we investigated the antimicrobial and anti-inflammatory activity of the peptide TB_KKG6A against Pseudomonas aeruginosa. Interestingly, we found that the peptide exhibits antimicrobial activity at low concentrations, being able to downregulate the pro-inflammatory chemokines and cytokines interleukin (IL)-8, IL-1β, IL-6 and tumor necrosis factor-α produced downstream infected human bronchial epithelial cells. Experiments were carried out also with temporin B, which was found to show pro-inflammatory activity. Details on the interaction between TB_KKG6A and the P. aeruginosa LPS were obtained by circular dichroism and fluorescence studies. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

Antimicrobial Activity and Phytochemical Analysis of Organic Extracts from Cleome spinosa Jaqc.

PubMed Central

da Silva, Ana P. Sant'Anna; Nascimento da Silva, Luís C.; Martins da Fonseca, Caíque S.; de Araújo, Janete M.; Correia, Maria T. dos Santos; Cavalcanti, Marilene da Silva; Lima, Vera L. de Menezes

2016-01-01

Due to the use of Cleome spinosa Jacq. (Cleomaceae) in traditional medicine against inflammatory and infectious processes, this study evaluated the in vitro antimicrobial potential and phytochemical composition of extracts from its roots and leaves. From leaves (L) and roots (R) of C. spinosa different extracts were obtained (cyclohexane: ChL and ChR; chloroform: CL and CR; ethyl acetate: EAL and EAR, methanol: ML and MR). The antimicrobial activity was evaluated by the broth microdilution method to obtain the minimum inhibitory (MIC) and microbicidal (MMC) concentrations against 17 species, including bacteria and yeasts. Additionally, antimicrobial and combinatory effects with oxacillin were assessed against eight clinical isolates of Staphylococcus aureus. All C. spinosa extracts showed a broad spectrum of antimicrobial activity, as they have inhibited all tested bacteria and yeasts. This activity seems to be related to the phytochemicals (flavonoid, terpenoids and saponins) detected into the extracts of C. spinosa. ChL and CL extracts were the most actives, with MIC less than 1 mg/mL against S. aureus, Bacillus subtilis, and Micrococcus luteus. It is important to note that these concentrations are much lower than their 50% hemolysis concentration (HC50) values. Strong correlations were found between the average MIC against S. aureus and their phenolic (r = −0.89) and flavonoid content (r = −0.87), reinforcing the possible role of these metabolite classes on the antimicrobial activity of C. spinosa derived extracts. Moreover, CL and CR showed the best inhibitory activity against S. aureus clinical isolates, they also showed synergistic action with oxacillin against all these strains (at least at one combined proportion). These results encourage the identification of active substances which could be used as lead(s) molecules in the development of new antimicrobial drugs. PMID:27446005

Strategies for transformation of naturally-occurring amphibian antimicrobial peptides into therapeutically valuable anti-infective agents.

PubMed

Conlon, J Michael; Al-Ghaferi, Nadia; Abraham, Bency; Leprince, Jérôme

2007-08-01

The emergence of strains of pathogenic microorganisms with resistance to commonly used antibiotics has necessitated a search for novel types of antimicrobial agents. Many frog species produce amphipathic alpha-helical peptides with broad spectrum antimicrobial activity in the skin but their therapeutic potential is limited by varying degrees of cytolytic activity towards eukaryotic cells. Methods for development of such peptides into anti-infective drugs are illustrated by the example of temporin-1DRa (HFLGTLVNLAK KIL.NH(2)). Studies with model alpha-helical peptides have shown that increase in cationicity promotes antimicrobial activity whereas increases in hydrophobicity, helicity and amphipathicity promote hemolytic activity and loss of selectivity for microorganisms. Analogs of temporin-1DRa in which each amino acid is replaced by L-lysine and D-lysine were synthesized and their cytolytic activities tested against a range of microorganisms and human erythrocytes. Small changes in structure produced marked changes in conformation, as determined by retention time on reversed-phase HPLC, and in biological activity. However, peptides containing the substitutions (Val(7) -->L-Lys), (Thr(5)-->D-Lys) and (Asn(8)-->D-Lys) retained the high solubility and potent, broad spectrum antimicrobial activity of the naturally occurring peptide but were appreciably (up to 10-fold) less hemolytic. In contrast, analogs in which Leu(9) and Ile(13) were replaced by the more hydrophobic cyclohexylglycine residue showed slightly increased antimicrobial potencies (up to 2-fold) but a 4-fold increase in hemolytic activity. The data suggest a strategy of selective increases in cationicity concomitant with decreases in helicity and hydrophobicity in the transformation of naturally-occurring antimicrobial peptides into non-toxic therapeutic agents.

Antimicrobial activity of yeasts against some pathogenic bacteria

PubMed Central

Younis, Gamal; Awad, Amal; Dawod, Rehab E.; Yousef, Nehal E.

2017-01-01

Aim: This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species. Materials and Methods: A total of 160 milk and meat products samples were collected from random sellers and super markets in New Damietta city, Damietta, Egypt. Samples were subjected to yeast isolation procedures and tested for its antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In addition, all yeast species isolates were subjected to polymerase chain reaction (PCR) for detection of khs (kievitone hydratase) and pelA (pectate degrading enzyme)genes. Results: The recovery rate of yeasts from sausage was 20% (2/10) followed by kareish cheese, processed cheese, and butter 10% (1/10) each as well as raw milk 9% (9/100), and fruit yoghurt 30% (6/20). Different yeast species were recovered, namely, Candida kefyr (5 isolates), Saccharomyces cerevisiae (4 isolates), Candida intermedia (3 isolates), Candida tropicalis (2 isolates), Candida lusitaniae (2 isolates), and Candida krusei (1 isolate). khs gene was detected in all S. cerevisiae isolates, however, pelA gene was not detected in all identified yeast species. Antimicrobial activity of recovered yeasts against the selected bacterial species showed high activity with C. intermedia against S. aureus and E. coli, C. kefyr against E. coli, and C. lusitaniae against S. aureus. Moderate activities were obtained with C. tropicalis, C. lusitaniae, and S. cerevisiae against E. coli; meanwhile, all the tested yeasts revealed a very low antimicrobial activity against P. aeruginosa. Conclusion: The obtained results confirmed that some kinds of yeasts have the ability to produce antimicrobial compounds that could inhibit some pathogenic and spoilage bacteria and these antimicrobial activity of yeasts enables them to be one of the novel agents in controlling spoilage of food. PMID:28919693

Antimicrobial activity and mechanism of the human milk-sourced peptide Casein201

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Fan; Department of Endocrinology, Children's Hospital of Nanjing Medical University, Nanjing; Cui, Xianwei

Introduction: Casein201 is one of the human milk sourced peptides that differed significantly in preterm and full-term mothers. This study is designed to demonstrate the biological characteristics, antibacterial activity and mechanisms of Casein201 against common pathogens in neonatal infection. Methodology: The analysis of biological characteristics was done by bioinformatics. Disk diffusion method and flow cytometry were used to detect the antimicrobial activity of Casein201. Killing kinetics of Casein201 was measured using microplate reader. The antimicrobial mechanism of Casein201 was studied by electron microscopy and electrophoresis. Results: Bioinformatics analysis indicates that Casein201 derived from β-casein and showed significant sequence overlap. Antibacterialmore » assays showed Casein201 inhibited the growth of S taphylococcus aureus and Y ersinia enterocolitica. Ultrastructural analyses revealed that the antibacterial activity of Casein201 is through cytoplasmic structures disintegration and bacterial cell envelope alterations but not combination with DNA. Conclusion: We conclude the antimicrobial activity and mechanism of Casein201. Our data demonstrate that Casein201 has potential therapeutic value for the prevention and treatment of pathogens in neonatal infection.« less

Antimicrobial activity and mechanism of the human milk-sourced peptide Casein201.

PubMed

Zhang, Fan; Cui, Xianwei; Fu, Yanrong; Zhang, Jun; Zhou, Yahui; Sun, Yazhou; Wang, Xing; Li, Yun; Liu, Qianqi; Chen, Ting

2017-04-08

Casein201 is one of the human milk sourced peptides that differed significantly in preterm and full-term mothers. This study is designed to demonstrate the biological characteristics, antibacterial activity and mechanisms of Casein201 against common pathogens in neonatal infection. The analysis of biological characteristics was done by bioinformatics. Disk diffusion method and flow cytometry were used to detect the antimicrobial activity of Casein201. Killing kinetics of Casein201 was measured using microplate reader. The antimicrobial mechanism of Casein201 was studied by electron microscopy and electrophoresis. Bioinformatics analysis indicates that Casein201 derived from β-casein and showed significant sequence overlap. Antibacterial assays showed Casein201 inhibited the growth of S taphylococcus aureus and Y ersinia enterocolitica. Ultrastructural analyses revealed that the antibacterial activity of Casein201 is through cytoplasmic structures disintegration and bacterial cell envelope alterations but not combination with DNA. We conclude the antimicrobial activity and mechanism of Casein201. Our data demonstrate that Casein201 has potential therapeutic value for the prevention and treatment of pathogens in neonatal infection. Copyright © 2017 Elsevier Inc. All rights reserved.

Benzothiazole analogues: Synthesis, characterization, MO calculations with PM6 and DFT, in silico studies and in vitro antimalarial as DHFR inhibitors and antimicrobial activities.

PubMed

Thakkar, Sampark S; Thakor, Parth; Ray, Arabinda; Doshi, Hiren; Thakkar, Vasudev R

2017-10-15

Benzothiazole analogues are of interest due to their potential activity against malarial and microbial infections. In search of suitable antimicrobial and antimalarial agents, we report here the synthesis, characterization and biological activities of benzothiazole analogues (J 1-J 10). The molecules were characterized by IR, Mass, 1 H NMR, 13 C NMR and elemental analysis. The in vitro antimicrobial activity was investigated against pathogenic strains; the results were explained with the help of DFT and PM6 molecular orbital calculations. In vitro cytotoxicity and genotoxicity of the molecules were studied against S. pombe cells. In vitro antimalarial activity was studied. The active compounds J 1, J 2, J 3, J 5 and J 6 were further evaluated for enzyme inhibition efficacy against the receptor Pf-DHFR, computational and in vitro studies were carried out to examine their candidatures as lead dihydrofolate reductase inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antimicrobial and Efflux Inhibitor Activity of Usnic Acid Against Mycobacterium abscessus.

PubMed

Ramis, Ivy B; Vianna, Júlia S; Reis, Ana Júlia; von Groll, Andrea; Ramos, Daniela F; Viveiros, Miguel; da Silva, Pedro E Almeida

2018-06-18

New drugs are needed to treat infections with antimicrobial-resistant Mycobacterium abscessus ; therefore, we evaluated usnic acid as an antimicrobial agent and efflux inhibitor (EI) against M. abscessus . Usnic acid showed antimicrobial activity, and synergistically, the EI verapamil increased this activity. In addition, when we evaluated the interaction of antimicrobials with usnic acid, the increase of their activity was observed. Finally, usnic acid showed an efflux inhibitory effect between the classical EIs verapamil and carbonyl cyanide m-chlorophenylhydrazine. In conclusion, usnic acid showed both antimicrobial and EI activity, indicating that this natural compound may be a promising scaffold for new drugs against this difficult-to-treat microorganism. Georg Thieme Verlag KG Stuttgart · New York.

Chemical composition, antioxidant and antimicrobial activities of essential oil from Wedelia prostrata

PubMed Central

Dai, Jiali; Zhu, Liang; Yang, Li; Qiu, Jun

2013-01-01

The following study deals with the chemical composition, antioxidant and antimicrobial activity of essential oils of Wedelia prostrata and their main constituents in vitro. A total of 70 components representing 99.26 % of the total oil were identified. The main compounds in the oil were limonene (11.38 %) and α-pinene (10.74 %). Antioxidant assays (1,1-diphenyl-2-picrylhydrazyl, superoxide anion radical, and reducing power test) demonstrate moderate activities for the essential oil and its main components (limonene and α-pinene). The essential oil (1000 μg/disc) exhibited promising antimicrobial activity against 10 strains of test microorganisms as a diameter of zones of inhibition (20.8 to 22.2 mm) and MIC values (125 to 250 µg/ml). The activities of limonene and α-pinene were also determined as main components of the oil. α-Pinene showed higher antimicrobial activity than the essential oil with a diameter of zones of inhibition (20.7 to 22.3 mm) and MIC values (62.5 to 125 µg/ml). The antioxidant and antimicrobial properties of the essential oil may be attributed to the synergistic effects of its diverse major and minor components. PMID:26648809

Effects of nisin on the antimicrobial activity of d-limonene and its nanoemulsion.

PubMed

Zhang, Zijie; Vriesekoop, Frank; Yuan, Qipeng; Liang, Hao

2014-05-01

d-Limonene has been considered to be a safer alternative compared to synthetic antimicrobial food additives. However, its hydrophobic and oxidative nature has limited its application in foods. The purpose of this research was to study effects of nisin on the antimicrobial activity of d-limonene and its nanoemulsion and develop a novel antimicrobial delivery system by combining the positive effect of these two antibacterial agents at the same time. By the checkerboard method, both the synergistic and additive effects of d-limonene and nisin were found against four selected food-related microorganisms. Then, d-limonene nanoemulsion with or without nisin was prepared by catastrophic phase inversion method, which has shown good droplet size and stability. The positive effects and outstanding antimicrobial activity of d-limonene nanoemulsion with nisin were confirmed by MICs comparison, scanning electron microscopy and determination of cell constituents released. Overall, the research described in the current article would be helpful in developing a more effective antimicrobial system for the production and preservation of foods. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Antibacterial activity of fresh pomegranate juice against clinical strains of Staphylococcus epidermidis

PubMed Central

Betanzos-Cabrera, Gabriel; Montes-Rubio, Perla Y.; Fabela-Illescas, Héctor E.; Belefant-Miller, Helen; Cancino-Diaz, Juan C.

2015-01-01

Background Polyphenols have received a great deal of attention due to their biological functions. Pomegranate (Punica granatum L.) is a polyphenol-rich fruit. In the past decade, studies testing the antimicrobial activity of pomegranates almost exclusively used solvent extracts instead of fresh pomegranate juice (FPJ). The use of FPJ instead of solvent extracts would reduce toxicity issues while increasing patient acceptance. We established a model to test FPJ as a natural antimicrobial agent. Objective To evaluate the antimicrobial activity of FPJ on clinical isolates of multidrug-resistant Staphylococcus epidermidis strains. Design Sixty strains of S. epidermidis isolated from ocular infections were grown in the presence of FPJ, and minimum inhibitory concentration (MIC) was determined by broth and agar dilution methods. Results FPJ at 20% had a MIC equal to 100% (MIC100%) on all 60 strains tested. This inhibition of FPJ was confirmed by the growth kinetics of a multidrug-resistant strain exposed to different concentrations of FPJ. Additionally, the antimicrobial activity of FPJ was compared against commercial beverages containing pomegranate: Ocean Spray® had a MIC100% at 20%, followed by Del Valle® with a MIC15% at 20% concentration only. The beverages Jumex® and Sonrisa® did not have any antimicrobial activity. FPJ had the highest polyphenol content and antioxidant capacity. Conclusions Overall, FPJ had antimicrobial activity, which might be attributed to its high polyphenol content and antioxidant capacity. PMID:25999265

Artichoke and milk thistle pills and syrups as sources of phenolic compounds with antimicrobial activity.

PubMed

Pereira, Carla; Barros, Lillian; José Alves, Maria; Santos-Buelga, Celestino; Ferreira, Isabel C F R

2016-07-13

Dietary supplements based on hepatoprotective plants have been increasingly used in the prevention of liver injuries. In the present work, the aim was to study the phenolic profile and possibly relate it to the in vitro antimicrobial activity of two different formulations (pills and syrups) of artichoke and milk thistle, the antioxidant and anti-hepatocellular carcinoma activities of which were previously reported by our research group. The phenolic profiles were obtained by HPLC-DAD-ESI/MS, and the antimicrobial activity evaluation was performed with the clinical isolates of multiresistant bacteria (Escherichia coli, extended spectrum β-lactamases (ESBL) producing Escherichia coli, Proteus mirabilis, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa). Artichoke syrup revealed the presence of vanillic acid and luteolin-7-O-glucoside while the pills possessed higher concentrations of 4-O-caffeoylquinic, 5-O-caffeoylquinic and 1,3-O-dicaffeoylquinic acids, this latest being able to inhibit the growth of MRSA. Regarding milk thistle formulations, the syrup presented isorhamnetin-O-deoxyhexoside-O-dihexoside, isorhamnetin-O-deoxyhexoside-O-hexoside and isorhamnetin-3-O-rutinoside as the major phenolic constituents whereas the pills were richer in taxifolin, silymarin derivatives and hydroxylated silibinin; the syrup revealed antimicrobial activity against all the studied bacteria with the exception of Proteus mirabilis whereas the pills revealed activity against ESBL producing Escherichia coli. Overall, all of the studied formulations revealed to be a good source of phenolic compounds, among which milk thistle syrup presented the highest variety and concentration of flavonoids, which is possibly related to its strongest antimicrobial activity.

Anti-microbial Activity of Urine after Ingestion of Cranberry: A Pilot Study.

PubMed

Lee, Yee Lean; Najm, Wadie I; Owens, John; Thrupp, Laurie; Baron, Sheryl; Shanbrom, Edward; Cesario, Thomas

2010-06-01

We explore the anti-microbial activity of urine specimens after the ingestion of a commercial cranberry preparation. Twenty subjects without urinary infection, off antibiotics and all supplements or vitamins were recruited. The study was conducted in two phases: in phase 1, subjects collected the first morning urine prior to ingesting 900 mg of cranberry and then at 2, 4 and 6 h. In phase 2, subjects collected urine on 2 consecutive days: on Day 1 no cranberry was ingested (control specimens), on Day 2, cranberry was ingested. The pH of all urine specimens were adjusted to the same pH as that of the first morning urine specimen. Aliquots of each specimen were independently inoculated with Escherichia coli, Klebsiella pneumoniae or Candida albicans. After incubation, colony forming units/ml (CFU ml(-1)) in the control specimen was compared with CFU ml(-1) in specimens collected 2, 4 and 6 h later. Specimens showing ≥50% reduction in CFU ml(-1) were considered as having 'activity' against the strains tested. In phase 1, 7/20 (35%) subjects had anti-microbial activity against E. coli, 13/20 (65%) against K. pneumoniae and 9/20 (45%) against C. albicans in specimens collected 2-6 h after ingestion of cranberry. In phase 2, 6/9 (67%) of the subjects had activity against K. pneumoniae. This pilot study demonstrates weak anti-microbial activity in urine specimens after ingestion of a single dose of commercial cranberry. Anti-microbial activity was noted only against K. pneumoniae 2-6 h after ingestion of the cranberry preparation.

The AMPK-PPARGC1A pathway is required for antimicrobial host defense through activation of autophagy.

PubMed

Yang, Chul-Su; Kim, Jwa-Jin; Lee, Hye-Mi; Jin, Hyo Sun; Lee, Sang-Hee; Park, Ji-Hoon; Kim, Soung Jung; Kim, Jin-Man; Han, Yong-Mahn; Lee, Myung-Shik; Kweon, Gi Ryang; Shong, Minho; Jo, Eun-Kyeong

2014-05-01

AMP-activated protein kinase (AMPK) is a crucial energy sensor and plays a key role in integration of cellular functions to maintain homeostasis. Despite this, it is largely unknown whether targeting the AMPK pathway can be used as a therapeutic strategy for infectious diseases. Herein, we show that AMPK activation robustly induces antibacterial autophagy, which contributes to antimicrobial defense against Mycobacterium tuberculosis (Mtb). AMPK activation led to inhibition of Mtb-induced phosphorylation of the mechanistic target of rapamycin (MTOR) in macrophages. In addition, AMPK activation increased the genes involved in oxidative phosphorylation, mitochondrial ATP production, and biogenesis in Mtb-infected macrophages. Notably, peroxisome proliferator-activated receptor-gamma, coactivator 1α (PPARGC1A) was required for AMPK-mediated antimicrobial activity, as well as enhancement of mitochondrial function and biogenesis, in macrophages. Further, the AMPK-PPARGC1A pathway was involved in the upregulation of multiple autophagy-related genes via CCAAT/enhancer binding protein (C/EBP), β (CEBPB). PPARGC1A knockdown inhibited the AMPK-mediated induction of autophagy and impaired the fusion of phagosomes with MAP1LC3B (LC3B) autophagosomes in Mtb-infected macrophages. The link between autophagy, mitochondrial function, and antimicrobial activity was further demonstrated by studying LysMCre-mediated knockout of atg7, demonstrating mitochondrial ultrastructural defects and dysfunction, as well as blockade of antimicrobial activity against mycobacteria. Collectively, our results identify the AMPK-PPARGC1A axis as contributing to autophagy activation leading to an antimicrobial response, as a novel host defense mechanism.

Triterpenoids from Acacia ataxacantha DC: antimicrobial and antioxidant activities.

PubMed

Amoussa, Abdou Madjid O; Lagnika, Latifou; Bourjot, Mélanie; Vonthron-Senecheau, Cathérine; Sanni, Ambaliou

2016-08-12

Acacia ataxacantha is a medicinal specie used extensively in traditional medicine of Benin republic to treat infectious diseases. Our previous study showed interesting antibacterial and antifungal activities against six strains of bacteria and six strains of fungi. The aim of this study was to investigate the antimicrobial and antioxidant activities of compounds isolated from A. ataxacantha. Chromatographic and spectroscopic methods were used to isolate and identify three compounds (1-3) from the bark of A. ataxacantha. Phytochemical investigation of A. ataxacantha (Fabaceae) led to the isolation of three triterpenoids (1-3). The structure of isolated compounds was established by differents spectroscopic methods such as UV, (1)H NMR, (13)C NMR, 2D NMR and Mass. All isolated compounds were tested for antimicrobial activity using agar disc-diffusion and microdilution methods. The radical scavenging activity of isolated compounds was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Phytochemical investigation led to the isolation and identification of lupeol (1), betulinic acid (2) and betulinic acid-3-trans-caffeate (3). Moderate antimicrobial activity was obtained with compound 3 against methicillin-resitant Staphylococcus aureus, Enterococcus feacalis and Pseudomonas aeruginosa with MIC value of 25 μg/ml and Staphylococcus aureus (MIC of 50 μg/ml). Compounds 3 was more active against Staphylococcus epidermidis and Candida albicans with a MIC value of 12.5 μg/ml in boths cases. Compounds 3 had also interesting antioxidant activity with an IC50 of 3.57 μg/ml compared to quercetin (1.04 μg/ml). The overall results of this study provide evidence that the compound 3, isolated from A. ataxacantha, exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria and yeast, especially against C. albicans.

Proline-rich antimicrobial peptides: potential therapeutics against antibiotic-resistant bacteria.

PubMed

Li, Wenyi; Tailhades, Julien; O'Brien-Simpson, Neil M; Separovic, Frances; Otvos, Laszlo; Hossain, M Akhter; Wade, John D

2014-10-01

The increasing resistance of pathogens to antibiotics causes a huge clinical burden that places great demands on academic researchers and the pharmaceutical industry for resolution. Antimicrobial peptides, part of native host defense, have emerged as novel potential antibiotic alternatives. Among the different classes of antimicrobial peptides, proline-rich antimicrobial peptides, predominantly sourced from insects, have been extensively investigated to study their specific modes of action. In this review, we focus on recent developments in these peptides. They show a variety of modes of actions, including mechanism shift at high concentration, non-lytic mechanisms, as well as possessing different intracellular targets and lipopolysaccharide binding activity. Furthermore, proline-rich antimicrobial peptides display the ability to not only modulate the immune system via cytokine activity or angiogenesis but also possess properties of penetrating cell membranes and crossing the blood brain barrier suggesting a role as potential novel carriers. Ongoing studies of these peptides will likely lead to the development of more potent antimicrobial peptides that may serve as important additions to the armoury of agents against bacterial infection and drug delivery.

Production of the antimicrobial peptides Caseicin A and B by Bacillus isolates growing on sodium caseinate.

PubMed

Kent, R M; Guinane, C M; O'Connor, P M; Fitzgerald, G F; Hill, C; Stanton, C; Ross, R P

2012-08-01

The aim of this study was to identify Bacillus isolates capable of degrading sodium caseinate and subsequently to generate bioactive peptides with antimicrobial activity. Sodium caseinate (2.5% w/v) was inoculated separately with 16 Bacillus isolates and allowed to ferment overnight. Protein breakdown in the fermentates was analysed using gel permeation-HPLC (GP-HPLC) and screened for peptides (<3-kDa) with MALDI-TOF mass spectrometry. Caseicin A (IKHQGLPQE) and caseicin B (VLNENLLR), two previously characterized antimicrobial peptides, were identified in the fermentates of both Bacillus cereus and Bacillus thuringiensis isolates. The caseicin peptides were subsequently purified by RP-HPLC and antimicrobial assays indicated that the peptides maintained the previously identified inhibitory activity against the infant formula pathogen Cronobacter sakazakii. We report a new method using Bacillus sp. to generate two previously characterized antimicrobial peptides from casein. This study highlights the potential to exploit Bacillus sp. or the enzymes they produce for the generation of bioactive antimicrobial peptides from bovine casein. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

Synthesis, crystal structure, ABTS radical-scavenging activity, antimicrobial and docking studies of some novel quinoline derivatives

NASA Astrophysics Data System (ADS)

Tabassum, Sumaiya; Suresha Kumara, T. H.; Jasinski, Jerry P.; Millikan, Sean P.; Yathirajan, H. S.; Sujan Ganapathy, P. S.; Sowmya, H. B. V.; More, Sunil S.; Nagendrappa, Gopalpur; Kaur, Manpreet; Jose, Gilish

2014-07-01

In this study, a series of nine novel 2-chloroquinolin-3-yl ester derivatives have been synthesized via a two-step protocol from 2-chloroquinoline-3-carbaldehyde. The structures of all these compounds were confirmed by spectral data. The single crystal X-ray structure of two derivatives, (2-chloroquinolin-3-yl)methyl acetate [6a] and (2-chloro-6-methylquinolin-3-yl)methyl acetate [6e] have also been determined. The synthesized compounds were further evaluated for their ABTS radical-scavenging activity and antimicrobial activities. Amongst all the tested compounds, 6a exhibited maximum scavenging activity with ABTS. Concerning antibacterial and antifungal activities, compound (2-chloro-6-methoxyquinolin-3-yl)methyl 2,4-dichlorobenzoate [6i] was found to be the most active in the series against B. subtilis, S. aureus, E. coli, K. pneumonia, C. albicans and A. niger species. The structure-antimicrobial activity relationship of these derivatives were studied using Autodock.

Chemical Profile and Antioxidant, Anti-Inflammatory, Antimutagenic and Antimicrobial Activities of Geopropolis from the Stingless Bee Melipona orbignyi

PubMed Central

dos Santos, Helder Freitas; Campos, Jaqueline Ferreira; dos Santos, Cintia Miranda; Balestieri, José Benedito Perrella; Silva, Denise Brentan; Carollo, Carlos Alexandre; de Picoli Souza, Kely; Estevinho, Leticia Miranda; dos Santos, Edson Lucas

2017-01-01

Geopropolis is a resin mixed with mud, produced only by stingless bees. Despite being popularly known for its medicinal properties, few scientific studies have proven its biological activities. In this context, the objective of this study was to determine the chemical composition and antioxidant, anti-inflammatory, antimutagenic and antimicrobial activities of the Melipona orbignyi geopropolis. The hydroalcoholic extract of geopropolis (HEGP) was prepared and its chemical composition determined by high performance liquid chromatography coupled to diode array detector and mass spectrometry (HPLC-DAD-MS). The antioxidant activity was determined by the capture of free radicals and inhibition of lipid peroxidation in human erythrocytes. The anti-inflammatory activity was evaluated by the inhibition of the hyaluronidase enzyme and the antimutagenic action was investigated in Saccharomyces cerevisiae colonies. The antimicrobial activities were determined against bacteria and yeasts, isolated from reference strains and hospital origin. The chemical composition of HEGP included flavonoids, derivatives of glycosylated phenolic acids and terpenoids. HEGP showed high antioxidant activity, it inhibited the activity of the inflammatory enzyme hyaluronidase and reduced the mutagenic effects in S. cerevisiae. In relation to the antimicrobial activity, it promoted the death of all microorganisms evaluated. In conclusion, this study reveals for the first time the chemical composition of the HEGP of M. orbignyi and demonstrates its pharmacological properties. PMID:28467350

Chemical Profile and Antioxidant, Anti-Inflammatory, Antimutagenic and Antimicrobial Activities of Geopropolis from the Stingless Bee Melipona orbignyi.

PubMed

Santos, Helder Freitas Dos; Campos, Jaqueline Ferreira; Santos, Cintia Miranda Dos; Balestieri, José Benedito Perrella; Silva, Denise Brentan; Carollo, Carlos Alexandre; de Picoli Souza, Kely; Estevinho, Leticia Miranda; Dos Santos, Edson Lucas

2017-05-03

Geopropolis is a resin mixed with mud, produced only by stingless bees. Despite being popularly known for its medicinal properties, few scientific studies have proven its biological activities. In this context, the objective of this study was to determine the chemical composition and antioxidant, anti-inflammatory, antimutagenic and antimicrobial activities of the Melipona orbignyi geopropolis. The hydroalcoholic extract of geopropolis (HEGP) was prepared and its chemical composition determined by high performance liquid chromatography coupled to diode array detector and mass spectrometry (HPLC-DAD-MS). The antioxidant activity was determined by the capture of free radicals and inhibition of lipid peroxidation in human erythrocytes. The anti-inflammatory activity was evaluated by the inhibition of the hyaluronidase enzyme and the antimutagenic action was investigated in Saccharomyces cerevisiae colonies. The antimicrobial activities were determined against bacteria and yeasts, isolated from reference strains and hospital origin. The chemical composition of HEGP included flavonoids, derivatives of glycosylated phenolic acids and terpenoids. HEGP showed high antioxidant activity, it inhibited the activity of the inflammatory enzyme hyaluronidase and reduced the mutagenic effects in S. cerevisiae . In relation to the antimicrobial activity, it promoted the death of all microorganisms evaluated. In conclusion, this study reveals for the first time the chemical composition of the HEGP of M. orbignyi and demonstrates its pharmacological properties.

Synthesis, spectral, thermal and antimicrobial studies on cobalt(II), nickel(II), copper(II), zinc(II) and palladium(II) complexes containing thiosemicarbazone ligand

NASA Astrophysics Data System (ADS)

El-Sawaf, Ayman K.; El-Essawy, Farag; Nassar, Amal A.; El-Samanody, El-Sayed A.

2018-04-01

The coordination characteristic of new N4-morpholinyl isatin-3-thiosemicarbazone (HL) towards Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) has been studies. The structures of the complexes were described by elemental analyses, molar conductivity, magnetic, thermal and spectral (IR, UV-Vis, 1H and 13C NMR and ESR) studies. On the basis of analytical and spectral studies the ligand behaves as monobasic tridentate ONS donor forming two five membered rings towards cobalt, copper and palladium and afforded complexes of the kind [M(L)X], (Mdbnd Co, Cu or Pd; Xdbnd Cl, Br or OAc). Whereas the ligand bound to NiCl2 as neutral tridentate ONS donor and with ZnCl2 as neutral bidentate NS donor. The newly synthesized thiosemicarbazone ligand and some of its complexes were examined for antimicrobial activity against 2 gram negative bacterial strains (Escherichia coli Pseudomonas and aeruginosa), 2 gram positive bacterial strains (Streptococcus pneumoniae and Staphylococcus aureus)} and two Pathogenic fungi (Aspergillus fumigatus and Candida albicans). All metal complexes possess higher antimicrobial activity comparing with the free thiosemicarbazone ligand. The high potent activities of the complexes may arise from the coordination and chelation, which tends to make metal complexes act as more controlling and potent antimicrobial agents, thus hindering the growing of the microorganisms. The antimicrobial results also show that copper bromide complex is better antimicrobial agent as compared to the Schiff base and its metal complexes.

Synthesis and Antibacterial Activities of Antibacterial Peptides with a Spiropyran Fluorescence Probe

PubMed Central

Chen, Lei; Zhu, Yu; Yang, Danling; Zou, Rongfeng; Wu, Junchen; Tian, He

2014-01-01

In this report, antibacterial peptides1-3 were prepared with a spiropyran fluorescence probe. The probe exhibits a change in fluorescence when isomerized from a colorless spiro-form (spiropyran, Sp) to a colored open-form (merocyanine, Mc) under different chemical environments, which can be used to study the mechanism of antimicrobial activity. Peptides 1-3 exhibit a marked decrease in antimicrobial activity with increasing alkyl chain length. This is likely due to the Sp-Mc isomers in different polar environments forming different aggregate sizes in TBS, as demonstrated by time-dependent dynamic light scattering (DLS). Moreover, peptides 1-3 exhibited low cytotoxicity and hemolytic activity. These probe-modified peptides may provide a novel approach to study the effect of structural changes on antibacterial activity, thus facilitating the design of new antimicrobial agents to combat bacterial infection. PMID:25358905

The antimicrobial efficacy of sustained release silver–carbene complex-loaded l-tyrosine polyphosphate nanoparticles: Characterization, in vitro and in vivo studies

PubMed Central

Hindi, Khadijah M.; Ditto, Andrew J.; Panzner, Matthew J.; Medvetz, Douglas A.; Han, Daniel S.; Hovis, Christine E.; Hilliard, Julia K.; Taylor, Jane B.; Yun, Yang H.; Cannon, Carolyn L.; Youngs, Wiley J.

2009-01-01

The pressing need to treat multi-drug resistant bacteria in the chronically infected lungs of cystic fibrosis (CF) patients has given rise to novel nebulized antimicrobials. We have synthesized a silver–carbene complex (SCC10) active against a variety of bacterial strains associated with CF and chronic lung infections. Our studies have demonstrated that SCC10-loaded into l-tyrosine polyphosphate nanoparticles (LTP NPs) exhibits excellent antimicrobial activity in vitro and in vivo against the CF relevant bacteria Pseudomonas aeruginosa. Encapsulation of SCC10 in LTP NPs provides sustained release of the antimicrobial over the course of several days translating into efficacious results in vivo with only two administered doses over a 72 h period. PMID:19395021

Specific Midgut Region Controlling the Symbiont Population in an Insect-Microbe Gut Symbiotic Association

PubMed Central

Kim, Jiyeun Kate; Kim, Na Hyang; Jang, Ho Am; Kikuchi, Yoshitomo; Kim, Chan-Hee

2013-01-01

Many insects possess symbiotic bacteria that affect the biology of the host. The level of the symbiont population in the host is a pivotal factor that modulates the biological outcome of the symbiotic association. Hence, the symbiont population should be maintained at a proper level by the host's control mechanisms. Several mechanisms for controlling intracellular symbionts of insects have been reported, while mechanisms for controlling extracellular gut symbionts of insects are poorly understood. The bean bug Riptortus pedestris harbors a betaproteobacterial extracellular symbiont of the genus Burkholderia in the midgut symbiotic organ designated the M4 region. We found that the M4B region, which is directly connected to the M4 region, also harbors Burkholderia symbiont cells, but the symbionts therein are mostly dead. A series of experiments demonstrated that the M4B region exhibits antimicrobial activity, and the antimicrobial activity is specifically potent against the Burkholderia symbiont but not the cultured Burkholderia and other bacteria. The antimicrobial activity of the M4B region was detected in symbiotic host insects, reaching its highest point at the fifth instar, but not in aposymbiotic host insects, which suggests the possibility of symbiont-mediated induction of the antimicrobial activity. This antimicrobial activity was not associated with upregulation of antimicrobial peptides of the host. Based on these results, we propose that the M4B region is a specialized gut region of R. pedestris that plays a critical role in controlling the population of the Burkholderia gut symbiont. The molecular basis of the antimicrobial activity is of great interest and deserves future study. PMID:24038695

Do Aloe vera and Ageratum conyzoides enhance the anti-microbial activity of traditional medicinal soft soaps (Osedudu)?

PubMed

Moody, J O; Adebiyi, O A; Adeniyi, B A

2004-05-01

The Nigerian traditional soft soaps prepared using varied locally sourced raw materials such as cocoa pod ash (Theobroma cacao) palm kernel shaft ash (Elaies guineensis) have been evaluated for their physico-chemical properties and anti-microbial activities using standard pharmacopoeia protocols and an in-vitro agar diffusion bioassay method. The anti-microbial evaluation was done with and without incorporation of Aloe vera and Ageratum conyzoides extractives into the soap samples. Results showed that the physico-chemical properties of the soaps are dependent on the raw materials utilised. The incorporated medicinal plants used in this study, however, did not show any significant effect on the anti-microbial activities exhibited by the various soaps against the bacterial and fungal test organisms. Copyright 2004 Elsevier Ireland Ltd.

Antimicrobial activity of fluoride and its in vivo importance: identification of research questions.

PubMed

Van Loveren, C

2001-01-01

This manuscript discusses the antimicrobial activity of fluoride and its in vivo importance in order to identify research questions. There is a lot of information on mechanisms by which fluoride may interfere with bacterial metabolism and dental plaque acidogenicity. The antimicrobial activity of fluoride products is enhanced when fluoride is associated with antimicrobial cations like Sn(2+) and amine. It is not clear whether the antimicrobial mechanisms of fluoride are operating in vivo or even to what extent antimicrobial activity can contribute to caries prevention. This latter question may be the most important one in research. Copyright 2001 S. Karger AG, Basel.

Antimicrobial activities of bacteriocins E50-52 and B602 against MRSA and other nosocomial infections

USDA-ARS?s Scientific Manuscript database

Our objective was to determine the antimicrobial activities of previously published bacteriocins E50-52 and B602 against methicillin resistant Staphylococcus aureus (MRSA) and other prominent nosocomial bacterial infections. methods: Several Russian hospitals were enlisted into the study from 2003 ...

Antimicrobial efficacy of Cinnamomum javanicum plant extract against Listeria monocytogenes and its application potential with smoked salmon.

PubMed

Yuan, Wenqian; Lee, Hui Wen; Yuk, Hyun-Gyun

2017-11-02

Extracts from medicinal plants have been reported to possess good antimicrobial properties, but a majority of them remain unexplored. This study aimed at identifying a novel plant extract with antimicrobial activity, to validate its efficacy in food model, and to elucidate its composition and antimicrobial mechanism. A total of 125 plant extracts were screened, and Cinnamomum javanicum leaf and stem extract showed potential antimicrobial activity against Listeria monocytogenes (MIC=0.13mg/mL). Total phenolic content of the extract was 78.3mg GAE/g extract and its antioxidant activity was 57.2-326.5mg TE/g extract. When applied on cold smoked salmon, strong strain-dependent antimicrobial effectiveness was observed, with L. monocytogenes LM2 (serotype 4b) and LM8 (serotype 3a) being more resistant compared to SSA81 (serotype 1/2a). High extract concentration (16mg/mL) was needed to inhibit or reduce the growth of L. monocytogenes on smoked salmon, which resulted in surface color change. GC-MS revealed that eucalyptol (25.54 area%) was the most abundant compound in the crude extract. Both crude extract and eucalyptol induced significant membrane damages in treated L. monocytogenes. These results suggest anti-L. monocytogenes activity of C. javanicum plant extract, identified its major volatile components, and elucidated its membrane-damaging antimicrobial mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Bionano Interaction Study on Antimicrobial Star-Shaped Peptide Polymer Nanoparticles.

PubMed

Lam, Shu J; Wong, Edgar H H; O'Brien-Simpson, Neil M; Pantarat, Namfon; Blencowe, Anton; Reynolds, Eric C; Qiao, Greg G

2016-12-14

'Structurally nanoengineered antimicrobial peptide polymers' (SNAPPs), in the form of star-shaped peptide polymer nanoparticles, have been recently demonstrated as a new class of antimicrobial agents with superior in vitro and in vivo efficacy against Gram-negative pathogens, including multidrug-resistant species. Herein, we present a detailed bionano interaction study on SNAPPs by assessing their antimicrobial activities against several Gram-negative bacteria in complex biological matrices. Simulated body fluid and animal serum were used as test media to reveal factors that influence the antimicrobial efficacy of SNAPPs. With the exception of Acinetobacter baumannii, the presence of divalent cations at physiological concentrations reduced the antimicrobial efficacy of SNAPPs from minimum inhibitory concentrations (MICs) within the nanomolar range (40-300 nM) against Escherichia coli, Pseudomanas aeruginosa, and Klebsiella pneumoniae to 0.6-4.7 μM. By using E. coli as a representative bacterial species, we demonstrated that the reduction in activity was due to a decrease in the ability of SNAPPs to cause outer and inner membrane disruption. This effect could be reversed through coadministration with a chelating agent. Interestingly, the potency of SNAPPs against A. baumannii was retained even under high salt concentrations. The presence of serum proteins was also found to affect the interaction of SNAPPs with bacterial membranes, possibly through intermolecular binding. Collectively, this study highlights the need to consider the possible interactions of (bio)molecules present in vivo with any new antimicrobial agent under development. We also demonstrate that outer membrane disruption/destabilization is an important but hitherto under-recognized target for the antimicrobial action of peptide-based agents, such as antimicrobial peptides (AMPs). Overall, the findings presented herein could aid in the design of more efficient peptide-based antimicrobial agents with uncompromised potency even under physiological conditions.

Screening for antibacterial activity of some Turkish plants against fish pathogens: a possible alternative in the treatment of bacterial infections

PubMed Central

Turker, Hakan; Yıldırım, Arzu Birinci

2015-01-01

The antibacterial activity of ethanolic and aqueous crude extracts from 36 plants in Turkey, including seven endemic species, against fish pathogens was studied using the disc diffusion assay. The extract that was most active against all microbial strains, except Aeromonas salmonicida, was that of Dorycnium pentaphyllum. Some of the extracts also showed a very broad spectrum of potent antimicrobial activity. The extract of Anemone nemorosa showed the highest antimicrobial activity against Vibrio anguillarum. V. anguillarum, a Gram-negative bacterium, appeared to be the most susceptible to the plant extracts used in this experiment. To the best of our knowledge, this is the first report on the antimicrobial activity of 11 of the studied plants. The preliminary screening assay indicated that some of the Turkish plants with antibacterial properties may offer alternative therapeutic agents against bacterial infections in aquaculture industry. PMID:26019642

Hyaluronan- and heparin-reduced silver nanoparticles with antimicrobial properties

PubMed Central

Kemp, Melissa M; Kumar, Ashavani; Clement, Dylan; Ajayan, Pulickel; Mousa, Shaker

2009-01-01

Aims Silver nanoparticles exhibit unique antibacterial properties that make these ideal candidates for biological and medical applications. We utilized a clean method involving a single synthetic step to prepare silver nanoparticles that exhibit antimicrobial activity. Materials & methods These nanoparticles were prepared by reducing silver nitrate with diaminopyridinylated heparin (DAPHP) and hyaluronan (HA) polysaccharides and tested for their efficacy in inhibiting microbial growth. Results & discussion The resulting silver nanoparticles exhibit potent antimicrobial activity against Staphylococcus aureus and modest activity against Escherichia coli. Silver–HA showed greater antimicrobial activity than silver–DAPHP, while silver–glucose nanoparticles exhibited very weak antimicrobial activity. Neither HA nor DAPHP showed activity against S. aureus or E. coli. Conclusion These results suggest that DAPHP and HA silver nanoparticles have potential in antimicrobial therapeutic applications. PMID:19505245

Food Antimicrobials Nanocarriers

PubMed Central

Blanco-Padilla, Adriana; Soto, Karen M.; Hernández Iturriaga, Montserrat

2014-01-01

Natural food antimicrobials are bioactive compounds that inhibit the growth of microorganisms involved in food spoilage or food-borne illness. However, stability issues result in degradation and loss of antimicrobial activity. Nanoencapsulation allows protection of antimicrobial food agents from unfavorable environmental conditions and incompatibilities. Encapsulation of food antimicrobials control delivery increasing the concentration of the antimicrobials in specific areas and the improvement of passive cellular absorption mechanisms resulted in higher antimicrobial activity. This paper reviews the present state of the art of the nanostructures used as food antimicrobial carriers including nanoemulsions, nanoliposomes, nanoparticles, and nanofibers. PMID:24995363

Antimicrobial synergism and cytotoxic properties of Citrus limon L., Piper nigrum L. and Melaleuca alternifolia (Maiden and Betche) Cheel essential oils.

PubMed

Nikolić, Miloš M; Jovanović, Katarina K; Marković, Tatjana Lj; Marković, Dejan Lj; Gligorijević, Nevenka N; Radulović, Siniša S; Kostić, Marina; Glamočlija, Jasmina M; Soković, Marina D

2017-11-01

The chemical composition, antimicrobial and synergistic effect, and cytotoxic activity of Citrus limon (lemon), Piper nigrum (green pepper) and Melaleuca alternifoila (tea tree) essential oils (EOs) were investigated. Chemical analyses of essential oils were tested by GC-FID and GC-MS spectroscopy. The antimicrobial activity assay was conducted using microdilution method against several oral bacteria and Candida spp. originating from the humans with oral disorders. The synergistic antimicrobial activity was evaluated using checkerboard method. The cytotoxicity evaluation of EOs was assessed using MTT test. Limonene (37.5%) and β-pinene (17.9%) were the major compounds in C. limon oil, β-pinene (34.4%), δ-3-carene (19.7%), limonene (18.7%) and α-pinene (10.4%) in P. nigrum oil and terpinen-4-ol (38.6%) and γ-terpinene (21.7%) in M. alternifolia oil. The broad-spectrum antimicrobial activity was achieved by tested three EOs, with C. limon oil being the strongest against bacteria and M. alternifolia oil strongest against fungi. The EOs demonstrated synergism; their combined application revealed an increase in antimicrobial activity. All tested essential oils showed lower cytotoxic activity in comparison with the positive control, and the obtained results confirmed a dose-dependent activity. The results of this study encourage use of tested EOs in development of a novel agent intended for prevention or therapy of corresponding oral disorders. © 2017 Royal Pharmaceutical Society.

Synthesis and Antimicrobial Activity of Silver-Doped Hydroxyapatite Nanoparticles

PubMed Central

Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Chifiriuc, Mariana Carmen; Costescu, Adrian; Le Coustumer, Philippe; Predoi, Daniela

2013-01-01

The synthesis of nanosized particles of Ag-doped hydroxyapatite with antibacterial properties is of great interest for the development of new biomedical applications. The aim of this study was the evaluation of Ca10−xAgx(PO4)6(OH)2 nanoparticles (Ag:HAp-NPs) for their antibacterial and antifungal activity. Resistance to antimicrobial agents by pathogenic bacteria has emerged in the recent years and became a major health problem. Here, we report a method for synthesizing Ag doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionised water. Also, in this paper Ag:HAp-NPs are evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria and fungal strains. The specific antimicrobial activity revealed by the qualitative assay is demonstrating that our compounds are interacting differently with the microbial targets, probably due to the differences in the microbial wall structures. PMID:23509801

Synthesis and antimicrobial activity of silver-doped hydroxyapatite nanoparticles.

PubMed

Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Chifiriuc, Mariana Carmen; Costescu, Adrian; Le Coustumer, Philippe; Predoi, Daniela

2013-01-01

The synthesis of nanosized particles of Ag-doped hydroxyapatite with antibacterial properties is of great interest for the development of new biomedical applications. The aim of this study was the evaluation of Ca(10-x)Ag(x)(PO4)6(OH)2 nanoparticles (Ag:HAp-NPs) for their antibacterial and antifungal activity. Resistance to antimicrobial agents by pathogenic bacteria has emerged in the recent years and became a major health problem. Here, we report a method for synthesizing Ag doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionised water. Also, in this paper Ag:HAp-NPs are evaluated for their antimicrobial activity against gram-positive and gram-negative bacteria and fungal strains. The specific antimicrobial activity revealed by the qualitative assay is demonstrating that our compounds are interacting differently with the microbial targets, probably due to the differences in the microbial wall structures.

The antimicrobial assessment of some Nigerian herbal soap.

PubMed

Igbeneghu, O A

2013-01-01

Twenty samples of herbal soaps were evaluated for their antimicrobial activity against bacteria and yeast of significance in skin infections with the aim to provide some justification for the continued use of the soaps in the management of superficial skin infections. All the soaps were found to possess antimicrobial activity in a concentration and organism dependent manner. The soaps were more active against the gram positive organisms than the Gram negative organisms while none of the soaps had activity against the tested yeasts. Only 35% of the soaps were appropriately packaged with adequate directions for use and storage. The study showed that the tested soaps possessed antimicrobial properties and they can contribute to the treatment and management of skin infections caused by bacteria if well prepared with the appropriate plant materials to target specific causative organisms and packaged with appropriate directions for use and storage.

Antimicrobial activity of chemically modified dextran derivatives.

PubMed

Tuchilus, Cristina G; Nichifor, Marieta; Mocanu, Georgeta; Stanciu, Magdalena C

2017-04-01

Cationic amphiphilic dextran derivatives with a long alkyl group attached to the reductive end of the polysaccharide chain and quaternary ammonium groups attached as pendent groups to the main dextran backbone were synthesized and tested for their antimicrobial properties against several bacteria and fungi strains. Dependence of antimicrobial activity on both polymer chemical composition (dextran molar mass, length of end alkyl group and chemical structure of ammonium groups) and type of microbes was highlighted by disc-diffusion method (diameter of inhibition zone) and broth microdilution method (minimum inhibitory concentrations). Polymers had antimicrobial activity for all strains studied, except for Pseudomonas aeruginosa ATCC 27853. The best activity against Staphylococcus aureus (Minimun Inhibitory Concentration 60μg/mL) was provided by polymers obtained from dextran with lower molecular mass (Mn=4500), C 12 H 25 or C 18 H 37 end groups, and N,N-dimethyl-N-benzylammonium pendent groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antibacterial Effect of Human Mesenchymal Stem Cells Is Mediated in Part from Secretion of the Antimicrobial Peptide LL-37

PubMed Central

Krasnodembskaya, Anna; Song, Yuanlin; Fang, Xiaohui; Gupta, Naveen; Serikov, Vladimir; Lee, Jae-Woo; Matthay, Michael A.

2012-01-01

Recent in vivo studies indicate that mesenchymal stem cells (MSCs) may have beneficial effects in the treatment of sepsis induced by bacterial infection. Administration of MSCs in these studies improved survival and enhanced bacterial clearance. The primary objective of this study was to test the hypothesis that human MSCs possessed intrinsic antimicrobial properties. We studied the effect of human MSCs derived from bone marrow on the bacterial growth of Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. MSCs as well as their conditioned medium (CM) demonstrated marked inhibition of bacterial growth in comparison with control medium or normal human lung fibroblasts (NHLF). Analysis of expression of major antimicrobial peptides indicated that one of the factors responsible for the antimicrobial activity of MSC CM against Gram-negative bacteria was the human cathelicidin antimicrobial peptide, hCAP-18/LL-37. Both m-RNA and protein expression data showed that the expression of LL-37 in MSCs increased after bacterial challenge. Using an in vivo mouse model of E. coli pneumonia, intratracheal administration of MSCs reduced bacterial growth (in colony-forming unit) in the lung homogenates and in the bronchoalveolar lavage (BAL) fluid, and administration of MSCs simultaneously with a neutralizing antibody to LL-37 resulted in a decrease in bacterial clearance. In addition, the BAL itself from MSC-treated mice had a greater antimicrobial activity in comparison with the BAL of phosphate buffered saline (PBS)-treated mice. Human bone marrow-derived MSCs possess direct antimicrobial activity, which is mediated in part by the secretion of human cathelicidin hCAP-18/LL-37. PMID:20945332

Silver Sucrose Octasulfate (IASOS™) as a Valid Active Ingredient into a Novel Vaginal Gel against Human Vaginal Pathogens: In Vitro Antimicrobial Activity Assessment

PubMed Central

Marianelli, Cinzia; Petrucci, Paola; Comelli, Maria Cristina; Calderini, Gabriella

2014-01-01

This in vitro study assessed the antimicrobial properties of a novel octasilver salt of Sucrose Octasulfate (IASOS) as well as of an innovative vaginal gel containing IASOS (SilSOS Femme), against bacterial and yeast pathogens isolated from human clinical cases of symptomatic vaginal infections. In BHI and LAPT culture media, different ionic silver concentrations and different pHs were tested. IASOS exerted a strong antimicrobial activity towards all the pathogens tested in both culture media. The results demonstrated that salts and organic compounds present in the culture media influenced IASOS efficacy only to a moderate extent. Whereas comparable MBCs (Minimal Bactericidal Concentrations) were observed for G. vaginalis (10 mg/L Ag+), E. coli and E. aerogenes (25 mg/L Ag+) in both media, higher MBCs were found for S. aureus and S. agalactiae in LAPT cultures (50 mg/L Ag+ versus 25 mg/L Ag+). No minimal concentration totally inhibiting the growth of C. albicans was found. Nevertheless, in both media at the highest ionic silver concentrations (50–200 mg/L Ag+), a significant 34–52% drop in Candida growth was observed. pH differently affected the antimicrobial properties of IASOS against bacteria or yeasts; however, a stronger antimicrobial activity at pH higher than the physiological pH was generally observed. It can be therefore concluded that IASOS exerts a bactericidal action against all the tested bacteria and a clear fungistatic action against C. albicans. The antimicrobial activity of the whole vaginal gel SilSOS Femme further confirmed the antimicrobial activity of IASOS. Overall, our findings support IASOS as a valid active ingredient into a vaginal gel. PMID:24897299

Antimicrobial and antimalarial properties of medicinal plants used by the indigenous tribes of Andaman and Nicobar Islands, India.

PubMed

Chander, M Punnam; Pillai, C R; Sunish, I P; Vijayachari, P

2016-07-01

In this study, methanol extracts of six medicinal plants (Alstonia macrophylla, Claoxylon indicum, Dillenia andamanica, Jasminum syringifolium, Miliusia andamanica and Pedilanthus tithymaloides) traditionally used by Nicobarese tribes of Andaman and Nicobar Islands were studied for antimicrobial and antimalarial activities as well as preliminary photochemical analysis. Plants were collected from Car Nicobar of Andaman and Nicobar Islands and the ethnobotanical data were gathered from traditional healers who inhabit the study area. The methanol extracts were obtained by cold percolation method and the antimicrobial activity was found using agar well diffusion method. Among the plants tested, J. syringifolium, D. andamanica, C. indicum were most active. The antimalarial activity was evaluated against Plasmodium falciparum chloroquine-sensitive MRC-2 isolate. The crude extract of M. andamanica showed excellent antimalarial activity followed by extracts of P. tithymaloides, J. syringifolium and D. andamanica. The chemical injury to erythrocytes was also carried out and it showed that, there were no morphological changes in erythrocytes by the methanol crude extracts. The in vitro antimicrobial and antimalarial activity might be due to the presence of alkaloids, flavonoids, triterpenes, sterols, tannins and saponins in the methanol extracts of tested plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative study of anthocyanin composition, antimicrobial and antioxidant activity in bilberry (Vaccinium myrtillus L.) and blueberry (Vaccinium corymbosum L.) fruits.

PubMed

Burdulis, Deividas; Sarkinas, Antanas; Jasutiené, Ina; Stackevicené, Elicija; Nikolajevas, Laurynas; Janulis, Valdimaras

2009-01-01

Simultaneous comparison of bilberry (Vaccinium myrtillus L.) and blueberry (Vaccinium corymbosum L) fruits for their anthocyanin composition, antimicrobial and antioxidant activity is reported. The aim of this study was to investigate and to compare anthocyanin composition, antimicrobial and antioxidant activity in bilberry and blueberry fruits and their skins. The investigations revealed that the highest amount of total anthocyanins was observed in fruits skins of blueberry cultivars. The results, obtained by chromatographic analysis, indicated that cyanidin is a dominant anthocyanidin in bilberry and malvidin in blueberry samples. Extracts of "Herbert", "Coville", "Toro" blueberry cultivars and bilberry fruits revealed antimicrobial properties. Citrobacter freundii (ATCC 8090) and Enterococcus faecalis (ATCC29212) were the most sensitive among eight tested Gram-negative and Gram-positive bacteria. Significant differences between berry and skin extracts were not established. Studies with fruits showed that the strongest antioxidant activity possesses blueberry cultivar "Berkeley" (82.13 +/- 0.51%). Meanwhile, the amount of quenched free radicals in bilberry samples was 63.72 +/- 1.11%, respectively. The lowest antioxidant activity was estimated in blueberry cultivar "Coville". Accordingly, the strongest antiradical properties were estimated in blueberry cultivar "Ama" fruit skins. Bilberry fruit skin samples possess strong antiradical activity as well (82.69 +/- 0.37%).

In vitro antimicrobial activity and antagonistic effect of essential oils from plant species.

PubMed

Toroglu, Sevil

2007-07-01

Kahramanmaras, is a developing city located in the southern part of Turkey Thymus eigii (M. Zohary and RH. Davis) Jalas, Pinus nigraAm. sub sp pallasiana and Cupressus sempervirens L. are the useful plants of the Kahramanmaras province and have been understudy since 2004 for the traditional uses of plants empiric drug, spice, herbal tea industry herbal gum and fuel. The study was designed to examine the antimicrobial activities of essential oils of these plants by the disc diffusion and minimum inhibitory concentration (MIC) methods. In addition, antimicrobial activity of Thymus eigii was researched by effects when it was used together with antibiotics and even when it was combined with other essential oils. When the results of this study were compared with vancomycin (30 mcg) and erytromycin (15 mcg) standards, it was found that Thymus eigii essential oil was particularly found to possess strongerantimicrobial activity whereas other essential oils showed susceptible or moderate activity However, antimicrobial activity changed also by in vitro interactions between antibiotics and Thymus eigii essential oil, also between essential oils of these plants and that of Thymus eigii causing synergic, additive, antagonist effect.

Alginate edible films containing microencapsulated lemongrass oil or citral: effect of encapsulating agent and storage time on physical and antimicrobial properties.

PubMed

Alarcón-Moyano, Jessica K; Bustos, Rubén O; Herrera, María Lidia; Matiacevich, Silvia B

2017-08-01

Active edible films have been proposed as an alternative to extend shelf life of fresh foods. Most essential oils have antimicrobial properties; however, storage conditions could reduce their activity. To avoid this effect the essential oil (EO) can be microencapsulated prior to film casting. The aim of this study was to determine the effects of the type of encapsulating agent (EA), type of EO and storage time on physical properties and antimicrobial activity of alginate-based films against Escherichia coli ATCC 25922. Trehalose (TH), Capsul ® (CAP) and Tween 20 (Tw20) were used as EA. Lemongrass essential oil (LMO) and citral were used as active agents. The results showed that the type of EA affected the stability of the film forming-emulsions as well as the changes in opacity and colour of the films during storage but not the antimicrobial activity of them. Both microencapsulated EOs showed a prolonged release from the alginate films during the 28 days of storage. Trehalose was selected to encapsulate both active compounds because the films made with this microencapsulated EA showed the greatest physical stability and the lowest color variation among all the films studied.

Volatiles in Inter-Specific Bacterial Interactions

PubMed Central

Tyc, Olaf; Zweers, Hans; de Boer, Wietse; Garbeva, Paolina

2015-01-01

The importance of volatile organic compounds for functioning of microbes is receiving increased research attention. However, to date very little is known on how inter-specific bacterial interactions effect volatiles production as most studies have been focused on volatiles produced by monocultures of well-described bacterial genera. In this study we aimed to understand how inter-specific bacterial interactions affect the composition, production and activity of volatiles. Four phylogenetically different bacterial species namely: Chryseobacterium, Dyella, Janthinobacterium, and Tsukamurella were selected. Earlier results had shown that pairwise combinations of these bacteria induced antimicrobial activity in agar media whereas this was not the case for monocultures. In the current study, we examined if these observations were also reflected by the production of antimicrobial volatiles. Thus, the identity and antimicrobial activity of volatiles produced by the bacteria were determined in monoculture as well in pairwise combinations. Antimicrobial activity of the volatiles was assessed against fungal, oomycetal, and bacterial model organisms. Our results revealed that inter-specific bacterial interactions affected volatiles blend composition. Fungi and oomycetes showed high sensitivity to bacterial volatiles whereas the effect of volatiles on bacteria varied between no effects, growth inhibition to growth promotion depending on the volatile blend composition. In total 35 volatile compounds were detected most of which were sulfur-containing compounds. Two commonly produced sulfur-containing volatile compounds (dimethyl disulfide and dimethyl trisulfide) were tested for their effect on three target bacteria. Here, we display the importance of inter-specific interactions on bacterial volatiles production and their antimicrobial activities. PMID:26733959

Isolation and analysis of bacteria with antimicrobial activities from the marine sponge Haliclona simulans collected from Irish waters.

PubMed

Kennedy, Jonathan; Baker, Paul; Piper, Clare; Cotter, Paul D; Walsh, Marcella; Mooij, Marlies J; Bourke, Marie B; Rea, Mary C; O'Connor, Paula M; Ross, R Paul; Hill, Colin; O'Gara, Fergal; Marchesi, Julian R; Dobson, Alan D W

2009-01-01

Samples of the marine sponge Haliclona simulans were collected from Irish coastal waters, and bacteria were isolated from these samples. Phylogenetic analyses of the cultured isolates showed that four different bacterial phyla were represented; Bacteriodetes, Actinobacteria, Proteobacteria, and Firmicutes. The sponge bacterial isolates were assayed for the production of antimicrobial substances, and biological activities against Gram-positive and Gram-negative bacteria and fungi were demonstrated, with 50% of isolates showing antimicrobial activity against at least one of the test strains. Further testing showed that the antimicrobial activities extended to the important pathogens Pseudomonas aeruginosa, Clostridium difficile, multi-drug-resistant Staphylococcus aureus, and pathogenic yeast strains. The Actinomycetes were numerically the most abundant producers of antimicrobial activities, although activities were also noted from Bacilli and Pseudovibrio isolates. Surveys for the presence of potential antibiotic encoding polyketide synthase and nonribosomal peptide synthetase genes also revealed that genes for the biosynthesis of these secondary metabolites were present in most bacterial phyla but were particularly prevalent among the Actinobacteria and Proteobacteria. This study demonstrates that the culturable fraction of bacteria from the sponge H. simulans is diverse and appears to possess much potential as a source for the discovery of new medically relevant biological active agents.

Antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.

PubMed

Ginjupalli, Kishore; Alla, Rama Krishna; Tellapragada, Chaitanya; Gupta, Lokendra; Upadhya Perampalli, Nagaraja

2016-06-01

Conventional spray and the immersion disinfection of irreversible hydrocolloid impression materials may lead to dimensional changes. The purpose of this in vitro study was to investigate the antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles. The antimicrobial activity and properties of 2 commercially available irreversible hydrocolloid impression materials were evaluated after incorporating varying concentrations of silver nanoparticles. Antimicrobial activity was determined using the disk diffusion method. The gel strength, permanent deformation, flow, and gelation time were measured according to American Dental Association specification #18. Analysis of variance was used to identify the significant differences within and across the groups (α=.05). Adding silver nanoparticles to irreversible hydrocolloid impression materials resulted in superior antimicrobial activity without adversely affecting their properties. Adding silver nanoparticles to Zelgan significantly increased the gel strength compared with the control group, except at 5 wt%. However, the gel strength of Tropicalgin was unaffected except at 5 wt%. An increase in the permanent deformation was found with the incorporation of silver nanoparticles in both Zelgan and Tropicalgin. The flow of Zelgan increased with the incorporation of silver nanoparticles, whereas a decrease in the flow of Tropicalgin was observed at 1 wt% and 2 wt%. An increase in the gelation time of both Zelgan and Tropicalgin was observed with the incorporation of silver nanoparticles. Based on this in vitro study, silver nanoparticles can be incorporated into irreversible hydrocolloid impression materials as antimicrobial agents without adversely affecting their properties. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Structure-activity relationship of HP (2-20) analog peptide: enhanced antimicrobial activity by N-terminal random coil region deletion.

PubMed

Park, Yoonkyung; Park, Seong-Cheol; Park, Hae-Kyun; Shin, Song Yub; Kim, Yangmee; Hahm, Kyung-Soo

2007-01-01

HP (2-20) (AKKVFKRLEKLFSKIQNDK) is a 19-aa antimicrobial peptide derived from N-terminus of Helicobacter pylori Ribosomal protein L1 (RpL1). In the previous study, several analogs with amino acid substitutions were designed to increase or decrease only the net hydrophobicity. In particular, substitutions of Gln(16) and Asp(18) with Trp (Anal 3) for hydrophobic amino acid caused a dramatic increase in antibiotic activity without a hemolytic effect. HP-A3 is a potent antimicrobial peptide that forms, in a hydrophobic medium, an amphipathic structure consisting of an N-terminal random coil region (residues 2-5) and extended C-terminal regular alpha-helical region (residues 6-20). To obtain the short and potent alpha-helical antimicrobial peptide, we synthesized a N-terminal random coil deleted HP-A3 (A3-NT) and examined their antimicrobial activity and mechanism of action. The resulting 15mer peptide showed increased antibacterial and antifungal activity to 2- and 4-fold, respectively, without hemolysis. Confocal fluorescence microscopy studies showed that A3-NT was accumulated in the plasma membrane. Flow cytometric analysis revealed that A3-NT acted in salt- and energy-independent manner. Furthermore, A3-NT causes significant morphological alterations of the bacterial surfaces as shown by scanning electron microscopy. Circular dichroism (CD) analysis revealed that A3-NT showed higher alpha-helical contents than the HP-A3 peptide in 50% TFE solution. Therefore, the cell-lytic efficiency of HP-A3, which depended on the alpha-helical content of peptide, correlated linearly with their antimicrobial potency.

Active edible coating and γ-irradiation as cold combined treatments to assure the safety of broccoli florets (Brassica oleracea L.).

PubMed

Ben-Fadhel, Yosra; Saltaji, Sabrina; Khlifi, Mohamed Ali; Salmieri, Stephane; Dang Vu, Khanh; Lacroix, Monique

2017-01-16

The antimicrobial activity of essential oils (EOs), organic acid (OA) salts and natamycin, a natural antifungal produced during fermentation by the bacterium Streptomyces natalensis, was assessed against four pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Aspergillus niger). The Minimum Inhibitory Concentration (MIC) of each antimicrobial (AM) was assessed to determine their efficiency on tested microbial species in order to select the most efficient. Then, the interactions between different antimicrobial compounds showing the lowest MIC were determined by the checkerboard method. The most effective antimicrobial formulation showing synergistic or additive effects was then encapsulated in an alginate matrix to protect the antimicrobial efficiency during storage. The effectiveness of the formulation was then evaluated in situ using broccoli as a food model. A combined treatment of active coating and γ-irradiation (0.4 and 0.8kGy) was also done in order to evaluate the possible synergistic effect between treatments. The results of this study allowed the selection of 4 EOs, one OA salt and the natamycin as an antifungal agent exhibiting lower MIC values. The interactive antimicrobial effects between them showed that an antimicrobial formulation composed of 300ppm of lemongrass EO, 5000ppm of sodium diacetate and 80ppm of natamycin resulted in an additive effect against A. niger, E. coli and S. Typhimurium and showing synergistic effect against L. monocytogenes. Finally, in situ analyses showed a synergistic antimicrobial activity between active coating and γ-irradiation and allowed the extension of the shelf-life of ready-to-eat (RTE) broccoli during storage at 4°C. Copyright © 2016 Elsevier B.V. All rights reserved.

CHARACTERIZATION OF A NARROW SPECTRUM ANTIMICROBIAL THAT EXHIBITS SPECIFIC ACTIVITY AGAINST UROPATHOGENIC BACTERIA

DTIC Science & Technology

2017-08-28

NARROW-SPECTRUM ANTIMICROBIAL THAT EXHIBITS SPECIFIC ACTIVITY AGAINST UROPATHOGENIC BACTERIA by Caitlin M. Barrows Courtney M. Cowell Jennifer...From - To) October 2015 – September 2016 4. TITLE AND SUBTITLE CHARACTERIZATION OF A NARROW-SPECTRUM ANTIMICROBIAL THAT EXHIBITS SPECIFIC ACTIVITY ...objective of the work described in this report is to identify a narrow-spectrum antimicrobial that exhibits targeted activity against uropathogenic

Antimicrobial Activities and Time-Kill Kinetics of Extracts of Selected Ghanaian Mushrooms

PubMed Central

Appiah, Theresa; Boakye, Yaw Duah

2017-01-01

The rapid rise of antimicrobial resistance is a worldwide problem. This has necessitated the need to search for new antimicrobial agents. Mushrooms are rich sources of potential antimicrobial agents. This study investigated the antimicrobial properties of methanol extracts of Trametes gibbosa, Trametes elegans, Schizophyllum commune, and Volvariella volvacea. Agar well diffusion, broth microdilution, and time-kill kinetic assays were used to determine the antimicrobial activity of the extracts against selected test organisms. Preliminary mycochemical screening revealed the presence of tannins, flavonoids, triterpenoids, anthraquinones, and alkaloids in the extracts. Methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea showed mean zone of growth inhibition of 10.00 ± 0.0 to 21.50 ± 0.84, 10.00 ± 0.0 to 22.00 ± 1.10, 9.00 ± 0.63 to 21.83 ± 1.17, and 12.00 ± 0.0 to 21.17 ± 1.00 mm, respectively. The minimum inhibitory concentration of methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea ranged from 4.0 to 20, 6.0 to 30.0, 8.0 to 10.0, and 6.0 to 20.0 mg/mL, respectively. Time-kill kinetics studies showed that the extracts possess bacteriostatic action. Methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea exhibited antimicrobial activity and may contain bioactive compounds which may serve as potential antibacterial and antifungal agents. PMID:29234399

Dual evaluation of some novel 2-amino-substituted coumarinylthiazoles as anti-inflammatory-antimicrobial agents and their docking studies with COX-1/COX-2 active sites.

PubMed

Chandak, Navneet; Kumar, Pawan; Kaushik, Pawan; Varshney, Parul; Sharma, Chetan; Kaushik, Dhirender; Jain, Sudha; Aneja, Kamal R; Sharma, Pawan K

2014-08-01

Synthesis of total eighteen 2-amino-substituted 4-coumarinylthiazoles including sixteen new compounds (3a-o and 5b) bearing the benzenesulfonamide moiety is described in the present report. All the synthesized target compounds were examined for their in vivo anti-inflammatory (AI) activity and in vitro antimicrobial activity. Results revealed that six compounds (3 d, 3 f, 3 g, 3 h, 3 j and 3 n) exhibited pronounced anti-inflammatory activity comparable to the standard drug indomethacin. AI results were further confirmed by the docking studies of the most active (3n) and the least active compound (3a) with COX-1 and COX-2 active sites. In addition, most of the compounds exhibited moderate antimicrobial activity against Gram-positive bacteria as well as fungal yeast, S. cervisiae. Comparison between 3 and 5 indicated that incorporation of additional substituted pyrazole nucleus into the scaffold significantly enhanced AI activity.

Antimicrobial activity of jasmine oil against oral microorganisms

NASA Astrophysics Data System (ADS)

Thaweboon, S.; Thaweboon, B.; Kaypetch, R.

2018-02-01

Jasmine sambac is a species of jasmine indigenous to the tropical and warm temperature regions in particular West and Southeast Asia. Essential oil extracted from the flowers of J. sambac has been shown to have anti-oxidant activity. However, very little information regarding antimicrobial activity especially oral microorganisms exists. Objective: To investigate antimicrobial effect of essential oil extracted from flowers of J. sambac against various oral microorganisms. Materials and Methods: Oral microbial strains used in the study were Streptococcus mutans KPSK2, Staphylococcus aureus ATCC 5638, Lactobacillus casei ATCC 6363, Klebsiella pneumoniae (clinical isolate), Escherichia coli ATCC 25922, Candida albicans ATCC 10231, Candida krusei ATCC 6258, Candida parapsilosis ATCC 22019, Candida tropicalis (clinical isolate), Candida glabrata ATCC 90030, Candida pseudotropicalis (clinical isolate) and Candida stellatoidia (clinical isolate). The potential of microbial growth inhibition of the oil was firstly screened by Kirby-Bauer disk diffusion method and then the minimum inhibitory concentration (MIC) was determined by agar dilution method. Results: Jasmine oil showed antimicrobial activities against S. mutans, L. casei, E. coli and all strains of Candida species with the zones of inhibition ranging from 9 to 26 mm and MIC values of 0.19-1.56 %v/v. Conclusion: Results from the present study are scientific evidence to demonstrate that jasmine oil could be employed as a natural antimicrobial agent against oral microorganisms.

Antimicrobial effects of Thai medicinal plants against acne-inducing bacteria.

PubMed

Chomnawang, Mullika Traidej; Surassmo, Suvimol; Nukoolkarn, Veena S; Gritsanapan, Wandee

2005-10-03

Propionibacterium acnes and Staphylococcus epidermidis have been recognized as pus-forming bacteria triggering an inflammation in acne. The present study was conducted to evaluate antimicrobial activities of Thai medicinal plants against these etiologic agents of acne vulgaris. Crude extracts were tested for antimicrobial activities by disc diffusion and broth dilution methods. The results from the disc diffusion method showed that 13 medicinal plants could inhibit the growth of Propionibacterium acnes. Among those, Senna alata, Eupatorium odoratum, Garcinia mangostana, and Barleria lupulina had strong inhibitory effects. Based on a broth dilution method, the Garcinia mangostana extract had the greatest antimicrobial effect. The MIC values were the same (0.039 mg/ml) for both bacterial species and the MBC values were 0.039 and 0.156 mg/ml against Propionibacterium acnes and Staphylococcus epidermidis, respectively. In bioautography assay, the Garcinia mangostana extract produced strong inhibition zones against Propionibacterium acnes. Antimicrobial activity from fractions of column chromatography revealed one of the active compounds in Garcinia mangostana could be mangostin, a xanthone derivative. Taken together, our data indicated that Garcinia mangostana had a strong inhibitory effect on Propionibacterium acnes and Staphylococcus epidermidis. Therefore, this plant would be an interesting topic for further study and possibly for an alternative treatment for acne.

Improving short antimicrobial peptides despite elusive rules for activity.

PubMed

Mikut, Ralf; Ruden, Serge; Reischl, Markus; Breitling, Frank; Volkmer, Rudolf; Hilpert, Kai

2016-05-01

Antimicrobial peptides (AMPs) can effectively kill a broad range of life threatening multidrug-resistant bacteria, a serious threat to public health worldwide. However, despite great hopes novel drugs based on AMPs are still rare. To accelerate drug development we studied different approaches to improve the antibacterial activity of short antimicrobial peptides. Short antimicrobial peptides seem to be ideal drug candidates since they can be synthesized quickly and easily, modified and optimized. In addition, manufacturing a short peptide drug will be more cost efficient than long and structured ones. In contrast to longer and structured peptides short AMPs seem hard to design and predict. Here, we designed, synthesized and screened five different peptide libraries, each consisting of 600 9-mer peptides, against Pseudomonas aeruginosa. Each library is presenting a different approach to investigate effectiveness of an optimization strategy. The data for the 3000 peptides were analyzed using models based on fuzzy logic bioinformatics and plausible descriptors. The rate of active or superior active peptides was improved from 31.0% in a semi-random library from a previous study to 97.8% in the best new designed library. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. Copyright © 2015 Elsevier B.V. All rights reserved.

In vitro activity of ABT-492 against anaerobic bacteria.

PubMed

Sillerström, E; Wahlund, E; Nord, C E

2004-06-01

The purpose of the study was to determine the in vitro activity of ABT-492 compared with that of other antimicrobial agents against anaerobic bacteria. The activity of ABT-492 was investigated against 369 clinical isolates of anaerobic bacteria by the agar dilution method and was compared with that of moxifloxacin, piperacillin, cefoxitin, imipenem, clindamycin and metronidazole. ABT-492 and imipenem were the most active antimicrobial agents tested.

Evaluation of new antimicrobial agents on Bacillus spp. strains: docking affinity and in vitro inhibition of glutamate-racemase.

PubMed

Tamay-Cach, Feliciano; Correa-Basurto, José; Villa-Tanaca, Lourdes; Mancilla-Percino, Teresa; Juárez-Montiel, Margarita; Trujillo-Ferrara, José G

2013-10-01

Three glutamic acid derivatives, two boron-containing and one imide-containing compound, were synthesized and tested for antimicrobial activity targeting glutamate-racemase. Antimicrobial effect was evaluated over Bacillus spp. Docking analysis shown that the test compounds bind near the active site of racemase isoforms, suggesting an allosteric effect. The boron derivatives had greater affinity than the imide derivative. In vitro assays shown good antimicrobial activity for the boron-containing compounds, and no effectiveness for the imide-containing compounds. The minimum inhibitory concentration of tetracycline, used as standard, was lower than that of the boron-containing derivatives. However, it seems that the boron-containing derivatives are more selective for bacteria. Experimental evidence suggests that the boron-containing derivatives act by inhibiting the racemase enzyme. Therefore, these test compounds probably impede the formation of the bacterial cell wall. Thus, the boron-containing glutamic acid derivatives should certainly be of interest for future studies as antimicrobial agents for Bacillus spp.

Antimicrobial Active Clothes Display No Adverse Effects on the Ecological Balance of the Healthy Human Skin Microflora

PubMed Central

Hoefer, Dirk; Hammer, Timo R.

2011-01-01

The progressive public use of antimicrobial clothes has raised issues concerning skin health. A placebo-controlled side-to-side study was run with antimicrobial clothes versus fabrics of similar structure but minus the antimicrobial activity, to evaluate possible adverse effects on the healthy skin microflora. Sixty volunteers were enrolled. Each participant received a set of form-fitting T-shirts constructed in 2 halves: an antibacterial half, displaying activities of 3–5 log-step reductions due to silver-finishes or silver-loaded fibres and a nonantibacterial control side. The microflora of the scapular skin was analyzed weekly for opportunistic and pathogenic microorganisms over six weeks. The antibacterial halves did not disturb the microflora in number or composition, whereas a silver-containing deodorant displayed a short-term disturbance. Furthermore, parameters of skin morphology and function (TEWL, pH, moisture) did not show any significant shifts. In summary, antimicrobial clothes did not show adverse effects on the ecological balance of the healthy skin microflora. PMID:22363849

Antimicrobial efficacy of Syzygium antisepticum plant extract against Staphylococcus aureus and methicillin-resistant S. aureus and its application potential with cooked chicken.

PubMed

Yuan, Wenqian; Yuk, Hyun-Gyun

2018-06-01

For the past decades, there has been a growing demand for natural antimicrobials in the food industry. Plant extracts have attracted strong research interests due to their wide-spectrum antimicrobial activities, but only a limited number have been investigated thoroughly. The present study aimed at identifying a novel anti-staphylococcal plant extract, to validate its activity in a food model, and to investigate on its composition and antimicrobial mechanism. Four plant extracts were evaluated against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in vitro, with Syzygium antisepticum leaf extract showing the strongest antimicrobial activity (MIC = 0.125 mg/mL). Relatively high total phenolic content (276.3 mg GAE/g extract) and antioxidant activities (90.2-138.0 mg TE/g extract) were measured in S. antisepticum extract. Food validation study revealed that higher extract concentration (32 mg/mL) was able to inhibit or reduce staphylococcal growth in cooked chicken, but caused color change on meat surface. By GC-MS, β-caryophyllene (12.76 area%) was identified as the dominant volatile compound in extract. Both crude extract and pure β-caryophyllene induced membrane damages in S. aureus. These results suggested good anti-staphylococcal properties of S. antisepticum plant extract, identified its major volatile composition and its membrane-damaging antimicrobial mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

The intrinsic antimicrobial activity of citric acid-coated manganese ferrite nanoparticles is enhanced after conjugation with the antifungal peptide Cm-p5

PubMed Central

Lopez-Abarrategui, Carlos; Figueroa-Espi, Viviana; Lugo-Alvarez, Maria B; Pereira, Caroline D; Garay, Hilda; Barbosa, João ARG; Falcão, Rosana; Jiménez-Hernández, Linnavel; Estévez-Hernández, Osvaldo; Reguera, Edilso; Franco, Octavio L; Dias, Simoni C; Otero-Gonzalez, Anselmo J

2016-01-01

Diseases caused by bacterial and fungal pathogens are among the major health problems in the world. Newer antimicrobial therapies based on novel molecules urgently need to be developed, and this includes the antimicrobial peptides. In spite of the potential of antimicrobial peptides, very few of them were able to be successfully developed into therapeutics. The major problems they present are molecule stability, toxicity in host cells, and production costs. A novel strategy to overcome these obstacles is conjugation to nanomaterial preparations. The antimicrobial activity of different types of nanoparticles has been previously demonstrated. Specifically, magnetic nanoparticles have been widely studied in biomedicine due to their physicochemical properties. The citric acid-modified manganese ferrite nanoparticles used in this study were characterized by high-resolution transmission electron microscopy, which confirmed the formation of nanocrystals of approximately 5 nm diameter. These nanoparticles were able to inhibit Candida albicans growth in vitro. The minimal inhibitory concentration was 250 µg/mL. However, the nanoparticles were not capable of inhibiting Gram-negative bacteria (Escherichia coli) or Gram-positive bacteria (Staphylococcus aureus). Finally, an antifungal peptide (Cm-p5) from the sea animal Cenchritis muricatus (Gastropoda: Littorinidae) was conjugated to the modified manganese ferrite nanoparticles. The antifungal activity of the conjugated nanoparticles was higher than their bulk counterparts, showing a minimal inhibitory concentration of 100 µg/mL. This conjugate proved to be nontoxic to a macrophage cell line at concentrations that showed antimicrobial activity. PMID:27563243

76 FR 18564 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-04

... attractive antimicrobial target. The chrysophaetin exhibits antimicrobial activity against drug resistant... analogues will show similar antimicrobial activity to the natural products and will utilize the same... distinct antimicrobial compounds. Attack newly validated antibacterial targeted protein FtsZ. These...

Antimicrobial nanoparticle-coated electrostatic air filter with high filtration efficiency and low pressure drop.

PubMed

Sim, Kyoung Mi; Park, Hyun-Seol; Bae, Gwi-Nam; Jung, Jae Hee

2015-11-15

In this study, we demonstrated an antimicrobial nanoparticle-coated electrostatic (ES) air filter. Antimicrobial natural-product Sophora flavescens nanoparticles were produced using an aerosol process, and were continuously deposited onto the surface of air filter media. For the electrostatic activation of the filter medium, a corona discharge electrification system was used before and after antimicrobial treatment of the filter. In the antimicrobial treatment process, the deposition efficiency of S. flavescens nanoparticles on the ES filter was ~12% higher than that on the pristine (Non-ES) filter. In the evaluation of filtration performance using test particles (a nanosized KCl aerosol and submicron-sized Staphylococcus epidermidis bioaerosol), the ES filter showed better filtration efficiency than the Non-ES filter. However, antimicrobial treatment with S. flavescens nanoparticles affected the filtration efficiency of the filter differently depending on the size of the test particles. While the filtration efficiency of the KCl nanoparticles was reduced on the ES filter after the antimicrobial treatment, the filtration efficiency was improved after the recharging process. In summary, we prepared an antimicrobial ES air filter with >99% antimicrobial activity, ~92.5% filtration efficiency (for a 300-nm KCl aerosol), and a ~0.8 mmAq pressure drop (at 13 cm/s). This study provides valuable information for the development of a hybrid air purification system that can serve various functions and be used in an indoor environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of anti-inflammatory and antimicrobial activity of AHPL/AYTOP/0213 cream

PubMed Central

Nipanikar, Sanjay U.; Nagore, Dheeraj; Chitlange, Soham S.; Buzruk, Devashree

2017-01-01

Background: Acne vulgaris is almost a widespread disease occurring in all races. Propionibacterium acnes initiate acne and inflammatory mediators aggravate it. Conventional therapies for acne include comedolytic, anti-inflammatory, and anti-biotic agents. Due to adverse effects of these therapies, people are searching for alternative options. In this context, a polyherbal formulation AHPL/AYTOP/0213 cream was developed for the treatment of Acne. Objective: The objective of this study is to study anti-inflammatory and antimicrobial activities of AHPL/AYTOP/0213 cream. Materials and Methods: Skin irritation study was conducted on AHPL/AYTOP/0213 cream as per OECD guidelines. (1) Anti-inflammatory activity: Anti-inflammatory activity of AHPL/AYTOP/0213 cream in comparison with diclofenac sodium cream was assessed in carrageenan-induced rat paw edema model. (2) Antimicrobial activity for P. acnes: P. acnes were incubated under anaerobic conditions. Aliquots of molten brain–heart infusion with glucose agar were used as the agar base. Formulation and clindamycin (10 mg/ml) were introduced in to the Agar wells randomly. (3) Antimicrobial activity for Staphylococcus epidermidis and Staphylococcus aureus: bacteria were incubated under aerobic conditions at 37°C. Tryptic soy broth with glucose agar was used as the agar base. A volume of 0.5 ml of formulation and clindamycin (10 mg/ml) were introduced in to the wells randomly. The antibacterial activity was evaluated by measuring zones of inhibition (in mm). Results: AHPL/AYTOP/0213 cream is nonirritant. Significant reduction in rat paw edema (43%) was observed with AHPL/AYTOP/0213 which was also comparable to diclofenac sodium cream (56.09%). Zone of inhibition for formulation was 20.68 mm, 28.20 mm, and 21.40 mm for P. acnes, S. epidermidis and S. aureus, respectively, which was comparable to clindamycin. The minimum inhibitory concentration of formulation AHPL/AYTOP/0213 obtained in anti-microbial study was 2.5 mg/mL. Conclusion: AHPL/AYTOP/0213 cream is nonirritant and possesses significant anti-inflammatory and antimicrobial activities, which further justifies its role in the management of acne vulgaris. PMID:29861599

Comparative evaluation of antibacterial activity of caffeic acid phenethyl ester and PLGA nanoparticle formulation by different methods

NASA Astrophysics Data System (ADS)

Arasoglu, Tülin; Derman, Serap; Mansuroglu, Banu

2016-01-01

The aim of the present study was to evaluate the antimicrobial activity of nanoparticle and free formulations of the CAPE compound using different methods and comparing the results in the literature for the first time. In parallel with this purpose, encapsulation of CAPE with the PLGA nanoparticle system (CAPE-PLGA-NPs) and characterization of nanoparticles were carried out. Afterwards, antimicrobial activity of free CAPE and CAPE-PLGA-NPs was determined using agar well diffusion, disk diffusion, broth microdilution and reduction percentage methods. P. aeroginosa, E. coli, S. aureus and methicillin-resistant S. aureus (MRSA) were chosen as model bacteria since they have different cell wall structures. CAPE-PLGA-NPs within the range of 214.0 ± 8.80 nm particle size and with an encapsulation efficiency of 91.59 ± 4.97% were prepared using the oil-in-water (o-w) single-emulsion solvent evaporation method. The microbiological results indicated that free CAPE did not have any antimicrobial activity in any of the applied methods whereas CAPE-PLGA-NPs had significant antimicrobial activity in both broth dilution and reduction percentage methods. CAPE-PLGA-NPs showed moderate antimicrobial activity against S. aureus and MRSA strains particularly in hourly measurements at 30.63 and 61.25 μg ml-1 concentrations (both p < 0.05), whereas they failed to show antimicrobial activity against Gram-negative bacteria (P. aeroginosa and E. coli, p > 0.05). In the reduction percentage method, in which the highest results of antimicrobial activity were obtained, it was observed that the antimicrobial effect on S. aureus was more long-standing (3 days) and higher in reduction percentage (over 90%). The appearance of antibacterial activity of CAPE-PLGA-NPs may be related to higher penetration into cells due to low solubility of free CAPE in the aqueous medium. Additionally, the biocompatible and biodegradable PLGA nanoparticles could be an alternative to solvents such as ethanol, methanol or DMSO. Consequently, obtained results show that the method of selection is extremely important and will influence the results. Thus, broth microdilution and reduction percentage methods can be recommended as reliable and useful screening methods for determination of antimicrobial activity of PLGA nanoparticle formulations used particularly in drug delivery systems compared to both agar well and disk diffusion methods.

Herbal Extract Incorporated Nanofiber Fabricated by an Electrospinning Technique and its Application to Antimicrobial Air Filtration.

PubMed

Choi, Jeongan; Yang, Byeong Joon; Bae, Gwi-Nam; Jung, Jae Hee

2015-11-18

Recently, with the increased attention to indoor air quality, antimicrobial air filtration techniques have been studied widely to inactivate hazardous airborne microorganisms effectively. In this study, we demonstrate herbal extract incorporated (HEI) nanofibers synthesized by an electrospinning technique and their application to antimicrobial air filtration. As an antimicrobial herbal material, an ethanolic extract of Sophora flavescens, which exhibits great antibacterial activity against pathogens, was mixed with the polymer solution for the electrospinning process. We measured various characteristics of the synthesized HEI nanofibers, such as fiber morphology, fiber size distribution, and thermal stability. For application of the electrospun HEI nanofibers, we made highly effective air filters with 99.99% filtration efficiency and 99.98% antimicrobial activity against Staphylococcus epidermidis. The pressure drop across the HEI nanofiber air filter was 4.75 mmH2O at a face air velocity of 1.79 cm/s. These results will facilitate the implementation of electrospun HEI nanofiber techniques to control air quality and protect against hazardous airborne microorganisms.

Investigation of the antimicrobial activities of Snakin-Z, a new cationic peptide derived from Zizyphus jujuba fruits.

PubMed

Daneshmand, Fatemeh; Zare-Zardini, Hadi; Ebrahimi, Leila

2013-01-01

Snakin-Z is a novel antimicrobial peptide (AMP) that is identified from the fruit of Zizyphus jujuba. This peptide is composed of 31 amino acids which is determined with the sequence of CARLNCVPKGTSGNTETCPCYASLHSCRKYG and molecular weight of 3318.82 Da. Snakin-Z is not identical to any AMP in the peptide database. According to this study, Snakin-Z potentially has antimicrobial property against bacteria and fungi. Minimal inhibitory concentration (MIC) value of this peptide is suitable for antimicrobial activity. We assessed that Snakin-Z could affect Phomopsis azadirachtae with the MIC value of 7.65 μg/mL and vice versa Staphylococcus aureus with the MIC value of 28.8 μg/mL. Interestingly, human red blood cells also showed good tolerance to the Snakin-Z. On the basis of this study, Snakin-Z can be an appropriate candidate for therapeutic applications in the future due to its antimicrobial property.

Antimicrobial activity of methanolic extracts of Sambucus ebulus and Urtica dioica against clinical isolates of methicillin resistant Staphylococcus aureus.

PubMed

Salehzadeh, Ali; Asadpour, Leila; Naeemi, Akram Sadat; Houshmand, Elham

2014-01-01

Increase in the emergence of drug -resistant pathogens led to the development of natural antimicrobials. In this study the antimicrobial effect of methanolic extracts of Sambucus ebulus and Urtica dioica on 16 skin and wound infections isolates of methicillin resistant S. aureus have been studied. Solvent extraction procedure was done using soxhlet apparatus for extracting antimicrobial agents from freeze dried plants. Antibacterial activity was measured using agar well diffusion method. The MIC of Sambucus ebulus and Urtica dioica extracts against the standard strain of S. aureus ATCC 6538 were determined using the micro dilution method at 15 mg and 20 mg respectively. All the test bacteria were found sensitive to the Sambucus ebulus extract and only one isolate was resistant to Urtica dioica extract. Extracts of Sambucus ebulus and Urtica dioica possess antibacterial potency against MRSA isolates and may be used as a natural antiseptics and antimicrobial agents in medicine.

Antioxidant and antimicrobial activity of stingless bee bread and propolis extracts

NASA Astrophysics Data System (ADS)

Akhir, Rabieatul Adawieah Md; Bakar, Mohd Fadzelly Abu; Sanusi, Shuaibu Babaji

2017-10-01

Bee bread and propolis are by-products of honey bee. The main objective of this research was to investigate the antioxidant and antimicrobial activity of stingless bee bread and propolis extracted using 70% ethanol and n-hexane. The antioxidant activity of the sample extracts were determined by spectrophotometry analysis while for the antimicrobial activity, the sample extracts were analyzed using disc diffusion and broth dilution assays. For DPPH and ABTS assays, the results showed that ethanolic extract of bee bread showed the highest free radical scavenging (%) as compared to other samples. However, FRAP values for both hexanic extracts are higher as compared to the ethanolic extracts. For disc diffusion assay, the results showed that the ethanolic extract of bee bread and propolis as well as hexanic extract of propolis were able to inhibit all tested bacteria. Meanwhile, broth dilution assay showed minimum inhibition zone (MIC) ranging from <6.67 to 33.33 µL/mL. As the conclusion, both bee bread and propolis produced by stingless bee in this study displayed antioxidant and antimicrobial effect but there are different in the degree of antioxidant and antimicrobial activity exhibited between each of the samples.

Antimicrobial and antioxidant activities of substituted 4H-1, 4-benzothiazines

NASA Astrophysics Data System (ADS)

Sharma, Praveen Kumar; Chaucer, Puneet; Kumar, Gulshan; Parihar, Leena

2017-07-01

Antioxidant and antimicrobial activity of substituted benzothiazine was investigated. Antioxidant activity of 3,7-dimethyl-2-(4'-morpholinylcarbonyl)-4H-1,4-benzothiazine was tested by the use of 2-diphenyl-1-picrylhydrazyl radical(DPPH). In addition 3,7-dimethyl-2-(4'-morpholinylcarbonyl)-4H-1,4-benzothiazine was examined for its antimicrobial activity against bacteria, Bacillus subtilis, B. flexus, B. alkalophilus, as well as their antifungal activity against Aspergillus nigrum, A. Flexus and show potential antimicrobial activities.

Antimicrobial and antifungal activities of the extracts and essential oils of Bidens tripartita.

PubMed

Tomczykowa, Monika; Tomczyk, Michał; Jakoniuk, Piotr; Tryniszewska, Elzbieta

2008-01-01

The aim of this study was to determine the antibacterial and antifungal properties of the extracts, subextracts and essential oils of Bidens tripartita flowers and herbs. In the study, twelve extracts and two essential oils were investigated for activity against different Gram-positive Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Gram-negative bacteria Escherichia coli, E. coli (beta-laktamase+), Klebsiella pneumoniae (ESBL+), Pseudomonas aeruginosa and some fungal organisms Candida albicans, C. parapsilosis, Aspergillus fumigatus, A. terreus using a broth microdilution and disc diffusion methods. The results obtained indicate antimicrobial activity of the tested extracts (except butanolic extracts), which however did not inhibit the growth of fungi used in this study. Bacteriostatic effect of both essential oils is insignificant, but they have strong antifungal activity. These results support the use of B. tripartita to treat a microbial infections and it is indicated as an antimicrobial and antifungal agent, which may act as pharmaceuticals and preservatives.

Antimicrobial activity of Calendula officinalis petal extracts against fungi, as well as Gram-negative and Gram-positive clinical pathogens.

PubMed

Efstratiou, Efstratios; Hussain, Abdullah I; Nigam, Poonam S; Moore, John E; Ayub, Muhammad A; Rao, Juluri R

2012-08-01

The aim of the present study was to assess the antimicrobial activity of methanol and ethanol extracts of pot marigold (Calendula officinalis) petals against clinical pathogens. The antimicrobial potential of C. officinalis extracts was evaluated against a panel of microorganisms isolated from patients at the Belfast City Hospital (BCH), including bacteria and fungi, using disc diffusion assay. Methanol extract of C. officinalis exhibited better antibacterial activity against most of the bacteria tested, than ethanol extract. Both methanol and ethanol extracts showed excellent antifungal activity against tested strains of fungi, while comparing with Fluconazole. Copyright © 2012 Elsevier Ltd. All rights reserved.

Isolation and Identification of Phyllospheric Bacteria Possessing Antimicrobial Activity from Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium and Hippocrepis unisiliqousa

PubMed Central

Mazinani, Zohreh; Zamani, Marzieh

2017-01-01

Background: The widespread utilization of antimicrobial compounds has caused emergence of resistant microorganisms in the world. Hence, the research to probe the products with antimicrobial features has led to finding natural habitats and discovering new pharmaceutical products. Methods: In this study, an attempt was made to explore the niche of novel habitat to isolate pyllospheric bacteria from the above ground parts (stems and leaves) of Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium, and Hippocrepis unisiliqousa to evaluate their antimicrobial features. The inhibitory effects of these strains on the growth of two fungi (Aspergillus niger, Aspergillus fumigatus), two yeasts (Saccharomyces cerevisiae, Candida albicans) and six bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella typhi, Streptococcus pyogenes) were tested. Results: In total, 113 bacterial strains were isolated. Twenty five bacterial strains (B-1 to B-25) indicated promising antimicrobial (antibacterial and antifungal) activities against aforementioned pathogens. The identification of the bacterial strains was ascertained by morphological, physiological, biochemical tests and two strains with the strongest antimicrobial activities were further characterized based on 16s rRNA sequencing. These two strains were identified as Bacillus amyloliquefaciens. Conclusion: Our results provide evidence that phyllospheric microorganisms are capable of producing some compounds with antimicrobial properties. PMID:28090278

Isolation and Identification of Phyllospheric Bacteria Possessing Antimicrobial Activity from Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium and Hippocrepis unisiliqousa.

PubMed

Mazinani, Zohreh; Zamani, Marzieh; Sardari, Soroush

2017-01-01

The widespread utilization of antimicrobial compounds has caused emergence of resistant microorganisms in the world. Hence, the research to probe the products with antimicrobial features has led to finding natural habitats and discovering new pharmaceutical products. In this study, an attempt was made to explore the niche of novel habitat to isolate pyllospheric bacteria from the above ground parts (stems and leaves) of Astragalus obtusifolius , Prosopis juliflora , Xanthium strumarium , and Hippocrepis unisiliqousa to evaluate their antimicrobial features. The inhibitory effects of these strains on the growth of two fungi ( Aspergillus niger , Aspergillus fumigatus ), two yeasts ( Saccharomyces cerevisiae , Candida albicans ) and six bacteria ( Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Bacillus subtilis , Salmonella typhi , Streptococcus pyogenes ) were tested. In total, 113 bacterial strains were isolated. Twenty five bacterial strains (B-1 to B-25) indicated promising antimicrobial (antibacterial and antifungal) activities against aforementioned pathogens. The identification of the bacterial strains was ascertained by morphological, physiological, biochemical tests and two strains with the strongest antimicrobial activities were further characterized based on 16s rRNA sequencing. These two strains were identified as Bacillus amyloliquefaciens . Our results provide evidence that phyllospheric microorganisms are capable of producing some compounds with antimicrobial properties.

Antimicrobial potential of two traditional herbometallic drugs against certain pathogenic microbial species.

PubMed

Wijenayake, A U; Abayasekara, C L; Pitawala, H M T G A; Bandara, B M R

2016-09-15

Mineral based preparations are widely used for centuries as antimicrobial agents. However, the efficacy and the mode of action of mineral based preparations are uncertain due to the insufficient antimicrobial studies. Arogyawardhana Vati (AV) and Manikya Rasa (MR) are such two Rasashastra herbo-minerallic drugs commonly in India and other countries in South Asia. Despite of their well known traditional use of skin diseases, reported antimicrobial and mineralogical studies are limited. Therefore, in this study antimicrobial activities of the drugs and their organic, inorganic fractions were evaluated against Pseudomonas aeruginosa, Escherischia coli, Staphylococcus aureus, Methecilline Resistance Staphylococcus aureus - MRSA and Candida albicans. Antimicrobial activity of the drugs, their inorganic residues and organic extracts were determined using four assay techniques viz agar well diffusion, modified well diffusion, Miles and Misra viable cell counting and broth turbidity measurements. Mineralogical constituents of the drugs were determined using X-ray diffraction, while total cation constituents and water soluble cation constituents were determined using inductively coupled plasma-mass spectrometer and the atomic absorption spectrophotometer respectively. Thermogravimetric analysis was used to determine the weight percentages of organic and inorganic fraction of the drugs. Particle sizes of the drugs were determined using the particle size analyzer. AV and MR drugs showed antibacterial activity against both gram positive and gram negative bacterial species when analyzed separately. Inorganic residues of the drugs and organic extracts showed activity at least against two or more bacterial species tested. All tested components were inactive against C. albicans. Common mineral constituents of drugs are cinnabar, biotite and Fe-rich phases. Drugs were rich in essential elements such as Na, K, Ca, Mg and Fe and toxic elements such as Zn, Cu and As. However, the water soluble concentrations of the toxic elements were below the detection limits. Both drugs have significantly higher percentages of organic constituents and volatile minerals and particle sizes of drugs are in the nanometer range. AV and MR Rasashastra preparations could provide alternatives to synthetic antibiotics against human bacterial infections. Improved solubility and reduced particle sizes are influential physicochemical properties used to enhance the antimicrobial efficacy of the drugs. Therefore, traditional knowledge on the use of antimicrobial mineral sources could provide a novel path for the producing of effective antimicrobial drugs. However, further chemical and toxicological studies are urgently needed for a greater understanding of their toxicity to humans.

Raman spectroscopy, electronic microscopy and SPME-GC-MS to elucidate the mode of action of a new antimicrobial food packaging material.

PubMed

Clemente, Isabel; Aznar, Margarita; Salafranca, Jesús; Nerín, Cristina

2017-02-01

One critical challenge when developing a new antimicrobial packaging material is to demonstrate the mode of action of the antimicrobials incorporated into the packaging. For this task, several analytical techniques as well as microbiology are required. In this work, the antimicrobial properties of benzyl isothiocyanate, allyl isothiocyanate and essential oils of cinnamon and oregano against several moulds and bacteria have been evaluated. Benzyl isothiocyanate showed the highest antimicrobial activity and it was selected for developing the new active packaging material. Scanning electron microscopy and Raman spectroscopy were successfully used to demonstrate the mode of action of benzyl isothiocyanate on Escherichia coli. Bacteria exhibited external modifications such as oval shape and the presence of septum surface, but they did not show any disruption or membrane damage. To provide data on the in vitro action of benzyl isothiocyanate and the presence of inhibition halos, the transfer mechanism to the cells was assessed using solid-phase microextraction-gas chromatography-mass spectrometry. Based on the transfer system, action mechanism and its stronger antimicrobial activity, benzyl isothiocyanate was incorporated to two kinds of antimicrobial labels. The labels were stable and active for 140 days against two mould producers of ochratoxin A; Penicillium verrucosum is more sensitive than Aspergillus ochraceus. Details about the analytical techniques and the results obtained are shown and discussed. Graphical Abstract Antimicrobial evaluation of pure compounds, incorporation in the packaging and study for mode of action on S. coli by Raman, SEM and SPME-GC-MS.

In vitro antimicrobial activity of five essential oils on multidrug resistant Gram-negative clinical isolates

PubMed Central

Sakkas, Hercules; Gousia, Panagiota; Economou, Vangelis; Sakkas, Vassilios; Petsios, Stefanos; Papadopoulou, Chrissanthy

2016-01-01

Aim/Background: The emergence of drug-resistant pathogens has drawn attention on medicinal plants for potential antimicrobial properties. The objective of the present study was the investigation of the antimicrobial activity of five plant essential oils on multidrug resistant Gram-negative bacteria. Materials and Methods: Basil, chamomile blue, origanum, thyme, and tea tree oil were tested against clinical isolates of Acinetobacter baumannii (n = 6), Escherichia coli (n = 4), Klebsiella pneumoniae (n = 7), and Pseudomonas aeruginosa (n = 5) using the broth macrodilution method. Results: The tested essential oils produced variable antibacterial effect, while Chamomile blue oil demonstrated no antibacterial activity. Origanum, Thyme, and Basil oils were ineffective on P. aeruginosa isolates. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values ranged from 0.12% to 1.50% (v/v) for tea tree oil, 0.25-4% (v/v) for origanum and thyme oil, 0.50% to >4% for basil oil and >4% for chamomile blue oil. Compared to literature data on reference strains, the reported MIC values were different by 2SD, denoting less successful antimicrobial activity against multidrug resistant isolates. Conclusions: The antimicrobial activities of the essential oils are influenced by the strain origin (wild, reference, drug sensitive, or resistant) and it should be taken into consideration whenever investigating the plants’ potential for developing new antimicrobials. PMID:27366345

Proteolytic and antimicrobial activity of lactic acid bacteria grown in goat milk.

PubMed

Atanasova, Jivka; Moncheva, Penka; Ivanova, Iskra

2014-11-02

We examined 62 strains and 21 trade starter cultures from the collection of LB Bulgaricum PLC for proteolytic and antimicrobial activity of lactic acid bacteria (LAB) grown in goat milk. The aim of this study was to investigate the fermentation of caseins, α-lactalbumin and β-lactoglobulin by LAB, using the o -phthaldialdehyde (OPA) spectrophotometric assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The proteolysis targeted mainly caseins, especially β-casein. Whey proteins were proteolyzed, essentially β-lactoglobulin. The proteolytic activity of Lactococcus lactis l598, Streptococcus thermophilus t3D1, Dt1, Lactobacillus lactis 1043 and L. delbrueckii subsp. bulgaricus b38, b122 and b24 was notably high. The proteolysis process gave rise to medium-sized peptide populations. Most of the examined strains showed antimicrobial activity against some food pathogens, such as Escherichia coli , Staphylococcus aureus , Salmonella cholere enteridis , Listeria monocytogenes , Listeria innocua and Enterobacter aerogenes . The most active producers of antimicrobial-active peptides were strains of L. delbrueckii subsp. bulgaricus and S. thermophilus , which are of practical importance. The starter cultures containing the examined species showed high proteolytic and antimicrobial activity in skimmed goat milk. The greatest antimicrobial activity of the cultures was detected against E. aerogenes . The obtained results demonstrated the significant proteolytic potential of the examined strains in goat milk and their potential for application in the production of dairy products from goat's milk. The present results could be considered as the first data on the proteolytic capacity of strains and starter cultures in goat milk for the purposes of trade interest of LB Bulgaricum PLC.

Exposure of the grass shrimp, Palaemonetes pugio, to antimicrobial compounds affects associated Vibrio bacterial density and development of antibiotic resistance.

PubMed

DeLorenzo, M E; Brooker, J; Chung, K W; Kelly, M; Martinez, J; Moore, J G; Thomas, M

2016-04-01

Antimicrobial compounds are widespread, emerging contaminants in the aquatic environment and may threaten ecosystem and human health. This study characterized effects of antimicrobial compounds common to human and veterinary medicine, aquaculture, and consumer personal care products [erythromycin (ERY), sulfamethoxazole (SMX), oxytetracycline (OTC), and triclosan (TCS)] in the grass shrimp Palaemonetes pugio. The effects of antimicrobial treatments on grass shrimp mortality and lipid peroxidation activity were measured. The effects of antimicrobial treatments on the bacterial community of the shrimp were then assessed by measuring Vibrio density and testing bacterial isolates for antibiotic resistance. TCS (0.33 mg/L) increased shrimp mortality by 37% and increased lipid peroxidation activity by 63%. A mixture of 0.33 mg/L TCS and 60 mg/L SMX caused a 47% increase in shrimp mortality and an 88% increase in lipid peroxidation activity. Exposure to SMX (30 mg/L or 60 mg/L) alone and to a mixture of SMX/ERY/OTC did not significantly affect shrimp survival or lipid peroxidation activity. Shrimp exposure to 0.33 mg/L TCS increased Vibrio density 350% as compared to the control whereas SMX, the SMX/TCS mixture, and the mixture of SMX/ERY/OTC decreased Vibrio density 78-94%. Increased Vibrio antibiotic resistance was observed for all shrimp antimicrobial treatments except for the mixture of SMX/ERY/OTC. Approximately 87% of grass shrimp Vibrio isolates displayed resistance to TCS in the control treatment suggesting a high level of TCS resistance in environmental Vibrio populations. The presence of TCS in coastal waters may preferentially increase the resistance and abundance of pathogenic bacteria. These results indicate the need for further study into the potential interactions between antimicrobials, aquatic organisms, and associated bacterial communities. © 2014 Wiley Periodicals, Inc.

Antimicrobial properties of conventional restorative filling materials and advances in antimicrobial properties of composite resins and glass ionomer cements-A literature review.

PubMed

Farrugia, Cher; Camilleri, Josette

2015-04-01

It has been reported that complete caries removal from cavities during restoration of teeth is difficult. Furthermore with the tissue saving approach it is expected that more of the saved affected tissue will possibly harbor more residual bacteria. Antimicrobial restorative filling materials would be ideal to prevent the spread of caries after completion of tooth restoration, thus preventing recurrent decay and eventually restoration failure. This paper reviews the literature on the antimicrobial properties of dental restorative filling materials. Pubmed searches on the antibacterial properties of restorative materials were carried out. Keywords were chosen to assess antibacterial properties of conventional filling materials. Methods of introducing antimicrobial agents in restorative materials were also reviewed together with the methodology used to assess antimicrobial activity. 174 articles from 1983 till 2014 were included. Adhesive materials have decreased antimicrobial activity when compared to amalgams and zinc oxides. Several techniques have been employed in order to increase the antimicrobial activity of restorative materials. Although antimicrobial activity of restorative materials is important, the introduction of antimicrobial agents/techniques should not be at the expense of other material properties. Environmental changes within a material may affect the bacterial response to the antimicrobial. Bacterial adhesion to the restorative materials should be assessed. Long term assessment of antimicrobial activity is important and is clinically relevant. The use of antimicrobial dental materials is important unless such characteristics are gained to the detriment of other material properties. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Preparation, characterization, and antimicrobial activity of nanoemulsions incorporating citral essential oil.

PubMed

Lu, Wen-Chien; Huang, Da-Wei; Wang, Chiun-C R; Yeh, Ching-Hua; Tsai, Jen-Chieh; Huang, Yu-Ting; Li, Po-Hsien

2018-01-01

Citral is a typical essential oil used in the food, cosmetic, and drug industries and has shown antimicrobial activity against microorganisms. Citral is unstable and hydrophobic under normal storage conditions, so it can easily lose its bactericide activity. Nanoemulsion technology is an excellent way to hydrophilize, microencapsulate, and protect this compound. In our studies, we used a mixed surfactant to form citral-in-water nanoemulsions, and attempted to optimize the formula for preparing nanoemulsions. Citral-in-water nanoemulsions formed at S o 0.4 to 0.6 and ultrasonic power of 18 W for 120 seconds resulted in a droplet size of < 100 nm for nanoemulsions. The observed antimicrobial activities were significantly affected by the formulation of the nanoemulsions. The observed relationship between the formulation and activity can lead to the rational design of nanoemulsion-based delivery systems for essential oils, based on the desired function of antimicrobials in the food, cosmetics, and agrochemical industries. Copyright © 2017. Published by Elsevier B.V.

The effect of feed moisture and temperature on tannin content, antioxidant and antimicrobial activities of extruded chestnuts.

PubMed

Obiang-Obounou, Brice Wilfried; Ryu, Gi Hyung

2013-12-15

This study focuses on the effect of extrusion processing on tannin reduction, phenolic content, flavonoid content, antioxidant and anitimicrobial activity. Extrusion temperature (120 and 140 °C) and feed moisture (25% and 28%) were used on the tannin content, antioxidant and antimicrobial activities. Extrusion cooking reduced tannin content up to 78%, and improved antioxidant activity from 12.89% to 21.17% in a concentration dependant manner without affecting its antimicrobial activity that varied from 250 to 500 mg. The time-kill assay confirmed the ability of extruded chestnut to reduce Pseudomonas aeruginosa count below detectable limit that reduced the original inoculum by 3log10 CFU/mL. Overall, the results showed that extrusion cooking might serve as a tool for tannin reduction and could improve the antioxidant and antimicrobial properties of chestnut, which might be helpful for chestnut related products in the food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Chemical composition, in vitro antioxidant, antimicrobial and insecticidal activities of essential oil from Cladanthus arabicus

USDA-ARS?s Scientific Manuscript database

The essential oil obtained from the aerial parts of Cladanthus arabicus (L.) Cass was studied for its chemical composition, antioxidant, antimicrobial and insecticidal activities. The essential oil (EO) was analyzed by GC-MS. Sixty seven compounds representing 94.2% of the oil were identified. The m...

Imidazolium tagged acridines: Synthesis, characterization and applications in DNA binding and anti-microbial activities

NASA Astrophysics Data System (ADS)

Raju, Gembali; Vishwanath, S.; Prasad, Archana; Patel, Basant K.; Prabusankar, Ganesan

2016-03-01

New water soluble 4,5-bis imidazolium tagged acridines have been synthesized and structurally characterized by multinuclear NMR and single crystal X-ray diffraction techniques. The DNA binding and anti-microbial activities of these acridine derivatives were investigated by fluorescence and far-UV circular dichroism studies.

Antimicrobial properties of nano-silver: a cautionary approach to ionic interference.

PubMed

Sheehy, K; Casey, A; Murphy, A; Chambers, G

2015-04-01

Metallic nanoparticles such as nano-silver have found many applications as alternative antimicrobials in recent years. However methods for determining their proposed antimicrobial activity have received little attention to date. The disk diffusion assay is commonly used as a demonstration of antimicrobial properties and is a regular feature in synthetic nanoparticle papers. The aim of this study was to assess its effectiveness in demonstrating the "nanoparticle specific" antimicrobial properties in the absence of ionic contributions from unreacted reducing agents and or impurities. The disk diffusion assay was carried out on a range of silver nanoparticles, both in-house synthesised and commercially available, using Escherichia coli ATCC 25922 as a model organism. Capped and purified nanoparticles show no antimicrobial activity despite claims to the contrary for this assay. Results will be discussed in terms of the need for researchers without a background in microbiology to understand the mechanism of antimicrobial action before choosing an assay. Also discussed is the importance understanding the physiochemical characteristics of when interpreting results. Finally the relevance of the results in terms establishing protocols for method development for 'nanoparticle specific' antimicrobial properties will also be considered. Copyright © 2014 Elsevier Inc. All rights reserved.

Extracellular synthesis of gold bionanoparticles by Nocardiopsis sp. and evaluation of its antimicrobial, antioxidant and cytotoxic activities.

PubMed

Manivasagan, Panchanathan; Alam, Moch Syaiful; Kang, Kyong-Hwa; Kwak, Minseok; Kim, Se-Kwon

2015-06-01

Advancement of biological process for the synthesis of bionanoparticles is evolving into a key area of research in nanotechnology. The present study deals with the biosynthesis, characterization of gold bionanoparticles by Nocardiopsis sp. MBRC-48 and evaluation of their antimicrobial, antioxidant and cytotoxic activities. The gold bionanoparticles obtained were characterized by UV-visible spectroscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis and transmission electron microscopy (TEM). The synthesized gold bionanoparticles were spherical in shape with an average of 11.57 ± 1.24 nm as determined by TEM and dynamic light scattering (DLS) particle size analyzer, respectively. The biosynthesized gold nanoparticles exhibited good antimicrobial activity against pathogenic microorganisms. It showed strong antioxidant activity as well as cytotoxicity against HeLa cervical cancer cell line. The present study demonstrated the potential use of the marine actinobacterial strain of Nocardiopsis sp. MBRC-48 as an important source for gold nanoparticles with improved biomedical applications including antimicrobial, antioxidant as well as cytotoxic agent.

Novel silver-based nanoclay as an antimicrobial in polylactic acid food packaging coatings.

PubMed

Busolo, Maria A; Fernandez, Patricia; Ocio, Maria J; Lagaron, Jose M

2010-11-01

This paper presents a comprehensive performance study of polylactic acid (PLA) biocomposites, obtained by solvent casting, containing a novel silver-based antimicrobial layered silicate additive for use in active food packaging applications. The silver-based nanoclay showed strong antimicrobial activity against Gram-negative Salmonella spp. Despite the fact that no exfoliation of the silver-based nanoclay in PLA was observed, as suggested by transmission electron microscopy (TEM) and wide angle X-ray scattering (WAXS) experiments, the additive dispersed nicely throughout the PLA matrix to a nanoscale, yielding nanobiocomposites. The films were highly transparent with enhanced water barrier and strong biocidal properties. Silver migration from the films to a slightly acidified water medium, considered an aggressive food simulant, was measured by stripping voltammetry. Silver migration accelerated after 6 days of exposure. Nevertheless, the study suggests that migration levels of silver, within the specific migration levels referenced by the European Food Safety Agency (EFSA), exhibit antimicrobial activity, supporting the potential application of this biocidal additive in active food-packaging applications to improve food quality and safety.

Animal Venom Peptides: Potential for New Antimicrobial Agents.

PubMed

Primon-Barros, Muriel; José Macedo, Alexandre

2017-01-01

Microbial infections affect people worldwide, causing diseases with significant impact on public health, indicating the need for research and development of new antimicrobial agents. Animal venoms represent a vast and largely unexploited source of biologically active molecules with attractive candidates for the development of novel therapeutics. Venoms consist of complex mixtures of molecules, including antimicrobial peptides (AMPs). Since the discovery of AMPs, they have been studied as promising new antimicrobial drugs. Amongst the remarkable sources of AMPs with known antimicrobial activities are ants, bees, centipedes, cone snails, scorpions, snakes, spiders, and wasps. The antimicrobial tests against bacteria, protozoans, fungi and viruses using 170 different peptides isolated directly from crude venoms or cDNA libraries of venom glands are listed and discussed in this review, as well as hemolytic ativity. The potential of venoms as source of new compounds, including AMPs, is extensively discussed. Currently, there are six FDA-approved drugs and many others are undergoing preclinical and clinical trials. The search for antimicrobial "weapons" makes the AMPs from venoms promising candidates. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain and aloe vera (all in gel formulation), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis: An in vitro study.

PubMed

Bhardwaj, Anuj; Ballal, Suma; Velmurugan, Natanasabapathy

2012-07-01

A comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain, and aloe vera (all in gel formulations), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis-an in vitro study. The antimicrobial efficacy was assessed in vitro using dentin shavings collected at 2 depths of 200 and 400 μm. The total colony forming units at the end of 1, 3, and 5 days were assessed. The overall percentage inhibition of bacterial growth (200 and 400 μm depth) was 100% with chlorhexidine gel. This was followed by M. citrifolia gel (86.02%), which showed better antimicrobial efficacy as compared with aloe vera gel (78.9%), papain gel (67.3%), and calcium hydroxide (64.3%). There was no statistical difference between data at 200 and 400 μm depth. Chlorhexidine gel showed the maximum antimicrobial activity against E. faecalis, whereas calcium hydroxide showed the least. Among the natural intracanal medicaments, M. citrifolia gel consistently exhibited good inhibition up to the 5(th) day followed by aloe vera gel and papain gel.

Thaulin-1: The first antimicrobial peptide isolated from the skin of a Patagonian frog Pleurodema thaul (Anura: Leptodactylidae: Leiuperinae) with activity against Escherichia coli.

PubMed

Marani, Mariela M; Perez, Luis O; de Araujo, Alyne Rodrigues; Plácido, Alexandra; Sousa, Carla F; Quelemes, Patrick Veras; Oliveira, Mayara; Gomes-Alves, Ana G; Pueta, Mariana; Gameiro, Paula; Tomás, Ana M; Delerue-Matos, Cristina; Eaton, Peter; Camperi, Silvia A; Basso, Néstor G; de Souza de Almeida Leite, Jose Roberto

2017-03-20

Patagonia's biodiversity has been explored from many points of view, however, skin secretions of native amphibians have not been evaluated for antimicrobial peptide research until now. In this sense, Pleurodema thaul is the first amphibian specie to be studied from this large region of South America. Analysis of cDNA-encoding peptide in skin samples allowed identification of four new antimicrobial peptides. The predicted mature peptides were synthesized and all of them showed weak or null antimicrobial activity against Klebsiella pneumoniae, Staphylococcus aureus and Escherichia coli with the exception of thaulin-1, a cationic 26-residue linear, amphipathic, Gly- and Leu-rich peptide with moderate antimicrobial activity against E. coli (MIC of 24.7μM). AFM and SPR studies suggested a preferential interaction between these peptides and bacterial membranes. Cytotoxicity assays showed that thaulin peptides had minimal effects at MIC concentrations towards human and animal cells. These are the first peptides described for amphibians of the Pleurodema genus. These findings highlight the potential of the Patagonian region's unexplored biodiversity as a source for new molecule discovery. Copyright © 2016 Elsevier B.V. All rights reserved.

Antibacterial activity and proposed action mechanism of a new class of synthetic tricyclic flavonoids.

PubMed

Babii, C; Bahrin, L G; Neagu, A-N; Gostin, I; Mihasan, M; Birsa, L M; Stefan, M

2016-03-01

This study reports on the inhibitory and bactericidal properties of a new synthetized flavonoid. Tricyclic flavonoid 1 has been synthesized through a two-step reaction sequence. The antimicrobial effects were tested using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Also DNA fragmentation assay, fluorescence microscopy and SEM were used to study the mechanism of action. Our tested flavonoid displayed a strong antimicrobial activity with MIC and MBC values as low as 0·24 μg ml(-1) against Staphylococcus aureus and 3·9 μg ml(-1) against Escherichia coli. Flavonoid 1 displayed antimicrobial properties, causing not only the inhibition of bacterial growth, but also killing bacterial cells. The mechanism of action is related to the impairment of the cell membrane integrity and to cell agglutination. Tricyclic flavonoid 1 was found to have a stronger antibacterial effect at lower concentrations than those described in the earlier reports. Based on the strong antimicrobial activity observed, this new tricyclic flavonoid has a good potential for the design of new antimicrobial agents. © 2016 The Society for Applied Microbiology.

Chemical composition and antimicrobial activity of fatty acid methyl ester of Quercus leucotrichophora fruits.

PubMed

Sati, Ankita; Sati, Sushil Chandra; Sati, Nitin; Sati, O P

2017-03-01

Natural fats and dietary oils are chief source of fatty acids and are well known to have antimicrobial activities against various microbes. The chemical composition and antimicrobial activities of fatty acids from fruits of white Oak (Quercus leucotrichophora) are yet unexplored and therefore the present study for the first time determines the fatty acid composition, and the antibacterial and antifungal activities of fatty acid methyl esters (FAME) of the white Oak plant found along the Himalayan region of Uttarakhand, India. The GCMS analysis revealed the presence of higher amount of saturated fatty acids than unsaturated fatty acids. FAME extract of fruits of Q. leucotrichophora demonstrated better antibacterial activity against Gram-positive bacteria than the Gram-negative bacteria. The present studies clearly establish the potential of the fruits of Q. leucotrichophora for use in soap, cosmetics and pharmaceutical industries.

Antimalarial, antimicrobial, cytotoxic, DNA interaction and SOD like activities of tetrahedral copper(II) complexes

NASA Astrophysics Data System (ADS)

Mehta, Jugal V.; Gajera, Sanjay B.; Patel, Mohan N.

2015-02-01

The mononuclear copper(II) complexes with P, O-donor ligand and different fluoroquinolones have been synthesized and characterized by elemental analysis, electronic spectra, TGA, EPR, FT-IR and LC-MS spectroscopy. An antimicrobial efficiency of the complexes has been tested against five different microorganisms in terms of minimum inhibitory concentration (MIC) and displays very good antimicrobial activity. The binding strength and binding mode of the complexes with Herring Sperm DNA (HS DNA) have been investigated by absorption titration and viscosity measurement studies. The studies suggest the classical intercalative mode of DNA binding. Gel electrophoresis assay determines the ability of the complexes to cleave the supercoiled form of pUC19 DNA. Synthesized complexes have been tested for their SOD mimic activity using nonenzymatic NBT/NADH/PMS system and found to have good antioxidant activity. All the complexes show good cytotoxic and in vitro antimalarial activities.

Bioactive molecules in Kalanchoe pinnata leaves: extraction, purification, and identification.

PubMed

El Abdellaoui, Saïda; Destandau, Emilie; Toribio, Alix; Elfakir, Claire; Lafosse, Michel; Renimel, Isabelle; André, Patrice; Cancellieri, Perrine; Landemarre, Ludovic

2010-10-01

Kalanchoe pinnata (Lam.) Pers. (syn. Bryophyllum pinnatum; family Crassulaceae) is a popular plant used in traditional medicine in many temperate regions of the world and particularly in South America. In Guyana, the leaves are traditionally used as an anti-inflammatory and antiseptic to treat coughs, ulcers, and sores. The purpose of this study was to implement a method for targeting and identifying molecules with antimicrobial activity, which could replace chemical preservatives in cosmetic applications. The leaves were extracted by a method based on pressurized liquid extraction (PLE), using different solvents. A study of antimicrobial activity and cytotoxicity tests were performed to select the most interesting extract. To isolate one or more active molecules, the selected crude extract was fractionated by centrifugal partition chromatography (CPC) and then antimicrobial activity and cytotoxicity of each fraction were tested under the same procedure. The last step consisted of identifying the main compounds in the most active fraction by LC-MS/MS.

Trachyspermum ammi (L.) sprague: chemical composition of essential oil and antimicrobial activities of respective fractions.

PubMed

Moein, Mahmoodreza R; Zomorodian, Kamiar; Pakshir, Keyvan; Yavari, Farnoosh; Motamedi, Marjan; Zarshenas, Mohammad M

2015-01-01

Resistance to antibacterial agents has become a serious problem for global health. The current study evaluated the antimicrobial activities of essential oil and respective fractions of Trachyspermum ammi (L.) Sprague. Seeds of the essential oil were extracted and fractionated using column chromatography. All fractions were then analyzed by gas chromatography/mass spectrometry. Antifungal and antibacterial activities of the oil and its fractions were assessed using microdilution method. Compounds γ-terpinene (48.07%), ρ-cymene (33.73%), and thymol (17.41%) were determined as major constituents. The effect of fraction II was better than total essential oil, fraction I, and standard thymol. The greater effect of fraction II compared to standard thymol showed the synergistic effects of the ingredients in this fraction. As this fraction and also total oil were effective on the studied microorganism, the combination of these products with current antimicrobial agents could be considered as new antimicrobial compounds in further investigations. © The Author(s) 2014.

Plant Phenols as Antibiotic Boosters: In Vitro Interaction of Olive Leaf Phenols with Ampicillin.

PubMed

Lim, Anxy; Subhan, Nusrat; Jazayeri, Jalal A; John, George; Vanniasinkam, Thiru; Obied, Hassan K

2016-03-01

The antimicrobial properties of olive leaf extract (OLE) have been well recognized in the Mediterranean traditional medicine. Few studies have investigated the antimicrobial properties of OLE. In this preliminary study, commercial OLE and its major phenolic secondary metabolites were evaluated in vitro for their antimicrobial activities against Escherichia coli and Staphylococcus aureus, both individually and in combination with ampicillin. Besides luteolin 7-O-glucoside, OLE and its major phenolic secondary metabolites were effective against both bacteria, with more activity on S. aureus. In combination with ampicillin, OLE, caffeic acid, verbascoside and oleuropein showed additive effects. Synergistic interaction was observed between ampicillin and hydroxytyrosol. The phenolic composition of OLE and the stability of olive phenols in assay medium were also investigated. While OLE and its phenolic secondary metabolites may not be potent enough as stand-alone antimicrobials, their abilities to boost the activity of co-administered antibiotics constitute an imperative future research area. Copyright © 2016 John Wiley & Sons, Ltd.

Development of antimicrobial active packaging materials based on gluten proteins.

PubMed

Gómez-Heincke, Diana; Martínez, Inmaculada; Partal, Pedro; Guerrero, Antonio; Gallegos, Críspulo

2016-08-01

The incorporation of natural biocide agents into protein-based bioplastics, a source of biodegradable polymeric materials, manufactured by a thermo-mechanical method is a way to contribute to a sustainable food packaging industry. This study assesses the antimicrobial activity of 10 different biocides incorporated into wheat gluten-based bioplastics. The effect that formulation, processing, and further thermal treatments exert on the thermo-mechanical properties, water absorption characteristics and rheological behaviour of these materials is also studied. Bioplastics containing six of the 10 examined bioactive agents have demonstrated suitable antimicrobial activity at 37 °C after their incorporation into the bioplastic. Moreover, the essential oils are able to create an antimicrobial atmosphere within a Petri dish. Depending on the selected biocide, its addition may alter the bioplastics protein network in a different extent, which leads to materials exhibiting less water uptake and different rheological and thermo-mechanical behaviours. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Novel antimicrobial peptides isolated from the skin secretions of Hainan odorous frog, Odorrana hainanensis.

PubMed

Wang, Hui; Yu, Zhijun; Hu, Yuhong; Li, Fengjiao; Liu, Limeng; Zheng, Hongyuan; Meng, Hao; Yang, Shujie; Yang, Xiaolong; Liu, Jingze

2012-06-01

Long time geographical isolation of Hainan Island from the China continent has resulted in appearance of many novel frog species. As one of them, Hainan odorous frog, Odorrana hainanensis possesses some special antimicrobial peptides distinct from those found in other Odorrana. In this study, three antimicrobial peptides have been purified and characterized from the skin secretion of O. hainanensis. With the similarity to the temporin family, two peptides are characterized by amidated C-terminals, so they are named as temporin-HN1 (AILTTLANWARKFL-NH(2)) and temporin-HN2 (NILNTIINLAKKIL-NH(2)). The third antimicrobial peptide belongs to the brevinin-1 family which is widely distributed in Eurasian ranids, and thus, it is named as brevinin-1HN1 (FLPLIASLAANFVPKIFCKITKKC). Furthermore, after sequencing 68 clones, eight cDNAs encoding antimicrobial peptide precursors were cloned from the skin-derived cDNA library of O. hainanensis. These eight cDNAs can encode seven mature antimicrobial peptides including the above three, as well as brevinin-1V, brevinin-2HS2, odorranain-A6, and odorranain-B1. Twelve different species of microorganisms were chosen, including Gram-positive, Gram-negative and fungi, to test the antimicrobial activities of temporin-HN1, temporin-HN2, brevinin-1HN1, brevinin-1V, and brevinin-2HS2. The result shows that, in addition to their activities against Gram-positive bacteria, temporin-HN1 and temporin-HN2 also possess activities against some Gram-negative bacteria and fungi. However, the two antimicrobial peptides, brevinin-1HN1 and brevinin-1V of the brevinin-1 family have stronger antimicrobial activities than temporin-HN1 and temporin-HN2 of the temporin family. Brevinin-1HN1 possesses activity against Staphylococcus aureus (ATCC25923), Rhodococcus rhodochrous X15, and Slime mould 090223 at the concentration of 1.2 μM. Copyright © 2012 Elsevier Inc. All rights reserved.

Rationally designed dual functional block copolymers for bottlebrush-like coatings: In vitro and in vivo antimicrobial, antibiofilm, and antifouling properties.

PubMed

Gao, Qiang; Yu, Meng; Su, Yajuan; Xie, Meihua; Zhao, Xin; Li, Peng; Ma, Peter X

2017-03-15

Numerous antimicrobial coatings have been developed for biomedical devices/implants, but few can simultaneously fulfill the requirements for antimicrobial and antifouling ability and biocompatibility. In this study, to develop an antimicrobial and antibiofilm surface coating, diblock amphiphilic molecules with antimicrobial and antifouling segments in a single chain were rationally designed and synthesized. Cationic antimicrobial polypeptides (AMP) were first synthesized by N-carboxyanhydride ring-opening polymerization (NCA-ROP). Heterofunctionalized poly(ethylene glycol) with different lengths (methacrylate-PEG n -tosyl, n=10/45/90) was synthesized and site-specifically conjugated with polypeptides to form diblock amphiphiles. Along with increased PEG chain length, hemolytic activity was considerably improved, and broad-spectrum antimicrobial activity is retained. Three MA-PEG n -b-AMP copolymers were further grafted onto the surface of silicone rubber (a commonly used catheter material) via plasma/UV-induced surface polymerizations to form a bottlebrush-like coating with excellent antimicrobial activity against several pathogenic bacteria (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus), and effectively prevent biofilm formation. This bottlebrush coating also greatly reduced protein adsorption and platelet adhesion, indicating its excellent antifouling ability. An in vitro cytotoxicity study also demonstrated that this coating is biocompatible with mammalian cells. After subcutaneous implantation of the materials in rats, we demonstrated that the g-PEG 45 -b-AMP bottlebrush coating exhibits significant anti-infective activity in vivo. Thus, this facilely synthesized PEGylated AMP bottlebrush coating is a feasible method to prevent biomedical devices-associated infections. Current antimicrobial coatings are often associated with concerns such as antibiotic resistance, environmental pollution, short-time antimicrobial activity, biofouling, poor blood compatibility and cytotoxicity, etc. To overcome these drawbacks, a robust PEGylated cationic amphiphilic peptides-based bottlebrush-like surface coating is demonstrated here, which fulfil the requirements of antimicrobial and antifouling as well as biocompatibility in the meantime. Briefly, the rational designed g-PEG n -b-AMP block copolymers (n=10/45/90) were synthesized and grafted on silicone surface. This bottlebrush-like coating efficiently kill the contacted bacteria and prevent the biofilm formation, greatly reduced protein and platelet adhesion. It also exhibits excellent blood compatibility and low cytotoxicity in vitro. In particular, g-PEG 45 -b-AMP coating exhibits significant anti-infection effect in vivo. This coating offering an effective strategy for combating biomedical devices-associated infections. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Rosmarinic Acid and Its Methyl Ester as Antimicrobial Components of the Hydromethanolic Extract of Hyptis atrorubens Poit. (Lamiaceae).

PubMed

Abedini, Amin; Roumy, Vincent; Mahieux, Séverine; Biabiany, Murielle; Standaert-Vitse, Annie; Rivière, Céline; Sahpaz, Sevser; Bailleul, François; Neut, Christel; Hennebelle, Thierry

2013-01-01

Primary biological examination of four extracts of the leaves and stems of Hyptis atrorubens Poit. (Lamiaceae), a plant species used as an antimicrobial agent in Guadeloupe, allowed us to select the hydromethanolic extract of the stems for further studies. It was tested against 46 microorganisms in vitro. It was active against 29 microorganisms. The best antibacterial activity was found against bacteria, mostly Gram-positive ones. Bioautography enabled the isolation and identification of four antibacterial compounds from this plant: rosmarinic acid, methyl rosmarinate, isoquercetin, and hyperoside. The MIC and MBC values of these compounds and their combinations were determined against eight pathogenic bacteria. The best inhibitory and bactericidal activity was found for methyl rosmarinate (0.3 mg/mL). Nevertheless, the bactericidal power of rosmarinic acid was much faster in the time kill study. Synergistic effects were found when combining the active compounds. Finally, the inhibitory effects of the compounds were evaluated on the bacterial growth phases at two different temperatures. Our study demonstrated for the first time antimicrobial activity of Hyptis atrorubens with identification of the active compounds. It supports its traditional use in French West Indies. Although its active compounds need to be further evaluated in vivo, this work emphasizes plants as potent sources of new antimicrobial agents when resistance to antibiotics increases dramatically.

Rosmarinic Acid and Its Methyl Ester as Antimicrobial Components of the Hydromethanolic Extract of Hyptis atrorubens Poit. (Lamiaceae)

PubMed Central

Abedini, Amin; Roumy, Vincent; Mahieux, Séverine; Biabiany, Murielle; Standaert-Vitse, Annie; Rivière, Céline; Sahpaz, Sevser; Bailleul, François

2013-01-01

Primary biological examination of four extracts of the leaves and stems of Hyptis atrorubens Poit. (Lamiaceae), a plant species used as an antimicrobial agent in Guadeloupe, allowed us to select the hydromethanolic extract of the stems for further studies. It was tested against 46 microorganisms in vitro. It was active against 29 microorganisms. The best antibacterial activity was found against bacteria, mostly Gram-positive ones. Bioautography enabled the isolation and identification of four antibacterial compounds from this plant: rosmarinic acid, methyl rosmarinate, isoquercetin, and hyperoside. The MIC and MBC values of these compounds and their combinations were determined against eight pathogenic bacteria. The best inhibitory and bactericidal activity was found for methyl rosmarinate (0.3 mg/mL). Nevertheless, the bactericidal power of rosmarinic acid was much faster in the time kill study. Synergistic effects were found when combining the active compounds. Finally, the inhibitory effects of the compounds were evaluated on the bacterial growth phases at two different temperatures. Our study demonstrated for the first time antimicrobial activity of Hyptis atrorubens with identification of the active compounds. It supports its traditional use in French West Indies. Although its active compounds need to be further evaluated in vivo, this work emphasizes plants as potent sources of new antimicrobial agents when resistance to antibiotics increases dramatically. PMID:24348709

Antimicrobial, antioxidant and cytotoxic properties of essential oil from Dictamnus angustifolius.

PubMed

Sun, Jianbo; Wang, Xinzhi; Wang, Pei; Li, Linzhen; Qu, Wei; Liang, Jingyu

2015-01-15

Dictamnus angustifolius (Rutaceae) has been used as an alternative for folk medicine, Dictamnus dasycarpus in the treatment of rheumatism, bleeding, itching, jaundice, chronic hepatitis, and skin diseases in Xinjiang Province of China. The aim of this study was to evaluate the antimicrobial and antioxidant activities of essential oil (EO) from Dictamnus angustifolius, correlated with their chemical composition and evaluate their cytotoxicity. The EO were extracted by water-distillation using a Clevenger-type apparatus. The chemical composition of EO was identified by GC-MS analysis. The antimicrobial activity was evaluated against five microorganisms by the agar disc diffusion method and minimal inhibitory concentration (MIC) assay. The antioxidant activity was measured by employing DPPH and FRAP assays. The cytotoxic activity was evaluated in the mammalian cells lines A549, MCF7, B16 and LoVo using the MTT method to assess cell viability. 52 compounds representing the 97.2% of the total oil were identified by GC/MS. The major constituents of the oil were tetramethylenecyclobutane (42.07%) and fraxinellone (19.06%). The antimicrobial activity showed that the EO possess significant inhibition in Monilia albican ATCC 10231 and Staphylococcus aureus ATCC 6538. The antioxidant activity suggested that the EO possess significant reducing power. The cytotoxic activity of the EO in MCF7 and LoVo cells was significant stronger than in the other cell lines. This study is the first characterization of the chemical composition and biological activities of EO from Dictamnus angustifolius. All experimental data indicate that the EO have not only remarkable antioxidant properties but also potential antimicrobial activity and cytotoxic activities. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Antimicrobial activity of bovine NK-lysin-derived peptides on bovine respiratory pathogen Histophilus somni

PubMed Central

Falkenberg, Shollie M.; Briggs, Robert E.; Tatum, Fred M.; Sacco, Randy E.

2017-01-01

Bovine NK-lysins, which are functionally and structurally similar to human granulysin and porcine NK-lysin, are predominantly found in the granules of cytotoxic T-lymphocytes and NK-cells. Although antimicrobial activity of bovine NK-lysin has been assessed for several bacterial pathogens, not all the important bacterial pathogens that are involved in the bovine respiratory disease complex have been studied. Therefore the objective of the present study was to evaluate the antimicrobial activity of bovine NK-lysin-derived peptides on bovine respiratory pathogen Histophilus somni. Four, 30-mer peptides corresponding to the functional region of NK-lysin helices 2 and 3 were synthesized and assessed for antibacterial activity on four bovine pneumonic H. somni isolates. Although there were some differences in the efficiency of bactericidal activity among the NK-lysin peptides at lower concentrations (2–5 μM), all four peptides effectively killed most H. somni isolates at higher concentrations (10–30 μM) as determined by a bacterial killing assay. Confocal microscopic and flow cytometric analysis of Live/Dead Baclight stained H. somni (which were preincubated with NK-lysin peptides) were consistent with the killing assay findings and suggest NK-lysin peptides are bactericidal for H. somni. Among the four peptides, NK2A-derived peptide consistently showed the highest antimicrobial activity against all four H. somni isolates. Electron microscopic examination of H. somni following incubation with NK-lysin revealed extensive cell membrane damage, protrusions of outer membranes, and cytoplasmic content leakage. Taken together, the findings from this study clearly demonstrate the antimicrobial activity of all four bovine NK-lysin-derived peptides against bovine H. somni isolates. PMID:28827826

Antimicrobial activity of bovine NK-lysin-derived peptides on bovine respiratory pathogen Histophilus somni.

PubMed

Dassanayake, Rohana P; Falkenberg, Shollie M; Briggs, Robert E; Tatum, Fred M; Sacco, Randy E

2017-01-01

Bovine NK-lysins, which are functionally and structurally similar to human granulysin and porcine NK-lysin, are predominantly found in the granules of cytotoxic T-lymphocytes and NK-cells. Although antimicrobial activity of bovine NK-lysin has been assessed for several bacterial pathogens, not all the important bacterial pathogens that are involved in the bovine respiratory disease complex have been studied. Therefore the objective of the present study was to evaluate the antimicrobial activity of bovine NK-lysin-derived peptides on bovine respiratory pathogen Histophilus somni. Four, 30-mer peptides corresponding to the functional region of NK-lysin helices 2 and 3 were synthesized and assessed for antibacterial activity on four bovine pneumonic H. somni isolates. Although there were some differences in the efficiency of bactericidal activity among the NK-lysin peptides at lower concentrations (2-5 μM), all four peptides effectively killed most H. somni isolates at higher concentrations (10-30 μM) as determined by a bacterial killing assay. Confocal microscopic and flow cytometric analysis of Live/Dead Baclight stained H. somni (which were preincubated with NK-lysin peptides) were consistent with the killing assay findings and suggest NK-lysin peptides are bactericidal for H. somni. Among the four peptides, NK2A-derived peptide consistently showed the highest antimicrobial activity against all four H. somni isolates. Electron microscopic examination of H. somni following incubation with NK-lysin revealed extensive cell membrane damage, protrusions of outer membranes, and cytoplasmic content leakage. Taken together, the findings from this study clearly demonstrate the antimicrobial activity of all four bovine NK-lysin-derived peptides against bovine H. somni isolates.

Antimicrobial activity and cytotoxic effects of Magnolia dealbata and its active compounds.

PubMed

Jacobo-Salcedo, Maria del Rosario; Gonzalez-Espindola, Luis Angel; Alonso-Castro, Angel Josabad; Gonzalez-Martinez, Marisela del Rocio; Domínguez, Fabiola; Garcia-Carranca, Alejandro

2011-08-01

Multi-drug resistance is of great concern for public health worldwide and necessitates the search for new antimicrobials from sources such as plants. Several Magnolia (Magnoliaceae) species have been reported to exert antimicrobial effects on sensitive and multidrug-resistant microorganisms. However, the antimicrobial properties of Magnolia dealbata have not been experimentally evaluated. The antimicrobial effects of an ethanol extract of Magnolia dealbata seeds (MDE) and its active compounds honokiol (HK) and magnolol (MG) were tested against the phytopathogen Clavibacter michiganensis subsp. michiganensis and several human multi-drug resistant pathogens using the disk-diffusion assay. The effects of MDE and its active compounds on the viability of human peripheral blood mononuclear cells (PBMC) were evaluated using MTT assay. MDE and its active compounds had antimicrobial activity (inhibition zone > 10 mm) against C. michiganensis, Pseudomonas aeruginosa, Acinetobacter baumannii, Acinetobacter lwoffii, Candida albicans, Candida tropicalis and Trichosporon belgeii. The results suggest that M. dealbata and its active compounds have selective antimicrobial effects against drug-resistant fungal and Gram (-) bacteria and exert minimal toxic effects on human PMBC.

Antimicrobial activity of allylic thiocyanates derived from the Morita-Baylis-Hillman reaction

PubMed Central

Sá, Marcus Mandolesi; Ferreira, Misael; Lima, Emerson Silva; dos Santos, Ivanildes; Orlandi, Patrícia Puccinelli; Fernandes, Luciano

2014-01-01

Bacterial resistance to commonly used antibiotics has been recognized as a significant global health issue. In this study, we carried out the screening of a family of allylic thiocyanates for their action against a diversity of bacteria and fungi with a view to developing new antimicrobial agents. Allylic thiocyanates bearing halogenated aryl groups, which were readily obtained in two steps from the Morita-Baylis-Hillman adducts, showed moderate-to-high activity against selective pathogens, including a methicillin-resistant S. aureus (MRSA) strain. In particular cases, methyl (Z)-3-(2,4-dichlorophenyl)-2-(thiocyanomethyl)-2-propenoate exhibited antimicrobial activity comparable to the reference antibiotic Imipenem. PMID:25477911

Antimicrobial agents from selected medicinal plants in Libya.

PubMed

Muhaisen, Hasan M H; Ab-Mous, Miftah Mailoud; Ddeeb, Fadel A; Rtemi, Aboclaid Ali; Taba, Omer M; Parveen, Mehtab

2016-03-01

To test the in vitro antimicrobial efficacy of water and methanol extracts of 23 plant species that are commonly used in Libyan folk medicine. The antimicrobial activity was determined using the well-diffusion method. Four test microorganisms were used namely, Escherichia coli, Salmonella species, Staphylococcus aureus and Bacillus subtilis. The minimum inhibitory concentration (MIC) was determined for the high biologically active crude plant extracts. Among 23 medicinal plants used in the study, only 5 methanolic extracts [Rosmarinus offcinalis L., Carduus marianium L., Lantana camara L., Rhus tripartite (ueria) Grande, and Thymus capitatus (L.) Hoffm (link)] showed the highest antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Salmonella species, while 22 methanolic and aqueous extracts showed moderate to weak antimicrobial activity on all tested organisms. However 19 of the extracts showed no activity at all against Gram-ve and Gram +ve microorganisms. MIC was found to be 1.25 mg/mL (Thymus capitatus), 3 mg/mL (Rhus tripartite), 4 mg/mL (Carduus marianium), 5 mg/mL (Rosamarinus officinalis) and 5 mg/mL (Lantana camara), respectively. The present results revealed that, crude methanolic extracts of the investigated Libyan folk medicinal plants exhibited mild to high in vitro antibacterial activities against Gram-positive and Gram-negative microorganisms.

Evaluation of antitumoral and antimicrobial activity of Morinda lcitrifolia L. grown in Southeast Brazil.

PubMed

Candida, Thamyris; França, Jerônimo Pereira de; Chaves, Alba Lucilvânia Fonseca; Lopes, Fernanda Andrade Rodrigues; Gaiba, Silvana; Sacramento, Celio Kersul do; Ferreira, Lydia Masako; França, Lucimar Pereira de

2014-01-01

To evaluate the antitumor and antimicrobial activity of ethanolic extract of Morinda citrifolia L. fruit cultivated in southeastern Brazil. Preparation ethanolic extract of the fruit of Morinda citrifolia L. Culture of melanoma cells B16-F10 for treatment with ethanolic extract of Morinda citrifolia L. fruit to determine cell viability by MTT and determination temporal effect of ethanolic extract fruit on the cell growth B16-F10 for 8 days. Evaluation of antimicrobial activity of ethanolic extract fruit against Staphylococcus aureus and Escherichia coli by determination of Minimum Inhibitory Concentration (MIC). The ethanolic extract of Morinda citrifolia L. fruit (10mg/mL) decreased cellular activity and inhibited 45% the rate of cell proliferation of B16-F10 melanoma treated during period studied. The ethanolic extract of Morinda citrifolia L. fruit demonstrated antimicrobial activity inhibiting the growth of both microorganisms studied. Staphylococcus aureus was less resistant to ethanolic extract of Morinda citrifolia L. fruit than Escherichia coli, 1 mg/mL and 10 mg/mL, respectively. What these results indicate that the ethanolic extract of the fruit of Morinda citrifolia L. showed antitumor activity with inhibition of viability and growth of B16-F10 cells and also showed antibacterial activity as induced inhibition of growth of Staphylococcus aureus and Escherichia coli.

Effect of white mustard essential oil on the growth of foodborne pathogens and spoilage microorganisms and the effect of food components on its efficacy.

PubMed

Monu, Emefa A; David, Jairus R D; Schmidt, Marcel; Davidson, P Michael

2014-12-01

Antimicrobial preservative compounds are added to foods to target specific pathogens and spoilage organisms. White mustard essential oil (WMEO) is an extract that contains 4-hydroxybenzyl isothiocyanate, a compound which has been demonstrated to have antimicrobial activity in limited studies. The objective of this research was to determine the in vitro antimicrobial activity of WMEO against gram-positive and gram-negative spoilage and pathogenic bacteria and determine the effect of food components on the antimicrobial activity. The bacteria Escherichia coli, Salmonella enterica serovar Enteritidis, Enterobacter aerogenes, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and Lactobacillus fermentum, as well as the acid- and preservative-resistant yeast Schizosaccharomyces pombe, were evaluated. All microorganisms were inhibited by WMEO at 8.3 g/liter (equivalent to 1,000 mg/liter 4-hydroxybenzyl isothiocyanate). In general, WMEO was more effective against gram-negative than against gram-positive bacteria. Salmonella Enteritidis and S. pombe were the most sensitive, with inhibition at as low as 2.1 g/liter. The effects on growth profiles varied but included increased lag phases and lethality, indicating both bacteriostatic and bactericidal activity. Soybean oil had a negative effect on the efficacy of WMEO against L. monocytogenes, and at 5% soybean oil, the antimicrobial activity against Salmonella Enteritidis was eliminated after 48 h. Sodium caseinate at 1% also negated the antimicrobial effect of WMEO against Salmonella Enteritidis and decreased its effectiveness against L. monocytogenes. The presence of starch had no significant effect on the antimicrobial activity of WMEO against L. monocytogenes and Salmonella Enteritidis. Thus, WMEO is effective against a wide range of microorganisms and has potential to be used in foods, depending upon the target microorganism and food components present.

In vitro antimicrobial activity and chemical composition of the essential oil of Foeniculum vulgare Mill.

PubMed

Aprotosoaie, Ana Clara; Hăncianu, Monica; Poiată, Antonia; Tuchiluş, Cristina; Spac, A; Cioană, Oana; Gille, Elvira; Stănescu, Ursula

2008-01-01

In our study, four samples of volatile oil from Foeniculum vulgare, cultivated in different pedoclimatic conditions, were investigated for their antimicrobial activity and chemical composition. Organisms. Staphylococcus aureus ATCC 25923, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli ATCC 25922, Candida albicans were included in the report. Antimicrobial susceptibility tests. The comparative inhibitory activity of volatile oil samples with other antimicrobial agents was quantitative determined by minimum inhibitory concentration (MIC). Oil samples are the volatile oils extracted by steam distillation, from two ecological vegetative populations of Foeniculum vulgare. Gas chromatography coupled to mass spectrometry (GC-MS) was used to determine the chemical composition of the essential oils. All oil samples have a good activity against E. coli and S. aureus at low concentrations. Against B. cereus and P. aeruginosa these oil samples are less active. The oil samples were generally bactericidal at a concentration up to twofold or fourfold higher than the MIC value. Significantly synergic activity with amoxicillin or tetracycline showed all fennel samples against E. coli, Sarcina lutea and B. subtilis strains. Fennel oil samples have shown high activity against Candida albicans. No significant antimicrobial activity variations were observed for Foeniculum vulgare volatile oil samples obtained after two or three years cultivation period. The most important identified compounds in all samples of fennel volatile oils were trans-anethole, estragole, fenchone, limonene, alpha-pinene and gamma-terpinene.

Engineering antimicrobial peptides with improved antimicrobial and hemolytic activities.

PubMed

Zhao, Jun; Zhao, Chao; Liang, Guizhao; Zhang, Mingzhen; Zheng, Jie

2013-12-23

The rapid rise of antibiotic resistance in pathogens becomes a serious and growing threat to medicine and public health. Naturally occurring antimicrobial peptides (AMPs) are an important line of defense in the immune system against invading bacteria and microbial infection. In this work, we present a combined computational and experimental study of the biological activity and membrane interaction of the computationally designed Bac2A-based peptide library. We used the MARTINI coarse-grained molecular dynamics with adaptive biasing force method and the umbrella sampling technique to investigate the translocation of a total of 91 peptides with different amino acid substitutions through a mixed anionic POPE/POPG (3:1) bilayer and a neutral POPC bilayer, which mimic the bacterial inner membrane and the human red blood cell (hRBC) membrane, respectively. Potential of mean force (PMF, free energy profile) was obtained to measure the free energy barrier required to transfer the peptides from the bulk water phase to the water-membrane interface and to the bilayer interior. Different PMF profiles can indeed identify different membrane insertion scenarios by mapping out peptide-lipid energy landscapes, which are correlated with antimicrobial activity and hemolytic activity. Computationally designed peptides were further tested experimentally for their antimicrobial and hemolytic activities using bacteria growth inhibition assay and hemolysis assay. Comparison of PMF data with cell assay results reveals a good correlation of the peptides between predictive transmembrane activity and antimicrobial/hemolytic activity. Moreover, the most active mutants with the balanced substitutions of positively charged Arg and hydrophobic Trp residues at specific positions were discovered to achieve the improved antimicrobial activity while minimizing red blood cell lysis. Such substitutions provide more effective and cooperative interactions to distinguish the peptide interaction with different lipid bilayers. This work provides a useful computational tool to better understand the mechanism and energetics of membrane insertion of AMPs and to rationally design more effective AMPs.

'Honey ointment': a natural remedy of skin wound infections.

PubMed

Tasleem, Samiyah; Naqvi, Syed Baqir Shyum; Khan, Saadat Ali; Hashimi, Khursheed

2011-01-01

Honey is a gift of nature, principally identified and valued to possess antimicrobial and anti-inflammatory activity and has been used as a natural remedy of wounds since ancient times. The objectives of this study were to evaluate the antimicrobial activity of honey against micro-organisms, to formulate a honey ointment and to evaluate the efficacy of such ointment by conducting clinical trials on skin wound infection. This experimental study was conducted at Department of Pharmaceutics, Faculty of Pharmacy, University of Karachi and Out-patient Department of Dermatology, Fauji Foundation Hospital, Rawalpindi from November 2009 to October 2010. The antimicrobial activity of Pakistani floral sources (Trachysperm copticum, Acacia nilotica species indica, Zizyphus) honey samples was investigated by disc diffusion method against freshly isolated wound infecting bacteria (Staphylococci aureus, Staphylococci epidermidis, Streptococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli, Proteus vulgaris and Candida albicans), and Staphylococci aureus ATCC 6538, Pseudomonas aeruginosa ATCC 9022, Escherichia coli ATCC 25922, Candida albican ATCC 15146. An ointment containing 20% active antimicrobial honey was formulated. The efficacy of such ointment was evaluated by passing thought clinical trials. A total number of 27 patients (23 skin wound infection, and 4 diabetic foot ulcer) were involved in the study. Thin layer of newly formulated honey ointment on gauze were applied two to three times per day till complete healing. In microbiological assay the honey samples were found to exhibit a very promising antimicrobial activity against all the micro-organisms tested. In clinical trial very significant results (99.15%) healing was observed in skin wound infections cases with mean healing time of 5.86 (2-20) days, and 95% diabetic foot ulcers healed with the mean healing time of 20 (8-40) days. Newly formulated ointment containing 20% active antimicrobial honey is very effective and alternative low-cost product for the treatment of wound infections.

Synthetic hepcidin from fish: Uptake and protection against Vibrio anguillarum in sea bass (Dicentrarchus labrax).

PubMed

Álvarez, Claudio Andrés; Acosta, Félix; Montero, Daniel; Guzmán, Fanny; Torres, Elisa; Vega, Belinda; Mercado, Luis

2016-08-01

The generation of a variety of new therapeutic agents to control and reduce the effects of pathogen in aquaculture is urgently needed. The antimicrobial peptides (AMPs) are one of the major components of the innate defenses and typically have broad-spectrum antimicrobial activity. However, absorption and distributions of exogenous AMPs for therapeutics application on farmed fish species need to be studied. Previous studies in our laboratory have shown the properties of hepcidin as an effective antimicrobial peptide produced in fish in response to LPS and iron. Therefore, we decided to investigate the antimicrobial activity of four synthetic variants of hepcidin against Vibrio anguillarum in vitro, and using the more effective peptide we demonstrated the pathogen's ability to protect against the infection in European Sea bass. Additionally the uptake of this peptide after ip injection was demonstrated, reaching its distribution organs such as intestine, head kidney, spleen and liver. The synthetic peptide did not show cytotoxic effects and significantly reduced the accumulated mortalities percentage (23.5%) compared to the European Sea bass control (72.5%) at day 21. In conclusion, synthetic hepcidin shows antimicrobial activity against V. anguillarum and the in vivo experiments suggest that synthetic hepcidin was distributed trough the different organs in the fish. Thus, synthetic hepcidin antimicrobial peptide could have high potential for therapeutic application in farmed fish species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Purification and characterization of two new cell-bound bioactive compounds produced by wild Lactococcus lactis strain.

PubMed

Saraiva, Margarete Alice Fontes; Brede, Dag Anders; Nes, Ingolf Figved; Baracat-Pereira, Maria Cristina; de Queiroz, Marisa Vieira; de Moraes, Célia Alencar

2017-07-03

Novel compounds and innovative methods are required considering that antibiotic resistance has reached a crisis point. In the study, two cell-bound antimicrobial compounds produced by Lactococcus lactis ID1.5 were isolated and partially characterized. Following purification by cationic exchange and a solid-phase C18 column, antimicrobial activity was recovered after three runs of RPC using 60% (v/v) and 100% (v/v) of 2-propanol for elution, suggesting that more than one antimicrobial compound were produced by L. lactis ID1.5, which were in this study called compounds AI and AII. The mass spectrum of AI and AII showed major intensity ions at m/z 1070.05 and 955.9 Da, respectively. The compound AI showed a spectrum of antimicrobial activity mainly against L. lactis species, while the organisms most sensitive to compound AII were Bacillus subtilis, Listeria innocua, Streptococcus pneumoniae and Pseudomonas aeruginosa. The antimicrobial activity of both compounds was suppressed by treatment with Tween 80. Nevertheless, both compounds showed high stability to heat and proteases treatments. The isolated compounds, AI and AII, showed distinct properties from other antimicrobial substances already reported as produced by L. lactis, and have a significant inhibitory effect against two clinically important respiratory pathogens. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Interaction of Antibiotics with Innate Host Defense Factors against Salmonella enterica Serotype Newport

PubMed Central

Kumaraswamy, Monika; Kousha, Armin; Nizet, Victor

2017-01-01

ABSTRACT This study examines the pharmacodynamics of antimicrobials that are used to treat Salmonella with each other and with key components of the innate immune system. Antimicrobial synergy was assessed using time-kill and checkerboard assays. Antimicrobial interactions with innate immunity were studied by employing cathelicidin LL-37, whole-blood, and neutrophil killing assays. Ceftriaxone and ciprofloxacin were found to be synergistic in vitro against Salmonella enterica serotype Newport. Ceftriaxone, ciprofloxacin, and azithromycin each demonstrated synergy with the human cathelicidin defense peptide LL-37 in killing Salmonella. Exposure of Salmonella to sub-MICs of ceftriaxone resulted in enhanced susceptibility to LL-37, whole blood, and neutrophil killing. The activity of antibiotics in vivo against Salmonella may be underestimated in bacteriologic media lacking components of innate immunity. The pharmacodynamic interactions of antibiotics used to treat Salmonella with each other and with components of innate immunity warrant further study in light of recent findings showing in vivo selection of antimicrobial resistance by single agents in this pathogen. IMPORTANCE It is becoming increasingly understood that the current paradigms of in vitro antimicrobial susceptibility testing may have significant shortcomings in predicting activity in vivo. This study evaluated the activity of several antibiotics alone and in combination against clinical isolates of Salmonella enterica serotype Newport (meningitis case) utilizing both conventional and physiological media. In addition, the interactions of these antibiotics with components of the innate immune system were evaluated. Azithromycin, which has performed quite well clinically despite high MICs in conventional media, was shown to be more active in physiological media and to enhance innate immune system killing. Alternatively, chloramphenicol did not show enhanced immune system killing, paralleling its inferior clinical performance to other antibiotics that have been used to treat Salmonella meningitis. These findings are important additions to the building understanding of current in vitro antimicrobial assay limitations that hopefully will amount to future improvements in these assays to better predict clinical efficacy and activity in vivo. PMID:29242830

Antimicrobial activity and agricultural properties of bitter melon (Momordica charantia L.) grown in northern parts of Turkey: a case study for adaptation.

PubMed

Yaldız, Gülsüm; Sekeroglu, Nazım; Kulak, Muhittin; Demirkol, Gürkan

2015-01-01

This study was designed to determine the adaptation capability of bitter melon (Momordica charantia L.), which is widely grown in tropical and subtropical climates, in northern parts of Turkey. In this study, plant height, number of fruits, fruit length, fruit width, number of seeds and fruit weight of bitter melon grown in field conditions were determined. The antimicrobial effect of the ethanol extract of fruit and seeds against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Salmonella typhi, Aspergillus niger and Candida albicans microorganisms was tested in vitro by the disc diffusion method. In conclusion, plant height (260 cm), number of fruits (16 per  plant), number of seeds (30.2  per fruit), fruit width (3.8 cm), fruit length (10.6 cm) and fruit weight (117.28 g fruit(- 1)) were determined; fruits were found to have antimicrobial activity against A. niger; oil and seeds were found to have antimicrobial activity against A. niger and E. coli.

Material Properties and Antimicrobial Activity of Polyhydroxybutyrate (PHB) Films Incorporated with Vanillin.

PubMed

Xavier, Janifer Raj; Babusha, Sudalaimuthu Thangaraj; George, Johnsy; Ramana, Karna Venkata

2015-07-01

Polyhydroxybutyrate (PHB) was produced by Bacillus mycoides DFC 1, isolated from garden soil. Antimicrobial (AM) films of PHB were prepared by incorporating vanillin (4-hydroxy-3-methoxybenzaldehyde) from 10 to 200 μg/g of PHB. The films were assessed for antimicrobial activity against foodborne pathogens and spoilage bacteria comprising of Escherichia coli, Salmonella typhimurium, Shigella flexneri, and Staphylococcus aureus and fungi such as Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus parasiticus, Aspergillus ochraceus, Penicillium viridicatum, and Penicillium clavigerum. The minimum concentration of vanillin required to exhibit antimicrobial activity was ≥80 μg/g PHB for bacteria and ≥50 μg/g PHB for fungi. The PHB films with and without vanillin were studied for mechanical and thermal properties such as tensile strength, Young's modulus, percentage elongation to break, melting temperature, and heat of fusion. The thermal stability of the films was studied using thermogravimetric analysis. The release kinetics of vanillin into food matrices was also checked using food stimulants. The study is intended to find applications for PHB films containing vanillin to enhance the shelf life of foods in the form of biodegradable wrapper.

Antimicrobial activity of biopolymeric thin films containing flavonoid natural compounds and silver nanoparticles fabricated by MAPLE: A comparative study

NASA Astrophysics Data System (ADS)

Cristescu, R.; Visan, A.; Socol, G.; Surdu, A. V.; Oprea, A. E.; Grumezescu, A. M.; Chifiriuc, M. C.; Boehm, R. D.; Yamaleyeva, D.; Taylor, M.; Narayan, R. J.; Chrisey, D. B.

2016-06-01

The purpose of this study was to investigate the interactions between microorganisms, including the planktonic and adherent organisms, and biopolymer (polyvinylpyrrolidone), flavonoid (quercetin dihydrate and resveratrol)-biopolymer, and silver nanoparticles-biopolymer composite thin films that were deposited using matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF* excimer laser source was used to deposit the aforementioned composite thin films, which were characterized using Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), Grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The antimicrobial activity of thin films was quantified using an adapted disk diffusion assay against Gram-positive and Gram-negative bacteria strains. FT-IR, AFM and SEM studies confirmed that MAPLE may be used to fabricate thin films with chemical properties corresponding to the input materials as well as surface properties that are appropriate for medical use. The silver nanoparticles and flavonoid-containing films exhibited an antimicrobial activity both against Gram-positive and Gram-negative bacterial strains demonstrating the potential use of these hybrid systems for the development of novel antimicrobial strategies.

Ribonucleases 6 and 7 have antimicrobial function in the human and murine urinary tract

PubMed Central

Becknell, Brian; Eichler, Tad; Beceiro, Susana; Li, Birong; Easterling, Robert; Carpenter, Ashley R.; James, Cindy; McHugh, Kirk M.; Hains, David S.; Partida-Sanchez, Santiago; Spencer, John David

2014-01-01

Recent evidence suggests antimicrobial peptides protect the urinary tract from infection. Ribonuclease 7 (RNase 7), a member of the RNase A superfamily, is a potent epithelial-derived protein that maintains human urinary tract sterility. RNase 7 expression is restricted to primates, limiting evaluation of its antimicrobial activity in vivo. Here we identified Ribonuclease 6 (RNase 6) as the RNase A Superfamily member present in humans and mice that is most conserved at the amino acid level relative to RNase 7. Like RNase 7, recombinant human and murine RNase 6 has potent antimicrobial activity against uropathogens. Quantitative real-time PCR and immunoblot analysis indicate that RNase 6 mRNA and protein are up-regulated in the human and murine urinary tract during infection. Immunostaining located RNase 6 to resident and infiltrating monocytes, macrophages, and neutrophils. Uropathogenic E. coli induces RNase 6 peptide expression in human CD14+ monocytes and murine bone marrow derived macrophages. Thus, RNase 6 is an inducible, myeloid-derived protein with markedly different expression from the epithelial-derived RNase 7 but with equally potent antimicrobial activity. Our studies suggest RNase 6 serves as an evolutionarily conserved antimicrobial peptide that participates in the maintenance of urinary tract sterility. PMID:25075772

Antimicrobial nanocapsules: from new solvent-free process to in vitro efficiency

PubMed Central

Steelandt, Julie; Salmon, Damien; Gilbert, Elodie; Almouazen, Eyad; Renaud, François NR; Roussel, Laurène; Haftek, Marek; Pirot, Fabrice

2014-01-01

Skin and mucosal infections constitute recurrent pathologies resulting from either inappropriate antiseptic procedures or a lack of efficacy of antimicrobial products. In this field, nanomaterials offer interesting antimicrobial properties (eg, long-lasting activity; intracellular and tissular penetration) as compared to conventional products. The aim of this work was to produce, by a new solvent-free process, a stable and easily freeze-dryable chlorhexidine-loaded polymeric nanocapsule (CHX-NC) suspension, and then to assess the antimicrobial properties of nanomaterials. The relevance of the process and the physicochemical properties of the CHX-NCs were examined by the assessment of encapsulation efficiency, stability of the nanomaterial suspension after 1 month of storage, and by analysis of granulometry and surface electric charge of nanocapsules. In vitro antimicrobial activities of the CHX-NCs and chlorhexidine digluconate solution were compared by measuring the inhibition diameters of two bacterial strains (Escherichia coli and Staphylococcus aureus) and one fungal strain (Candida albicans) cultured onto appropriate media. Based on the findings of this study, we report a new solvent-free process for the production of nanomaterials exhibiting antimicrobial activity, suitable stability, and easily incorporable as a new ingredient in various pharmaceutical products. PMID:25278751

Determination quercetin content, antioxidant and antimicrobial activity of genotype mutant Samosir shallots irradiated by gamma rays

NASA Astrophysics Data System (ADS)

Sinuraya, M.; Hanafiah, D. S.; Romulo, A.; Barus, A.

2018-02-01

The aim of the research was to study the variation in antioxidant and antimicrobial activity as well as the total quercetin content of the fifth generation genotypes mutant Samosir shallot irradiated by gamma rays. The studies conducted included the assessment of quercetin content, antioxidant and antimicrobial activity in shallot bulbs after long-term storage (6 months in the room temperature). Quercetin content of 20 selected genotype mutants of irradiated shallot bulbs along with untreated populations were calculated using quercetin (QU) as a standard. Antioxidant activities of 8 genotype mutant were determined using DPPH. Antimicrobial activity of bulb extracts were tested against six bacteria including Staphylococcus aurous, Enterococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae and oneyeastCandida albicans. The results showed that population of genotype mutants irradiated with dosage 2Gy, 4 Gy, 5 Gy and 6 Gy have higher quercetin content than control samples. None of the genotype mutants exhibited antibacterial inhibitory against all microorganism tested except for the sample number 2 and 6 (bulbs generated from the plants irradiated by gamma rays with dosage at 2 Gy and 6 Gy). There was also none of the genotypes observed exhibited significant antioxidant efficacy.

Antimicrobial activity of essential oils from Mediterranean aromatic plants against several foodborne and spoilage bacteria.

PubMed

Silva, Nuno; Alves, Sofia; Gonçalves, Alexandre; Amaral, Joana S; Poeta, Patrícia

2013-12-01

The antimicrobial activity of essential oils extracted from a variety of aromatic plants, often used in the Portuguese gastronomy was studied in vitro by the agar diffusion method. The essential oils of thyme, oregano, rosemary, verbena, basil, peppermint, pennyroyal and mint were tested against Gram-positive (Listeria monocytogenes, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, and Staphylococcus epidermidis) and Gram-negative strains (Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa). For most essential oils examined, S. aureus, was the most susceptible bacteria, while P. aeruginosa showed, in general, least susceptibility. Among the eight essential oils evaluated, thyme, oregano and pennyroyal oils showed the greatest antimicrobial activity, followed by rosemary, peppermint and verbena, while basil and mint showed the weakest antimicrobial activity. Most of the essential oils considered in this study exhibited a significant inhibitory effect. Thyme oil showed a promising inhibitory activity even at low concentration, thus revealing its potential as a natural preservative in food products against several causal agents of foodborne diseases and food spoilage. In general, the results demonstrate that, besides flavoring the food, the use of aromatic herbs in gastronomy can also contribute to a bacteriostatic effect against pathogens.

Fatty acid conjugation enhances the activities of antimicrobial peptides.

PubMed

Li, Zhining; Yuan, Penghui; Xing, Meng; He, Zhumei; Dong, Chuanfu; Cao, Yongchang; Liu, Qiuyun

2013-04-01

Antimicrobial peptides are small molecules that play a crucial role in innate immunity in multi-cellular organisms, and usually expressed and secreted constantly at basal levels to prevent infection, but local production can be augmented upon an infection. The clock is ticking as rising antibiotic abuse has led to the emergence of many drug resistance bacteria. Due to their broad spectrum antibiotic and antifungal activities as well as anti-viral and anti-tumor activities, efforts are being made to develop antimicrobial peptides into future microbial agents. This article describes some of the recent patents on antimicrobial peptides with fatty acid conjugation. Potency and selectivity of antimicrobial peptide can be modulated with fatty acid tails of variable length. Interaction between membranes and antimicrobial peptides was affected by fatty acid conjugation. At concentrations above the critical miscelle concentration (CMC), propensity of solution selfassembly hampered binding of the peptide to cell membranes. Overall, fatty acid conjugation has enhanced the activities of antimicrobial peptides, and occasionally it rendered inactive antimicrobial peptides to be bioactive. Antimicrobial peptides can not only be used as medicine but also as food additives.

Recent advances in microencapsulation of natural sources of antimicrobial compounds used in food - A review.

PubMed

Castro-Rosas, Javier; Ferreira-Grosso, Carlos Raimundo; Gómez-Aldapa, Carlos Alberto; Rangel-Vargas, Esmeralda; Rodríguez-Marín, María Luisa; Guzmán-Ortiz, Fabiola Araceli; Falfan-Cortes, Reyna Nallely

2017-12-01

Food safety and microbiological quality are major priorities in the food industry. In recent years, there has been an increasing interest in the use of natural antimicrobials in food products. An ongoing challenge with natural antimicrobials is their degradation during food storage and/or processing, which reduces their antimicrobial activity. This creates the necessity for treatments that maintain their stability and/or activity when applied to food. Microencapsulation of natural antimicrobial compounds is a promising alternative once this technique consists of producing microparticles, which protect the encapsulated active substances. In other words, the material to be protected is embedded inside another material or system known as wall material. There are few reports in the literature about microencapsulation of antimicrobial compounds. These published articles report evidence of increased antimicrobial stability and activity when the antimicrobials are microencapsulated when compared to unprotected ones during storage. This review focuses mainly on natural sources of antimicrobial compounds and the methodological approach for encapsulating these natural compounds. Current data on the microencapsulation of antimicrobial compounds and their incorporation into food suggests that 1) encapsulation increases compound stability during storage and 2) encapsulation of antimicrobial compounds reduces their interaction with food components, preventing their inactivation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inorganic antimicrobial coating for titanium alloy and its effect on bacteria.

PubMed

Tamai, Katsuya; Kawate, Kenji; Kawahara, Ikuo; Takakura, Yoshinori; Sakaki, Kazuhiko

2009-03-01

For orthopedic implants, infection is a serious problem. Therefore, we considered an implant with antimicrobial ability can prevent infection. We tried to coat a titanium alloy surface with Novaron, a commercially available inorganic antimicrobial. The purpose of this study was to analyze the differences among the surfaces of materials coated using different processing pressures of the working gas and analysis of the antimicrobial activity. One of the inorganic antimicrobials Novaron (grade VZ 600) was applied to titanium alloy (Ti6Al4V) plates. This antimicrobial has limited heat resistance, so we used cold spray technology to coat the titanium alloy with it. The principle of cold spray technology is spraying a powder in a high-velocity gas jet, accelerated by adiabatic expansion, against a substrate. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) were used to analyze the differences among the surfaces of materials coated using different processing pressures of the working gas. The Japanese Industrial Standard (JIS) method (JIS Z2801: 2000) was used to analyze the antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Antimicrobial activity was analyzed only for the sample coated at 3.0 MPa. The SEM and EDS results indicated that when the pressure of the working gas was increased, the antimicrobial coated the titanium adequately. This material showed good effects against S. aureus and P. aeruginosa and some effect for K. pneumoniae. Antimicrobial implants represent a preventive method against infection. There is a possibility of using them not only for clean operations but also for operations with suspected bacterial contamination, such as fixation of slight compound fractures.

Activity of Polish unifloral honeys against pathogenic bacteria and its correlation with colour, phenolic content, antioxidant capacity and other parameters.

PubMed

Kuś, P M; Szweda, P; Jerković, I; Tuberoso, C I G

2016-03-01

The use of honey as an antimicrobial agent gains importance due to often ineffectiveness of conventional treatment. However, activity of honey depends mainly on its botanical and geographical origin. To date, antimicrobial potential of Polish honeys has not yet been entirely investigated. In this study, 37 unifloral samples of 14 honey types (including rare varieties) from Poland were analysed and compared with manuka honey. The most active were cornflower, thyme and buckwheat honeys. Their MICs ranged from 3·12 to 25·00%, (depending on tested micro-organism) and often were lower than for manuka honey. Additionally, colour, antioxidant activity, total phenols, pH and conductivity were assessed and significant correlations (P < 0·05) of MICs with several parameters were found. The most active were darker honeys, with strong yellow colour component, rich in phenolics, with high conductivity and water content. The honey antibacterial properties depended mainly on peroxide mechanism and were vulnerable to excessive heating, but quite stable during storage in cold. A number of honey samples showed potential as effective antimicrobial agents. The observed correlations of MICs and physical-chemical parameters help to understand better the factors impacting the antibacterial activity. Honey is a promising agent in the treatment of non-healing infected wounds. Thirty-seven unifloral samples of 14 honey varieties from Poland were analysed for their antimicrobial activity and compared with manuka honey. Several honey types exert even higher antimicrobial potential and could be introduced to wound therapy. Additionally, positive correlations of the antimicrobial activity were found, especially with yellow colour and could be important in the search and screening of the honey active against Escherichia coli. © 2015 The Society for Applied Microbiology.

Phytochemical characterization, antimicrobial activity and reducing potential of seed oil, latex, machine oil and presscake of Jatropha curcas

PubMed Central

Sharma, Amit Kumar; Gangwar, Mayank; Kumar, Dharmendra; Nath, Gopal; Kumar Sinha, Akhoury Sudhir; Tripathi, Yamini Bhushan

2016-01-01

Objective: This study aims to evaluate the antimicrobial activity, phytochemical studies and thin layer chromatography analysis of machine oil, hexane extract of seed oil and methanol extract of presscake & latex of Jatropha curcas Linn (family Euphorbiaceae). Materials and Methods: J. curcas extracts were subjected to preliminary qualitative phytochemical screening to detect the major phytochemicals followed by its reducing power and content of phenol and flavonoids in different fractions. Thin layer chromatography was also performed using different solvent systems for the analysis of a number of constituents in the plant extracts. Antimicrobial activity was evaluated by the disc diffusion method, while the minimum inhibitory concentration, minimum bactericidal concentration and minimum fungicidal concentration were calculated by micro dilution method. Results: The methanolic fraction of latex and cake exhibited marked antifungal and antibacterial activities against Gram-positive and Gram-negative bacteria. Phytochemical analysis revealed the presence of alkaloids, saponins, tannins, terpenoids, steroids, glycosides, phenols and flavonoids. Reducing power showed dose dependent increase in concentration compared to standard Quercetin. Furthermore, this study recommended the isolation and separation of bioactive compounds responsible for the antibacterial activity which would be done by using different chromatographic methods such as high-performance liquid chromatography (HPLC), GC-MS etc. Conclusion: The results of the above study suggest that all parts of the plants possess potent antibacterial activity. Hence, it is important to isolate the active principles for further testing of antimicrobial and other biological efficacy. PMID:27516977

Phytochemical characterization, antimicrobial activity and reducing potential of seed oil, latex, machine oil and presscake of Jatropha curcas.

PubMed

Sharma, Amit Kumar; Gangwar, Mayank; Kumar, Dharmendra; Nath, Gopal; Kumar Sinha, Akhoury Sudhir; Tripathi, Yamini Bhushan

2016-01-01

This study aims to evaluate the antimicrobial activity, phytochemical studies and thin layer chromatography analysis of machine oil, hexane extract of seed oil and methanol extract of presscake & latex of Jatropha curcas Linn (family Euphorbiaceae). J. curcas extracts were subjected to preliminary qualitative phytochemical screening to detect the major phytochemicals followed by its reducing power and content of phenol and flavonoids in different fractions. Thin layer chromatography was also performed using different solvent systems for the analysis of a number of constituents in the plant extracts. Antimicrobial activity was evaluated by the disc diffusion method, while the minimum inhibitory concentration, minimum bactericidal concentration and minimum fungicidal concentration were calculated by micro dilution method. The methanolic fraction of latex and cake exhibited marked antifungal and antibacterial activities against Gram-positive and Gram-negative bacteria. Phytochemical analysis revealed the presence of alkaloids, saponins, tannins, terpenoids, steroids, glycosides, phenols and flavonoids. Reducing power showed dose dependent increase in concentration compared to standard Quercetin. Furthermore, this study recommended the isolation and separation of bioactive compounds responsible for the antibacterial activity which would be done by using different chromatographic methods such as high-performance liquid chromatography (HPLC), GC-MS etc. The results of the above study suggest that all parts of the plants possess potent antibacterial activity. Hence, it is important to isolate the active principles for further testing of antimicrobial and other biological efficacy.

Antimicrobial Compounds in Tears

PubMed Central

McDermott, Alison M.

2013-01-01

The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. PMID:23880529

Antioxidant and antimicrobial potential of the Bifurcaria bifurcata epiphytic bacteria.

PubMed

Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

2014-03-24

Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.

Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

PubMed Central

Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

2014-01-01

Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds. PMID:24663118

Mechanism of action and in vitro activity of short hybrid antimicrobial peptide PV3 against Pseudomonas aeruginosa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Memariani, Hamed; Shahbazzadeh, Delavar; Sabatier, Jean-Marc

Antimicrobial peptides are attractive candidates for developing novel therapeutic agents, since they are lethal to a broad spectrum of pathogens and have a unique low tendency for resistance development. In this study, mechanism of action and in vitro anti-pseudomonal activity of previously designed short hybrid antimicrobial peptide PV3 were investigated. Compared to ceftazidime, PV3 had not only higher antibacterial activity but also faster bactericidal activity. PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. Although the antimicrobial activity of PV3 was reduced in Mueller-Hinton broth (MHB) containing human serum, it was still active enough to eradicationmore » of bacteria at low concentrations. Compared with standard condition (MHB only), there was no significant decrease in antibacterial activity of PV3 against P. aeruginosa strains under 150 mM NaCl (p = 0.615) and 1 mM MgCl{sub 2} (p = 0.3466). Fluorescence microscopy and field emission scanning electron microscopy further indicated that PV3 killed bacteria by disrupting the cell membrane. Since PV3 has potent anti-pseudomonal activity and has little cytotoxicity in vitro, it seems plausible that the peptide should be further investigated with animal studies to support future pharmacological formulations and potential topical applications. - Highlights: • PV3 killed Pseudomonas aeruginosa by membrane-disrupting mechanism. • PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. • Short hybrid antimicrobial peptide PV3 exhibited higher and faster bactericidal activity comparing to ceftazidime.« less

A case study of preservation of semi-solid preparations using the European Pharmacopoeia test: comparative efficacy of antimicrobial agents in zinc gelatin.

PubMed

Favet, J; Chappuis, M L; Doelker, E

2001-09-01

The present study was undertaken with the aim of finding an alternative preservative system to methyl parahydroxybenzoate in zinc gelatin, which was described in the monographs of the Swiss Pharmacopoeia (until Ph. Helv. 8) and in previous editions of the German Pharmacopoeia (until DAB 7). This antimicrobial agent has now been withdrawn in the DAB, because of its potential allergy risks. As for the USP and DAB-DDR zinc gelatin preparations, they have always been devoid of any preservative agent, probably relying on the mild antimicrobial activity of zinc. A literature survey did not reveal if such an aqueous preparation containing the water-insoluble zinc oxide shows efficacious antimicrobial activity by itself. Thus, a comparative evaluation of differently preserved zinc gelatin preparations was performed using a test for the efficacy of antimicrobial preservation that has been modified with regard to the European Pharmacopoeia (EP) test to take into account the solid state of the preparations and the bactericidal effect of the zinc. Three zinc gelatin preparations were checked, either: (i), without any agent; or (ii), with 0.1% methyl parahydroxybenzoate; or (iii), with 0.5% phenoxyethanol, a broad-spectrum antimicrobial agent almost devoid of allergy risks. The three preparations behave quite differently, in particular with respect to fungi. All three preparations passed the modified EP test as far as bacteria are concerned. Even zinc gelatin without preservative is very effective, not only because of the mild antimicrobial activity of zinc (the soluble fraction of zinc oxide in the liquid phase of zinc gelatin was determined to be 13 microg/ml), but most probably because of the low water activity of the preparation (measured as around 0.81), as shown by the absence of growth of a zinc-resistant strain of Pseudomonas aeruginosa. Zinc gelatin preserved with methyl parahydroxybenzoate has a weak, although satisfactory, activity against Staphylococcus aureus. Regarding fungi, gelatin without an antimicrobial agent and that preserved with methyl parahydroxybenzoate meet the requirements for efficacy against Candida albicans, but are only bacteriostatic against Aspergillus niger. As for zinc gelatin preserved with phenoxyethanol, it displays the best activity against C. albicans and, above all, appears to be the only formulation exhibiting fungicidal activity against A. niger. It is therefore recommended to preserve zinc gelatin with this antimicrobial agent, as recently adopted in Supplement 2000 of the Swiss Pharmacopoeia.

Ammonium chloride catalyzed synthesis of novel Schiff bases from spiro[indoline-3,4'-pyran]-3'-carbonitriles and evaluation of their antimicrobial and anti-breast cancer activities.

PubMed

Al-Shareef, Hossa F; Elhady, Heba A; Aboellil, Amany H; Hussein, Essam M

2016-01-01

Indolinone and spiro-indoline derivatives have been employed in the preparation of different important therapeutic compounds required for treatment of anticonvulsants, antibacterial, Antitubercular, and anticancer activities. Schiff bases have been found to possess various pharmacological activities such as antitubercular, plant growth inhibiting, insecticsidal, central nerve system depressant, antibacterial, anticancer, anti-inflammatory, and antimicrobial. Mannich bases have a variety of biological activities such as antibacterial and antifungal activities. In this study, a green, rapid and efficient protocol for the synthesis of a new series of Schiff bases from spiro[indoline-3,4'-pyran]-3'-carbonitrile derivatives using ammonium chloride as a very inexpensive and readily available reagent. The prepared compounds were assessed in vitro for their antimicrobial activity. Also, the cytotoxic activity of the prepared compounds was assessed in vitro against human cells line MCF7 breast cancer. Good activity was distinguished for Schiff bases from spiro[indoline-3,4'-pyran]-3'-carbonitriles, with some members recorded higher antimicrobial and anti-breast cancer activities.Graphical abstractNovel Schiff bases from spiro[indoline-3,4'-pyran]-3'-carbonitriles.

Estimation of the bacteriocin ColE7 conjugation-based "kill" - "anti-kill" antimicrobial system by real-time PCR, fluorescence staining and bioluminescence assays.

PubMed

Maslennikova, I L; Kuznetsova, M V; Toplak, N; Nekrasova, I V; Žgur Bertok, D; Starčič Erjavec, M

2018-05-07

The efficiency of the bacteriocin, colicin ColE7, bacterial conjugation-based "kill" - "anti-kill" antimicrobial system, was assessed using real-time PCR, flow cytometry and bioluminescence. The ColE7 antimicrobial system consists of the genetically modified Escherichia coli strain Nissle 1917 harbouring a conjugative plasmid (derivative of the F-plasmid) encoding the "kill" gene (ColE7 activity gene) and a chromosomally encoded "anti-kill" gene (ColE7 immunity gene). On the basis of traJ gene expression in the killer donor cells, our results showed that the efficiency of the here studied antimicrobial system against target E. coli was higher at 4 than at 24 h. Flow cytometry was used to indirectly estimate DNase activity of the antimicrobial system, as lysis of target E. coli cells in the conjugative mixture with the killer donor strain led to reduction in cell cytosol fluorescence. According to a lux assay, E. coli TG1 (pXen lux + Ap r ) with constitutive luminescence were killed already after 2 h of treatment. Target sensor E. coli C600 with DNA damage SOS-inducible luminescence showed significantly lower SOS induction 6 and 24 h following treatment with the killer donor strain. Our results thus showed that bioluminescent techniques are quick and suitable for estimation of the ColE7 bacterial conjugation-based antimicrobial system antibacterial activity. Bacterial antimicrobial resistance is worldwide rising and causing deaths of thousands of patients infected with multi-drug resistant bacterial strains. In addition, there is a lack of efficient alternative antimicrobial agents. The significance of our research is the use of a number of methods (real-time PCR, flow cytometry and bioluminescence-based technique) to assess the antibacterial activity of the bacteriocin, colicin ColE7, bacterial conjugation-based "kill" - "anti-kill" antimicrobial system. Bioluminescent techniques proved to be rapid and suitable for estimation of antibacterial activity of ColE7 bacterial conjugation-based antimicrobial system and possibly other related systems. © 2018 The Society for Applied Microbiology.

Bioinspired green synthesis of copper oxide nanoparticles from Syzygium alternifolium (Wt.) Walp: characterization and evaluation of its synergistic antimicrobial and anticancer activity

NASA Astrophysics Data System (ADS)

Yugandhar, Pulicherla; Vasavi, Thirumalanadhuni; Uma Maheswari Devi, Palempalli; Savithramma, Nataru

2017-10-01

In recent times, nanoparticles are attributed to green nanotechnology methods to know the synergistic biological activities. To accomplish this phenomenon, present study was aimed to synthesize copper oxide nanoparticles (CuO NPs) by using Syzygium alternifolium stem bark, characterized those NPs using expository tools and to elucidate high prioritized antimicrobial and anticancer activities. Synthesized particles exhibited a color change pattern upon synthesis and affirmed its respective broad peak at 285 nm which was analyzed through UV-vis spectroscopy. FT-IR study confirmed that phenols and primary amines were mainly involved in capping and stabilization of nanoparticles. DLS and Zeta potential studies revealed narrow size of particles with greater stability. XRD studies revealed the crystallographic nature of particles with 17.2 nm average size. Microscopic analysis by using TEM revealed that particle size range from 5-13 nm and most of them were spherical in shape, non-agglomerated and poly-dispersed in condition. Antimicrobial studies of particles showed highest inhibitory activity against E. coli and T. harzianum among bacterial and fungal strains, respectively. The scope of this study is extended by examining anticancer activity of CuO NPs. This study exhibited potential anticancer activity towards MDA-MB-231 human breast cancer lines. Overall, these examinations relate that the S. alternifolium is described as efficient well-being plant and probabilistically for the design and synthesis of nanoparticles for human health. This study paves a way to better understand antimicrobial and anticancer therapeutic drug potentials of nanoparticles to design and analysis of pharmaceuticals by in vivo and in vitro approaches.

Chromatographic Characterization and GC-MS Evaluation of the Bioactive Constituents with Antimicrobial Potential from the Pigmented Ink of Loligo duvauceli

PubMed Central

Girija, Smiline; Duraipandiyan, Veeramuthu; Kuppusamy, Pandi Suba; Gajendran, Hariprasad; Rajagopal, Raghuraman

2014-01-01

Chromatographic characterization and the GC-MS evaluation of the black pigmented ink of Loligo duvauceli in the present study have yielded an array of bioactive compounds with potent antimicrobial property. Facing an alarm of antimicrobial resistance globally, a need for elucidating antimicrobial agents from natural sources will be the need for the hour. In this view, this study is aimed at characterizing the black pigmented ink of the Indian squid L. duvauceli. The squid ink was subjected to crude solvent extraction and was fractionated by silica gel column chromatography. TLC and HPTLC profiles were recorded. Antimicrobial bioassay of the squid ink fractions was done by agar well diffusion method. The antimicrobial fraction was then characterized using GC-MS analysis. The results showed that the n-hexane extract upon column fractionation yielded a total of 8 fractions with the mobile phase of Hex/EtOAc in different gradients. TLC and HPTLC profiles showed a single spot with a retention factor of 0.76. Fraction 1 showed significant antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Lactobacillus acidophilus and a promising antifungal activity against Candida albicans. The antimicrobial fraction upon GC-MS analysis of bis(2-ethylhexyl) phthalate (BEHP) possesses the highest percentage of area normalisation (91%) with other few minor constituents. The study is concluded by stating that the antimicrobial efficacy of the squid ink might be due to the synergistic effects of the phthalate derivative and the other minor volatile compounds analysed in the squid ink. PMID:27437466

Chromatographic Characterization and GC-MS Evaluation of the Bioactive Constituents with Antimicrobial Potential from the Pigmented Ink of Loligo duvauceli.

PubMed

Girija, Smiline; Duraipandiyan, Veeramuthu; Kuppusamy, Pandi Suba; Gajendran, Hariprasad; Rajagopal, Raghuraman

2014-01-01

Chromatographic characterization and the GC-MS evaluation of the black pigmented ink of Loligo duvauceli in the present study have yielded an array of bioactive compounds with potent antimicrobial property. Facing an alarm of antimicrobial resistance globally, a need for elucidating antimicrobial agents from natural sources will be the need for the hour. In this view, this study is aimed at characterizing the black pigmented ink of the Indian squid L. duvauceli. The squid ink was subjected to crude solvent extraction and was fractionated by silica gel column chromatography. TLC and HPTLC profiles were recorded. Antimicrobial bioassay of the squid ink fractions was done by agar well diffusion method. The antimicrobial fraction was then characterized using GC-MS analysis. The results showed that the n-hexane extract upon column fractionation yielded a total of 8 fractions with the mobile phase of Hex/EtOAc in different gradients. TLC and HPTLC profiles showed a single spot with a retention factor of 0.76. Fraction 1 showed significant antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Lactobacillus acidophilus and a promising antifungal activity against Candida albicans. The antimicrobial fraction upon GC-MS analysis of bis(2-ethylhexyl) phthalate (BEHP) possesses the highest percentage of area normalisation (91%) with other few minor constituents. The study is concluded by stating that the antimicrobial efficacy of the squid ink might be due to the synergistic effects of the phthalate derivative and the other minor volatile compounds analysed in the squid ink.

Antimicrobial activity of nanoemulsion in combination with cetylpyridinium chloride in multidrug-resistant Acinetobacter baumannii.

PubMed

Hwang, Yoon Y; Ramalingam, Karthikeyan; Bienek, Diane R; Lee, Valerie; You, Tao; Alvarez, Rene

2013-08-01

Acinetobacter baumannii has emerged as a serious problematic pathogen due to the ever-increasing presence of antibiotic resistance, demonstrating a need for novel, broad-spectrum antimicrobial therapeutic options. Antimicrobial nanoemulsions are emulsified mixtures of detergent, oil, and water (droplet size, 100 to 800 nm) which have broad antimicrobial activity against bacteria, enveloped viruses, and fungi. Here, we screened the antimicrobial activities of five nanoemulsion preparations against four Acinetobacter baumannii isolates to identify the most suitable preparation for further evaluation. Among them, N5, which contains 10% (vol/vol) Triton X-100, 25% (vol/vol) soybean oil, and 1% (wt/vol) cetylpyridinium chloride (CPC), showed the best efficacy against A. baumannii in both its planktonic and biofilm forms and was selected for further study. Our data demonstrate that, while the killing of planktonic forms of A. baumannii was due to the 1% CPC component of our nanoemulsions, the breakdown of biofilms was achieved via the emulsified oil and detergent fractions. Furthermore, we documented the effect of ethanol and NaCl in combination with N5 on planktonic A. baumannii. In killing curves of N5 combined with other agents (ethanol or NaCl), a synergistic effect of a ≥ 2-log decrease in CFU/ml was observed. The antibiofilm activity of N5 was confirmed via a cell proliferation test and scanning electron microscopy. The effects of exposure to severe environmental conditions, which simulates the field conditions in Iraq and Afghanistan, were evaluated, and this exposure did not affect the overall antimicrobial activity of N5. These studies lay a solid foundation for the utilization of nanoemulsions against the antibiotic-resistant forms of A. baumannii.

Antimicrobial Activity of Nanoemulsion in Combination with Cetylpyridinium Chloride in Multidrug-Resistant Acinetobacter baumannii

PubMed Central

Hwang, Yoon Y.; Ramalingam, Karthikeyan; Bienek, Diane R.; Lee, Valerie; You, Tao

2013-01-01

Acinetobacter baumannii has emerged as a serious problematic pathogen due to the ever-increasing presence of antibiotic resistance, demonstrating a need for novel, broad-spectrum antimicrobial therapeutic options. Antimicrobial nanoemulsions are emulsified mixtures of detergent, oil, and water (droplet size, 100 to 800 nm) which have broad antimicrobial activity against bacteria, enveloped viruses, and fungi. Here, we screened the antimicrobial activities of five nanoemulsion preparations against four Acinetobacter baumannii isolates to identify the most suitable preparation for further evaluation. Among them, N5, which contains 10% (vol/vol) Triton X-100, 25% (vol/vol) soybean oil, and 1% (wt/vol) cetylpyridinium chloride (CPC), showed the best efficacy against A. baumannii in both its planktonic and biofilm forms and was selected for further study. Our data demonstrate that, while the killing of planktonic forms of A. baumannii was due to the 1% CPC component of our nanoemulsions, the breakdown of biofilms was achieved via the emulsified oil and detergent fractions. Furthermore, we documented the effect of ethanol and NaCl in combination with N5 on planktonic A. baumannii. In killing curves of N5 combined with other agents (ethanol or NaCl), a synergistic effect of a ≥2-log decrease in CFU/ml was observed. The antibiofilm activity of N5 was confirmed via a cell proliferation test and scanning electron microscopy. The effects of exposure to severe environmental conditions, which simulates the field conditions in Iraq and Afghanistan, were evaluated, and this exposure did not affect the overall antimicrobial activity of N5. These studies lay a solid foundation for the utilization of nanoemulsions against the antibiotic-resistant forms of A. baumannii. PMID:23669390

Antibacterial activity and composition of essential oils from Pelargonium graveolens L'Her and Vitex agnus-castus L.

PubMed

Ghannadi, A; Bagherinejad, Mr; Abedi, D; Jalali, M; Absalan, B; Sadeghi, N

2012-12-01

Essential oils are volatile compounds that have been used since Middle Ages as antimicrobial, anti-inflammatory, sedative, local anesthetic and food flavoring agents. In the current study, essential oils of Pelargonium graveolens L'Her and Vitex agnus-castus L. were analyzed for their antibacterial activities. The chemical compositions of essential oils were characterized by GC-MS. Disc diffusion method was used to study antimicrobial activity. Inhibition zones showed that the essential oils of the two plants were active against all of the studied bacteria (except Listeria monocytogenes). The susceptibility of the strains changed with the dilution of essential oils in DMSO. The pure essential oils showed the most extensive inhibition zones and they were very effective antimicrobial compounds compared to chloramphenicol and amoxicillin. The most susceptible strain against these two essential oils was Staphylococcus aureus. It seems that β-citronellol is a prominent part of P. graveolens volatile oil and caryophyllene oxide is a famous and important part of V. agnus-castus volatile oil and their probable synergistic effect with other constituents are responsible for the antibacterial effects of these oils. However further studies must be performed to confirm the safety of these oils for use as antimicrobial agents and natural preservatives in different products.

Advances in the Fabrication of Antimicrobial Hydrogels for Biomedical Applications.

PubMed

González-Henríquez, Carmen M; Sarabia-Vallejos, Mauricio A; Rodriguez-Hernandez, Juan

2017-02-26

This review describes, in an organized manner, the recent developments in the elaboration of hydrogels that possess antimicrobial activity. The fabrication of antibacterial hydrogels for biomedical applications that permits cell adhesion and proliferation still remains as an interesting challenge, in particular for tissue engineering applications. In this context, a large number of studies has been carried out in the design of hydrogels that serve as support for antimicrobial agents (nanoparticles, antibiotics, etc.). Another interesting approach is to use polymers with inherent antimicrobial activity provided by functional groups contained in their structures, such as quaternary ammonium salt or hydrogels fabricated from antimicrobial peptides (AMPs) or natural polymers, such as chitosan. A summary of the different alternatives employed for this purpose is described in this review, considering their advantages and disadvantages. Finally, more recent methodologies that lead to more sophisticated hydrogels that are able to react to external stimuli are equally depicted in this review.

Advances in the Fabrication of Antimicrobial Hydrogels for Biomedical Applications

PubMed Central

González-Henríquez, Carmen M.; Sarabia-Vallejos, Mauricio A.; Rodriguez-Hernandez, Juan

2017-01-01

This review describes, in an organized manner, the recent developments in the elaboration of hydrogels that possess antimicrobial activity. The fabrication of antibacterial hydrogels for biomedical applications that permits cell adhesion and proliferation still remains as an interesting challenge, in particular for tissue engineering applications. In this context, a large number of studies has been carried out in the design of hydrogels that serve as support for antimicrobial agents (nanoparticles, antibiotics, etc.). Another interesting approach is to use polymers with inherent antimicrobial activity provided by functional groups contained in their structures, such as quaternary ammonium salt or hydrogels fabricated from antimicrobial peptides (AMPs) or natural polymers, such as chitosan. A summary of the different alternatives employed for this purpose is described in this review, considering their advantages and disadvantages. Finally, more recent methodologies that lead to more sophisticated hydrogels that are able to react to external stimuli are equally depicted in this review. PMID:28772591

Antimicrobial activity of bovine NK-lysin-derived peptides on Mycoplasma bovis

PubMed Central

Falkenberg, Shollie M.; Register, Karen B.; Samorodnitsky, Daniel; Nicholson, Eric M.; Reinhardt, Timothy A.

2018-01-01

Antimicrobial peptides (AMPs) are a diverse group of molecules which play an important role in the innate immune response. Bovine NK-lysins, a type of AMP, have been predominantly found in the granules of cytotoxic T-lymphocytes and NK-cells. Bovine NK-lysin-derived peptides demonstrate antimicrobial activity against various bacterial pathogens, including several involved in bovine respiratory disease complex (BRDC) in cattle; however, such studies are yet to be performed with one important contributor to the BRDC, Mycoplasma bovis. Therefore, the goal of this study was to assess the antimicrobial activity of bovine NK-lysin-derived peptides on M. bovis. Thirty-mer synthetic peptides corresponding to the functional region helices 2 and 3 of bovine NK-lysins NK1, NK2A, NK2B, and NK2C were evaluated for killing activity on M. bovis isolates. Among four peptides, NK2A and NK2C showed the highest antimicrobial activity against the M. bovis isolates tested. All four NK-lysin peptides induced rapid plasma membrane depolarization in M. bovis at two concentrations tested. However, based on propidium iodide uptake, only NK2A and NK2C appeared capable of causing structural damage to M. bovis plasma membrane. Confocal microscopy, flow cytometry, and transmission electron microscopy further suggested NK-lysin-induced damage to the plasma membrane. Taken together, the findings in this study suggest that plasma membrane depolarization alone was insufficient to induce lethality, but disruption/permeabilization of the M. bovis plasma membrane was the cause of lethality. PMID:29771981

In Vitro and In Vivo Activities of Antimicrobial Peptides Developed Using an Amino Acid-Based Activity Prediction Method

PubMed Central

Wu, Xiaozhe; Wang, Zhenling; Li, Xiaolu; Fan, Yingzi; He, Gu; Wan, Yang; Yu, Chaoheng; Tang, Jianying; Li, Meng; Zhang, Xian; Zhang, Hailong; Xiang, Rong; Pan, Ying; Liu, Yan; Lu, Lian

2014-01-01

To design and discover new antimicrobial peptides (AMPs) with high levels of antimicrobial activity, a number of machine-learning methods and prediction methods have been developed. Here, we present a new prediction method that can identify novel AMPs that are highly similar in sequence to known peptides but offer improved antimicrobial activity along with lower host cytotoxicity. Using previously generated AMP amino acid substitution data, we developed an amino acid activity contribution matrix that contained an activity contribution value for each amino acid in each position of the model peptide. A series of AMPs were designed with this method. After evaluating the antimicrobial activities of these novel AMPs against both Gram-positive and Gram-negative bacterial strains, DP7 was chosen for further analysis. Compared to the parent peptide HH2, this novel AMP showed broad-spectrum, improved antimicrobial activity, and in a cytotoxicity assay it showed lower toxicity against human cells. The in vivo antimicrobial activity of DP7 was tested in a Staphylococcus aureus infection murine model. When inoculated and treated via intraperitoneal injection, DP7 reduced the bacterial load in the peritoneal lavage solution. Electron microscope imaging and the results indicated disruption of the S. aureus outer membrane by DP7. Our new prediction method can therefore be employed to identify AMPs possessing minor amino acid differences with improved antimicrobial activities, potentially increasing the therapeutic agents available to combat multidrug-resistant infections. PMID:24982064

Antimicrobial and Immunomodulatory Activities of PR-39 Derived Peptides

PubMed Central

Veldhuizen, Edwin J. A.; Schneider, Viktoria A. F.; Agustiandari, Herfita; van Dijk, Albert; Tjeerdsma-van Bokhoven, Johanna L. M.; Bikker, Floris J.; Haagsman, Henk P.

2014-01-01

The porcine cathelicidin PR-39 is a host defence peptide that plays a pivotal role in the innate immune defence of the pig against infections. Besides direct antimicrobial activity, it is involved in immunomodulation, wound healing and several other biological processes. In this study, the antimicrobial- and immunomodulatory activity of PR-39, and N- and C-terminal derivatives of PR-39 were tested. PR-39 exhibited an unexpected broad antimicrobial spectrum including several Gram positive strains such as Bacillus globigii and Enterococcus faecalis. Of organisms tested, only Staphylococcus aureus was insensitive to PR-39. Truncation of PR-39 down to 15 (N-terminal) amino acids did not lead to major loss of activity, while peptides corresponding to the C-terminal part of PR-39 were hampered in their antimicrobial activity. However, shorter peptides were all much more sensitive to inhibition by salt. Active peptides induced ATP leakage and loss of membrane potential in Bacillus globigii and Escherichia coli, indicating a lytic mechanism of action for these peptides. Finally, only the mature peptide was able to induce IL-8 production in porcine macrophages, but some shorter peptides also had an effect on TNF-α production showing differential regulation of cytokine induction by PR-39 derived peptides. None of the active peptides showed high cytotoxicity highlighting the potential of these peptides for use as an alternative to antibiotics. PMID:24755622

Diverse deep-sea fungi from the South China Sea and their antimicrobial activity.

PubMed

Zhang, Xiao-Yong; Zhang, Yun; Xu, Xin-Ya; Qi, Shu-Hua

2013-11-01

We investigated the diversity of fungal communities in nine different deep-sea sediment samples of the South China Sea by culture-dependent methods followed by analysis of fungal internal transcribed spacer (ITS) sequences. Although 14 out of 27 identified species were reported in a previous study, 13 species were isolated from sediments of deep-sea environments for the first report. Moreover, these ITS sequences of six isolates shared 84-92 % similarity with their closest matches in GenBank, which suggested that they might be novel phylotypes of genera Ajellomyces, Podosordaria, Torula, and Xylaria. The antimicrobial activities of these fungal isolates were explored using a double-layer technique. A relatively high proportion (56 %) of fungal isolates exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among four marine pathogenic microbes (Micrococcus luteus, Pseudoaltermonas piscida, Aspergerillus versicolor, and A. sydowii). Out of these antimicrobial fungi, the genera Arthrinium, Aspergillus, and Penicillium exhibited antibacterial and antifungal activities, while genus Aureobasidium displayed only antibacterial activity, and genera Acremonium, Cladosporium, Geomyces, and Phaeosphaeriopsis displayed only antifungal activity. To our knowledge, this is the first report to investigate the diversity and antimicrobial activity of culturable deep-sea-derived fungi in the South China Sea. These results suggest that diverse deep-sea fungi from the South China Sea are a potential source for antibiotics' discovery and further increase the pool of fungi available for natural bioactive product screening.

Antimicrobial and cytotoxic activity of red propolis: an alert for its safe use.

PubMed

Lopez, B G-C; de Lourenço, C C; Alves, D A; Machado, D; Lancellotti, M; Sawaya, A C H F

2015-09-01

Red propolis is a resinous product popularly consumed in Brazil as it improves health, and it is considered a nutraceutical. The objective of this study was to test the antimicrobial activity of eight samples of red propolis from Brazil and Cuba to assess the possibility of application of this natural product as an antimicrobial agent, along with a study of its cytotoxic activity against non-tumor cell lines to evaluate at which concentrations it could be safely used. The chemical profile of the samples was evaluated by UHPLC-MS. All the samples presented antimicrobial activity which was tested using agar diffusion and serial dilution methods; and these samples displayed a better activity against most Gram-negative bacteria with minimum inhibitory concentration (MIC) in the range between 6·25 μg ml(-1) and 500 μg ml(-1). However our studies also revealed an inherent cytotoxic effect against HaCaT human keratinocytes and BALBc 3T3. To have a noncytotoxic and safe use of red propolis, it is necessary to use a concentration below the IC50 cytotoxic values. The traditional use of propolis does not necessarily guarantee its safety. The evaluation of the safety of bioactive natural products should always be considered together with the evaluation of the activity. © 2015 The Society for Applied Microbiology.

Investigation of the potential antimicrobial efficacy of sealants used in HVAC systems.

PubMed

Foarde, K K; VanOsdell, D W; Menetrez, M Y

2001-08-01

Recent experiments confirm field experience that duct cleaning alone may not provide adequate protection from regrowth of fungal contamination on fiberglass duct liner (FGDL). Current recommendations for remediation of fungally contaminated fiberglass duct materials specify complete removal of the materials. But removal of contaminated materials can be extremely expensive. Therefore, a common practice in the duct-cleaning industry is the postcleaning use of antimicrobial surface coatings with the implication that they may contain or limit regrowth. Little information is available on the efficacy of these treatments. This paper describes a study to evaluate whether three commercially available antimicrobial coatings, placed on a cleaned surface that 1 year previously had been actively growing microorganisms, would be able to prevent regrowth. The three coatings contained different active antimicrobial compounds. All three of the coatings were designed for use on heating, ventilation, and air conditioning (HVAC) system components or interior surfaces of lined and unlined duct systems. Coating I was a polyacrylate copolymer containing zinc oxide and borates. Coating II was an acrylic coating containing decabromodiphenyl oxide and antimony trioxide. Coating III was an acrylic primer containing a phosphated quaternary amine complex. The study included field and laboratory assessments. The three treatments were evaluated in an uncontrolled field setting in an actual duct system. The laboratory study broadened the field study to include a range of humidities under controlled conditions. Both static and dynamic chamber laboratory experiments were performed. The results showed that two of the three antimicrobial coatings limited the regrowth of fungal contamination, at least in the short term (the 3-month time span of the study); the third did not. Before use in the field, testing of the efficacy of antimicrobial coatings under realistic use conditions is recommended because antimicrobials have different baseline activities and interact differently with the substrate that contains them and their local environment.

Antiproliferative and antimicrobial efficacy of the compounds isolated from the roots of Oenothera biennis L.

PubMed

Singh, Shilpi; Dubey, Vijaya; Singh, Dhananjay Kumar; Fatima, Kaneez; Ahmad, Ateeque; Luqman, Suaib

2017-09-01

Oenothera biennis L., commonly known as evening primrose, harbours the flavonoids, steroids, tannins, fatty acids and terpenoids responsible for a diverse range of biological activity, such as antitumour, anti-arthritic and anti-inflammatory effects. In addition to the previous reports from aerial parts of this plant, studies related to antiproliferative or antimicrobial activity from the roots are warranted. To investigate antiproliferative and antimicrobial activity of compounds/mixture (1-8) isolated and characterized from the roots of O. biennis L. A possible mechanism of antiproliferative activity was also studied by targeting ornithine decarboxylase (ODC) and cathepsin D (CATD). Antiproliferative efficacy of the compounds/mixture was examined in selected cancer cell lines along with their probable mechanism of action. The antimicrobial activity was also studied against selected microbes (bacteria and fungi). Antiproliferative potential was evaluated by MTT assay against selected cell lines. The mechanism of action was studied spectrophotometrically by targeting ODC and CATD using both an in-vitro and an in-silico approach. The antimicrobial efficiency was analysed using the disc diffusion and broth dilution methods. Oenotheralanosterol B (3) and the mixture of oenotheralanosterol A and oenotheralanosterol B (4) exhibited antiproliferative activity against breast, hepatic, prostate and leukaemia cancer cell lines as well as in mouse macrophages (IC 50 8.35-49.69 μg/ml). Oenotheralanosterol B (3) and the mixture of oenotheralanosterol A and oenotheralanosterol B (4) displayed a strong molecular interaction with succinate dehydrogenase (binding energy -6.23 and -6.84 kcal/mol and Ki 27.03 and 9.6 μm, respectively). Oenotheralanosterol A (1), oenotheralanosterol B (3) and mixture of oenotheralanosterol A and oenotheralanosterol B (4) potently inhibited the ODC activity with IC 50 ranging from 4.65 ± 0.35 to 19.06 ± 4.16 μg/ml and also showed a strong interaction with ODC (BE -4.17 to -4.46 kcal/mol). Oenotheralanosterol A (1), cetoleilyl diglucoside (2), oenotheralanosterol B (3), dihydroxyprenylxanthone acetylated (6) and dihydroxyprenylxanthone (7) inhibited CATD activity (IC 50 3.95 ± 0.49 to 24.35 ± 2.89 μg/ml). The in-silico molecular interaction analysis of compounds with CATD revealed the non-specific interaction. A moderate antimicrobial activity was observed against selected microbes with a growth inhibition ranging from 6 to 14 mm and minimum inhibitory concentration between 125 and 500 μg/ml. Oenotheralanosterol B (3) and dihydroxyprenylxanthone acetylated (6) exhibited better antimicrobial activity with an MIC range from 62.50 to 500 μg/ml. Oenotheralanosterol B (3) exhibited stronger antiproliferative and antimicrobial potential with respect to the other compounds tested, whereas oenotheralanosterol A (1) was a potent inhibitor of ODC and CATD. Hence, it is suggested that these in-vitro findings could be studied further in vivo for biological activity, safety evaluation and derivatization to enhance potency and efficacy. © 2017 Royal Pharmaceutical Society.

A Nanolayer Copper Coating for Prevention Nosocomial Multi-Drug Resistant Infections

DTIC Science & Technology

2016-10-01

done using a standard antimicrobial assay defined in ASTM method E2149-01 for determining antibacterial activity of immobilized agents under...are optimized for bacterial growth and do not represent typical conditions. Therefore, most studies reporting on the antimicrobial activity of a...given substance are done in physiological buffer (with the exception of many antibiotics as these require active metabolism for efficacy). This can be

Entrapment of Bacteriocin 105B onto Fabric with Titania

DTIC Science & Technology

2017-02-09

to fabricate a multifunctional textile exhibiting an alternative range of antimicrobial activity from that of nisin, by titania encapsulation of...105b onto fabric. The results of these initial studies suggest that both pure preparations and semi-pure preparations of 105b are active when...encapsulated in titania in solution. However, when the pure preparation of 105b is titania encapsulated on fabric, antimicrobial activity is not observed

Embedment of silver into temperature- and pH-responsive microgel for the development of smart textiles with simultaneous moisture management and controlled antimicrobial activities.

PubMed

Štular, Danaja; Jerman, Ivan; Naglič, Iztok; Simončič, Barbara; Tomšič, Brigita

2017-03-01

Silver nanoparticles were embedded into a temperature- and pH-responsive microgel based on poly-(N-isopropylacrylamide) and chitosan (PNCS) before or after its application to cotton fabric to create a smart stimuli-responsive textile with simultaneous moisture management and controlled antimicrobial activities. Two different methods of silver embedment into the PNCS microgel using two different forms of silver nanoparticles were studied, i.e., in-situ synthesis of AgCl nanocrystals into PNCS microgel particles that had previously been applied to cotton fabric, as well as the direct incorporation of colloidal silver into the microgel suspension prior to its deposition on cellulose fibres. SEM and FT-IR analysis were employed to determine the morphological and chemical changes of the modified cotton fibres, while EDS and ICP MS analysis were used to confirm the presence of the silver nanoparticles. The influence of silver embedment on the swelling/deswelling activity of the PNCS microgel was studied using the temperature- and pH-responsiveness, as determined by the moisture content, water vapour transmission rate and water uptake. The antimicrobial activity against the bacteria Staphylococcus aureus and Escherichia coli was assessed. Regardless of the embedment technique, the presence of silver nanoparticles resulted in impaired moisture management activity of the studied microgel. The PNCS microgel proved to be a suitable carrier of antimicrobial agents, assuring the effective controlled release of silver triggered by changes in the temperature and pH of the surroundings, which granted the cotton fabric excellent antimicrobial activity against Gram-negative E. coli (>99%) and Gram-positive S. aureus (>85%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative analyses of the bacterial microbiota of rearing environment, tilapia and common carp cultured in earthen ponds and inhibitory activity of its lactic acid bacteria on fish spoilage and pathogenic bacteria.

PubMed

Kaktcham, Pierre Marie; Temgoua, Jules-Bocamdé; Ngoufack Zambou, François; Diaz-Ruiz, Gloria; Wacher, Carmen; Pérez-Chabela, María de Lourdes

2017-02-01

The present study aimed to evaluate the bacterial load of water, Nile Tilapia and common Carp intestines from earthen ponds, isolate lactic acid bacteria (LAB) and assess their antimicrobial activity against fish spoilage and pathogenic bacteria. Following enumeration and isolation of microorganisms the antimicrobial activity of the LAB isolates was evaluated. Taxonomic identification of selected antagonistic LAB strains was assessed, followed by partial characterisation of their antimicrobial metabolites. Results showed that high counts (>4 log c.f.u ml -1 or 8 log c.f.u g -1 ) of total aerobic bacteria were recorded in pond waters and fish intestines. The microbiota were also found to be dominated by Salmonella spp., Vibrio spp., Staphylococcus spp. and Escherichia coli. LAB isolates (5.60%) exhibited potent direct and extracellular antimicrobial activity against the host-derived and non host-derived spoilage and pathogenic bacteria. These antagonistic isolates were identified and Lactococcus lactis subsp. lactis was found as the predominant (42.85%) specie. The strains displayed the ability to produce lactic, acetic, butyric, propionic and valeric acids. Bacteriocin-like inhibitory substances with activity against Gram-positive and Gram-negative (Vibrio spp. and Pseudomonas aeruginosa) bacteria were produced by three L. lactis subsp. lactis strains. In this study, the LAB from the microbiota of fish and pond water showed potent antimicrobial activity against fish spoilage or pathogenic bacteria from the same host or ecological niche. The studied Cameroonian aquatic niche is an ideal source of antagonistic LAB that could be appropriate as new fish biopreservatives or disease control agents in aquaculture under tropical conditions in particular or worldwide in general.

Antimicrobial efficacy of amine fluoride based tooth gels compared to a toothpaste in a phase 2/step 2 in-vitro test model

PubMed Central

Schiller, Anne; Großjohann, Beatrice; Welk, Alexander; Hübner, Nils-Olaf; Braun, Dagmar; Assadian, Ojan; Kramer, Axel

2012-01-01

Introduction: The aim of the present study was to determine the antimicrobial effect of various gel formulations on plaque formation; different tooth gels were compared to a toothpaste containing comparable antimicrobial ingredients with regard to its microbiocidal activity. The study was conducted under the assumption, that a chief requirement for the prevention of plaque formation is the combination of mechanical removal and antimicrobial activity, and not the sole capability of mechanical plaque removal. Methods: Ledermix® fluoride gel as commercially available with preservative, and without preservative and perfume oils, Elmex® gelée, and Meridol® toothpaste were tested in a standardized in-vitro test modification of the quantitative suspension test EN 1040. Instead of testing in a suspension, the respective product was directly placed on a standardized contaminated sterile stainless steel disk without adding any bio-burden. 50% egg yolk in Aqua dest. was used as a neutralizer. Results: Within 1 min, Elmex® gelée showed a RF >5 log10 against S. pyogenes and S. sanguinis. Against S. mutans, a log10 RF of ≥5 was achieved after 2 min, against C. albicans after 5 min, and against P. aeruginosa after 10 min S. aureus was the most difficult organisms to be reduced. After an application time of 10 min, only a log10 RF of 2.4 was achieved. Ledermix exceeded the antimicrobial efficacy of Elmex® gelée against S. mutans and C. albicans and was already effective against these organisms after 1 min, but did not show the same antimicrobial efficacy as Elmex® gelée against P. aeruginosa. Similar to Elmex® gelée, a required reduction of >5 log10 for antimicrobials under no organic challenge was not achieved against S. aureus. Ledermix® fluoride gel without preservatives and Ledermix® fluoride gel without preservatives and perfume oil did not show the antimicrobial efficacy of the standard Ledermix® fluoride gel formulation, indicating that the observed antimicrobial efficacy is chiefly based on the preservative, and possibly the perfume oil. Compared to the tested gels, Meridol® toothpaste was less effective and reached any antimicrobial effect >5 log10 only against S. sanguinis after 10 min. Conclusion: All unmodified tested gels showed an antimicrobial effect. Because no relevant antimicrobial efficacy against plaque forming bacteria was achieved within 2 min, in practice, an anti-plaque forming effect based on the antimicrobial action of gels cannot be assumed when used in the oral cavity. However, the results of the present study indicate that the antimicrobial efficacy of gels is determined by their formulation and that for the prevention of plaque formation the combination of mechanical removal and antimicrobial activity is not the chief requirement only, but a sustained antimicrobial effect may be of greater importance. PMID:22558041

Determination of Chlortetracycline Residues, Antimicrobial Activity and Presence of Resistance Genes in Droppings of Experimentally Treated Broiler Chickens.

PubMed

Cornejo, Javiera; Yevenes, Karina; Avello, Constanza; Pokrant, Ekaterina; Maddaleno, Aldo; Martin, Betty San; Lapierre, Lisette

2018-05-25

Tetracyclines are important antimicrobial drugs for poultry farming that are actively excreted via feces and urine. Droppings are one of the main components in broiler bedding, which is commonly used as an organic fertilizer. Therefore, bedding becomes an unintended carrier of antimicrobial residues into the environment and may pose a highly significant threat to public health. For this depletion study, 60 broiler chickens were treated with 20% chlortetracycline (CTC) under therapeutic conditions. Concentrations of CTC and 4-epi-CTC were then determined in their droppings. Additionally, this work also aimed to detect the antimicrobial activity of these droppings and the phenotypic susceptibility to tetracycline in E. coli isolates, as well as the presence of tet(A) , tet(B) , and tet(G) resistance genes. CTC and 4-epi-CTC concentrations that were found ranged from 179.5 to 665.8 µg/kg. Based on these data, the depletion time for chicken droppings was calculated and set at 69 days. All samples presented antimicrobial activity, and a resistance to tetracyclines was found in bacterial strains that were isolated from these samples. Resistance genes tet(A) and tet(B) were also found in these samples.

Synthesis of fluorine substituted hydroxyapatite nanopowders and application of the central composite design for determination of its antimicrobial effects

NASA Astrophysics Data System (ADS)

Stanić, Vojislav; Dimitrijević, Suzana; Antonović, Dušan G.; Jokić, Bojan M.; Zec, Slavica P.; Tanasković, Sladjana T.; Raičević, Slavica

2014-01-01

Synthetic biomaterials based on fluorine substituted hydroxyapatite are potentially attractive for orthopedic and dental implant applications. The new synthesis of fluorine substituted hydroxyapatite samples were done by neutralization, which consists of adding the solution of HF and H3PO4 in suspension of Ca(OH)2. Characterization studies from XRD, SEM and FTIR spectra showed that crystals are obtained with apatite structure and those particles of all samples are nano size, with an average length of 80 nm and about 15-25 nm in diameter. The central composite design was used in order to determine the optimal conditions for the antimicrobial activity of the synthesized samples. In order to evaluate the influence of operating parameters on the percent of viable cell reduction of Streptococcus mutans, three independent variables were chosen: exposure time, pH of saline and floride concentration in apatite samples. The experimental and predicted antimicrobial activities were in close agreement. Antimicrobial activity of the samples increases with the increase of fluoride concentration and the decreased pH of saline. The maximum antimicrobial activity was achieved at the initial pH of 4.

The Kolumbo submarine volcano of Santorini island is a large pool of bacterial strains with antimicrobial activity.

PubMed

Bourbouli, Maria; Katsifas, Efstathios A; Papathanassiou, Evangelos; Karagouni, Amalia D

2015-05-01

Microbes in hydrothermal vents with their unique secondary metabolism may represent an untapped potential source of new natural products. In this study, samples were collected from the hydrothermal field of Kolumbo submarine volcano in the Aegean Sea, in order to isolate bacteria with antimicrobial activity. Eight hundred and thirty-two aerobic heterotrophic bacteria were isolated and then differentiated through BOX-PCR analysis at the strain level into 230 genomic fingerprints, which were screened against 13 different type strains (pathogenic and nonpathogenic) of Gram-positive, Gram-negative bacteria and fungi. Forty-two out of 176 bioactive-producing genotypes (76 %) exhibited antimicrobial activity against at least four different type strains and were selected for 16S rDNA sequencing and screening for nonribosomal peptide (NRPS) and polyketide (PKS) synthases genes. The isolates were assigned to genus Bacillus and Proteobacteria, and 20 strains harbored either NRPS, PKS type I or both genes. This is the first report on the diversity of culturable mesophilic bacteria associated with antimicrobial activity from Kolumbo area; the extremely high proportion of antimicrobial-producing strains suggested that this unique environment may represent a potential reservoir of novel bioactive compounds.

Comparative study of singlet oxygen production by photosensitiser dyes encapsulated in silicone: towards rational design of anti-microbial surfaces.

PubMed

Noimark, Sacha; Salvadori, Enrico; Gómez-Bombarelli, Rafael; MacRobert, Alexander J; Parkin, Ivan P; Kay, Christopher W M

2016-10-12

Surfaces with built-in antimicrobial activity have the potential to reduce hospital-acquired infections. One promising strategy is to create functionalised surfaces which, following illumination with visible light, are able to generate singlet oxygen under aerobic conditions. In contrast to antibiotics, the mechanism of bacterial kill by species derived from reactions with singlet oxygen is completely unselective, therefore offering little room for evolutionary adaptation. Here we consider five commercially available organic photosensitiser dyes encapsulated in silicone polymer that show varied antimicrobial activity. We correlate density functional theory calculations with UV-Vis spectroscopy, electron paramagnetic resonance spectroscopy and singlet oxygen production measurements in order to define and test the elements required for efficacious antimicrobial activity. Our approach forms the basis for the rational in silico design and spectroscopic screening of simple and efficient self-sterilising surfaces made from cheap, low toxicity photosensitiser dyes encapsulated in silicone.

Synthesis of Some Benzofuran Derivatives Containing Pyrimidine Moiety as Potent Antimicrobial Agents.

PubMed

Venkatesh, Talavara; Bodke, Yadav Dasharathrao; Joy, Muthipeedika Nibin; Dhananjaya, Bhadrapura Lakkappa; Venkataraman, Sivaramakrishnan

2018-01-01

In this investigation, the synthesis of 2-substituted pyrimidines by the reaction of benzofuran chalcones (3a-d) with urea, thiourea and guanidine hydrochloride was reported. The structures of title compounds (4a-d), (5a-d) and (6a-d) were established on the basis of analytical and spectral data. The synthesized compounds were screened for antimicrobial activity and molecular docking studies. Some of the compounds displayed excellent antimicrobial activity. The molecular docking analysis revealed that compounds 5a and 5c with the lowest binding energy in comparison to others suggesting its potential as best inhibitor of GluN-6-P. Consequently, it is confirmed from the above analysis that the compounds 5a and 5c might serve as a useful backbone scaffold for rational design, adaptation and investigation of more active analogs as potential broad spectrum antimicrobial agents.

Antimicrobial Activity and Brine Shrimp Lethality Bioassay of the Leaves Extract of Dillenia indica Linn.

PubMed

Apu, As; Muhit, Ma; Tareq, Sm; Pathan, Ah; Jamaluddin, Atm; Ahmed, M

2010-01-01

The crude methanolic extract of Dillenia indica Linn. (Dilleniaceae) leaves has been investigated for the evaluation of antimicrobial and cytotoxic activities. Organic solvent (n-hexane, carbon tetrachloride and chloroform) fractions of methanolic extract and methanolic fraction (aqueous) were screened for their antimicrobial activity by disc diffusion method. Besides, the fractions were screened for cytotoxic activity using brine shrimp (Artemia salina) lethality bioassay. Among the four fractions tested, n-hexane, carbon tetrachloride, and chloroform fractions showed moderate antibacterial and antifungal activity compared to standard antibiotic, kanamycin. The average zone of inhibition was ranged from 6 to 8 mm at a concentration of 400 µg/disc. But the aqueous fraction was found to be insensitive to microbial growth. Compared to vincristine sulfate (with LC(50) of 0.52 µg/ ml), n-hexane and chloroform fractions demonstrated a significant cytotoxic activity (having LC(50) of 1.94 µg/ml and 2.13 µg/ml, respectively). The LC(50) values of the carbon tetrachloride and aqueous fraction were 4.46 µg/ml and 5.13 µg/ ml, respectively. The study confirms the moderate antimicrobial and potent cytotoxic activities of Dillenia indica leaves extract and therefore demands the isolation of active principles and thorough bioassay.

Chemical composition of the SFE-CO extracts from Cajanus cajan (L.) Huth and their antimicrobial activity in vitro and in vivo.

PubMed

Zu, Yuan-gang; Liu, Xiao-lei; Fu, Yu-jie; Wu, Nan; Kong, Yu; Wink, Michael

2010-12-01

The in vitro and in vivo antimicrobial activities of SFE-CO₂(supercritical fluid extraction) extracts and ethanol extracts from Cajanus cajan (L.) Huth were investigated. The flavonoid compounds orientin, vitexin, isovitexin, pinostrobin and the stilbene cajaninstilbene acid were detected in SFE-CO₂ extracts by HPLC-DAD. In vitro antimicrobial activities of the extracts were evaluated against eight microbial strains (the bacteria Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris, Pseudomonas aeruginosa, Escherichia coli; and the fungi Aspergillus niger and Candida albicans). A marked inhibitory effect of the SFE extracts was observed against Staphylococcus epidermidis, Staphylococcus aureus and Bacillus subtilis. The IC(50) of SFE-CO₂ extracts ranged from 0.0557 mg/ml to 0.0689 mg/ml consisting of cancer (MCF-7 (0.0557 mg/ml)) as well as non-cancer (BHK-21 (0.0641 mg/ml), RAW264.7 (0.0689 mg/ml) and Vero (0.0625 mg/ml)) cells. Flow cytometry (FCM) was used to analyze death rate of the most sensitive strain (Staphylococcus aureus) caused by the SFE extracts. Additionally, the whole cell proteins of Staphylococcus aureus were analyzed by SDS-PAGE to detect if there were changes in protein patterns. In vivo antimicrobial activity was studies in mice that had been inoculated with Staphylococcus aureus. The potential mechanism of antimicrobial activity in vivo was studied by histopathology. Copyright © 2010 Elsevier GmbH. All rights reserved.

Inducible factors with antimicrobial activity after immune challenge in the haemolymph of Red Palm Weevil (Insecta).

PubMed

Mastore, Maristella; Binda Rossetti, Simona; Giovannardi, Stefano; Scarì, Giorgio; Brivio, Maurizio F

2015-05-01

Insects are capable of innate immune responses elicited after microbial infection. In this process, the receptor-mediated recognition of foreign bodies and the subsequent activation of immunocompetent cells lead to the synthesis ex novo of a peptide pool with antimicrobial activity. We investigated the inducible immune response of a coleopteran, Rhynchophorus ferrugineus, challenged with both Gram-negative and Gram-positive bacteria. After immunization, we evaluated the presence of antimicrobial peptides using either biochemical analyses or microbiological techniques. The antimicrobial properties of the newly synthesized protein pool, detectable in haemolymph fractions of low molecular mass, showed strong antibacterial activity against various bacterial strains (Escherichia coli, Pseudomonas sp. OX1, Bacillus subtilis and Micrococcus luteus). In addition to the preliminary study of the mechanism of action of the pool of antimicrobial peptides, we also investigated its effects on bacterial cell walls by means of fluorescence microscopy and scanning electron microscopy. The data suggest that the main effects seem to be directed at destabilizing and damaging the bacterial wall. This study provides data that help us to understand some aspects of the inducible innate immunity in a system model that lacks anticipatory responses. However, the weevil has finely tuned its defensive strategies to counteract effectively microbial infection. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Identification of Peptides in Flowers of Sambucus nigra with Antimicrobial Activity against Aquaculture Pathogens.

PubMed

Álvarez, Claudio Andrés; Barriga, Andrés; Albericio, Fernando; Romero, María Soledad; Guzmán, Fanny

2018-04-27

The elder ( Sambucus spp.) tree has a number of uses in traditional medicine. Previous studies have demonstrated the antimicrobial properties of elderberry liquid extract against human pathogenic bacteria and also influenza viruses. These properties have been mainly attributed to phenolic compounds. However, other plant defense molecules, such as antimicrobial peptides (AMPs), may be present. Here, we studied peptide extracts from flowers of Sambucus nigra L. The mass spectrometry analyses determined peptides of 3 to 3.6 kDa, among them, cysteine-rich peptides were identified with antimicrobial activity against various Gram-negative bacteria, including recurrent pathogens of Chilean aquaculture. In addition, membrane blebbing on the bacterial surface after exposure to the cyclotide was visualized by SEM microscopy and SYTOX Green permeabilization assay showed the ability to disrupt the bacterial membrane. We postulate that these peptides exert their action by destroying the bacterial membrane.

Anti-microbial Activity of Tulsi {Ocimum Sanctum (Linn.)} Extract on a Periodontal Pathogen in Human Dental Plaque: An Invitro Study

PubMed Central

Devaraj, C.G.; Agarwal, Payal

2016-01-01

Introduction Tulsi is a popular healing herb in Ayurvedic medicine. It is widely used in the treatment of several systemic diseases because of its anti-microbial property. However, studies documenting the effect of Tulsi on oral disease causing organisms are rare. Hence, an attempt was made to determine the effect of Tulsi on a periodontal microorganism in human dental plaque. Aim To determine if Ocimum sanctum (Linn.) has an anti-microbial activity (Minimum Inhibitory Concentration and zone of inhibition) against Actinobacillus actinomycetemcomitans in human dental plaque and to compare the antimicrobial activity of Ocimum sanctum(Linn.) extract with 0.2% chlorhexidine as the positive control and dimethyl sulfoxide as the negative control. Materials and Methods A lab based invitro experimental study design was adopted. Ethanolic extract of Ocimum sanctum (Linn.) was prepared by the cold extraction method. The extract was diluted with an inert solvent, dimethyl sulfoxide, to obtain ten different concentrations (1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%) of extract. Plaque sample was collected from 05 subjects diagnosed with periodontal disease. Isolation of Actinobacillus actinomycetemcomitans from plaque samples was done using Tryptic Soy Serum Bacitracin Vancomycin agar (TSBV) medium. Identification of Actinobacillus actinomycetemcomitans was done based on cultural, microscopic, biochemical characterization and multiple drug resistance patterns. Anti-microbial activity of Ocimum sanctum (Linn.) extract was tested by agar well-diffusion method against 0.2% chlorhexidine as a positive control and dimethyl sulfoxide as a negative control. The zone of inhibition was measured in millimeters using Vernier callipers. Results At the 6% w/v concentration of Ocimum sanctum (Linn.) extract, a zone of inhibition of 22 mm was obtained. This was the widest zone of inhibition observed among all the 10 different concentrations tested. The zone of inhibition for positive control was 25mm and no zone of inhibition was observed around the negative control. Conclusion Ocimum sanctum (Linn.) extract demonstrated an antimicrobial activity against Actinobacillus actinomycetemcomitans. The maximum antimicrobial potential was observed at the 6% concentration level. PMID:27135002

Anti-microbial Activity of Tulsi {Ocimum Sanctum (Linn.)} Extract on a Periodontal Pathogen in Human Dental Plaque: An Invitro Study.

PubMed

Eswar, Pranati; Devaraj, C G; Agarwal, Payal

2016-03-01

Tulsi is a popular healing herb in Ayurvedic medicine. It is widely used in the treatment of several systemic diseases because of its anti-microbial property. However, studies documenting the effect of Tulsi on oral disease causing organisms are rare. Hence, an attempt was made to determine the effect of Tulsi on a periodontal microorganism in human dental plaque. To determine if Ocimum sanctum (Linn.) has an anti-microbial activity (Minimum Inhibitory Concentration and zone of inhibition) against Actinobacillus actinomycetemcomitans in human dental plaque and to compare the antimicrobial activity of Ocimum sanctum(Linn.) extract with 0.2% chlorhexidine as the positive control and dimethyl sulfoxide as the negative control. A lab based invitro experimental study design was adopted. Ethanolic extract of Ocimum sanctum (Linn.) was prepared by the cold extraction method. The extract was diluted with an inert solvent, dimethyl sulfoxide, to obtain ten different concentrations (1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%) of extract. Plaque sample was collected from 05 subjects diagnosed with periodontal disease. Isolation of Actinobacillus actinomycetemcomitans from plaque samples was done using Tryptic Soy Serum Bacitracin Vancomycin agar (TSBV) medium. Identification of Actinobacillus actinomycetemcomitans was done based on cultural, microscopic, biochemical characterization and multiple drug resistance patterns. Anti-microbial activity of Ocimum sanctum (Linn.) extract was tested by agar well-diffusion method against 0.2% chlorhexidine as a positive control and dimethyl sulfoxide as a negative control. The zone of inhibition was measured in millimeters using Vernier callipers. At the 6% w/v concentration of Ocimum sanctum (Linn.) extract, a zone of inhibition of 22 mm was obtained. This was the widest zone of inhibition observed among all the 10 different concentrations tested. The zone of inhibition for positive control was 25mm and no zone of inhibition was observed around the negative control. Ocimum sanctum (Linn.) extract demonstrated an antimicrobial activity against Actinobacillus actinomycetemcomitans. The maximum antimicrobial potential was observed at the 6% concentration level.

Insights into Antimicrobial Peptides from Spiders and Scorpions

PubMed Central

Wang, Xiuqing; Wang, Guangshun

2015-01-01

The venoms of spiders and scorpions contain a variety of chemical compounds. Antimicrobial peptides (AMPs) from these organisms were first discovered in the 1990s. As of May 2015, there were 42 spider’s and 63 scorpion’s AMPs in the Antimicrobial Peptide Database (http://aps.unmc.edu/AP). These peptides have demonstrated broad or narrow-spectrum activities against bacteria, fungi, viruses, and parasites. In addition, they can be toxic to cancer cells, insects and erythrocytes. To provide insight into such an activity spectrum, this article discusses the discovery, classification, structure and activity relationships, bioinformatics analysis, and potential applications of spider and scorpion AMPs. Our analysis reveals that, in the case of linear peptides, spiders use both glycine-rich and helical peptide models for defense, whereas scorpions use two distinct helical peptide models with different amino acid compositions to exert the observed antimicrobial activities and hemolytic toxicity. Our structural bioinformatics study improves the knowledge in the field and can be used to design more selective peptides to combat tumors, parasites, and viruses. PMID:27165405

Assessment of antinociceptive, antipyretic and antimicrobial activity of Piper cubeba L. essential oil in animal models.

PubMed

Mothana, Ramzi; Alsaid, Mansour; Khaled, Jamal M; Alharbi, Naiyf S; Alatar, Abdulrahman; Raish, Mohammad; Al-Yahya, Mohammed; Rafatullah, Syed; Parvez, Mohammad Khalid; Ahamad, Syed Rizwan

2016-03-01

This study was designed to investigate the possible antiniciceptive, antipyretic and antimicrobial activities of the essential oil obtained from the fruits of Piper Cubeba (L.). To assess the antinociceptive and antipyretic activities, three doses (150, 300 and 600 mg/kg, i.p.) were tested in acetic acid-induced abdominal writhing, tail flick reaction and hot-plate and Brewer's yeast-induced hyperpyrexia test models in animals. Moreover, the antimicrobial activity was examined using agar diffusion method and broth micro-dilution assay for minimum inhibitory concentrations (MIC). The Piper Cubeba essential oil (PCEO) showed a marked antinociception (17, 30 and 54%) and an increase in reaction time in mice in the flick tailed and hot-plate tests. The brewer's yeast induced hyperpyrexia was decreased in a dose dependent manner. PCEO also exhibited a strong antimicrobial potential. These findings confirm the traditional analgesic indications of P. cubeba oil and provide persuasive evidence and support its use in Arab traditional medicine.

Chemical composition and antimicrobial activity of the essential oil of Tanacetum walteri (Anthemideae-Asteraceae) from Iran.

PubMed

Ghaderi, Airin; Sonboli, Ali

2018-02-06

The composition and antimicrobial activity of the essential oil of Tanacetum walteri were studied. Aerial flowering parts of plant were collected from North Khorasan Province of Iran and the essential oil was isolated by hydrodistillation and analysed by GC-FID and GC-MS. Antimicrobial activity of the essential oil was determined by disc diffusion and MIC and MBC determination. Thirty-five compounds were identified in the oil of T. walteri accounting for 94.4% of the total oil. Thymol (22.5%), 1,8-cineole (8.2%), umbellulone (6.9%), α-bisabolol (6.3%) and camphor (5.3%) were as the principal constituents. The highest antimicrobial activity of the essential oil was observed against Staphylococcus aureus, Enterococcus faecalis and Klebsiella pneumoniae with MIC value of 0.63 mg/mL. The inhibitory effect of the essential oil of T. walteri could be attributed mainly to the high levels of phenolic compound thymol and oxygenated terpenes in essential oil.

Synergistic effects of guanidine-grafted CMC on enhancing antimicrobial activity and dry strength of paper.

PubMed

Liu, Kai; Xu, Yaoguang; Lin, Xinxing; Chen, Lihui; Huang, Liulian; Cao, Shilin; Li, Jian

2014-09-22

In order to improve the strength property and antimicrobial activity of paper simultaneously, we prepared a novel multifunctional agent based on carboxymethyl cellulose (CMC) by a simple two-stage method. The first stage was the oxidation of CMC to obtain the dialdehyde CMC (DCMC), and the second stage was the graft of guanidine hydrochloride (GH) onto DCMC to obtain DCMC-GH polymer. The strength property and antimicrobial activity of DCMC-GH-coated copy paper have been studied by the tensile test and inhibition zone method, respectively. The results showed that the dry strength index could increase about 20% after the paper was coated with DCMC-GH. The coating of DCMC-GH on paper also resulted in excellent antimicrobial activities against Escherichia coli and Staphylococcus aureus, and the inhibition zone became larger as the GH content grafted on DCMC increased. The novel DCMC-GH polymer would be a multifunctional coating agent for food packaging paper. Copyright © 2014 Elsevier Ltd. All rights reserved.

Virtual screening of a milk peptide database for the identification of food-derived antimicrobial peptides.

PubMed

Liu, Yufang; Eichler, Jutta; Pischetsrieder, Monika

2015-11-01

Milk provides a wide range of bioactive substances, such as antimicrobial peptides and proteins. Our study aimed to identify novel antimicrobial peptides naturally present in milk. The components of an endogenous bovine milk peptide database were virtually screened for charge, amphipathy, and predicted secondary structure. Thus, 23 of 248 screened peptides were identified as candidates for antimicrobial effects. After commercial synthesis, their antimicrobial activities were determined against Escherichia coli NEB5α, E. coli ATCC25922, and Bacillus subtilis ATCC6051. In the tested concentration range (<2 mM), bacteriostatic activity of 14 peptides was detected including nine peptides inhibiting both Gram-positive and Gram-negative bacteria. The most effective fragment was TKLTEEEKNRLNFLKKISQRYQKFΑLPQYLK corresponding to αS2 -casein151-181 , with minimum inhibitory concentration (MIC) of 4.0 μM against B. subtilis ATCC6051, and minimum inhibitory concentrations of 16.2 μM against both E. coli strains. Circular dichroism spectroscopy revealed conformational changes of most active peptides in a membrane-mimic environment, transitioning from an unordered to α-helical structure. Screening of food peptide databases by prediction tools is an efficient method to identify novel antimicrobial food-derived peptides. Milk-derived antimicrobial peptides may have potential use as functional food ingredients and help to understand the molecular mechanisms of anti-infective milk effects. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solvent exchange-induced in situ forming gel comprising ethyl cellulose-antimicrobial drugs.

PubMed

Phaechamud, Thawatchai; Mahadlek, Jongjan

2015-10-15

Solvent-exchanged in situ forming gel is a drug delivery system which is in sol form before administration. When it contacts with the body fluid, then the water miscible organic solvent dissipates and water penetrates into the system, leading the polymer precipitation as in situ gel at the site of injection. The aim of this research was to study the parameters affecting the gel properties, drug release and antimicrobial activities of the in situ forming gels prepared from ethyl cellulose (EC) dissolved in N-methyl pyrrolidone (NMP) to deliver the antimicrobial agents (doxycycline hyclate, metronidazole and benzyl peroxide) for periodontitis treatment. The gel appearance, pH, viscosity, rheology, syringeability, gel formation, rate of water diffusion into the gels, in vitro degradation, drug release behavior and antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, Streptococcus mutans and Porphyrommonas gingivalis were determined. Increasing the amount of EC increased the viscosity of system while still exhibiting Newtonian flow and increased the work of syringeability whereas decreased the releasing of drug. The system transformed into the rigid gel formation after being injected into the simulated gingival crevicular fluid. The developed systems containing 5% w/w antimicrobial agent showed the antimicrobial activities against all test bacteria. Thus the developed solvent exchange-induced in situ forming gels comprising EC-antimicrobial drugs exhibited potential use for periodontitis treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Protamine as a Disinfectant for Contact Lenses.

PubMed

Bandara, Mahesh K; Masoudi, Simin; Zhu, Hua; Bandara, Rani; Willcox, Mark D P

2016-11-01

To investigate the ability of protamine, alone or in combination with other antimicrobial agents, to kill bacteria and fungi associated with contact lens-related keratitis. The International Organization for Standardization 14729:2001 procedure was used to test the antimicrobial activity of solutions of protamine (23-228 μM) with and without polyhexamethylene biguanide (PHMB) and ethylenediamine tetra-acetic acid (EDTA). The recommended ISO panel of microbes along with six clinical isolates was tested. The effect of increasing sodium chloride concentration on the antimicrobial activity was also assessed. The cytotoxicity of the final protamine/EDTA/PHMB solution was measured using ISO 10993-5 standard assays. Protamine gave a dose-dependent antimicrobial effect, with the highest effect for most strains being at 228 μM (≥6 log reductions of viable bacteria and ≥1 log reduction of viable fungi). Addition of EDTA and PHMB increased the antimicrobial effect for all strains except Pseudomonas aeruginosa ATCC6538, which had optimum activity (≥6 log inhibition) even in protamine alone. The optimum antimicrobial activity of all microbes was achieved in 0.2% sodium chloride, but even in 0.8% sodium chloride, the activity met or exceeded the ISO standard (>3 log reductions for bacteria and >1 log reduction for fungi). None of the formulations was cytotoxic to mammalian cells. This study highlights the potential for protamine to be used for the development of effective multipurpose disinfection solutions. Further investigations such as stability, compatibility with contact lenses, and in vivo toxicity are warranted.

Polymer-Based Surfaces Designed to Reduce Biofilm Formation: From Antimicrobial Polymers to Strategies for Long-Term Applications.

PubMed

Riga, Esther K; Vöhringer, Maria; Widyaya, Vania Tanda; Lienkamp, Karen

2017-10-01

Contact-active antimicrobial polymer surfaces bear cationic charges and kill or deactivate bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). The exact mechanism of this interaction is still under debate. While cationic antimicrobial polymer surfaces can be very useful for short-term applications, they lose their activity once they are contaminated by a sufficiently thick layer of adhering biomolecules or bacterial cell debris. This layer shields incoming bacteria from the antimicrobially active cationic surface moieties. Besides discussing antimicrobial surfaces, this feature article focuses on recent strategies that were developed to overcome the contamination problem. This includes bifunctional materials with simultaneously presented antimicrobial and protein-repellent moieties; polymer surfaces that can be switched from an antimicrobial, cell-attractive to a cell-repellent state; polymer surfaces that can be regenerated by enzyme action; degradable antimicrobial polymers; and antimicrobial polymer surfaces with removable top layers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In Vitro Evaluation of Nanoscale Hydroxyapatite-Based Bone Reconstructive Materials with Antimicrobial Properties.

PubMed

Ajduković, Zorica R; Mihajilov-Krstev, Tatjana M; Ignjatović, Nenad L; Stojanović, Zoran; Mladenović-Antić, Snezana B; Kocić, Branislava D; Najman, Stevo; Petrović, Nenad D; Uskoković, Dragan P

2016-02-01

In the field of oral implantology the loss of bone tissue prevents adequate patient care, and calls for the use of synthetic biomaterials with properties that resemble natural bone. Special attention is paid to the risk of infection after the implantation of these materials. Studies have suggested that some nanocontructs containing metal ions have antimicrobial properties. The aim of this study was to examine the antimicrobial and hemolytic activity of cobalt-substituted hydroxyapatite nanoparticles, compared to hydroxyapatite and hydroxyapatite/poly-lactide-co-glycolide. The antibacterial effects of these powders were tested against two pathogenic bacterial strains: Escherichia coi (ATCC 25922) and Staphylococcus aureus (ATCC 25923), using the disc diffusion method and the quantitative antimicrobial test in a liquid medium. The quantitative antimicrobial test showed that all of the tested biomaterials have some antibacterial properties. The effects of both tests were more prominent in case of S. aureus than in E coli. A higher percentage of cobalt in the crystal structure of cobalt-substituted hydroxyapatite nanoparticles led to an increased antimicrobial activity. All of the presented biomaterial samples were found to be non-hemolytic. Having in mind that the tested of cobalt-substituted hydroxyapatite (Ca/Co-HAp) material in given concentrations shows good hemocompatibility and antimicrobial effects, along with its previously studied biological properties, the conclusion can be reached that it is a potential candidate that could substitute calcium hydroxyapatite as the material of choice for use in bone tissue engineering and clinical practices in orthopedic, oral and maxillofacial surgery.

The Influence of Interfering Substances on the Antimicrobial Activity of Selected Quaternary Ammonium Compounds

PubMed Central

Araújo, Paula A.; Lemos, Madalena; Mergulhão, Filipe; Melo, Luís; Simões, Manuel

2013-01-01

Standard cleaning processes may not remove all the soiling typically found in food industry, such as carbohydrates, fats, or proteins. Contaminants have a high impact in disinfection as their presence may reduce the activity of disinfectants. The influence of alginic acid, bovine serum albumin, yeast extract, and humic acids was assessed on the antimicrobial activities of benzalkonium chloride and cetyltrimethyl ammonium bromide against Bacillus cereus vegetative cells and Pseudomonas fluorescens. The bacteria (single and consortium) were exposed to surfactants (single and combined) in the absence and presence of potential disinfection interfering substances. The antimicrobial effects of the surfactants were assessed based on the bacterial respiratory activity measured by oxygen uptake rate due to glucose oxidation. The tested surfactants were efficient against both bacteria (single and consortium) with minimum bactericidal concentrations ranging from 3 to 35 mg·L−1. The strongest effect was caused by humic acids that severely quenched antimicrobial action, increasing the minimum bactericidal concentration of the surfactants on P. fluorescens and the consortium. The inclusion of the other interfering substances resulted in mild interferences in the antibacterial activity. This study clearly demonstrates that humic acids should be considered as an antimicrobial interfering substance in the development of disinfection strategies. PMID:26904590

Phylloseptin-PBa—A Novel Broad-Spectrum Antimicrobial Peptide from the Skin Secretion of the Peruvian Purple-Sided Leaf Frog (Phyllomedusa Baltea) Which Exhibits Cancer Cell Cytotoxicity

PubMed Central

Wan, Yuantai; Ma, Chengbang; Zhou, Mei; Xi, Xinping; Li, Lei; Wu, Di; Wang, Lei; Lin, Chen; Lopez, Juan Chavez; Chen, Tianbao; Shaw, Chris

2015-01-01

Antimicrobial peptides from amphibian skin secretion display remarkable broad-spectrum antimicrobial activity and are thus promising for the discovery of new antibiotics. In this study, we report a novel peptide belonging to the phylloseptin family of antimicrobial peptides, from the skin secretion of the purple-sided leaf frog, Phyllomedusa baltea, which was named Phylloseptin-PBa. Degenerate primers complementary to putative signal peptide sites of frog skin peptide precursor-encoding cDNAs were designed to interrogate a skin secretion-derived cDNA library from this frog. Subsequently, the peptide was isolated and identified using reverse phase HPLC and MS/MS fragmentation. The synthetic replicate was demonstrated to have activity against S. aureus, E. coli and C. albicans at concentrations of 8, 128 and 8 mg/L, respectively. In addition, it exhibited anti-proliferative activity against the human cancer cell lines, H460, PC3 and U251MG, but was less active against a normal human cell line (HMEC). Furthermore, a haemolysis assay was performed to assess mammalian cell cytotoxicity of Phylloseptin-PBa. This peptide contained a large proportion of α-helical domain, which may explain its antimicrobial and anticancer activities. PMID:26633506

Novel antimicrobial peptide CPF-C1 analogs with superior stabilities and activities against multidrug-resistant bacteria.

PubMed

Xie, Junqiu; Zhao, Qian; Li, Sisi; Yan, Zhibin; Li, Jing; Li, Yao; Mou, Lingyun; Zhang, Bangzhi; Yang, Wenle; Miao, Xiaokang; Jiang, Xianxing; Wang, Rui

2017-11-01

As numerous clinical isolates are resistant to most conventional antibiotics, infections caused by multidrug-resistant bacteria are associated with a higher death rate. Antimicrobial peptides show great potential as new antibiotics. However, a major obstacle to the development of these peptides as useful drugs is their low stability. To overcome the problem of the natural antimicrobial peptide CPF-C1, we designed and synthesized a series of analogs. Our results indicated that by introducing lysine, which could increase the number of positive charges, and by introducing tryptophan, which could increase the hydrophobicity, we could improve the antimicrobial activity of the peptides against multidrug-resistant strains. The introduction of d-amino acids significantly improved stability. Certain analogs demonstrated antibiofilm activities. In mechanistic studies, the analogs eradicated bacteria not just by interrupting the bacterial membranes, but also by linking to DNA, which was not impacted by known mechanisms of resistance. In a mouse model, certain analogs were able to significantly reduce the bacterial load. Among the analogs, CPF-9 was notable due to its greater antimicrobial potency in vitro and in vivo and its superior stability, lower hemolytic activity, and higher antibiofilm activity. This analog is a potential antibiotic candidate for treating infections induced by multidrug-resistant bacteria. © 2017 John Wiley & Sons A/S.

Molecular mechanisms behind the antimicrobial activity of hop iso-α-acids in Lactobacillus brevis.

PubMed

Schurr, Benjamin C; Hahne, Hannes; Kuster, Bernhard; Behr, Jürgen; Vogel, Rudi F

2015-04-01

The main bittering component in beer, hop iso-α-acids, have been characterised as weak acids, which act as ionophores impairing microbial cells' function under acidic conditions as present in beer. Besides medium pH, divalent cations play a central role regarding the efficacy of the antimicrobial effect. The iso-α-acids' non-bitter derivatives humulinic acids can be found in isomerised hop extracts and can be generated during hop storage. Therefore, they have been under investigation concerning their influence on beer sensory properties. This study sketches the molecular mechanism behind iso-α-acids' antimicrobial activity in Lactobacillus (L.) brevis regarding their ionophore activity versus the dependence of the inhibitory potential on manganese binding, and suggests humulinic acids as novel tasteless food preservatives. We designed and synthesised chemically modified iso-α-acids to enhance the basic understanding of the molecular mechanism of antimicrobial iso-α-acids. It could be observed that a manganese-binding dependent transmembrane redox reaction (oxidative stress) plays a crucial role in inhibition. Privation of an acidic hydroxyl group neither erased ionophore activity, nor did it entirely abolish antimicrobial activity. Humulinic acids proved to be highly inhibitory, even outperforming iso-α-acids. Copyright © 2014 Elsevier Ltd. All rights reserved.

Phylloseptin-PBa--A Novel Broad-Spectrum Antimicrobial Peptide from the Skin Secretion of the Peruvian Purple-Sided Leaf Frog (Phyllomedusa Baltea) Which Exhibits Cancer Cell Cytotoxicity.

PubMed

Wan, Yuantai; Ma, Chengbang; Zhou, Mei; Xi, Xinping; Li, Lei; Wu, Di; Wang, Lei; Lin, Chen; Lopez, Juan Chavez; Chen, Tianbao; Shaw, Chris

2015-12-01

Antimicrobial peptides from amphibian skin secretion display remarkable broad-spectrum antimicrobial activity and are thus promising for the discovery of new antibiotics. In this study, we report a novel peptide belonging to the phylloseptin family of antimicrobial peptides, from the skin secretion of the purple-sided leaf frog, Phyllomedusa baltea, which was named Phylloseptin-PBa. Degenerate primers complementary to putative signal peptide sites of frog skin peptide precursor-encoding cDNAs were designed to interrogate a skin secretion-derived cDNA library from this frog. Subsequently, the peptide was isolated and identified using reverse phase HPLC and MS/MS fragmentation. The synthetic replicate was demonstrated to have activity against S. aureus, E. coli and C. albicans at concentrations of 8, 128 and 8 mg/L, respectively. In addition, it exhibited anti-proliferative activity against the human cancer cell lines, H460, PC3 and U251MG, but was less active against a normal human cell line (HMEC). Furthermore, a haemolysis assay was performed to assess mammalian cell cytotoxicity of Phylloseptin-PBa. This peptide contained a large proportion of α-helical domain, which may explain its antimicrobial and anticancer activities.

Antioxidant and antimicrobial effects of phenolic compounds extracts of Northeast Portugal honey.

PubMed

Estevinho, Letícia; Pereira, Ana Paula; Moreira, Leandro; Dias, Luís G; Pereira, Ermelinda

2008-12-01

Phenolic compounds of dark and clear honeys from Trás-os-Montes of Portugal were extracted with Amberlite XAD-2 and evaluated for their antioxidant and antimicrobial activities. The antioxidant effect was studied using the in vitro test capacity of scavenge the 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical and of reducing power of iron (III)/ferricyanide complex. The antimicrobial activity was screened using three Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, Staphylococcus lentus) and three Gram-negative bacteria (Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli). The results obtained from the partial identification of honey phenolic compounds by high-performance liquid chromatography with a diode array detector showed that p-hydroxibenzoic acid, cinnamic acid, naringenin, pinocembrin and chrysin are the phenolic compounds present in most of the samples analyzed. Antioxidant potential was dependent of honey extract concentration and the results showed that dark honey phenolic compounds had higher activity than the obtained from clear honey. In the biological assays, results showed that S. aureus were the most sensitive microrganisms and B. subtilis, S. lentus, K. pneumoniae and E. coli were each moderately sensitive to the antimicrobial activity of honey extracts. Nevertheless, no antimicrobial activity was observed in the test with P. aeruginosa.

Inhibition of Legionella pneumophila multiplication within human macrophages by antimicrobial agents.

PubMed Central

Vildé, J L; Dournon, E; Rajagopalan, P

1986-01-01

The activity of serial concentrations of different antimicrobial agents on the multiplication of Legionella pneumophila within human monocyte-derived macrophages was studied. The results led to the definition of a minimal extracellular concentration inhibiting intracellular multiplication (MIEC). According to the MIECs, the antimicrobial agents tested were classified in three groups: very active (MIEC less than or equal to 0.06 microgram/ml), such as erythromycin, rifampin, and pefloxacin; active (1 microgram/ml greater than or equal to MIEC greater than or equal to 0.1 microgram/ml), such as sulfamethoxazole-trimethoprim or doxycycline; and ineffective, such as cefoxitin, which was not active within macrophages at as high as 64 micrograms/ml despite a low MIC (0.2 microgram/ml) on bacterial charcoal-yeast extract agar. The activity of netilmicin was difficult to assess because of its effect on extracellular legionellae. Combinations of erythromycin with rifampin and pefloxacin with erythromycin, rifampin, doxycycline, or netilmicin showed an additive effect and no antagonism. These results obtained in a cellular model are in agreement with the efficacy of antimicrobial agents in experimental infections and in Legionnaires disease. They sustain clinical interest in the new quinolones, such as pefloxacin, and in combinations of antimicrobial agents for the treatment of Legionnaires disease. PMID:3492176

Influence of baking enzymes on antimicrobial activity of five bacteriocin-like inhibitory substances produced by lactic acid bacteria isolated from Lithuanian sourdoughs.

PubMed

Narbutaite, V; Fernandez, A; Horn, N; Juodeikiene, G; Narbad, A

2008-12-01

To evaluate the effect of four different baking enzymes on the inhibitory activity of five bacteriocin-like inhibitory substances (BLIS) produced by lactic acid bacteria (LAB) isolated from Lithuanian sourdoughs. The overlay assay and the Bioscreen methods revealed that the five BLIS exhibited an inhibitory effect against spore germination and vegetative outgrowth of Bacillus subtilis, the predominant species causing ropiness in bread. The possibility that the observed antibacterial activity of BLIS might be lost after treatment with enzymes used for baking purposes was also examined. The enzymes tested; hemicellulase, lipase, amyloglucosidase and amylase had little or no effect on the majority of the antimicrobial activities associated with the five BLIS studied. This study suggests a potential application in the sourdough baking industry for these antimicrobial producing LAB strains in the control of B. subtilis spore germination and vegetative outgrowth.

Synthesis and evaluation of hetero- and homo-dimers of ribosome-targeting antibiotics: Antimicrobial activity, in vitro inhibition of translation, and drug resistance

PubMed Central

Berkov-Zrihen, Yifat; Green, Keith D.; Labby, Kristin J.; Feldman, Mark; Garneau-Tsodikova, Sylvie; Fridman, Micha

2013-01-01

In this study, we describe the synthesis of a full set of homo- and hetero-dimers of three intact structures of different ribosome-targeting antibiotics: tobramycin, clindamycin, and chloramphenicol. Several aspects of the biological activity of the dimeric structures were evaluated including antimicrobial activity, inhibition of in vitro bacterial protein translation, and the effect of dimerization on the action of several bacterial resistance mechanisms that deactivate tobramycin and chloramphenicol. This study demonstrates that covalently linking two identical or different ribosome-targeting antibiotics may lead to (i) a broader spectrum of antimicrobial activity, (ii) improved inhibition of bacterial translation properties compared to that of the parent antibiotics, and (iii) reduction in the efficacy of some drug-modifying enzymes that confer high levels of resistance to the parent antibiotics from which the dimers were derived. PMID:23786357

Antifungal effect and action mechanism of antimicrobial peptide polybia-CP.

PubMed

Wang, Kairong; Jia, Fengjing; Dang, Wen; Zhao, Yanyan; Zhu, Ranran; Sun, Mengyang; Qiu, Shuai; An, Xiaoping; Ma, Zelin; Zhu, Yuanyuan; Yan, Jiexi; Kong, Ziqing; Yan, Wenjin; Wang, Rui

2016-01-01

The incidence of life-threatening invasive fungal infections increased significantly in recent years. However, the antifungal therapeutic options are very limited. Antimicrobial peptides are a class of potential lead chemical for the development of novel antifungal agents. Antimicrobial peptide polybia-CP was purified from the venom of the social wasp Polybia paulista. In this study, we synthesized polybia-CP and determined its antifungal effects against a series of Candidian species. Our results showed that polybia-CP has potent antifungal activity and fungicidal activity against the tested fungal cells with a proposed membrane-active action mode. In addition, polybia-CP could induce the increase of cellular reactive oxygen species production, which would attribute to its antifungal activity. In conclusion, the present study suggests that polybia-CP has potential as an antifungal agent or may offer a new strategy for antifungal therapeutic option. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

Activity of LL-37, CRAMP and antimicrobial peptide-derived compounds E2, E6 and CP26 against Mycobacterium tuberculosis.

PubMed

Rivas-Santiago, Bruno; Rivas Santiago, Cesar E; Castañeda-Delgado, Julio E; León-Contreras, Juan C; Hancock, Robert E W; Hernandez-Pando, Rogelio

2013-02-01

Tuberculosis (TB) is a major worldwide health problem in part due to the lack of development of new treatments and the emergence of new strains such as multidrug-resistant (MDR) and extensively drug-resistant strains that are threatening and impairing the control of this disease. In this study, the efficacy of natural and synthetic cationic antimicrobial (host defence) peptides that have been shown often to possess broad-spectrum antimicrobial activity was tested. The natural antimicrobial peptides human LL-37 and mouse CRAMP as well as synthetic peptides E2, E6 and CP26 were tested for their activity against Mycobacterium tuberculosis both in in vitro and in vivo models. The peptides had moderate antimicrobial activities, with minimum inhibitory concentrations ranging from 2 μg/mL to 10 μg/mL. In a virulent model of M. tuberculosis lung infection, intratracheal therapeutic application of these peptides three times a week at doses of ca. 1mg/kg led to significant 3-10-fold reductions in lung bacilli after 28-30 days of treatment. The treatments worked both against the drug-sensitive H37Rv strain and a MDR strain. These results indicate that antimicrobial peptides might constitute a novel therapy against TB. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Antimicrobial efficacy of 3 oral antiseptics containing octenidine, polyhexamethylene biguanide, or Citroxx: can chlorhexidine be replaced?

PubMed

Rohrer, Nadine; Widmer, Andreas F; Waltimo, Tuomas; Kulik, Eva M; Weiger, Roland; Filipuzzi-Jenny, Elisabeth; Walter, Clemens

2010-07-01

Use of oral antiseptics decreases the bacterial load in the oral cavity. To compare the antimicrobial activity of 3 novel oral antiseptics with that of chlorhexidine, which is considered the "gold standard" of oral hygiene. Comparative in vitro study. Four common oral microorganisms (Streptococcus sanguinis, Streptococcus mutans, Candida albicans, and Fusobacterium nucleatum) were tested under standard conditions and at different concentrations, by use of a broth dilution assay and an agar diffusion assay and by calculating the log10 reduction factor (RF). The antimicrobial activity of each antiseptic was assessed by counting the difference in bacterial densities (ie, the log10 number of colony-forming units of bacteria) before and after the disinfection process. The oral antiseptics containing octenidine (with an RF in the range of 7.1-8.24 CFU/mL) and polyhexamethylene biguanide (with an RF in the range of 7.1-8.24 CFU/mL) demonstrated antimicrobial activity comparable to that of chlorhexidine (with an RF in the range of 1.03-8.24 CFU/mL), whereas the mouth rinse containing Citroxx (Citroxx Biosciences; with an RF in the range of 0.22-1.36 CFU/mL) showed significantly weaker antimicrobial efficacy. Overall, octenidine and polyhexamethylene biguanide were more active at lower concentrations.conclusion. Oral antiseptics containing the antimicrobial agent octenidine or polyhexamethylene biguanide may be considered as potent alternatives to chlorhexidine-based preparations.

Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis.

PubMed

Ho, K Y; Tsai, C C; Chen, C P; Huang, J S; Lin, C C

2001-03-01

The antimicrobial activity of honokiol and magnolol, the main constituents of Magnolia officinalis was investigated. The antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (MIC) were determined for each compound using a twofold serial dilution assay. The results showed that honokiol and magnolol have a marked antimicrobial effect (MIC = 25 microg/mL) against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Micrococcus luteus and Bacillus subtilis, but did not show antimicrobial activity (MIC > or = 100 microg/mL) for Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa. Our results indicate that honokiol and magnolol, although less potent than tetracycline, show a significant antimicrobial activity for periodontal pathogens. Hence we suggest that honokiol and magnolol might have the potential to be an adjunct in the treatment of periodontitis. Copyright 2001 John Wiley & Sons, Ltd.

Relationship between Chemical Structure and Antimicrobial Activities of Isothiocyanates from Cruciferous Vegetables against Oral Pathogens.

PubMed

Ko, Mi-Ok; Kim, Mi-Bo; Lim, Sang-Bin

2016-12-28

We evaluated the potentials of 10 isothiocyanates (ITCs) from cruciferous vegetables and radish root hydrolysate for inhibiting the growth of oral pathogens, with an emphasis on assessing any structure-function relationship. Structural differences in ITCs impacted their antimicrobial activities against oral pathogens differently. The indolyl ITC (indol-3-carbinol) was the most potent inhibitor of the growth of oral pathogens, followed by aromatic ITCs (benzyl ITC (BITC) and phenylethyl ITC (PEITC)) and aliphatic ITCs (erucin, iberin, and sulforaphene). Sulforaphene, which is similar in structure, but has one double bond, showed higher antimicrobial activity than sulforaphane. Erucin, which has a thiol group, showed higher antimicrobial activity than sulforaphane, which has a sulfinyl group. BITC and iberin with a short chain exhibited higher antimicrobial potential than PEITC and sulforaphane with a longer chain, respectively. ITCs have strong antimicrobial activities and may be useful in the prevention and management of dental caries.

Novel natural food antimicrobials.

PubMed

Juneja, Vijay K; Dwivedi, Hari P; Yan, Xianghe

2012-01-01

Naturally occurring antimicrobial compounds could be applied as food preservatives to protect food quality and extend the shelf life of foods and beverages. These compounds are naturally produced and isolated from various sources, including plants, animals and microorganisms, in which they constitute part of host defense systems. Many naturally occurring compounds, such as nisin, plant essential oils, and natamycin, have been widely studied and are reported to be effective in their potential role as antimicrobial agents against spoilage and pathogenic microorganisms. Although some of these natural antimicrobials are commercially available and applied in food processing, their efficacy, consumer acceptance and regulation are not well defined. This manuscript reviews natural antimicrobial compounds with reference to their applications in food when applied individually or in combination with other hurdles. It also reviews the mechanism of action of selected natural antimicrobials, factors affecting their antimicrobial activities, and future prospects for use of natural antimicrobials in the food industry.

Rhanterium epapposum Oliv. essential oil: Chemical composition and antimicrobial,insect-repellent and anticholinesterase activities

USDA-ARS?s Scientific Manuscript database

Essential oils from Rhanterium epapposum Oliv. (Asteraceae) was investigated for its repellent, antimicrobial and acetyl- and butyrylcholine esterase inhibitory activities. The oil showed good repellent activity while oils demonstrated weak in antimicrobial and cholinesterase inhibitions. Terpenoids...

Antimicrobial Activity of Nanoemulsion in Combination with Cetylpyridinium Chloride in Multidrug-Resistant Acinetobacter baumannii

DTIC Science & Technology

2013-08-01

antimicrobial nanoparticles, chelating agents, and peptides . ACKNOWLEDGMENTS We thank Stephanie A. Brown and Hunter Radetsky for technical support. Funding...AUG 2013 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Antimicrobial activity of nanoemulsion in combination with...unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Antimicrobial Activity of Nanoemulsion in Combination

Antimicrobial susceptibility profiles of gram-negative bacteria causing infections collected across India during 2014-2016: Study for monitoring antimicrobial resistance trend report.

PubMed

Veeraraghavan, Balaji; Jesudason, Mark Ranjan; Prakasah, John Antony Jude; Anandan, Shalini; Sahni, Rani Diana; Pragasam, Agila Kumari; Bakthavatchalam, Yamuna Devi; Selvakumar, Rajesh Joseph; Dhole, T N; Rodrigues, Camilla; Roy, Indranil; Joshi, Sangeetha; Chaudhuri, Bhaskar Narayan; Chitnis, D S

2018-01-01

The emergence of antibiotic resistance among bacterial pathogens in the hospital and community has increased the concern to the health-care providers due to the limited treatment options. Surveillance of antimicrobial resistance (AMR) in frequently isolated bacterial pathogens causing severe infections is of great importance. The data generated will be useful for the clinicians to decide empiric therapy on the local epidemiological resistance profile of the antimicrobial agents. This study aims to monitor the distribution of bacterial pathogen and their susceptibility pattern to the commonly used antimicrobial agents. This study includes Gram-negative bacilli collected from intra-abdominal, urinary tract and respiratory tract infections during 2014-2016. Isolates were collected from seven hospitals across India. All the study isolates were characterised up to species level, and minimum inhibitory concentration was determined for a wide range of antimicrobials included in the study panel. The test results were interpreted as per standard Clinical Laboratory Standards Institute guidelines. A total of 2731 isolates of gram-negative bacteria were tested during study period. The most frequently isolated pathogens were 44% of Escherichia coli (n = 1205) followed by 25% of Klebsiella pneumoniae (n = 676) and 11% of Pseudomonas aeruginosa (n = 308). Among the antimicrobials tested, carbapenems were the most active, followed by amikacin and piperacillin/tazobactam. The rate of extended-spectrum beta-lactamase (ESBL)-positive isolates were ranged from 66%-77% in E. coli to 61%-72% in K. pneumoniae, respectively. Overall, colistin retains its activity in > 90% of the isolates tested and appear promising. Increasing rates of ESBL producers have been noted, which is alarming. Further, carbapenem resistance was also gradually increasing, which needs much attention. Overall, this study data show that carbapenems, amikacin and colistin continue to be the best agents available to treat drug-resistant infections. Thus continuous monitoring of susceptibility profile of the clinically important Gram-negative pathogens is of great importance to guide effective antimicrobial therapy.

Development and evaluation of thymol-chitosan hydrogels with antimicrobial-antioxidant activity for oral local delivery.

PubMed

Alvarez Echazú, María Inés; Olivetti, Christian Ezequiel; Anesini, Claudia; Perez, Claudio Javier; Alvarez, Gisela Solange; Desimone, Martin Federico

2017-12-01

Nowadays, the research of innovative drug delivery devices is focused on the design of multiple drug delivery systems, the prevention of drug side effects and the reduction of dosing intervals. Particularly, new mucosal delivery systems for antimicrobials, antioxidants and anti-inflammatory drugs has a growing development, regards to the avoidance of side effects, easy administration and a suitable drug concentration in the mucosa. In this work, chitosan hydrogels are evaluated as a biodegradable scaffold and as a bioactive agent carrier of an antioxidant-antimicrobial compound called thymol. Throughout the study, swelling behavior, viscoelastic properties and thermal analysis are highlighted to present its advantages for a biomedical application. Furthermore, the in vitro results obtained indicate that thymol-chitosan hydrogels are biocompatible when exposed to [3T3] fibroblasts, exhibit antimicrobial activity against Staphylococcus aureus and Streptococcus mutans for 72h and antioxidant activity for 24h. These are desirable properties for a mucosal delivery system for an antimicrobial-antioxidant dual therapy for periodontal disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Diversity and antimicrobial activity of endophytic fungi associated with the alpine plant Saussurea involucrata.

PubMed

Lv, Ya-li; Zhang, Fu-sheng; Chen, Juan; Cui, Jin-long; Xing, Yong-mei; Li, Xiang-dong; Guo, Shun-xing

2010-01-01

Endophytic fungi are rich in species diversity and may play an important role in the fitness of their host plants. This study investigated the diversity and antimicrobial potential of endophytic fungi obtained from Saussurea involucrata KAR. et KIR. A total of 49 endophytic fungi were isolated from S. involucrata and identified using morphological and molecular techniques. Extracts of fermentation broth from the 49 fungi were tested for antimicrobial activity against pathogenic microorganisms using the agar diffusion method. Forty-eight out of the 49 endophytic fungi were identified and grouped into 14 taxa. Cylindrocarpon sp. was the dominant species isolated from S. involucrata, followed by Phoma sp. and Fusarium sp. Among the 49 endophytic fungi, 9 root isolates having darkly pigmented, septate hyphae were identified as dark septate endophytic (DSE) fungus, and 12 fungi inhibited at least one test microorganism. Moreover, 5 strains showed a broader spectrum of antimicrobial activity and 4 strains displayed strong inhibition (+++) against pathogenic fungi. The results indicate that endophytic fungi isolated from S. involucrata are diverse in species and a potential source of antimicrobial agents.

Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the antimicrobial activity.

PubMed

Chen, Cynthia H; Ravishankar, Sadhana; Marchello, John; Friedman, Mendel

2013-07-01

Salmonella enterica is a predominant foodborne pathogen that causes diarrheal illness worldwide. A potential method of inhibiting pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. The objectives of this study were to investigate the influence of heat (70°C for 5 min) and subsequent cold storage (4°C up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella enterica serovar Typhimurium DT104 in ground pork and to evaluate the activity of the most effective antimicrobials (cinnamon oil and olive extract) at higher concentrations in heated ground pork. The surviving Salmonella populations in two groups (heated and unheated) of antimicrobial-treated pork were compared. Higher concentrations of the most effective compounds were then tested (cinnamon oil at 0.5 to 1.0% and olive extract at 3, 4, and 5%) against Salmonella Typhimurium in heated ground pork. Samples were stored at 4°C and taken on days 0, 3, 5, and 7 for enumeration of survivors. The heating process did not affect the activity of antimicrobials. Significant 1.3- and 3-log reductions were observed with 1.0% cinnamon oil and 5% olive extract, respectively, on day 7. The minimum concentration required to achieve . 1-log reduction in Salmonella population was 0.8% cinnamon oil or 4% olive extract. The results demonstrate the effectiveness of these antimicrobials against multidrug-resistant Salmonella Typhimurium in ground pork and their stability during heating and cold storage. The most active formulations have the potential to enhance the microbial safety of ground pork.

Genomewide Analysis of the Antimicrobial Peptides in Python bivittatus and Characterization of Cathelicidins with Potent Antimicrobial Activity and Low Cytotoxicity.

PubMed

Kim, Dayeong; Soundrarajan, Nagasundarapandian; Lee, Juyeon; Cho, Hye-Sun; Choi, Minkyeung; Cha, Se-Yeoun; Ahn, Byeongyong; Jeon, Hyoim; Le, Minh Thong; Song, Hyuk; Kim, Jin-Hoi; Park, Chankyu

2017-09-01

In this study, we sought to identify novel antimicrobial peptides (AMPs) in Python bivittatus through bioinformatic analyses of publicly available genome information and experimental validation. In our analysis of the python genome, we identified 29 AMP-related candidate sequences. Of these, we selected five cathelicidin-like sequences and subjected them to further in silico analyses. The results showed that these sequences likely have antimicrobial activity. The sequences were named Pb-CATH1 to Pb-CATH5 according to their sequence similarity to previously reported snake cathelicidins. We predicted their molecular structure and then chemically synthesized the mature peptide for three putative cathelicidins and subjected them to biological activity tests. Interestingly, all three peptides showed potent antimicrobial effects against Gram-negative bacteria but very weak activity against Gram-positive bacteria. Remarkably, ΔPb-CATH4 showed potent activity against antibiotic-resistant clinical isolates and also was observed to possess very low hemolytic activity and cytotoxicity. ΔPb-CATH4 also showed considerable serum stability. Electron microscopic analysis indicated that ΔPb-CATH4 exerts its effects via toroidal pore preformation. Structural comparison of the cathelicidins identified in this study to previously reported ones revealed that these Pb-CATHs are representatives of a new group of reptilian cathelicidins lacking the acidic connecting domain. Furthermore, Pb-CATH4 possesses a completely different mature peptide sequence from those of previously described reptilian cathelicidins. These new AMPs may be candidates for the development of alternatives to or complements of antibiotics to control multidrug-resistant pathogens. Copyright © 2017 American Society for Microbiology.

Genomewide Analysis of the Antimicrobial Peptides in Python bivittatus and Characterization of Cathelicidins with Potent Antimicrobial Activity and Low Cytotoxicity

PubMed Central

Kim, Dayeong; Soundrarajan, Nagasundarapandian; Lee, Juyeon; Cho, Hye-sun; Choi, Minkyeung; Cha, Se-Yeoun; Ahn, Byeongyong; Jeon, Hyoim; Le, Minh Thong; Song, Hyuk; Kim, Jin-Hoi

2017-01-01

ABSTRACT In this study, we sought to identify novel antimicrobial peptides (AMPs) in Python bivittatus through bioinformatic analyses of publicly available genome information and experimental validation. In our analysis of the python genome, we identified 29 AMP-related candidate sequences. Of these, we selected five cathelicidin-like sequences and subjected them to further in silico analyses. The results showed that these sequences likely have antimicrobial activity. The sequences were named Pb-CATH1 to Pb-CATH5 according to their sequence similarity to previously reported snake cathelicidins. We predicted their molecular structure and then chemically synthesized the mature peptide for three putative cathelicidins and subjected them to biological activity tests. Interestingly, all three peptides showed potent antimicrobial effects against Gram-negative bacteria but very weak activity against Gram-positive bacteria. Remarkably, ΔPb-CATH4 showed potent activity against antibiotic-resistant clinical isolates and also was observed to possess very low hemolytic activity and cytotoxicity. ΔPb-CATH4 also showed considerable serum stability. Electron microscopic analysis indicated that ΔPb-CATH4 exerts its effects via toroidal pore preformation. Structural comparison of the cathelicidins identified in this study to previously reported ones revealed that these Pb-CATHs are representatives of a new group of reptilian cathelicidins lacking the acidic connecting domain. Furthermore, Pb-CATH4 possesses a completely different mature peptide sequence from those of previously described reptilian cathelicidins. These new AMPs may be candidates for the development of alternatives to or complements of antibiotics to control multidrug-resistant pathogens. PMID:28630199

Enzymatic, antimicrobial and toxicity studies of the aqueous extract of Ananas comosus (pineapple) crown leaf.

PubMed

Dutta, Sangita; Bhattacharyya, Debasish

2013-11-25

Various parts of the plant pineapple (Ananas comosus) are used in traditional medicine worldwide for treatment of a number of diseases and disorders. In folk medicine, pineapple leaf extract was used as an antimicrobial, vermicide, purgative, emmenagoogue, abortifacient, anti-oedema and anti-inflammatory agent. Compared to the fruit and stem extracts of pineapple, information about its leaf extract is limited. The potential of pineapple crown leaf extract as an ethno-medicine has been evaluated in terms of its enzymatic activities related to wound healing, antimicrobial property and toxicity. Major protein components of the extract were revealed by 2-D gel electrophoresis followed by MS/MS analysis. Zymography, DQ-gelatin assay were performed to demonstrate proteolytic, fibrinolytic, gelatinase and collagenase activities. DNase and RNase activities were revealed from agarose gel electrophoresis. Antimicrobial activity was evaluated spectrophotometrically from growth inhibition. Sprague-Dawley rat model was used to measure acute and sub-acute toxicity of the extract by analyzing blood markers. The extract contains several proteins that were clustered under native condition. Proteomic studies indicated presence of fruit bromelain as major protein constituent of the extract. It showed nonspecific protease activity, gelatinolytic, collagenase, fibrinolytic, acid and alkaline phosphatase, peroxidase, DNase and RNase activities along with considerable anti-microbial property. The leaf extract did not induce any toxicity in rats after oral administration of acute and sub-acute doses. Pineapple leaf extract is nontoxic, contains enzymes related to damage tissue repairing, wound healing and possibly prevents secondary infections from microbial organisms. © 2013 Elsevier Ireland Ltd. All rights reserved.

Biological activity of lactoferrin-functionalized biomimetic hydroxyapatite nanocrystals

PubMed Central

Nocerino, Nunzia; Fulgione, Andrea; Iannaccone, Marco; Tomasetta, Laura; Ianniello, Flora; Martora, Francesca; Lelli, Marco; Roveri, Norberto; Capuano, Federico; Capparelli, Rosanna

2014-01-01

The emergence of bacterial strains resistant to antibiotics is a general public health problem. Progress in developing new molecules with antimicrobial properties has been made. In this study, we evaluated the biological activity of a hybrid nanocomposite composed of synthetic biomimetic hydroxyapatite surface-functionalized by lactoferrin (LF-HA). We evaluated the antimicrobial, anti-inflammatory, and antioxidant properties of LF-HA and found that the composite was active against both Gram-positive and Gram-negative bacteria, and that it modulated proinflammatory and anti-inflammatory responses and enhanced antioxidant properties as compared with LF alone. These results indicate the possibility of using LF-HA as an antimicrobial system and biomimetic hydroxyapatite as a candidate for innovative biomedical applications. PMID:24623976

N-terminal amphipathic helix as a trigger of hemolytic activity in antimicrobial peptides: a case study in latarcins.

PubMed

Polyansky, Anton A; Vassilevski, Alexander A; Volynsky, Pavel E; Vorontsova, Olga V; Samsonova, Olga V; Egorova, Natalya S; Krylov, Nicolay A; Feofanov, Alexei V; Arseniev, Alexander S; Grishin, Eugene V; Efremov, Roman G

2009-07-21

In silico structural analyses of sets of alpha-helical antimicrobial peptides (AMPs) are performed. Differences between hemolytic and non-hemolytic AMPs are revealed in organization of their N-terminal region. A parameter related to hydrophobicity of the N-terminal part is proposed as a measure of the peptide propensity to exhibit hemolytic and other unwanted cytotoxic activities. Based on the information acquired, a rational approach for selective removal of these properties in AMPs is suggested. A proof of concept is gained through engineering specific mutations that resulted in elimination of the hemolytic activity of AMPs (latarcins) while leaving the beneficial antimicrobial effect intact.

Effect of active packaging incorporated with triclosan on bacteria adhesion.

PubMed

Camilloto, Geany P; Pires, Ana Clarissa S; Soares, Nilda de Fátima F; Araújo, Emiliane A; Andrade, Nélio J; Ferreira, Sukarno O

2010-10-01

Antimicrobial polyethylene and cellulose based films incorporated with triclosan were studied. The antimicrobial efficacy, the hydrophobicity, microscopic and the mechanical characteristics of the films, as well free energy of adhesion between bacteria and antimicrobial films were evaluated. It was observed that both polyethylene and cellulose based films incorporated with the antimicrobial were homogeneous. Furthermore, the addition of triclosan did not affect mechanical characteristics of the films (P > 0.05). However, triclosan incorporated into polyethylene films reduced its hydrophobicity while antimicrobial cellulose based films became more hydrophobic. The adhesion was thermodynamically favorable between tested bacteria and polyethylene films. On the other hand, the adhesion to triclosan cellulose based film was thermodynamically unfavorable to Staphylococcus aureus and Escherichia coli and favorable to Listeria innocua and Pseudomonas aeruginosa. Polyethylene and cellulose based films showed inhibitory effect against S. aureus and E. coli, being the inhibition halo higher for polyethylene films. This study improves the knowledge about antimicrobial films.

Study of sporadical properties of crosslinked polyelectrolyte multilayers

NASA Astrophysics Data System (ADS)

Balu, Deebika

Polyelectrolyte multilayers (PEM) have become a highly studied class of materials due to the range of their applicability in many areas of research, including biology, chemistry and materials science. Recent advances in surface coatings have enabled modification of PEM surfaces to provide desirable properties such as controlled release, super-hydrophobicity, biocompatibility, antifouling and antibacterial properties. In the past decade, antimicrobial PEM coatings have been investigated as a safer alternative to the traditional disinfection methods that usually involve application of hazardous chemicals onto the surface to be cleaned. These antimicrobial coatings could be applied to common surfaces prone to colonization of bacteria (such as bench tops, faucet handles, etc) to supplement routine sanitization protocols by providing sustained antimicrobial activity. Vegetative bacteria (such as Escherichia coli) are more susceptible to antimicrobial agents than bacterial species that form spores. Hence, the antimicrobial activity of PEM coatings fabricated using Layer by Layer (LbL) technique were assayed using Bacillus anthracis spores (Sterne strain). In this thesis, the sporicidal effect of various polyelectrolyte multilayer coatings containing cross-linked polymers immersed in bleach have been evaluated as potential augmentation to existing disinfection methods.

Antimicrobial Peptides of Meat Origin - An In silico and In vitro Analysis.

PubMed

Keska, Paulina; Stadnik, Joanna

2017-01-01

The aim of this study was to evaluate the antimicrobial activity of meat protein-derived peptides against selected Gram-positive and Gram-negative bacteria. The in silico and in vitro approach was combined to determine the potency of antimicrobial peptides derived from pig (Sus scrofa) and cow (Bos taurus) proteins. The in silico studies consisted of an analysis of the amino acid composition of peptides obtained from the CAMPR database, their molecular weight and other physicochemical properties (isoelectric point, molar extinction coefficient, instability index, aliphatic index, hydropathy index and net charge). The degree of similarity was estimated between the antimicrobial peptide sequences derived from the slaughtered animals and the main meat proteins. Antimicrobial activity of peptides isolated from dry-cured meat products was analysed (in vitro) against two strains of pathogenic bacteria using the disc diffusion method. There was no evidence of growthinhibitory properties of peptides isolated from dry-cured meat products against Escherichia coli K12 ATCC 10798 and Staphylococcus aureus ATCC 25923. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Evaluation of anti-plaque microbial activity of Azadirachta indica (neem oil) in vitro: A pilot study.

PubMed

Elavarasu, Sugumari; Abinaya, P; Elanchezhiyan, S; Thangakumaran; Vennila, K; Naziya, K B

2012-08-01

Probably microbial plaque is the main etiology for periodontal tissue inflammation. Various chemical agents have been evaluated over the years with respect to their antimicrobial effects in the oral cavity. However, all are associated with side effects that prohibit regular long-term use. Therefore, the effectiveness of Azadirachta indica (neem) against plaque formation is considered to be vital, with lesser side effects. The aim of the present study is to evaluate and prove the antimicrobial activity of neem using plaque samples. Culture was prepared using brain heart infusion broth reagent. Dental plaque samples were used for that. Kirby-Bauer antimicrobial susceptibility test procedure was carried away with the sample. Neem oil was kept in the agar plate with culture and the diameter of inhibition zones was calculated. Results showed inhibition zones on the agar plate around neem oil. Study shows definite antiplaque activity of neem oil.

Antimicrobial properties of analgesic kyotorphin peptides unraveled through atomic force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ribeiro, Marta M.B.; Franquelim, Henri G.; Torcato, Ines M.

Highlights: Black-Right-Pointing-Pointer New kyotorphin derivatives have antimicrobial properties against S. aureus. Black-Right-Pointing-Pointer Atomic force microscopy show membrane disturbing effects of KTP-NH{sub 2} and IbKTP-NH{sub 2}. Black-Right-Pointing-Pointer None of the KTP derivatives are hemolytic. Black-Right-Pointing-Pointer The minimal peptidic sequence with antimicrobial activity is Tyr-Arg, if amidated. -- Abstract: Antimicrobial peptides (AMPs) are promising candidates as alternatives to conventional antibiotics for the treatment of resistant pathogens. In the last decades, new AMPs have been found from the cleavage of intact proteins with no antibacterial activity themselves. Bovine hemoglobin hydrolysis, for instance, results in AMPs and the minimal antimicrobial peptide sequence was definedmore » as Tyr-Arg plus a positively charged amino acid residue. The Tyr-Arg dipeptide alone, known as kyotorphin (KTP), is an endogenous analgesic neuropeptide but has no antimicrobial activity itself. In previous studies new KTP derivatives combining C-terminal amidation and Ibuprofen (Ib) - KTP-NH{sub 2}, IbKTP, IbKTP-NH{sub 2} - were designed in order to improve KTP brain targeting. Those modifications succeeded in enhancing peptide-cell membrane affinity towards fluid anionic lipids and higher analgesic activity after systemic injection resulted therefrom. Here, we investigated if this affinity for anionic lipid membranes also translates into antimicrobial activity because bacteria have anionic membranes. Atomic force microscopy revealed that KTP derivatives perturbed Staphylococcus aureus membrane structure by inducing membrane blebbing, disruption and lysis. In addition, these peptides bind to red blood cells but are non-hemolytic. From the KTP derivatives tested, amidated KTP proves to be the most active antibacterial agent. The combination of analgesia and antibacterial activities with absence of toxicity is highly appealing from the clinical point of view and broadens the therapeutic potential and application of kyotorphin peptides.« less

Antimicrobial activity of a 48-kDa protease (AMP48) from Artocarpus heterophyllus latex.

PubMed

Siritapetawee, J; Thammasirirak, S; Samosornsuk, W

2012-01-01

Artocarpus heterophyllus (jackfruit) is a latex producing plant. Plant latex is produced from secretory cells and contains many intergradients. It also has been used in folk medicine. This study aimed to purify and characterize the biological activities of a protease from jackfruit latex. A protease was isolated and purified from crude latex of a jackfruit tree by acid precipitation and ion exchange chromatography. The proteolytic activities of protein were tested using gelatin- and casein-zymography. The molecular weight and isoelectric point (pl) of protein were analysed by SDS/12.5% PAGE and 2D-PAGE, respectively. Antimicrobial activity of protein was analysed by broth microdilution method. In addition, the antibacterial activity of protein against Pseudomonas aeruginosa ATCC 27853 was observed and measured using atomic force microscopy (AFM) technique. The purified protein contained protease activity by digesting gelatin- and casein-substrates. The protease was designated as antimicrobial protease-48 kDa or AMP48 due to its molecular mass on SDS-PAGE was approximately 48 kDa. The isoelectric point (pl) of AMP48 was approximately 4.2. In addition, AMP48 contained antimicrobial activities by it could inhibit the growths of Pseudomonas aeruginosa ATCC 27853 and clinical isolated Candida albicans at minimum inhibitory concentration (MIC) 2.2 mg/ml and Minimum microbicidal concentration (MMC) 8.8 mg/ml. AFM image also supported the antimicrobial activities of AMP48 by the treated bacterial morphology and size were altered from normal.

Evaluation of wound healing, anti-microbial and antioxidant potential of Pongamia pinnata in wistar rats.

PubMed

Dwivedi, Deepak; Dwivedi, Mona; Malviya, Sourabh; Singh, Vinod

2017-01-01

To investigate wound healing, antimicrobial and antioxidant activity of leaf extract of Pongamia Pinnata . Methanolic extracts of P. pinnata leaf were studied for wound healing efficiency, and was assessed by the rate of wound contraction, tensile strength, breaking strength, hydroxyproline and hexosamine content, along with its effect on pro-inflammatory and anti-inflammatory cytokines was assessed using excision and incision model of wound repair in Wistar rats. Antimicrobial activity against ten microorganisms was also assessed. In vivo antioxidant activity was performed to understand the mechanism of wound healing potency. The results indicated that P. pinnata extract has potent wound healing capacity as evident from the wound contraction and increased tensile strength. Hydroxyproline and hexosamine expression were also well correlated with the healing pattern observed. extract exhibited significant antimicrobial activity, Staphylococcus aureus, Staphylococcus pyogenes, Staphylococcus epidermidis, Escherichia coli, Micrococcus luteus, Enterobacter aerogenes, Salmonella typhi, Pseudomonas aeruginosa, Candida albicans, Aspergillus niger also indicate that P. pinnata posses potent antioxidant activity by inhibition lipid peroxidation, reduce glutathione, superoxide dismutase level and increases catalase activity. During early wound healing phase TNF-α and IL-6 level were found to be up-regulated by P. pinnata treatment. Increased wound contraction and tensile strength, augmented hydroxyproline and hexosamine content, antioxidative activity and moderate antimicrobial activity support the early wound healing exhibited by P. pinnata . Induction in cytokine production may be one of the mechanisms in accelerating the wound healing. Results suggest that P. pinnata may be useful in tropical management of wound healing.

Cationic peptides from peptic hydrolysates of rice endosperm protein exhibit antimicrobial, LPS-neutralizing, and angiogenic activities.

PubMed

Taniguchi, Masayuki; Kawabe, Junya; Toyoda, Ryu; Namae, Toshiki; Ochiai, Akihito; Saitoh, Eiichi; Tanaka, Takaaki

2017-11-01

In this study, we hydrolyzed rice endosperm protein (REP) with pepsin and generated 20 fractions containing multifunctional cationic peptides with varying isoelectric point (pI) values using ampholyte-free isoelectric focusing (autofocusing). Subsequently, we determined antimicrobial activities of each fraction against the pathogens Prophyromonas gingivalis, Propionibacterium acnes, Streptocossus mutans, and Candida albicans. Fractions 18, 19, and 20 had pI values greater than 12 and exhibited antimicrobial activity against P. gingivalis, P. acnes, and C. albicans, but not against S. mutans. In further experiments, we purified and identified cationic peptides from fractions 18, 19, and 20 using reversed-phase high-performance liquid chromatography and matrix-assisted laser/desorption ionization-time-of-flight mass spectroscopy. We also chemically synthesized five identified peptides (RSVSKSR, RRVIEPR, ERFQPMFRRPG, RVRQNIDNPNRADTYNPRAG, and VVRRVIEPRGLL) with pI values greater than 10.5 and evaluated antimicrobial, lipopolysaccharide (LPS)-neutralizing, and angiogenic activities. Among these synthetic peptides, only VVRRVIEPRGLL exhibited antimicrobial activity against P. gingivalis, with an IC 50 value of 87μM. However, all five cationic peptides exhibited LPS-neutralizing and angiogenic activities with little or no hemolytic activity against mammalian red blood cells at functional concentrations. These present data show dual or multiple functions of the five identified cationic peptides with little or no hemolytic activity. Therefore, fractions containing cationic peptides from REP hydrolysates have the potential to be used as dietary supplements and functional ingredients in food products. Copyright © 2017 Elsevier Inc. All rights reserved.

The impact of plant-based antimicrobials on sensory properties of organic leafy greens

USDA-ARS?s Scientific Manuscript database

Plant extracts and essential oils are well known for their antibacterial activity. However, studies concerning their effect on the organoleptic properties of treated foods are limited. The objective was to study the sensory attributes of organic leafy greens treated with plant antimicrobials and ide...

Efficient synthesis, structural characterization and anti-microbial activity of chiral aryl boronate esters of 1,2-O-isopropylidene-α-D-xylofuranose.

PubMed

Trivedi, Rajiv; Rami Reddy, E; Kiran Kumar, Ch; Sridhar, B; Pranay Kumar, K; Srinivasa Rao, M

2011-07-01

A simple and efficient synthetic approach toward a series of chiral aryl boronate esters, starting from D-xylose, as anti-microbial agents, is described herein. Minimum inhibitory concentration and zone of inhibition revealed that these derivatives exhibit potent anti-bacterial and anti-fungal properties. Herein, we report the first anti-microbial activity of this class of compounds. All products have been characterized by NMR ((1)H, (13)C and (11)B), IR, elemental and mass spectral study. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain and aloe vera (all in gel formulation), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis: An in vitro study

PubMed Central

Bhardwaj, Anuj; Ballal, Suma; Velmurugan, Natanasabapathy

2012-01-01

Aim: A comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain, and aloe vera (all in gel formulations), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis—an in vitro study. Materials and Methods: The antimicrobial efficacy was assessed in vitro using dentin shavings collected at 2 depths of 200 and 400 μm. The total colony forming units at the end of 1, 3, and 5 days were assessed. Results: The overall percentage inhibition of bacterial growth (200 and 400 μm depth) was 100% with chlorhexidine gel. This was followed by M. citrifolia gel (86.02%), which showed better antimicrobial efficacy as compared with aloe vera gel (78.9%), papain gel (67.3%), and calcium hydroxide (64.3%). There was no statistical difference between data at 200 and 400 μm depth. Conclusion: Chlorhexidine gel showed the maximum antimicrobial activity against E. faecalis, whereas calcium hydroxide showed the least. Among the natural intracanal medicaments, M. citrifolia gel consistently exhibited good inhibition up to the 5th day followed by aloe vera gel and papain gel. PMID:22876022

Design of Embedded-Hybrid Antimicrobial Peptides with Enhanced Cell Selectivity and Anti-Biofilm Activity

PubMed Central

Xu, Wei; Zhu, Xin; Tan, Tingting; Li, Weizhong; Shan, Anshan

2014-01-01

Antimicrobial peptides have attracted considerable attention because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance which is the most common source of failure in bacterial infection treatment along with biofilms. The method to design hybrid peptide integrating different functional domains of peptides has many advantages. In this study, we designed an embedded-hybrid peptide R-FV-I16 by replacing a functional defective sequence RR7 with the anti-biofilm sequence FV7 embedded in the middle position of peptide RI16. The results demonstrated that the synthetic hybrid the peptide R-FV-I16 had potent antimicrobial activity over a wide range of Gram-negative and Gram-positive bacteria, as well as anti-biofilm activity. More importantly, R-FV-I16 showed lower hemolytic activity and cytotoxicity. Fluorescent assays demonstrated that R-FV-I16 depolarized the outer and the inner bacterial membranes, while scanning electron microscopy and transmission electron microscopy further indicated that this peptide killed bacterial cells by disrupting the cell membrane, thereby damaging membrane integrity. Results from SEM also provided evidence that R-FV-I16 inherited anti-biofilm activity from the functional peptide sequence FV7. Embedded-hybrid peptides could provide a new pattern for combining different functional domains and showing an effective avenue to screen for novel antimicrobial agents. PMID:24945359

Antimicrobial activity of extracts from macroalgae Ulva lactuca against clinically important Staphylococci is impacted by lunar phase of macroalgae harvest.

PubMed

Deveau, A M; Miller-Hope, Z; Lloyd, E; Williams, B S; Bolduc, C; Meader, J M; Weiss, F; Burkholder, K M

2016-05-01

Staphylococcus aureus is a common human bacterial pathogen that causes skin and soft tissue infections. Methicillin-resistant Staph. aureus (MRSA) are increasingly drug-resistant, and thus there is great need for new therapeutics to treat Staph. aureus infections. Attention has focused on potential utility of natural products, such as extracts of marine macroalgae, as a source of novel antimicrobial compounds. The green macroalgae Ulva lactuca produces compounds inhibitory to human pathogens, although the effectiveness of U. lactuca extracts against clinically relevant strains of Staph. aureus is poorly understood. In addition, macroalgae produce secondary metabolites that may be influenced by exogenous factors including lunar phase, but whether lunar phase affects U. lactuca antimicrobial capacity is unknown. We sought to evaluate the antibacterial properties of U. lactuca extracts against medically important Staphylococci, and to determine the effect of lunar phase on antimicrobial activity. We report that U. lactuca methanolic extracts inhibit a range of Staphylococci, and that lunar phase of macrolagae harvest significantly impacts antimicrobial activity, suggesting that antimicrobial properties can be maximized by manipulating time of algal harvest. These findings provide useful parameters for future studies aimed at isolating and characterizing U. lactuca anti-Staphylococcal agents. The growing prevalence of antibiotic-resistant human pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) has intensified efforts towards discovery and development of novel therapeutics. Marine macroalgae like Ulva lactuca are increasingly recognized as potential sources of antimicrobials, but the efficacy of U. lactuca extracts against common, virulent strains of Staph. aureus is poorly understood. We demonstrate that U. lactuca methanolic extracts inhibit a variety of clinically relevant Staphylococcus strains, and that the antimicrobial activity can be maximized by optimizing time of algal harvest. These findings provide potentially useful parameters for future work of isolating and identifying novel antimicrobial agents from macroalgae. © 2016 The Society for Applied Microbiology.

Antimicrobial activity of some Pacific Northwest woods against anaerobic bacteria and yeast.

PubMed

Johnston, W H; Karchesy, J J; Constantine, G H; Craig, A M

2001-11-01

Extracts of woods commonly used for animal bedding were tested for antimicrobial activity. Essential oils from Alaska cedar (Chamaecyparis nootkatensis), western juniper (Juniperus occidentalis) and old growth Douglas fir (Pseudotsuga menziesii) as well as methanol extracts of wood from these trees plus western red cedar (Thuja plicata) and ponderosa pine (Pinus ponderosa) were tested for antimicrobial activity against anaerobic bacteria and yeast. The test microbes included Fusobacterium necrophorum, Clostridium perfringens, Actinomyces bovis and Candida albicans which are common to foot diseases and other infections in animals. The essential oils and methanol extracts were tested using a standardized broth assay. Only extracts of Alaska cedar and western juniper showed significant antimicrobial activity against each of the microbes tested. The essential oil of Douglas fir did show antimicrobial activity against A. bovis at the concentrations tested. The methanol extracts of the heartwood of Douglas fir and the sapwood of ponderosa pine showed no antimicrobial activity. The major chemical components of western juniper (cedrol and alpha- and beta-cedrene) and Alaska cedar (nootkatin) were also tested. In western juniper, alpha- and beta-cedrene were found to be active components. Nootkatin showed activity only against C. albicans. The inhibitory activity in Alaska cedar oil was high enough to justify further efforts to define the other chemical components responsible for the antimicrobial activity. Copyright 2001 John Wiley & Sons, Ltd.

Antibacterial and antifungal activities of some Mexican medicinal plants.

PubMed

Ruiz-Bustos, E; Velazquez, C; Garibay-Escobar, A; García, Z; Plascencia-Jatomea, M; Cortez-Rocha, M O; Hernandez-Martínez, J; Robles-Zepeda, R E

2009-12-01

In Mexico about 4,000 plant species have some medicinal use. The aim of this work was to evaluate the antimicrobial activity of six Mexican medicinal plants against fungi and Gram-positive and Gram-negative bacteria. Methanolic extracts were prepared from the Mexican medicinal plants Amphypteringium adstrigens, Castella tortuosa, Coutarea latiflora, Ibervillea sonorae, Jatropha cuneata, and Selaginella lepidophylla. The antibacterial and antifungal activities of the plants were determined by the broth microdilution method and the radial growth inhibition assay, respectively. All Mexican plants tested showed antimicrobial activity. Among the six plant extracts analyzed, J. cuneata showed the highest growth-inhibitory activity against fungi, Gram-positive and Gram-negative bacteria (J. cuneata > A. adstrigens > C. latiflora > C. tortuosa > I. sonorae approximately S. lepidophylla). Shigella flexneri and Staphylococcus aureus were the most susceptible bacteria to plant extracts. Complete inhibition of S. flexneri growth was observed with J. cuneata methanolic extract at 90 microg/mL. This plant extract also showed the strongest antifungal activity against Fusarium verticillioides and Aspergillus niger. Our data suggest that the medicinal plants tested have important antimicrobial properties. This is the first report describing the antimicrobial activities of several of the Mexican medicinal plants used in this study.

D-amino acid substitution enhances the stability of antimicrobial peptide polybia-CP.

PubMed

Jia, Fengjing; Wang, Jiayi; Peng, Jinxiu; Zhao, Ping; Kong, Ziqing; Wang, Kairong; Yan, Wenjin; Wang, Rui

2017-10-01

With the increasing emergence of resistant microbes toward conventional antimicrobial agents, there is an urgent need for the development of antimicrobial agents with novel action mode. Antimicrobial peptides (AMPs) are believed to be one kind of ideal alternatives. However, AMPs can be easily degraded by protease, which limited their therapeutic use. In the present study, D-amino acid substitution strategy was employed to enhance the stability of polybia-CP. We investigated the stability of peptides against the degradation of trypsin and chymotrypsin by determining the antimicrobial activity or determining the HPLC profile of peptides after incubation with proteases. Our results showed that both the all D-amino acid derivative (D-CP) and partial D-lysine substitution derivative (D-lys-CP) have an improved stability against trypsin and chymotrypsin. Although D-CP takes left-hand α-helical conformation and D-lys-CP loses some α-helical content, both of the D-amino acid-substituted derivatives maintain their parental peptides' membrane active action mode. In addition, D-lys-CP showed a slight weaker antimicrobial activity than polybia-CP, but the hemolytic activity decreased greatly. These results suggest that D-CP and D-lys-CP can offer strategy to improve the property of AMPs and may be leading compounds for the development of novel antimicrobial agents. © The Author 2017. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Antimicrobial Activities of Three Medicinal Plants and Investigation of Flavonoids of Tripleurospermum disciforme.

PubMed

Tofighi, Zahra; Molazem, Maryam; Doostdar, Behnaz; Taban, Parisa; Shahverdi, Ahmad Reza; Samadi, Nasrin; Yassa, Narguess

2015-01-01

Rosa damascena, Tripleurospermum disciforme and Securigera securidaca were used as disinfectant agents and for treatment of some disease in folk medicine of Iran. The antimicrobial effects of different fractions of seeds extract of S. securidaca, petals extract of R. damascena and aerial parts extract of T. disciforme were examined against some gram positive, gram negative and fungi by cup plate diffusion method. The petroleum ether and chloroform fractions of S. securidaca showed antibacterial activities against Staphylococcus aureus and Pseudomonas aeruginosa, while its methanol fraction had no antibacterial effects. R. damascena petals extract demonstrated antibacterial activities against Bacillus cereus, Staphylococcus epidermidis, S. aureus and Pseudomonas aeruginosa. T. disciforme aerial parts extract exhibited antimicrobial effects only against S. aureus and S. epidermidis. None of the fractions had any antifungal activities. Therefore, present study confirmed utility of these plants as disinfectant agents. Six flavonoids were isolated from T. disciforme: Luteolin, Quercetin-7-O-glucoside, Kaempferol, Kaempferol-7-O-glucoside, Apigenin and Apigenin-7-O-glucoside. The flavonoids and the antimicrobial activity of T. disciforme are reported for the first time.

Antimicrobial Activities of Three Medicinal Plants and Investigation of Flavonoids of Tripleurospermum disciforme

PubMed Central

Tofighi, Zahra; Molazem, Maryam; Doostdar, Behnaz; Taban, Parisa; Shahverdi, Ahmad Reza; Samadi, Nasrin; Yassa, Narguess

2015-01-01

Rosa damascena, Tripleurospermum disciforme and Securigera securidaca were used as disinfectant agents and for treatment of some disease in folk medicine of Iran. The antimicrobial effects of different fractions of seeds extract of S. securidaca, petals extract of R. damascena and aerial parts extract of T. disciforme were examined against some gram positive, gram negative and fungi by cup plate diffusion method. The petroleum ether and chloroform fractions of S. securidaca showed antibacterial activities against Staphylococcus aureus and Pseudomonas aeruginosa, while its methanol fraction had no antibacterial effects. R. damascena petals extract demonstrated antibacterial activities against Bacillus cereus, Staphylococcus epidermidis, S. aureus and Pseudomonas aeruginosa. T. disciforme aerial parts extract exhibited antimicrobial effects only against S. aureus and S. epidermidis. None of the fractions had any antifungal activities. Therefore, present study confirmed utility of these plants as disinfectant agents. Six flavonoids were isolated from T. disciforme: Luteolin, Quercetin-7-O-glucoside, Kaempferol, Kaempferol-7-O-glucoside, Apigenin and Apigenin-7-O-glucoside. The flavonoids and the antimicrobial activity of T. disciforme are reported for the first time. PMID:25561928

Can disc diffusion susceptibility tests assess the antimicrobial activity of engineered nanoparticles?

NASA Astrophysics Data System (ADS)

Kourmouli, Angeliki; Valenti, Marco; van Rijn, Erwin; Beaumont, Hubertus J. E.; Kalantzi, Olga-Ioanna; Schmidt-Ott, Andreas; Biskos, George

2018-03-01

The use of disc diffusion susceptibility tests to determine the antibacterial activity of engineered nanoparticles (ENPs) is questionable because their low diffusivity practically prevents them from penetrating through the culture media. In this study, we investigate the ability of such a test, namely the Kirby-Bauer disc diffusion test, to determine the antimicrobial activity of Au and Ag ENPs having diameters from 10 to 40 nm on Escherichia coli cultures. As anticipated, the tests did not show any antibacterial effects of Au nanoparticles (NPs) as a result of their negligible diffusivity through the culture media. Ag NPs on the other hand exhibited a strong antimicrobial activity that was independent of their size. Considering that Ag, in contrast to Au, dissolves upon oxidation and dilution in aqueous solutions, the apparent antibacterial behavior of Ag NPs is attributed to the ions they release. The Kirby-Bauer method, and other similar tests, can therefore be employed to probe the antimicrobial activity of ENPs related to their ability to release ions rather than to their unique size-dependent properties. [Figure not available: see fulltext.

Antioxidant and Antimicrobial Activities of Quinoa (Chenopodium quinoa Willd.) Seeds Cultivated in Korea

PubMed Central

Park, Jin Hwa; Lee, Yun Jin; Kim, Yeon Ho; Yoon, Ki Sun

2017-01-01

The objective of this study was to investigate the antioxidant and antimicrobial properties of quinoa cultivated in Korea and to compare it with imported quinoa from the USA and Peru. The highest amount of total flavonoid contents (TFC) with 20.91 mg quercetin equivalents/100 g was measured in quinoa seed extract cultivated in Korea, while the total phenolic contents (TPC) were significantly higher in quinoa from the USA (16.28 mg gallic acid equivalents/100 g). In addition, quinoa extracts cultivated in Korea displayed a superior antioxidant ability in both, ferric reducing antioxidant power and 1,1-diphenyl-2-picrylhydrazyl values. There was a high correlation between TFC and antioxidant activity and a low correlation between TPC and antioxidant activity. The antimicrobial activity of the quinoa extracts was determined using a disc diffusion assay and optical density method. In both assays, the quinoa seed extracts did not have strong antimicrobial activity against foodborne bacteria, including Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Escherichia coli, Salmonella Typhimurium, and Campylobacter jejuni. PMID:29043217

Antimicrobial compounds in tears.

PubMed

McDermott, Alison M

2013-12-01

The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. Copyright © 2013 Elsevier Ltd. All rights reserved.

Alternative Hand Contamination Technique To Compare the Activities of Antimicrobial and Nonantimicrobial Soaps under Different Test Conditions▿

PubMed Central

Fuls, Janice L.; Rodgers, Nancy D.; Fischler, George E.; Howard, Jeanne M.; Patel, Monica; Weidner, Patrick L.; Duran, Melani H.

2008-01-01

Antimicrobial hand soaps provide a greater bacterial reduction than nonantimicrobial soaps. However, the link between greater bacterial reduction and a reduction of disease has not been definitively demonstrated. Confounding factors, such as compliance, soap volume, and wash time, may all influence the outcomes of studies. The aim of this work was to examine the effects of wash time and soap volume on the relative activities and the subsequent transfer of bacteria to inanimate objects for antimicrobial and nonantimicrobial soaps. Increasing the wash time from 15 to 30 seconds increased reduction of Shigella flexneri from 2.90 to 3.33 log10 counts (P = 0.086) for the antimicrobial soap, while nonantimicrobial soap achieved reductions of 1.72 and 1.67 log10 counts (P > 0.6). Increasing soap volume increased bacterial reductions for both the antimicrobial and the nonantimicrobial soaps. When the soap volume was normalized based on weight (∼3 g), nonantimicrobial soap reduced Serratia marcescens by 1.08 log10 counts, compared to the 3.83-log10 reduction caused by the antimicrobial soap (P < 0.001). The transfer of Escherichia coli to plastic balls following a 15-second hand wash with antimicrobial soap resulted in a bacterial recovery of 2.49 log10 counts, compared to the 4.22-log10 (P < 0.001) bacterial recovery on balls handled by hands washed with nonantimicrobial soap. This indicates that nonantimicrobial soap was less active and that the effectiveness of antimicrobial soaps can be improved with longer wash time and greater soap volume. The transfer of bacteria to objects was significantly reduced due to greater reduction in bacteria following the use of antimicrobial soap. PMID:18441107

Alternative hand contamination technique to compare the activities of antimicrobial and nonantimicrobial soaps under different test conditions.

PubMed

Fuls, Janice L; Rodgers, Nancy D; Fischler, George E; Howard, Jeanne M; Patel, Monica; Weidner, Patrick L; Duran, Melani H

2008-06-01

Antimicrobial hand soaps provide a greater bacterial reduction than nonantimicrobial soaps. However, the link between greater bacterial reduction and a reduction of disease has not been definitively demonstrated. Confounding factors, such as compliance, soap volume, and wash time, may all influence the outcomes of studies. The aim of this work was to examine the effects of wash time and soap volume on the relative activities and the subsequent transfer of bacteria to inanimate objects for antimicrobial and nonantimicrobial soaps. Increasing the wash time from 15 to 30 seconds increased reduction of Shigella flexneri from 2.90 to 3.33 log(10) counts (P = 0.086) for the antimicrobial soap, while nonantimicrobial soap achieved reductions of 1.72 and 1.67 log(10) counts (P > 0.6). Increasing soap volume increased bacterial reductions for both the antimicrobial and the nonantimicrobial soaps. When the soap volume was normalized based on weight (approximately 3 g), nonantimicrobial soap reduced Serratia marcescens by 1.08 log(10) counts, compared to the 3.83-log(10) reduction caused by the antimicrobial soap (P < 0.001). The transfer of Escherichia coli to plastic balls following a 15-second hand wash with antimicrobial soap resulted in a bacterial recovery of 2.49 log(10) counts, compared to the 4.22-log(10) (P < 0.001) bacterial recovery on balls handled by hands washed with nonantimicrobial soap. This indicates that nonantimicrobial soap was less active and that the effectiveness of antimicrobial soaps can be improved with longer wash time and greater soap volume. The transfer of bacteria to objects was significantly reduced due to greater reduction in bacteria following the use of antimicrobial soap.

Microwave-Assisted Synthesis of some Novel Azoles and Azolopyrimidines as Antimicrobial Agents.

PubMed

Gomha, Sobhi M; Farghaly, Thoraya A; Mabkhot, Yahia Nasser; Zayed, Mohie E M; Mohamed, Amany M G

2017-02-23

In this study, new derivatives of pyrazole, isoxazole, pyrazolylthiazole, and azolopyrimidine having a thiophene ring were synthesized under microwave irradiation. Their pharmacological activity toward bacteria and fungi inhibition was screened and compared to the references Chloramphenicol and Trimethoprim / sulphamethoxazole . The antimicrobial results of the investigated compounds revealed promising results and some derivatives have activities similar to the references used.

Antitumour and antimicrobial activities of endophytic streptomycetes from pharmaceutical plants in rainforest.

PubMed

Li, J; Zhao, G-Z; Chen, H-H; Wang, H-B; Qin, S; Zhu, W-Y; Xu, L-H; Jiang, C-L; Li, W-J

2008-12-01

The aim of this study was to screen antitumour and antimicrobial activities of endophytic actinomycetes isolated from pharmaceutical plants in rainforest in Yunnan province, China. Antitumour activity was studied by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and antimicrobial activity was determined by agar well diffusion method. The high bioactive endophytic isolates were identified and further investigated for the presence of polyketide synthases (PKS-I, PKS-II) and nonribosomal peptide synthetases (NRPS) sequences by specific amplification. The molecular identification confirmed that the 41 isolates showed significant activities were members of the genus Streptomyces. Among them, 31.7% of endophytic streptomycete cultures were cytotoxic against A549 cells, 29.3% against HL-60 cells, 85.4% against BEL-7404 cells, 90.2% against P388D1 cells, 65.9% were active against Escherichia coli, 24.4% against Staphylococcus aureus, 31.7% against Staphylococcus epidermidis, 12.2% against Candida albicans and no strain displayed antagonistic activity against Klebsiella pneumoniae. High frequencies of positive PCR amplification were obtained for PKS-I (34.1%), PKS-II (63.4%) and NRPS (61.0%) biosynthetic systems. Many endophytic streptomycetes isolated from pharmaceutical plants in rainforest possess remarkable and diverse antitumour and antimicrobial bioactivities. These endophytic streptomycetes are precious resources obtained from rainforests, and they could be a promising source for bioactive agents.

A comparative study of the antihyaluronidase, antiurease, antioxidant, antimicrobial and physicochemical properties of different unifloral degrees of chestnut (Castanea sativa Mill.) honeys.

PubMed

Kolayli, Sevgi; Can, Zehra; Yildiz, Oktay; Sahin, Huseyin; Karaoglu, Sengul Alpay

2016-01-01

This study was planned to investigate some physicochemical and anti-inflammatory, antioxidant, antimicrobial properties of three different degrees of unifloral characters of chestnut honeys. Antihyaluronidase, antiurease and antimicrobial activities were evaluated as anti-inflammatory characteristics. Total phenolic contents, flavonoids, tannins, phenolic profiles, ferric-reducing antioxidant power (FRAP), scavenging activities of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS + ) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals were evaluated as antioxidant properties. Color, optical rotation, conductivity, moisture, pH and ash content were evaluated as physicochemical parameters, and some sugars content, prolin, diastase, HMF and minerals (Na, K, Ca, P, Fe, Cu and Zn) were evaluated as chemical and biochemical parameters. All studied physicochemical and biological active properties were changed in line with the unifloral character of the chestnut honeys. A higher unifloral character was found associated with greater apitherapeutic capacity of the honey, as well as biological active compounds.

Pharmacological and phytochemical screening of Palestinian traditional medicinal plants Erodium laciniatum and Lactuca orientalis.

PubMed

Jaradat, Nidal; AlMasri, Motasem; Zaid, Abdel Naser; Othman, Dua'a Ghazi

2017-09-01

Various epidemiological studies showed that herbal remedies containing polyphenols may protect against various diseases such as cancers, vascular diseases and inflammatory pathologies. Currently, such groups of bioactive compounds have become a subject of many antimicrobials and antioxidant investigations. Accordingly, the current study aimed to conduct biological and phytochemical screening for two Palestinian traditional medicinal plants, Erodium laciniatum and Lactuca orientalis. Current plants phytoconstituents and their antioxidant activities were evaluated by using standard phytochemical methods; meanwhile, antimicrobial activities were estimated by using several types of American Type Culture Collection and multidrug resistant clinical isolates by using agar diffusion well-variant, agar diffusion disc-variant and broth microdilution methods. Phytochemical screenings showed that L. orientalis and E. laciniatum contain mixtures of secondary and primary metabolites Moreover, total flavonoid, tannins and phenols content in E. laciniatum extract were higher than the L. orientalis extracts with almost the same antioxidant potentials. Additionally, both plants organic and aqueous extracts showed various potentials of antimicrobial activity Conclusions: Overall, the studied species have a mixture of phytochemicals, flavonoids, phenols and tannins also have antioxidant and antimicrobial activities which approved their folk uses in treatments of infectious and Alzheimer diseases and simultaneously can be used as therapeutic agents in the pharmaceutical industries.

Antimicrobial activity of biogenic silver nanoparticles, and silver chloride nanoparticles: an overview and comments.

PubMed

Durán, Nelson; Nakazato, Gerson; Seabra, Amedea B

2016-08-01

The antimicrobial impact of biogenic-synthesized silver-based nanoparticles has been the focus of increasing interest. As the antimicrobial activity of nanoparticles is highly dependent on their size and surface, the complete and adequate characterization of the nanoparticle is important. This review discusses the characterization and antimicrobial activity of biogenic synthesized silver nanoparticles and silver chloride nanoparticles. By revising the literature, there is confusion in the characterization of these two silver-based nanoparticles, which consequently affects the conclusion regarding to their antimicrobial activities. This review critically analyzes recent publications on the synthesis of biogenic silver nanoparticles and silver chloride nanoparticles by attempting to correlate the characterization of the nanoparticles with their antimicrobial activity. It was difficult to correlate the size of biogenic nanoparticles with their antimicrobial activity, since different techniques are employed for the characterization. Biogenic synthesized silver-based nanoparticles are not completely characterized, particularly the nature of capped proteins covering the nanomaterials. Moreover, the antimicrobial activity of theses nanoparticles is assayed by using different protocols and strains, which difficult the comparison among the published papers. It is important to select some bacteria as standards, by following international foundations (Pharmaceutical Microbiology Manual) and use the minimal inhibitory concentration by broth microdilution assays from Clinical and Laboratory Standards Institute, which is the most common assay used in antibiotic ones. Therefore, we conclude that to have relevant results on antimicrobial effects of biogenic silver-based nanoparticles, it is necessary to have a complete and adequate characterization of these nanostructures, followed by standard methodology in microbiology protocols.

Graph Theoretical Analysis, In Silico Modeling, Synthesis, Anti-Microbial and Anti-TB Evaluation of Novel Quinoxaline Derivatives.

PubMed

Saravanan, Govindaraj; Selvam, Theivendren Panneer; Alagarsamy, Veerachamy; Kunjiappan, Selvaraj; Joshi, Shrinivas D; Indhumathy, Murugan; Kumar, Pandurangan Dinesh

2018-05-01

We designed to synthesize a number of 2-(2-(substituted benzylidene) hydrazinyl)-N-(4-((3-(phenyl imino)-3,4-dihydro quinoxalin-2(1 H)-ylidene)amino) phenyl) acetamide S1-S13: with the hope to obtain more active and less toxic anti-microbial and anti-TB agents. A series of novel quinoxaline Schiff bases S1-S13: were synthesized from o-phenylenediamine and oxalic acid by a multistep synthesis. In present work, we are introducing graph theoretical analysis to identify drug target. In the connection of graph theoretical analysis, we utilised KEGG database and Cytoscape software. All the title compounds were evaluated for their in-vitro anti-microbial activity by using agar well diffusion method at three different concentration levels (50, 100 and 150 µg/ml). The MIC of the compounds was also determined by agar streak dilution method. The identified study report through graph theoretical analysis were highlights that the key virulence factor for pathogenic mycobacteria is a eukaryotic-like serine/threonine protein kinase, termed PknG. All compounds were found to display significant activity against entire tested bacteria and fungi. In addition the synthesized scaffolds were screened for their in vitro antituberculosis (anti-TB) activity against Mycobacterium tuberculosis (Mtb) strain H 37 Ra using standard drug Rifampicin. A number of analogs found markedly potent anti-microbial and anti-TB activity. The relationship between the functional group variation and the biological activity of the evaluated compounds were well discussed. The observed study report was showing that the compound S6: (4-nitro substitution) exhibited most potent effective anti-microbial and anti-TB activity out of various tested compounds. © Georg Thieme Verlag KG Stuttgart · New York.

Activity of innate antimicrobial peptides and ivacaftor against clinical cystic fibrosis respiratory pathogens.

PubMed

Payne, Joanna E; Dubois, Alice V; Ingram, Rebecca J; Weldon, Sinead; Taggart, Clifford C; Elborn, J Stuart; Tunney, Michael M

2017-09-01

There is a clear need for new antimicrobials to improve current treatment of chronic lung infection in people with cystic fibrosis (CF). This study determined the activities of antimicrobial peptides (AMPs) and ivacaftor, a novel CF transmembrane conductance regulator potentiator, for CF treatment. Antimicrobial activities of AMPs [LL37, human β-defensins (HβD) 1-4 and SLPI] and ivacaftor against clinical respiratory isolates (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus spp., Achromobacter spp. and Stenotrophomonas maltophilia) were determined using radial diffusion and time-kill assays, respectively. Synergy of LL37 and ivacaftor with tobramycin was determined by time-kill, with in vivo activity of ivacaftor and tobramycin compared using a murine infection model. LL37 and HβD3 were the most active AMPs tested, with MICs ranging from 3.2- ≥ 200 mg/L and 4.8- ≥ 200 mg/L, respectively, except for Achromobacter that was resistant. HβD1 and SLPI demonstrated no antimicrobial activity. LL37 demonstrated synergy with tobramycin against 4/5 S. aureus and 2/5 Streptococcus spp. isolates. Ivacaftor demonstrated bactericidal activity against Streptococcus spp. (mean log 10 decrease 3.31 CFU/mL) and bacteriostatic activity against S. aureus (mean log 10 change 0.13 CFU/mL), but no activity against other genera. Moreover, ivacaftor demonstrated synergy with tobramycin, with mean log 10 decreases of 5.72 CFU/mL and 5.53 CFU/mL at 24 h for S. aureus and Streptococcus spp., respectively. Ivacaftor demonstrated immunomodulatory but no antimicrobial activity in a P. aeruginosa in vivo murine infection model. Following further modulation to enhance activity, AMPs and ivacaftor offer real potential as therapeutics to augment antibiotic therapy of respiratory infection in CF. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Molecular Design, Structures, and Activity of Antimicrobial Peptide-Mimetic Polymers

PubMed Central

Takahashi, Haruko; Palermo, Edmund F.; Yasuhara, Kazuma; Caputo, Gregory A.

2014-01-01

There is an urgent need for new antibiotics which are effective against drug-resistant bacteria without contributing to resistance development. We have designed and developed antimicrobial copolymers with cationic amphiphilic structures based on the mimicry of naturally occurring antimicrobial peptides. These copolymers exhibit potent antimicrobial activity against a broad spectrum of bacteria including methicillin-resistant Staphylococcus aureus with no adverse hemolytic activity. Notably, these polymers also did not result in any measurable resistance development in E. coli. The peptide-mimetic design principle offers significant flexibility and diversity in the creation of new antimicrobial materials and their potential biomedical applications. PMID:23832766

Evaluation of antimicrobial properties of cork.

PubMed

Gonçalves, Filipa; Correia, Patrícia; Silva, Susana P; Almeida-Aguiar, Cristina

2016-02-01

Cork presents a range of diverse and versatile properties making this material suitable for several and extremely diverse industrial applications. Despite the wide uses of cork, its antimicrobial properties and potential applications have deserved little attention from industry and the scientific community. Thus, the main purpose of this work was the evaluation of the antibacterial properties of cork, by comparison with commercially available antimicrobial materials (Ethylene-Vinyl Acetate copolymer and a currently used antimicrobial commercial additive (ACA)), following the previous development and optimization of a method for such antimicrobial assay. The AATCC 100-2004 standard method, a quantitative procedure developed for the assessment of antimicrobial properties in textile materials, was used as reference and optimized to assess cork antibacterial activity. Cork displayed high antibacterial activity against Staphylococcus aureus, with a bacterial reduction of almost 100% (96.93%) after 90 minutes of incubation, similar to the one obtained with ACA. A more reduced but time-constant antibacterial action was observed against Escherichia coli (36% reduction of the initial number of bacterial colonies). To complement this study, antibacterial activity was further evaluated for a water extract of cork and an MIC of 6 mg mL(-1) was obtained against the reference strain S. aureus. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Potential of the polymer poly-[2-(tert-butylamino) methylstyrene] as antimicrobial packaging material for meat products.

PubMed

Dohlen, S; Braun, C; Brodkorb, F; Fischer, B; Ilg, Y; Kalbfleisch, K; Lorenz, R; Robers, O; Kreyenschmidt, M; Kreyenschmidt, J

2016-10-01

The objective of the study was to investigate the antimicrobial potential of a new SAM(®) polymer poly(TBAMS) as packaging material for meat products. The influence of temperature, time and product factors on the antimicrobial activity of poly(TBAMS) against different bacteria was determined using a modified test method based on the Japanese Industrial Standard 2801:2000. Results showed a significant reduction in bacterial counts on poly(TBAMS) compared with the reference material of several meat-specific micro-organisms after 24 h at 7°C. Bacterial counts of Staphylococcus aureus, Listeria monocytogenes, Lactobacillus spp., Brochothrix thermosphacta and Escherichia coli were reduced by >4·0 log10  units. Pseudomonas fluorescens was less sensitive to poly(TBAMS) within 24 h between 2 and 7°C. Prolonging the storage time to 48 h, however, resulted in an increased reduction rate. Furthermore, antimicrobial activity was also observed if meat components in the form of meat extract, meat juice or bovine serum albumin protein were present. Antimicrobial activity was also achieved if inoculated with mixed cultures. Poly(TBAMS) showed antimicrobial properties under conditions typical for meat supply chains. Poly(TBAMS) bears a high potential to increase safety and shelf life of meat products. © 2016 The Society for Applied Microbiology.

Antimicrobial Potential of Helicanthus elastica (Desr.) Danser - A less explored Indian mistletoe Growing on Mango Trees

PubMed Central

Sunil Kumar, Koppala Narayana; Saraswathy, Ariyamuthu; Amerjothy, Swaminathan; Ravishankar, Basaviah

2014-01-01

Helicanthus elastica (Desr.) Danser (Loranthaceae) is a less-known medicinally important mistletoe species occurring in India. It is used to check abortion, and also in vesical calculi and kidney affections. There are no detailed studies reporting the antimicrobial potential of this plant. Based on the traditional use and the rich phenolic composition of the whole plant, the antimicrobial property of the alcohol extract was analyzed and the results are outlined in the present paper. For the analysis, zone of inhibition, and minimum inhibitory concentration were used, and the total activity was assayed by standard methodologies. The antimicrobial activity was studied against bacteria like Aeromonas hydrophila, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, Vibrio fischeri, and a fungus Candida albicans. Of the eight tested bacteria, the alcoholic extract of H. elastica was found to be active against K. pneumoniae, A. hydrophila, E. coli, and V. fischeri at concentration ranging from 250 to 500 μg/ml. C. albicans showed inhibition only at a concentration of 2000 μg/ml. PMID:25379468

Structural characterization and antimicrobial properties of silver nanoparticles prepared by inverse microemulsion method.

PubMed

Wani, Irshad A; Khatoon, Sarvari; Ganguly, Aparna; Ahmed, Jahangeer; Ahmad, Tokeer; Manzoor, Nikhat

2013-01-01

Silver nanoparticles have been synthesized in the inverse microemulsions formed using three different surfactants viz., cetyl-trimethyl ammonium bromide (CTAB), Tergitol and Triton X-100. We have done a systematic study of the effect of the surfactants on the particle size and properties of the silver nanoparticles. Microscopic studies show the formation of spheres, cubes and discs shaped silver nanostructures with the size in the range from 8 to 40 nm. Surface plasmon resonance (SPR) peak was observed around 400 nm and 500 nm. In addition to SPR some extra peaks have also been observed due to the formation of silver metal clusters. The surface area increases from 3.45 to 15.06 m(2)/g with decreasing the size of silver nanoparticles (40-8 nm). To investigate the antimicrobial activity of silver nanoparticles, the nanoparticles were tested against the yeast, Candida albicans and the bacterium, E. coli. The results suggest very good antimicrobial activity of the silver nanoparticles against the test microbes. The mode of action of the antimicrobial activity was also proposed. Copyright © 2012 Elsevier B.V. All rights reserved.

Antimicrobial potential of selected brown seaweeds from Vedalai coastal waters, Gulf of Mannar

PubMed Central

Manivannan, K; Karthikai devi, G; Anantharaman, P; Balasubramanian, T

2011-01-01

Objective To evaluate the antimicrobial activity of Turbinaria conoides (T. conoides), Padina gymnospora (P. gymnospora) and Sargassum tenerrimum against human bacterial and fungal pathogens. Methods The antimicrobial activities of the extracts against various organisms were tested by using disc diffusion method. Results The methanol extract showed the better result than the other extracts. Whereas, the strong antibacterial inhibition was noted in methanol extracts of P. gymnospora against Bacillus subtilus (26.33±1.86) and the mild inhibition of ethanol extracts from T. conoides against Klebsiella pneumoniae (2.33±0.51). Acetone extraction of P. gymnospora had strong antifungal inhibition against Cryptococcus neoformans (23.00±1.78), and acetone extract of T. conoides had mild inhibition against Aspergillus niger (3.00±0.89). Conclusions The seven different solvent extracts of seaweeds used in the present study have shown significant bacterial action. Further, a detailed study on the principle compound in the seaweeds which is responsible for antimicrobial activity is still needed and it can be achieved by using advanced separation techniques. PMID:23569739

Diverse antimicrobial interactions of halophilic archaea and bacteria extend over geographical distances and cross the domain barrier

PubMed Central

Atanasova, Nina S; Pietilä, Maija K; Oksanen, Hanna M

2013-01-01

The significance of antimicrobial substances, halocins, produced by halophilic archaea and bacteria thriving in hypersaline environments is relatively unknown. It is suggested that their production might increase species diversity and give transient competitive advances to the producer strain. Halocin production is considered to be common among halophilic archaea, but there is a lack of information about halocins produced by bacteria in highly saline environments. We studied the antimicrobial activity of 68 halophilic archaea and 22 bacteria isolated from numerous geographically distant hypersaline environments. Altogether 144 antimicrobial interactions were found between the strains and aside haloarchaea, halophilic bacteria from various genera were identified as halocin producers. Close to 80% of the interactions were detected between microorganisms from different genera and in few cases, even across the domain boundary. Several of the strains produced halocins with a wide inhibitory spectrum as has been observed before. Most of the antimicrobial interactions were found between strains from distant sampling sites indicating that hypersaline environments around the world have similar microorganisms with the potential to produce wide activity range antimicrobials. PMID:23929527

Application of Artificial Intelligence to the Prediction of the Antimicrobial Activity of Essential Oils.

PubMed

Daynac, Mathieu; Cortes-Cabrera, Alvaro; Prieto, Jose M

2015-01-01

Essential oils (EOs) are vastly used as natural antibiotics in Complementary and Alternative Medicine (CAM). Their intrinsic chemical variability and synergisms/antagonisms between its components make difficult to ensure consistent effects through different batches. Our aim is to evaluate the use of artificial neural networks (ANNs) for the prediction of their antimicrobial activity. Methods. The chemical composition and antimicrobial activity of 49 EOs, extracts, and/or fractions was extracted from NCCLS compliant works. The fast artificial neural networks (FANN) software was used and the output data reflected the antimicrobial activity of these EOs against four common pathogens: Staphylococcus aureus, Escherichia coli, Candida albicans, and Clostridium perfringens as measured by standardised disk diffusion assays. Results. ANNs were able to predict >70% of the antimicrobial activities within a 10 mm maximum error range. Similarly, ANNs were able to predict 2 or 3 different bioactivities at the same time. The accuracy of the prediction was only limited by the inherent errors of the popular antimicrobial disk susceptibility test and the nature of the pathogens. Conclusions. ANNs can be reliable, fast, and cheap tools for the prediction of the antimicrobial activity of EOs thus improving their use in CAM.

Application of Artificial Intelligence to the Prediction of the Antimicrobial Activity of Essential Oils

PubMed Central

Daynac, Mathieu; Cortes-Cabrera, Alvaro; Prieto, Jose M.

2015-01-01

Essential oils (EOs) are vastly used as natural antibiotics in Complementary and Alternative Medicine (CAM). Their intrinsic chemical variability and synergisms/antagonisms between its components make difficult to ensure consistent effects through different batches. Our aim is to evaluate the use of artificial neural networks (ANNs) for the prediction of their antimicrobial activity. Methods. The chemical composition and antimicrobial activity of 49 EOs, extracts, and/or fractions was extracted from NCCLS compliant works. The fast artificial neural networks (FANN) software was used and the output data reflected the antimicrobial activity of these EOs against four common pathogens: Staphylococcus aureus, Escherichia coli, Candida albicans, and Clostridium perfringens as measured by standardised disk diffusion assays. Results. ANNs were able to predict >70% of the antimicrobial activities within a 10 mm maximum error range. Similarly, ANNs were able to predict 2 or 3 different bioactivities at the same time. The accuracy of the prediction was only limited by the inherent errors of the popular antimicrobial disk susceptibility test and the nature of the pathogens. Conclusions. ANNs can be reliable, fast, and cheap tools for the prediction of the antimicrobial activity of EOs thus improving their use in CAM. PMID:26457111

Species of Genus Ganoderma (Agaricomycetes) Fermentation Broth: A Novel Antioxidant and Antimicrobial Agent.

PubMed

Cilerdzic, Jasmina; Kosanic, Marijana; Stajić, Mirjana; Vukojevic, Jelena; Ranković, Branislav

2016-01-01

The bioactivity of Ganoderma lucidum basidiocarps has been well documented, but there are no data on the medicinal properties of its submerged cultivation broth nor on the other species of the genus Ganoderma. Thus the aim of this study was to test the potential antimicrobial and antioxidant activity of fermentation broth obtained after submerged cultivation of G. applanatum, G. carnosum, and G. lucidum. DPPH· scavenging ability, total phenols, and flavonoid contents were measured to determine the antioxidative potential of Ganoderma spp. fermentation filtrates, whereas their antimicrobial potential was studied using the microdilution method. DPPH· scavenging activity of G. lucidum fermentation filtrates was significantly higher than that of G. applanatum and G. carnosum, with the maximum (39.67%) obtained from strain BEOFB 432. This filtrate also contained the highest concentrations of phenols (134.89 μg gallic acid equivalents/mL) and flavonoids (42.20 μg quercetin equivalent/mL). High correlations between the activity and phenol content in the extracts showed that these compounds were active components of the antioxidative activity. G. lucidum strain BEOFB 432 was the most effective antibacterial agent, whereas strain BEOFB 434 has proven to be the most effective antifungal agent. The study showed that Ganoderma spp. fermentation filtrates are novel potent antioxidative and antimicrobial agents that could be obtained more quickly and cheaper than basidiocarps.

Evaluation of antimicrobial effect of azadirachtin plant extract (Soluneem (™)) on commonly found root canal pathogenic microorganisms (viz. Enterococcus faecalis) in primary teeth: A microbiological study.

PubMed

Shah, Shanal; Venkataraghavan, Karthik; Choudhary, Prashant; Mohammad, Shameer; Trivedi, Krishna; Shah, Shalin G

2016-01-01

The aim of this study is to evaluate the antimicrobial activity of Soluneem ™ when used as an irrigating solution along with other commonly used irrigating solution sodium hypochlorite (NaOCl) against Enterococcus faecalis. Microorganism used in this study was E. faecalis (Microbial Type Culture Collection 439). Test substance used was Soluneem ™, which was obtained from Vittal Mallya Scientific Research Foundation (VMSRF), Bengaluru. This study was conducted in a microbiology laboratory (Biocare Research India Pvt., Ltd. Laboratory, Ahmedabad, Gujarat) to evaluate the antimicrobial effect of Soluneem ™ (Azadirachtin) on E. faecalis. Antimicrobial activity testing was performed using the macrobroth dilution method according to the Clinical Laboratory Standards Institute guidelines. All determinations were performed thrice. Minimum bactericidal concentration (MBC) was seen as 2.6% for Soluneem ™ while the same was seen at 0.1% for NaOCl. Independent sample t-test was carried out to compare the MBC of Soluneem ™ and NaOCl, which showed that there was no statistically significant difference between them, i.e., 2.6% Soluneem ™ was as effective as 0.1% NaOCl. Soluneem ™ showed antimicrobial activity against E. faecalis at various concentrations. It was also found that the efficacy of Soluneem ™ at 2.6% concentration and above was relatively similar to that of gold standard irrigating solution (NaOCl) on inhibition of E. faecalis.

Mode of action and safety of lactosporin, a novel antimicrobial protein produced by Bacillus coagulans ATCC 7050

PubMed Central

Riazi, Shadi; Dover, Sara E.; Chikindas, Michael L.

2012-01-01

Aims To determine the mechanism of action of antimicrobial protein, lactosporin, against Gardnerella vaginalis and to evaluate its safety in-vitro. Methods and Results Bacillus coagulans ATCC 7050 was grown at 37 °C for 18 hours. The cell free supernatant was concentrated 10-fold and screened for antimicrobial activity against indicator strain Micrococcus luteus. The mode of action of lactosporin was determined by measuring the potassium release and monitoring the changes in transmembrane potential (Δψ) and transmembrane pH (ΔpH) of the sensitive cells. Lactosporin caused efflux of potassium ions from M. luteus cells and dissipation of ΔpH in G. vaginalis while it had no effect on the Δψ. The safety of lactosporin was evaluated by using EpiVaginal™ ectocervical (VEC-100) tissue model. Over 80% of the cells in the vaginal tissue remained viable after exposure to lactosporin for 24 hours. Conclusions Lactosporin potentially exerts its antimicrobial activity by selective dissipation of ΔpH and/or by causing leakage of ions from the sensitive cells. Safety studies suggest that lactosporin is a non-cytotoxix antimicrobial for vaginal application. Significance and Impact of the Study This study revealed that lactosporin is an effective and safe antimicrobial preparation with potential application for control of bacterial vaginosis. PMID:22737982

Isolation, purification, and characterization of antimicrobial compound 6-[1,2-dimethyl-6-(2-methyl-allyloxy)-hexyl]-3-(2-methoxy-phenyl)-chromen-4-one from Penicillium sp. HT-28.

PubMed

Kaur, Harpreet; Arora, Daljit Singh; Sharma, Vishal

2014-08-01

A fungal culture (Penicillium sp., HT-28), isolated from soil has been evaluated for its bioactivity, which showed broad spectrum antimicrobial activity and was effective against methicillin-resistant Staphylococcus aureus (MRSA) also. Statistical optimization of the medium by response surface methodology (RSM) enhanced the antimicrobial activity up to 1.8-fold. Column chromatography was used to isolate the active compound (A), which was characterized to be 6-[1,2-dimethyl-6-(2-methyl-allyloxy)-hexyl]-3-(2-methoxy-phenyl)-chromen-4-one by various spectroscopic techniques such as infrared (IR), (1)H and (13)C nuclear magnetic resonance (NMR) spectra, and mass spectroscopy. Minimum inhibitory concentration (MIC) of the active compound (A) ranged from 0.5 to 15 μg/mL. Viable cell count studies of the active compound (A) showed S. aureus, Escherichia coli, Staphylococcus epidermidis, and Salmonella typhimurium 1 to be the most sensitive. The compound retained its bioactivity after treating it at 100 °C for 1 h. Furthermore, the compound (A) when tested for its biosafety was found neither to be cytotoxic nor mutagenic. The study demonstrated that an apparently novel compound isolated from Penicillium sp. (HT-28) seems to be a stable and potent antimicrobial.

Antimicrobial activity of Lactobacillus strains of chicken origin against bacterial pathogenss.

PubMed

Dec, Marta; Puchalski, Andrzej; Nowaczek, Anna; Wernicki, Andrzej

2016-03-01

This study was conducted to identify and evaluate the antimicrobial activity of some Lactobacillus isolates of chicken origin. Among 90 isolates 14 Lactobacillus species were distinguished using MALDI-TOF mass spectrometry and 16S-ARDRA. The dominant species was L. salivarius (34.4%), followed by L. johnsonii (23.3%), L. crispatus (13.3%) and L. reuteri (11.1%). All lactobacilli were screened for antimicrobial activity against wild-type strains of Salmonella enterica, Escherichia coli, and Clostridium perfringens. Results from the agar slab method showed that all Lactobacillus isolates were able to produce active compounds on solid media with antagonistic properties against these pathogens. The highest sensitivity to lactobacilli was observed in C. perfringens strains, and the lowest in E. coli. Lactobacillus salivarius exhibited particularly strong antagonism towards all of the indicator bacteria. Strains of L. ingluviei and L. johnsonii and one strain of L. salivarius (10d) selectively inhibited the growth of C. perfringens. No antimicrobial activity of many Lactobacillus isolates was observed when cell-free culture supernatant was used in a well diffusion assay. All Lactobacillus isolates exhibited the ability to produce H2O2 and proved to be hydrophobic (excluding one of L. salivarius). [Int Microbiol 19(1):57-67 (2016)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Synthesis, anti-microbial and molecular docking studies of quinazolin-4(3H)-one derivatives.

PubMed

Mabkhot, Yahia Nasser; Al-Har, Munirah S; Barakat, Assem; Aldawsari, Fahad D; Aldalbahi, Ali; Ul-Haq, Zaheer

2014-06-25

In this work, synthesis, antimicrobial activities and molecular docking studies of some new series of substituted quinazolinone 2a-h and 3a-d were described. Starting form 2-aminobenzamide derivatives 1, a new series of quinazolinone derivatives has been synthesized, in high yields, assisted by microwave and classical methods. Some of these substituted quinazolinones were tested for their antimicrobial activity against Gram-negative bacteria (Pseudomonas aeruginosa and Esherichia coli) and Gram-positive bacteria (Staphylococcus aureus, and Bacillus subtilis), and anti-fungal activity against (Aspergillus fumigatus, Saccharomyces cervevisiae, and Candida albicans) using agar well diffusion method. Among the prepared products, 3-benzyl-2-(4-chlorophenyl)quinazolin-4(3H)-one (3a) was found to exhibits the most potent in vitro anti-microbial activity with MICs of 25.6±0.5, 24.3±0.4, 30.1±0.6, and 25.1±0.5 µg/mL against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Esherichia coli, respectively. Compound 3a was found to exhibits the most potent in vitro anti-fungal activity with MICs of 18.3±0.6, 23.1±0.4, and 26.1±0.5 µg/mL against Aspergillus fumigatus, Saccharomyces cervevisiae, and Candidaal bicans, respectively.

Prevalence and Mechanisms of Dynamic Chemical Defenses in Tropical Sponges

PubMed Central

Rohde, Sven; Nietzer, Samuel; Schupp, Peter J.

2015-01-01

Sponges and other sessile invertebrates are lacking behavioural escape or defense mechanisms and rely therefore on morphological or chemical defenses. Studies from terrestrial systems and marine algae demonstrated facultative defenses like induction and activation to be common, suggesting that sessile marine organisms also evolved mechanisms to increase the efficiency of their chemical defense. However, inducible defenses in sponges have not been investigated so far and studies on activated defenses are rare. We investigated whether tropical sponge species induce defenses in response to artificial predation and whether wounding triggers defense activation. Additionally, we tested if these mechanisms are also used to boost antimicrobial activity to avoid bacterial infection. Laboratory experiments with eight pacific sponge species showed that 87% of the tested species were chemically defended. Two species, Stylissa massa and Melophlus sarasinorum, induced defenses in response to simulated predation, which is the first demonstration of induced antipredatory defenses in marine sponges. One species, M. sarasinorum, also showed activated defense in response to wounding. Interestingly, 50% of the tested sponge species demonstrated induced antimicrobial defense. Simulated predation increased the antimicrobial defenses in Aplysinella sp., Cacospongia sp., M. sarasinorum, and S. massa. Our results suggest that wounding selects for induced antimicrobial defenses to protect sponges from pathogens that could otherwise invade the sponge tissue via feeding scars. PMID:26154741

Anti-oxidant and anti-microbial properties of some ethno-therapeutically important medicinal plants of Indian Himalayan Region.

PubMed

Rawat, Sandeep; Jugran, Arun K; Bahukhandi, Amit; Bahuguna, Asutosh; Bhatt, Indra D; Rawal, Ranbeer S; Dhar, Uppeandra

2016-12-01

Therapeutic potential of medicinal plants as a source of noble natural anti-oxidants and anti-microbial agents has been well recognised all across the globe. In this study, phenolic compounds, in vitro anti-oxidant activity and anti-microbial properties have been investigated in five Himalayan medicinal plants, (e.g., Acorus calamus, Habenaria intermedia, Hedychium spicatum, Roscoea procera and Valeriana jatamansi) in different solvent systems. R. procera exhibited significantly (p < 0.05) higher phenolics; while H. spicatum was rich in flavonoids and V. jatamansi in anti-oxidant activity. Also, R. procera and H. spicatum were found rich in gallic acid; V. jatamansi in catechin, hydroxylbenzoic acid and caffeic acid and H. intermedia in hydroxyl benzoic acid. Solvent systems showed species specific response for extraction of total flavonoids and anti-oxidant activity. All the extracts were found effective against different bacterial and fungal strains in a dose dependent manner and maximum antimicrobial activity was found in R. procera as compared to other species. All the plant extracts showed greater activity against bacterial strains as compared to fungal strains. The results of this study suggest that extract of these species can be used as natural anti-oxidant to reduce free radical mediated disorders and as natural alternative for food preservation.

In-vitro susceptibility of 1982 respiratory tract pathogens and 1921 urinary tract pathogens against 19 antimicrobial agents: a Canadian multicentre study. Canadian Antimicrobial Study Group.

PubMed

Blondeau, J M; Yaschuk, Y; Suter, M; Vaughan, D

1999-03-01

A total of 3903 pathogens from 48 Canadian medical centres were tested against 19 antimicrobial agents. Five agents showed activity against > or = 90% of all 1982 respiratory tract pathogens tested (ciprofloxacin, 90%; cefoperazone, 91%; ticarcillin/clavulanate, 92%; ceftazidime and imipenem, 93% each). Nine agents had > or = 90% activity against Enterobacteriaceae from respiratory tract infection (cefotaxime and ticarcillin/clavulanate, 90% each; aztreonam, ceftizoxime and ceftriaxone, 91% each; ceftazidime, 93%; ciprofloxacin, 97%; imipenem and netilmicin, 98% each). Similarly, five agents had activity against > or = 90% of all 1921 urinary tract pathogens tested (ciprofloxacin and ticarcillin/clavulanate, 90% each; cefoperazone and netilmicin, 91% each; imipenem, 99%). Nine agents had > or = 95% activity against Enterobacteriaceae from urinary tract infection (ciprofloxacin, 95%; cefotetan, 97%; aztreonam, cefotaxime, ceftazidime, ceftizoxime, ceftriaxone and netilmicin, 98% each; imipenem, 99%). Seventeen agents had activity against > or = 95% of Staphylococcus aureus strains. Susceptibility of Pseudomonas aeruginosa isolates ranged from 2% to 91%.

Antibacterial and Barrier Properties of Gelatin Coated by Electrospun Polycaprolactone Ultrathin Fibers Containing Black Pepper Oleoresin of Interest in Active Food Biopackaging Applications

PubMed Central

Castro-Mayorga, Jinneth Lorena

2018-01-01

The present study evaluated the effect of using electrospun polycaprolactone (PCL) as a barrier coating and black pepper oleoresin (OR) as a natural extract on the morphology, thermal, mechanical, antimicrobial, oxygen, and water vapor barrier properties of solvent cast gelatin (GEL). The antimicrobial activity of the developed multilayer system obtained by the so-called electrospinning coating technique was also evaluated against Staphylococcus aureus strains for 10 days. The results showed that the multilayer system containing PCL and OR increased the thermal resistance, elongated the GEL film, and significantly diminished its permeance to water vapor. Active multilayer systems stored in hermetically closed bottles increased their antimicrobial activity after 10 days by inhibiting the growth of Staphylococcus aureus. This study demonstrates that addition of electrospun PCL ultrathin fibers and OR improved the properties of GEL films, which promoted its potential use in active food packaging applications. PMID:29597268

Antimicrobial agents from Licaria puchuri-major and their synergistic effect with polygodial.

PubMed

Himejima, M; Kubo, I

1992-05-01

The resistance of the seeds of Licaria puchuri-major (Lauraceae) to decomposition in nature seems to be due largely to chemical defense, since its n-hexane extract contains antimicrobial principles in quantity, with a broad antimicrobial spectrum. In order to identify the active principles, the n-hexane extract was steam-distilled to yield a distillate and a residue. Subsequent bioassay indicated that the distillate retained the original broad antimicrobial activity, while the residue exhibited almost no activity. Gc-ms analysis showed that the distillate contained four phenolic compounds, seven monoterpenes, and one sesquiterpene. In contrast, the residue contained, almost exclusively, lauric acid. In the detailed antimicrobial assay with the pure compounds identified, most of them showed broad, but moderate, antimicrobial activity. Some of the components identified in the distillate were combined with polygodial [1] in order to enhance their antifungal activity. Unexpectedly, while polygodial did not synergize the antifungal activity of any of the compounds tested, the antifungal activity of polygodial was significantly increased when combined with aromatic substances such as anethole, safrole, or methyleugenol.

Enhancement of the anti-inflammatory activity of temporin-1Tl-derived antimicrobial peptides by tryptophan, arginine and lysine substitutions.

PubMed

Rajasekaran, Ganesan; Kamalakannan, Radhakrishnan; Shin, Song Yub

2015-10-01

Temporin-1Tl (TL) is a 13-residue frog antimicrobial peptide (AMP) exhibiting potent antimicrobial and anti-inflammatory activity. To develop novel AMP with improved anti-inflammatory activity and antimicrobial selectivity, we designed and synthesized a series of TL analogs by substituting Trp, Arg and Lys at selected positions. Except for Escherichia coli and Staphylococcus epidermidis, all TL analogs exhibited retained or increased antimicrobial activity against seven bacterial strains including three methicillin-resistant Staphylococcus aureus strains compared with TL. TL-1 and TL-4 showed a little increase in antimicrobial selectivity, while TL-2 and TL-3 displayed slightly decreased antimicrobial selectivity because of their about twofold increased hemolytic activity. All TL analogs demonstrated greatly increased anti-inflammatory activity, evident by their higher inhibition of the production tumor necrosis factor-α (TNF-α) and nitric oxide and the mRNA expression of inducible nitric oxide synthase and TNF-α in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells, compared with TL. Taken together, the peptide anti-inflammatory activity is as follows: TL-2 ≈ TL-3 ≈ TL-4 > TL-1 > TL. In addition, LPS binding ability of the peptides corresponded with their anti-inflammatory activity. These results apparently suggest that the anti-inflammatory activity of TL analogs is associated with the direct binding ability between these peptides and LPS. Collectively, our designed TL analogs possess improved anti-inflammatory activity and retain antimicrobial activity without a significant increase in hemolysis. Therefore, it is evident that our TL analogs constitute promising candidates for the development of peptide therapeutics for gram-negative bacterial infection. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

Redesigned Spider Peptide with Improved Antimicrobial and Anticancer Properties.

PubMed

Troeira Henriques, Sónia; Lawrence, Nicole; Chaousis, Stephanie; Ravipati, Anjaneya S; Cheneval, Olivier; Benfield, Aurélie H; Elliott, Alysha G; Kavanagh, Angela Maria; Cooper, Matthew A; Chan, Lai Yue; Huang, Yen-Hua; Craik, David J

2017-09-15

Gomesin, a disulfide-rich antimicrobial peptide produced by the Brazilian spider Acanthoscurria gomesiana, has been shown to be potent against Gram-negative bacteria and to possess selective anticancer properties against melanoma cells. In a recent study, a backbone cyclized analogue of gomesin was shown to be as active but more stable than its native form. In the current study, we were interested in improving the antimicrobial properties of the cyclic gomesin, understanding its selectivity toward melanoma cells and elucidating its antimicrobial and anticancer mode of action. Rationally designed analogues of cyclic gomesin were examined for their antimicrobial potency, selectivity toward cancer cells, membrane-binding affinity, and ability to disrupt cell and model membranes. We improved the activity of cyclic gomesin by ∼10-fold against tested Gram-negative and Gram-positive bacteria without increasing toxicity to human red blood cells. In addition, we showed that gomesin and its analogues are more toxic toward melanoma and leukemia cells than toward red blood cells and act by selectively targeting and disrupting cancer cell membranes. Preference toward some cancer types is likely dependent on their different cell membrane properties. Our findings highlight the potential of peptides as antimicrobial and anticancer leads and the importance of selectively targeting cancer cell membranes for drug development.

Use of rosemary, oregano, and a commercial blend of essential oils in broiler chickens: in vitro antimicrobial activities and effects on growth performance.

PubMed

Mathlouthi, N; Bouzaienne, T; Oueslati, I; Recoquillay, F; Hamdi, M; Urdaci, M; Bergaoui, R

2012-03-01

The present study was conducted to characterize the in vitro antimicrobial activities of 3 essential oils [oregano, rosemary, and a commercial blend of essential oils (BEO)] against pathogenic and nonpathogenic bacteria and to evaluate their effects on broiler chicken performances. The chemical composition of the essential oils was determined using the gas chromatography interfaced with a mass spectroscopy. The disc diffusion method, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) were applied for the determination of antimicrobial activities of essential oils. In vivo study, a total of seven hundred fifty 1-d-old male broiler chickens were assigned to 6 dietary treatment groups: basal diet (control; CON), CON + 44 mg of avilamycin/kg (A), CON + 100 mg of rosemary essential oil/kg (ROS), CON + 100 mg of oregano essential oil/kg (OR), CON + 50 mg of rosemary and 50 mg of oregano essential oils/kg (RO), and CON + 1,000 mg of BEO/kg (essential oil mixture, EOM). The essential oils isolated from rosemary and oregano were characterized by their greater content of 1,8-cineole (49.99%) and carvacrol (69.55%), respectively. The BEO was mainly represented by the aldehyde (cinnamaldehyde) and the monoterpene (1,8-cineole) chemical groups. The results of the disc diffusion method indicated that the rosemary essential oil had antibacterial activity (P ≤ 0.05) against only 3 pathogenic bacteria, Escherichia coli (8 mm), Salmonella indiana (11 mm), and Listeria innocua (9 mm). The essential oil of oregano had antimicrobial activities (P ≤ 0.05) on the same bacteria as rosemary but also on Staphylococcus aureus (22 mm) and Bacillus subtilis (12 mm). Oregano essential oil had greater (P ≤ 0.05) antimicrobial activities against pathogenic bacteria than rosemary essential oil but they had no synergism between them. The BEO showed an increased antimicrobial activity (P ≤ 0.05) against all studied bacteria (pathogenic and nonpathogenic bacteria) except for Lactobacillus rhamnosus. The supplementation of the basal diet with avilamycin or essential oils improved (P ≤ 0.05) broiler chicken BW, BW gain, and G:F compared with the CON diet. There were no differences in growth performances among birds fed A, ROS, OR, RO, or EOM diets. In general, essential oils contained in rosemary, oregano, and BEO can substitute for growth promoter antibiotics. Although the 3 essential oils had different antimicrobial activities, they exhibited the same efficiency in broiler chickens.

Structural, spectroscopic and anti-microbial inspection of PEG capped ZnO nanoparticles for biomedical applications

NASA Astrophysics Data System (ADS)

Meshram, J. V.; Koli, V. B.; Kumbhar, S. G.; Borde, L. C.; Phadatare, M. R.; Pawar, S. H.

2018-04-01

Zinc oxide (ZnO) nanoparticles (NPs) have a wide range of biomedical applications. Present study demonstrates the new methodology in sol-gel technology for synthesizing Polyethylene glycol (PEG) capped ZnO NPs and its size effect on anti-microbial activity. The reaction time was increased from 1 h to 5 h for the synthesis of ZnO NPs at 130 °C. The size of PEG capped ZnO NPs is increased from 10 to 84 nm by increasing the reaction upto 5 h. The x-ray diffraction studies and transmission electron microscopy analysis reveals the phase purity and hexagonal wurtzite crystal structure with uniform PEG capping on the surface of ZnO NPs. UV–visible spectroscopy exhibits the peak at 366 nm which is attributed to ZnO NPs. No adverse effect is observed in case of absorbance spectroscopy. Further, Fourier transforms infrared spectroscopy and thermo gravimetric analysis depicts the adsorption of PEG molecules on the ZnO NPs surface. The anti-microbial activities for both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria were studied by optical density (OD) mesurement. The remarkable anti-microbial activity was observed for PEG capped ZnO NPs synthesized at 1 h reaction time showing higher activity in comparison with that synthesized from 2 h to 5 h reaction time. The microbial growth was found to be inhibited after 10 h OD measurement for both the bacteria. The anti-microbial activity may be attributed to the generation of ROS and H2O2. However, these generated species plays a vital role in inhibition of microbial growth. Hence, PEG capped ZnO NPs has promising biomedical applications.

Phylogenetic study of sponge associated bacteria from the Lakshadweep archipelago and the antimicrobial activities of their secondary metabolites.

PubMed

Gopi, M; Ajith Kumar, T T; Balagurunathan, R; Vinoth, R; Dhaneesh, K V; Rajasekaran, R; Balasubramanian, T

2012-02-01

Marine ecosystem of the Lakshadweep archipelago is unique and known to have a very high degree of biodiversity with a number of endemic flora and fauna. The present study focuses to isolate the endosymbiotic microorganism from sponges and its effectiveness against marine ornamental fish pathogens. The sponges were collected from Agatti island of Lakshadweep archipelago and identified as Clathria procera, Sigmadocia fibulata and Dysidea granulosa. In which, 15 different types of bacteria were isolated and screened against marine ornamental fish pathogens (A. hydrophila, Vibrio alginolyticus, V. harveyii, V. parahaemolyticus and Pseudomonas fluorescens). The strain S25 was found as potential bacteria based on their antimicrobial activity against the fish pathogens. Molecular identification of the potential strain (S25) of the 16S rRNA gene showed 99% identity with Acinetobacter sp. The sequenced 16 s rRNA gene with 1,081 bp in length was submitted in NCBI Genbank and Accession was obtained (GenBank Accession number HM004071). The strain exhibited high similarity (99%) with the 16S rRNA gene of Acinetobacter calcoaceticus from GenBank database. Crude extract obtained with acetone and ethyl acetate from extracellular products of S25 showed significant antimicrobial activity by disc diffusion assay using 1,500 μg/ml of crude extract. Extracellular metobolite of A. calcoaceticus was extracted by shake flask method and the crude extract was partially purified by thin layer chromatography. Partially purified crude extract showed significant inhibition zone of antimicrobial activity (A. hydrophila, V. alginolyticus, V. parahaemolyticus) and less similar activity against V. harveyii and P. fluorescens. This is the first report on A. calcoaceticus isolated from sponges of Lakshadweep archipelago and the studies are underway to characterize and purify the antimicrobial compounds of the potential bacteria.

Determination of the antibiofilm, antiadhesive, and anti-MRSA activities of seven Salvia species.

PubMed

Al-Bakri, Amal G; Othman, Ghadeer; Afifi, Fatma U

2010-10-01

Several Salvia species are indigenous to Jordan and are widely used as beverages and spices and for their medicinal properties. The objective of the study was to establish the antimicrobial activities, including the antiadhesive and antibiofilm effects of seven different Salvia species. Methods used for planktonic culture included agar diffusion, broth microdilution, and minimal biocidal concentration determination while viable count was used for the determination of the antibiofilm and antiadhesion activities. Overnight cultures of reference strains of Candida albicans, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus and clinical strains of methicillin-resistant S. aureus (MRSA) were used as test microorganisms. An antimicrobial activity toward planktonic cultures demonstrated a significant bacteriocidal activity (≥4 log cycle reduction) for the S. triloba extract against S. aureus including MRSA. Its volatile oil exhibited an antimicrobial activity covering all tested microorganisms with the exception of P. aeruginosa. S. triloba extract and volatile oil were successful in preventing and controlling the biofilm, demonstrating antiadhesion and antibiofilm activities, respectively. These reported activities for S. triloba extract and volatile oil allows their listing as potential antibiofilm and anti-MRSA natural agents. This might suggest their use as an antiseptic in the prophylaxis and treatment of S. aureus-associated skin infections. The antimicrobial activity of the other tested Salvia species was negligible.

Antimicrobial activity of Caesalpinia pulcherrima, Euphorbia hirta and Asystasia gangeticum.

PubMed

Sudhakar, M; Rao, Ch V; Rao, P M; Raju, D B; Venkateswarlu, Y

2006-07-01

The ethanolic extracts of the dry fruits of Caesalpinia pulcherrima, aerial parts of Euphorbia hirta and flowers of Asystasia gangeticum were tested for antimicrobial activity. The three plants exhibited a broad spectrum of antimicrobial activity, particularly against Escherichia coli (enteropathogen), Proteus vulgaris, Pseudomonas aeruginosa and Staphylococcus aureus.

Antimicrobial Compounds from Marine Invertebrates-Derived Microorganisms.

PubMed

Liu, Juan; Jung, Jee H; Liu, Yonghong

2016-01-01

It is known that marine invertebrates, including sponges, tunicates, cnidaria or mollusks, host affluent and various communities of symbiotic microorganisms. The microorganisms associated with the invertebrates metabolized various biologically active compounds, which could be an important resource for the discovery and development of potentially novel drugs. In this review, the new compounds with antimicrobial activity isolated from marine invertebrate-derived microorganisms in the last decade (2004-2014) will be presented, with focus on the relevant antimicrobial activities, origin of isolation, and information of strain species. New compounds without antimicrobial activity were not revealed.

Antimicrobial activity of an aspartic protease from Salpichroa origanifolia fruits.

PubMed

Díaz, M E; Rocha, G F; Kise, F; Rosso, A M; Guevara, M G; Parisi, M G

2018-05-08

Plant proteases play a fundamental role in several processes like growth, development and in response to biotic and abiotic stress. In particular, aspartic proteases (AP) are expressed in different plant organs and have antimicrobial activity. Previously, we purified an AP from Salpichroa origanifolia fruits called salpichroin. The aim of this work was to determine the cytotoxic activity of this enzyme on selected plant and human pathogens. For this purpose, the growth of the selected pathogens was analysed after exposure to different concentrations of salpichroin. The results showed that the enzyme was capable of inhibiting Fusarium solani and Staphylococcus aureus in a dose-dependent manner. It was determined that 1·2 μmol l -1 of salpichroin was necessary to inhibit 50% of conidial germination, and the minimal bactericidal concentration was between 1·9 and 2·5 μmol l -1 . Using SYTOX Green dye we were able to demonstrate that salpichroin cause membrane permeabilization. Moreover, the enzyme treated with its specific inhibitor pepstatin A did not lose its antibacterial activity. This finding demonstrates that the cytotoxic activity of salpichroin is due to the alteration of the cell plasma membrane barrier but not due to its proteolytic activity. Antimicrobial activity of the AP could represent a potential alternative for the control of pathogens that affect humans or crops of economic interest. This study provides insights into the antimicrobial activity of an aspartic protease isolated from Salpichroa origanifolia fruits on plant and human pathogens. The proteinase inhibited Fusarium solani and Staphylococcus aureus in a dose-dependent manner due to the alteration of the cell plasma membrane barrier but not due to its proteolytic activity. Antimicrobial activity of salpichroin suggests its potential applications as an important tool for the control of pathogenic micro-organisms affecting humans and crops of economic interest. Therefore, it would represent a new alternative to avoid the problems of environmental pollution and antimicrobial resistance. © 2018 The Society for Applied Microbiology.

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles

PubMed Central

Yun, Ji Ho; Lee, Jung Eun; Lee, Hee Ju; Nho, Chu Won; Bae, Gwi- Nam; Jung, Jae Hee

2015-01-01

Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2filter at 3-, 6-, and 9-min depositions, respectively). In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97%) than for M. luteus aerosols (~95%). High-performance liquid chromatography (HPLC) and electrospray ionization-tandem mass spectrometry (ESI/MS) analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß)-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a bioaerosol control system that is environmental friendly and suitable for use in indoor environments. PMID:25974109

Antagonism between Staphylococcus epidermidis and Propionibacterium acnes and its genomic basis.

PubMed

Christensen, Gitte J M; Scholz, Christian F P; Enghild, Jan; Rohde, Holger; Kilian, Mogens; Thürmer, Andrea; Brzuszkiewicz, Elzbieta; Lomholt, Hans B; Brüggemann, Holger

2016-02-29

Propionibacterium acnes and Staphylococcus epidermidis live in close proximity on human skin, and both bacterial species can be isolated from normal and acne vulgaris-affected skin sites. The antagonistic interactions between the two species are poorly understood, as well as the potential significance of bacterial interferences for the skin microbiota. Here, we performed simultaneous antagonism assays to detect inhibitory activities between multiple isolates of the two species. Selected strains were sequenced to identify the genomic basis of their antimicrobial phenotypes. First, we screened 77 P. acnes strains isolated from healthy and acne-affected skin, and representing all known phylogenetic clades (I, II, and III), for their antimicrobial activities against 12 S. epidermidis isolates. One particular phylogroup (I-2) exhibited a higher antimicrobial activity than other P. acnes phylogroups. All genomes of type I-2 strains carry an island encoding the biosynthesis of a thiopeptide with possible antimicrobial activity against S. epidermidis. Second, 20 S. epidermidis isolates were examined for inhibitory activity against 25 P. acnes strains. The majority of S. epidermidis strains were able to inhibit P. acnes. Genomes of S. epidermidis strains with strong, medium and no inhibitory activities against P. acnes were sequenced. Genome comparison underlined the diversity of S. epidermidis and detected multiple clade- or strain-specific mobile genetic elements encoding a variety of functions important in antibiotic and stress resistance, biofilm formation and interbacterial competition, including bacteriocins such as epidermin. One isolate with an extraordinary antimicrobial activity against P. acnes harbors a functional ESAT-6 secretion system that might be involved in the antimicrobial activity against P. acnes via the secretion of polymorphic toxins. Taken together, our study suggests that interspecies interactions could potentially jeopardize balances in the skin microbiota. In particular, S. epidermidis strains possess an arsenal of different mechanisms to inhibit P. acnes. However, if such interactions are relevant in skin disorders such as acne vulgaris remains questionable, since no difference in the antimicrobial activity against, or the sensitivity towards S. epidermidis could be detected between health- and acne-associated strains of P. acnes.

Antimicrobial and antiparasitic activities of three algae from the northwest coast of Algeria.

PubMed

Ghania, Aissaoui; Nabila, Belyagoubi-Benhammou; Larbi, Belyagoubi; Elisabeth, Mouray; Philippe, Grellier; Mariem, Benmahdjoub; Khadidja, Kerzabi-Kanoun; Wacila, Benguedda-Rahal; Fawzia, Atik-Bekkara

2017-11-22

The objective of this study was to investigate the biological activities of Algerian algae, Sargassum vulgare, Cladostephus hirsutus and Rissoella verruculosa. Antimicrobial activity of the crude extracts and their fractions was assessed using the disc diffusion assay, the minimum inhibitory concentration and the minimum bactericidal concentration. Antiparasitic activity was studied in vitro against the blood stream forms of Trypanosoma brucei brucei and the intraerythrocytic stages of Plasmodium falciparum. Ethyl acetate (EA) fractions of the three tested algae showed more potent antimicrobial activity against S. aureus (7-14.5 mm) and B. cereus (7-10.75 mm), MIC values ranged from 0.9375 to 7.5 mg mL -1 and MBC values > 15 mg mL -1 . Concerning the antiparasitic activity, EA factions of S. vulgare (IC 50  = 9.3 μg mL -1 ) and R. verruculosa (IC 50  = 11.0 μg mL -1 ) were found to be more effective against T. brucei brucei, whereas the three EA fractions were little active against P. falciparum.

Antimicrobial activities of essential oil and hexane extract of Florence fennel [Foeniculum vulgare var. azoricum (Mill.) Thell.] against foodborne microorganisms.

PubMed

Cetin, Bülent; Ozer, Hakan; Cakir, Ahmet; Polat, Taşkin; Dursun, Atilla; Mete, Ebru; Oztürk, Erdoğan; Ekinci, Melek

2010-02-01

The objective of this study was to determine the chemical compositions of the essential oil and hexane extract isolated from the inflorescence, leaf stems, and aerial parts of Florence fennel and the antimicrobial activities of the essential oil, hexane extract, and their major component, anethole, against a large variety of foodborne microorganisms. Gas chromatography and gas chromatography-mass spectrometry analysis showed that the essential oils obtained from inflorescence, leaf stems, and whole aerial parts contained (E)-anethole (59.28-71.69%), limonene (8.30-10.73%), apiole (trace to 9.23%), beta-fenchyl acetate (3.02-4.80%), and perillene (2.16-3.29%) as the main components. Likewise, the hexane extract of the plant sample exhibited a similar chemical composition, and it contained (E)-anethole (53.00%), limonene (27.16%), gamma-terpinene (4.09%), and perillene (3.78%). However, the hexane extract also contained less volatile components such as n-hexadecanoic acid (1.62%), methyl palmitate (1.17%), and linoleic acid (1.15%). The in vitro antimicrobial assays showed that the essential oil, anethole, and hexane extract were effective against most of the foodborne pathogenic, saprophytic, probiotic, and mycotoxigenic microorganisms tested. The results of the present study revealed that (E)-anethole, the main component of Florence fennel essential oil, is responsible for the antimicrobial activity and that the essential oils as well as the hexane extract can be used as a food preservative. This study is the first report showing the antimicrobial activities of essential oil and hexane extract of Florence fennel against probiotic bacteria.

Antibacterial activity and composition of essential oils from Pelargonium graveolens L'Her and Vitex agnus-castus L

PubMed Central

Ghannadi, A; Bagherinejad, MR; Abedi, D; Jalali, M; Absalan, B; Sadeghi, N

2012-01-01

Background and Objectives Essential oils are volatile compounds that have been used since Middle Ages as antimicrobial, anti-inflammatory, sedative, local anesthetic and food flavoring agents. In the current study, essential oils of Pelargonium graveolens L'Her and Vitex agnus-castus L. were analyzed for their antibacterial activities. Materials and Methods The chemical compositions of essential oils were characterized by GC-MS. Disc diffusion method was used to study antimicrobial activity. Results and Conclusion Inhibition zones showed that the essential oils of the two plants were active against all of the studied bacteria (except Listeria monocytogenes). The susceptibility of the strains changed with the dilution of essential oils in DMSO. The pure essential oils showed the most extensive inhibition zones and they were very effective antimicrobial compounds compared to chloramphenicol and amoxicillin. The most susceptible strain against these two essential oils was Staphylococcus aureus. It seems that β-citronellol is a prominent part of P. graveolens volatile oil and caryophyllene oxide is a famous and important part of V. agnus-castus volatile oil and their probable synergistic effect with other constituents are responsible for the antibacterial effects of these oils. However further studies must be performed to confirm the safety of these oils for use as antimicrobial agents and natural preservatives in different products. PMID:23205247

An in vitro investigation of indigenous South African medicinal plants used to treat oral infections.

PubMed

Akhalwaya, S; van Vuuren, S; Patel, M

2018-01-10

Over a 120 South African medicinal plants are used for the treatment of oral diseases. Despite the vast collection of antimicrobial studies being done on South African plants, there is still limited research on pathogens associated with oral infections. In consultation with the available ethnobotanical literature, this study investigates the antimicrobial efficacy of some South African medicinal plants against oral pathogens. To provide a detailed account of the antimicrobial properties of selected South African medicinal plants used traditionally to treat oral infections. The effect on Streptococcus mutans biofilm formation and the toxicity profiles of these plants are also investigated. A total of 136 aqueous and organic extracts and six essential oils were prepared from 31 different plant species. These plant samples were screened for antimicrobial efficacy against nine oral pathogens using the micro-titre plate dilution assay. Plant extracts that were found to have noteworthy antimicrobial activity against S. mutans were further evaluated on the effect on S. mutans biofilm formation using the glass slide technique. The toxicity profiles of plant samples that were found to have noteworthy antimicrobial activity were evaluated using the brine shrimp lethality assay. The organic extract of Cissampelos torulosa stems displayed the lowest MIC value of 0.05mg/mL against both Lactobacillus spp. This high antimicrobial activity was also observed with the organic extract of Spirostachys africana leaves against Candida albicans. In some instances, a direct relationship was found between the traditional use of the plant and the antimicrobial activity observed. For example, noteworthy activity (MIC < 1.00mg/mL) was observed against all three Candida spp. when tested against Clematis brachiata (leaves), a plant traditionally used to treat oral thrush. Englerophytum magalismonatanum stems displayed notable activity against both Streptococcus spp. (MIC 0.83mg/mL against S. mutans and MIC 0.67mg/mL against S. sanguis). Spirostachys africana leaves displayed the greatest anti-adherent properties against S. mutans biofilm formation at both 24 and 48h, reducing the biofilm by 97.56% and 86.58% respectively. The majority of plant samples tested in the brine shrimp lethality assay (BSLA) were considered safe, however, 13 plant samples were considered toxic, at a concentration of 1mg/mL. Noteworthy antimicrobial activity for plants species such as C. brachiata and E. magalismonatnum provides validation for the traditional use of these plants. Spirostachys africana displayed the greatest reduction of adherent S. mutans cells. The BSLA results revealed that the majority of the plant samples were not toxic in nature. The findings from the results favour the potential use of these plants in treating oral diseases such as dental caries, periodontal diseases and oral thrush. Copyright © 2017 Elsevier B.V. All rights reserved.

The US national antimicrobial resistance monitoring system.

PubMed

Gilbert, Jeffrey M; White, David G; McDermott, Patrick F

2007-10-01

The use of antimicrobial agents in food animals can select for resistant bacterial pathogens that may be transmitted to humans via the commercial meat supply. In the USA, the FDA's Center for Veterinary Medicine regulatory duties require a determination that antimicrobial drugs are safe and effective for use in food animals. In addition, a qualitative assessment of risks to human health from antimicrobial resistance requires development. This risk assessment process is supported by data generated by the FDA's National Antimicrobial Resistance Monitoring System (NARMS) for enteric bacteria. NARMS data on antimicrobial susceptibility among Salmonella, Campylobacter, Escherichia coli and Enterococcus is collected. Research activities defining the genetic bases of resistance helps to understand the potential public health risks posed by the spread of antimicrobial resistance from food animal antimicrobial use. These activities help insure that antimicrobials are used judiciously to promote human and animal health.

Efficient synthesis and antimicrobial evaluation of some Mannich bases from 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones.

PubMed

Hussein, Essam M; Masaret, Ghada S; Khairou, Khalid S

2015-01-01

Thiazolidinone, has been employed in the preparation of different important drugs required for treatment of inflammations, bacterial infections, and hypertension. Mannich bases have been shown to exhibit diverse biological activities, such as antibacterial, and antifungal activities. Spiroheterocycles including thiazolidine moiety have antimicrobial activity. In this study, a novel, rapid, and efficient protocol is developed for the synthesis of various 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones using sodium dodecylbenzene sulfonate (DBSNa) as an inexpensive and readily available reagent in acetic acid at room temperature. High yields, easy work-up, and short reaction times are advantages of this procedure. The synthesized arylidines were undergone Mannich reaction with formaldehyde and secondary amines in absolute ethanol at room temperature to afford the corresponding N-Mannich bases. All prepared Mannich bases were evaluated for their antimicrobial activity. Good activity was noted for Mannich bases from 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones, with some members recorded higher antimicrobial activity. Graphical abstractSynthesis of Mannich bases of 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones.

Synthesis of Trypsin-Resistant Variants of the Listeria-Active Bacteriocin Salivaricin P▿

PubMed Central

O'Shea, Eileen F.; O'Connor, Paula M.; Cotter, Paul D.; Ross, R. Paul; Hill, Colin

2010-01-01

Two-component salivaricin P-like bacteriocins have demonstrated potential as antimicrobials capable of controlling infections in the gastrointestinal tract (GIT). The anti-Listeria activity of salivaricin P is optimal when the individual peptides Sln1 and Sln2 are added in succession at a 1:1 ratio. However, as degradation by digestive proteases may compromise the functionality of these peptides within the GIT, we investigated the potential to create salivaricin variants with enhanced resistance to the intestinal protease trypsin. A total of 11 variants of the salivaricin P components, in which conservative modifications at the trypsin-specific cleavage sites were explored in order to protect the peptides from trypsin degradation while maintaining their potent antimicrobial activity, were generated. Analysis of these variants revealed that eight were resistant to trypsin digestion while retaining antimicrobial activity. Combining the complementary trypsin-resistant variants Sln1-5 and Sln2-3 resulted in a MIC50 of 300 nM against Listeria monocytogenes, a 3.75-fold reduction in activity compared to the level for wild-type salivaricin P. This study demonstrates the potential of engineering bacteriocin variants which are resistant to specific protease action but which retain significant antimicrobial activity. PMID:20581174

Antimicrobial activity and determination of bioactive components from marine Alcaligenes faecalis extract against a sulfate-reducing bacteria

NASA Astrophysics Data System (ADS)

AbdSharad, Ali; Usup, Gires; Sahrani, Fathul Karim; Ahmad, Asmat

2016-11-01

Biogenic souring and microbial-influenced corrosion is a common scenario in petroleum reservoir. The serious threat normally comes from sulfate-reducing bacteria (SRB). Alcaligenes faecalis was tested in this study for the ability to inhibit the growth of SRB. Ethyl acetate extraction of A. faecalis grown in marine broth was carried out to produce crude ethyl acetate of A. faecalis (CEAF). CEAF was diluted at concentrations 0.2-12.8 mg/mL and was tested for anti-microbial activity by microdilution susceptibility tests in 96-wells plate. CEAF was then analyzed by Gas Chromatography Mass Spectrometry (GC-MS). The microdilution susceptibility tests showed that the crude have anti- microbial activities on SRB. CEAF showed immediate killing effect against SRB in liquid medium which suggest the presence of active chemical compounds with antimicrobial activity. The GC-MS analysis showed the presence of 20 different chemical compounds in CEAF, The major components in CEAF can be related to antimicrobial, antifungal, antioxidant, pesticide, metabolism, toxicity, anticancer and corrosion inhibition activities. In conclusion, crude ethyl acetate extract of A. faecalis has the ability to inhibit SRB growth.