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Sample records for effective antimicrobial activity

  1. Antimicrobial Activity.

    PubMed

    2016-01-01

    Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter. PMID:26939268

  2. Effects and mechanisms of the secondary structure on the antimicrobial activity and specificity of antimicrobial peptides.

    PubMed

    Mai, Xuan-thanh; Huang, Jinfeng; Tan, Juanjuan; Huang, Yibing; Chen, Yuxin

    2015-07-01

    A 15-mer cationic α-helical antimicrobial peptide HPRP-A1 was used as the parent peptide to study the effects of peptide secondary structure on the biophysical properties and biological activities. Without changing the amino acid composition of HPRP-A1, we designed two α-helical peptides with either higher or lower helicity compared with the parent peptide, a β-sheet peptide and a random coiled peptide using de novo design approach. The secondary structures were confirmed by circular dichroism spectroscopy. The three α-helical peptides exhibited comparable antibacterial activities, but their hemolytic activity varied from extreme hemolysis to no hemolysis, which is correlated with their helicity. The β-sheet peptide shows poor antibacterial and strong hemolytic activities. More interestingly, the random coil peptide shows no antibacterial activity against Gram-negative bacteria, weak antibacterial activity against Gram-positive bacteria, and extremely weak hemolytic activity. Bacterial membrane permeabilization was also testified on peptides with different secondary structures. Tryptophan fluorescence experiment revealed that the peptide binding preference to the lipid vesicles for mimicking the prokaryotic or eukaryotic membranes was consistent with their biological activities. With the de novo design approach, we proved that it is important to maintain certain contents of amphipathic secondary structure for a desirable biological activity. We believe that the de novo design approach of relocation of the amino acids within a template sequence could be an effective approach in optimizing the specificity of an antimicrobial peptide. PMID:25826179

  3. Super-SERS-active and highly effective antimicrobial Ag nanodendrites

    NASA Astrophysics Data System (ADS)

    Li, H. B.; Liu, P.; Liang, Y.; Xiao, J.; Yang, G. W.

    2012-07-01

    We have developed simple and green electrochemistry to synthesize Ag nanostructures with high purity, good crystallinity and smooth surface for applications as super-SERS (surface-enhanced Raman scattering), SERS-active substrates and with highly effective antimicrobial activities. This synthesis takes place in a clean and slow reaction environment without any chemical additives, which ensures an ultrahigh active surface of the as-synthesized Ag nanostructures owing to their purity, good crystallinity and smooth morphology. Using this method, we synthesized nearly perfect Ag nanodendrites (NDs), which exhibit super-SERS sensitivity when they are used to detect the SERS spectra of rhodamine 6G at concentrations as low as 5 10-16 M, and have an ultrahigh electromagnetic (EM) enhancement factor of the order of 1013, breaking through the theoretical limit of EM enhancement. Meanwhile, the as-synthesized Ag NDs possess highly effective antimicrobial activities for Escherichia coli, Candida albicans and Staphylococcus aureus, which are over 10 times that of silver nanoparticles. Additionally, the basic physics and chemistry involved in the fabrication of Ag nanostructures are pursued. These investigations show that silver nanostructures with highly active surfaces can make the most of Ag nanostructures functioning as super-SERS-active substrates and multiple antibiotics.

  4. Antimicrobial Activities of Chemokines: Not Just a Side-Effect?

    PubMed Central

    Wolf, Marlene; Moser, Bernhard

    2012-01-01

    The large family of chemoattractant cytokines (chemokines) embraces multiple, in part unrelated functions that go well beyond chemotaxis. Undoubtedly, the control of immune cell migration (chemotaxis) is the single, unifying response mediated by all chemokines, which involves the sequential engagement of chemokine receptors on migrating target cells. However, numerous additional cellular responses are mediated by some (but not all) chemokines, including angiogenesis, tumor cell growth, T-cell co-stimulation, and control of HIV-1 infection. The recently described antimicrobial activity of several chemokines is of particular interest because antimicrobial peptides are thought to provide an essential first-line defense against invading microbes at the extremely large body surfaces of the skin, lungs, and gastrointestinal-urinary tract. Here we summarize the current knowledge about chemokines with antimicrobial activity and discuss their potential contribution to the control of bacterial infections that may take place at the earliest stage of antimicrobial immunity. In the case of homeostatic chemokines with antimicrobial function, such as CXCL14, we propose an immune surveillance function in healthy epithelial tissues characterized by low-level exposure to environmental microbes. Inflammatory chemokines, i.e., chemokines that are produced in tissue cells in response to microbial antigens (such as pathogen-associated molecular patterns) may be more important in orchestrating the cellular arm in antimicrobial immunity. PMID:22837760

  5. Antimicrobial activity of isopteropodine.

    PubMed

    García, Rubén; Cayunao, Cesia; Bocic, Ronny; Backhouse, Nadine; Delporte, Carle; Zaldivar, Mercedes; Erazo, Silvia

    2005-01-01

    Bioassay-directed fractionation for the determination of antimicrobial activity of Uncaria tomentosa, has led to the isolation of isopteropodine (0.3%), a known Uncaria pentacyclic oxindol alkaloid that exhibited antibacterial activity against Gram positive bacteria. PMID:16042336

  6. Effect of high hydrostatic pressure on antimicrobial activity and quality of Manuka honey.

    PubMed

    Al-Habsi, Nasser A; Niranjan, Keshavan

    2012-12-01

    The antimicrobial activity of Manuka honey is of major interest to beekeepers and the honey industry. In this study, the effect of high hydrostatic pressure and thermal treatments on antimicrobial activity and quality parameters (principally, diastase number and hydroxymethylfurfural levels (HMF)) of Manuka honey were investigated. The honey was subjected to different pressures (100-800MPa) at 25°C for a range of holding times (15-120min). The antimicrobial activity was found to increase with applied pressure for a given holding time, while the diastase number and HMF levels remained, more or less, unaffected. The percentage inhibition in microbial growth correlated linearly (R(2)=0.94) with methyglyoxal concentration in the honey after treatment over the entire range of pressure, temperature and holding times studied. Maximum percentage inhibition (78.83%) was achieved when honey was subjected to 800MPa compared to the control (57.93%). Thermal treatments at higher temperatures were found to have a detrimental effect on antimicrobial activity based on percentage inhibition as well as methylglyoxal content. Thus, it can be concluded that the levels of methylglyoxal, and therefore the antimicrobial effect of Manuka honey, can be enhanced by using high pressure processing without adversely affecting honey quality. PMID:22953879

  7. Automation of antimicrobial activity screening.

    PubMed

    Forry, Samuel P; Madonna, Megan C; López-Pérez, Daneli; Lin, Nancy J; Pasco, Madeleine D

    2016-03-01

    Manual and automated methods were compared for routine screening of compounds for antimicrobial activity. Automation generally accelerated assays and required less user intervention while producing comparable results. Automated protocols were validated for planktonic, biofilm, and agar cultures of the oral microbe Streptococcus mutans that is commonly associated with tooth decay. Toxicity assays for the known antimicrobial compound cetylpyridinium chloride (CPC) were validated against planktonic, biofilm forming, and 24 h biofilm culture conditions, and several commonly reported toxicity/antimicrobial activity measures were evaluated: the 50 % inhibitory concentration (IC50), the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC). Using automated methods, three halide salts of cetylpyridinium (CPC, CPB, CPI) were rapidly screened with no detectable effect of the counter ion on antimicrobial activity. PMID:26970766

  8. 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

  9. Antimicrobial activity of resveratrol analogues.

    PubMed

    Chalal, Malik; Klinguer, Agnès; Echairi, Abdelwahad; Meunier, Philippe; Vervandier-Fasseur, Dominique; Adrian, Marielle

    2014-01-01

    Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew). Stilbenes displayed a spectrum of activity ranging from low to high. Six of them, including the most active ones, were subsequently tested on the development of Botrytis cinerea (fungus responsible for grey mold). The results obtained allowed us to identify the most active stilbenes against both grapevine pathogens, to compare the antimicrobial activity of the evaluated series of stilbenes, and to discuss the relationship between their chemical structure (number and position of methoxy and hydroxy groups) and antimicrobial activity. PMID:24918540

  10. Antimicrobial Activity of Essential Oils against Streptococcus mutans and their Antiproliferative Effects

    PubMed Central

    Galvão, Lívia Câmara de Carvalho; Furletti, Vivian Fernandes; Bersan, Salete Meyre Fernandes; da Cunha, Marcos Guilherme; Ruiz, Ana Lúcia Tasca Góis; de Carvalho, João Ernesto; Sartoratto, Adilson; Rehder, Vera Lúcia Garcia; Figueira, Glyn Mara; Teixeira Duarte, Marta Cristina; Ikegaki, Masarahu; de Alencar, Severino Matias; Rosalen, Pedro Luiz

    2012-01-01

    This study aimed to evaluate the activity of essential oils (EOs) against Streptococcus mutans biofilm by chemically characterizing their fractions responsible for biological and antiproliferative activity. Twenty EO were obtained by hydrodistillation and submitted to the antimicrobial assay (minimum inhibitory (MIC) and bactericidal (MBC) concentrations) against S. mutans UA159. Thin-layer chromatography and gas chromatography/mass spectrometry were used for phytochemical analyses. EOs were selected according to predetermined criteria and fractionated using dry column; the resulting fractions were assessed by MIC and MBC, selected as active fractions, and evaluated against S. mutans biofilm. Biofilms formed were examined using scanning electron microscopy. Selected EOs and their selected active fractions were evaluated for their antiproliferative activity against keratinocytes and seven human tumor cell lines. MIC and MBC values obtained for EO and their active fractions showed strong antimicrobial activity. Chemical analyses mainly showed the presence of terpenes. The selected active fractions inhibited S. mutans biofilm formation (P < 0.05) did not affect glycolytic pH drop and were inactive against keratinocytes, normal cell line. In conclusion, EO showed activity at low concentrations, and their selected active fractions were also effective against biofilm formed by S. mutans and human tumor cell lines. PMID:22685486

  11. Antimicrobial activity of cecropins.

    PubMed

    Moore, A J; Beazley, W D; Bibby, M C; Devine, D A

    1996-06-01

    The lytic peptides, cecropins, were originally isolated from the haemolymph of the giant silk moth, Hyalophora cecropia and possess antibacterial and anticancer activity in vitro. This study investigated the antimicrobial activity of these peptides against human pathogens using standardised assay techniques, and the activity of cecropin B on outer and inner bacterial membranes. From a panel of 15 organisms, Gram-negative bacteria were generally more sensitive to cecropins than Gram-positive organisms, especially the lipopolysaccharide defective mutant, Escherichia coli BUE55. Cecropins B and P1 shared similar MIC values whereas Shiva-1, a cecropin B analogue, was less active. Through combination studies with hydrophobic antibiotics and electron microscopy, cecropin B was shown to disrupt the bacterial outer membrane. Protoplasts of Staphylococcus aureus and Staphylococcus epidermidis were resistant to cecropin B, suggesting that the cytoplasmic membranes of Gram-positive organisms were inherently more resistant to the peptide. PMID:8836811

  12. Antimicrobial effectiveness of six paradols. 1: A structure-activity relationship study.

    PubMed

    Oloke, J K; Kolawole, D O; Erhun, W O

    1989-02-01

    The pattern of antimicrobial effectiveness of (0)-, (2)-, (3)-, (4)-, (8)- and (9)-paradols was studied. (3)- Paradol was more active than the other homologues with a minimum inhibitory concentration (MIC) of 1 mg/ml when tested against Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus and Botryodiplodia theobromae. At 0.2 mg/ml, (3)-paradol completely inhibited the spore germination of Trichophyton mentagrophytes and after 3 h of exposure at 0.5 mg/ml, it inhibited the growth of a heavy inoculum of Staphylococcus aureus (1 X 10(9) cells/ml). PMID:2497275

  13. Which Approach Is More Effective in the Selection of Plants with Antimicrobial Activity?

    PubMed Central

    Silva, Ana Carolina Oliveira; Santana, Elidiane Fonseca; Saraiva, Antonio Marcos; Coutinho, Felipe Neves; Castro, Ricardo Henrique Acre; Pisciottano, Maria Nelly Caetano; Amorim, Elba Lúcia Cavalcanti; Albuquerque, Ulysses Paulino

    2013-01-01

    The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000 µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities. PMID:23878595

  14. Which approach is more effective in the selection of plants with antimicrobial activity?

    PubMed

    Silva, Ana Carolina Oliveira; Santana, Elidiane Fonseca; Saraiva, Antonio Marcos; Coutinho, Felipe Neves; Castro, Ricardo Henrique Acre; Pisciottano, Maria Nelly Caetano; Amorim, Elba Lúcia Cavalcanti; Albuquerque, Ulysses Paulino

    2013-01-01

    The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000 µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities. PMID:23878595

  15. Silver nanoparticles with antimicrobial activities against Streptococcus mutans and their cytotoxic effect.

    PubMed

    Pérez-Díaz, Mario Alberto; Boegli, Laura; James, Garth; Velasquillo, Cristina; Sánchez-Sánchez, Roberto; Martínez-Martínez, Rita-Elizabeth; Martínez-Castañón, Gabriel Alejandro; Martinez-Gutierrez, Fidel

    2015-10-01

    Microbial resistance represents a challenge for the scientific community to develop new bioactive compounds. The goal of this research was to evaluate the antimicrobial activity of silver nanoparticles (AgNPs) against a clinical isolate of Streptococcus mutans, antibiofilm activity against mature S. mutans biofilms and the compatibility with human fibroblasts. The antimicrobial activity of AgNPs against the planktonic clinical isolate was size and concentration dependent, with smaller AgNPs having a lower minimum inhibitory concentration. A reduction of 2.3 log in the number of colony-forming units of S. mutans was observed when biofilms grown in a CDC reactor were exposed to 100 ppm of AgNPs of 9.5±1.1 nm. However, AgNPs at high concentrations (>10 ppm) showed a cytotoxic effect upon human dermal fibroblasts. AgNPs effectively inhibited the growth of a planktonic S. mutans clinical isolate and killed established S. mutans biofilms, which suggests that AgNPs could be used for prevention and treatment of dental caries. Further research and development are necessary to translate this technology into therapeutic and preventive strategies. PMID:26117766

  16. Determination of antimicrobial effect, antioxidant activity and phenolic contents of desert truffle in Turkey.

    PubMed

    Doğan, Hasan Hüseyin; Aydın, Sema

    2013-01-01

    Terfezia boudieri Chatin (Scop.) Pers., is a famous macrofungus in the world as well as in Turkey for its pleasant aroma and flavour. People believe that this mushroom has some medicinal properties. Therefore, it is consumed as food and for medicinal purposes. Chloroform, acetone and methanol extracts of T. boudieri were tested to reveal its antimicrobial activity against four Gram-positive and five Gram-negative bacteria, and one yeast using a micro dilution method. In this study, the highest minimum inhibitory concentration (MIC) value was observed with the acetone extract (MIC, 4.8 µg/mL) against Candida albicans. Maximum antimicrobial effect was also determined with the acetone extract (MIC, 39-78 µg/mL). The scavenging effect of T. boudieri on 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals was measured as 0.031 mg/mL at 5 mg/mL concentration, and its reducing power was 0.214 mg/mL at 0.4 mg/mL. In addition, the phenolic contents were determined as follows: the catechin was 20 mg/g, the ferulic acid was 15 mg/g, the p-coumaric acid was 10 mg/g, and the cinnamic acid was 6 mg/g. The results showed that T. boudieri has antimicrobial activity on the gram negative and positive bacteria as well as yeast, and it also has a high antioxidant capacity. Therefore, T. boudieri can be recommended as an important natural food source. PMID:24146501

  17. Antimicrobial effect of silver particles on bacterial contamination of activated carbon fibers.

    PubMed

    Yoon, Ki Young; Byeon, Jeong Hoon; Park, Chul Woo; Hwang, Jungho

    2008-02-15

    Even though activated carbon fiber (ACF) filters have been widely used in air cleaning for the removal of hazardous gaseous pollutants, because of their extended surface area and high adsorption capacity, bacteria may breed on the ACF filters as a result of their good biocompatibility; ACF filters can themselves become a source of bioaerosols. In this study, silver particles were coated onto an ACF filter, using an electroless deposition method and their efficacy for bioaerosol removal was tested. First, various surface analyses, including scanning electron microscopy, inductively coupled plasma and X-ray diffraction were carried out to characterize the prepared ACF filters. Filtration and antimicrobial tests were then performed on the filters. The results showed that the silver-deposited ACF filters were effective for the removal of bioaerosols by inhibition of the survival of microorganisms, whereas pristine ACF filters were not. Two bacteria, Bacillus subtilis and Escherichia coli, were completely inhibited within 10 and 60 min, respectively. Electroless silver deposition did not influence the physical characteristics of ACF filters such as pressure drop and filtration efficiency. The gas adsorptive ability of the silver-deposited ACF filter, as represented by the micropore specific surface area, decreased by about 20% compared to the pristine filter because of the blockage of the ACF micropores by silver particles. Therefore, the amount of silver particles on the ACF filters needs to be optimized to avoid excessive reduction of their adsorptive characteristics and to show effective antimicrobial activity. PMID:18351101

  18. Antimicrobial activity against periodontopathogenic bacteria, antioxidant and cytotoxic effects of various extracts from endemic Thermopsis turcica

    PubMed Central

    Bali, Elif Burcu; Açık, Leyla; Akca, Gülçin; Sarper, Meral; Elçi, Mualla Pınar; Avcu, Ferit; Vural, Mecit

    2014-01-01

    Objective To investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan, Vural & Küçüködük against periodontopathogenic bacteria, its antioxidant activity and cytotoxic effect on various cancer cell lines. Methods In vitro antimicrobial activities of ethanol, methanol, ethyl acetate (EtAc), n-hexane and water extracts of Thermopsis turcica herb against periodontopathogenic bacteria, Aggregatibacter actinomycetemcomitans ATCC 29523 and Porphyromonas gingivalis ATCC 33277 were tested by agar well diffusion, minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Antioxidant properties of the extracts were evaluated by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity and β-carotene bleaching methods. Amounts of phenolic contents of the extracts were also analysed by using the Folin-Ciocalteu reagent. Additionally, cytotoxic activity of the extracts on androgen-insensitive prostate cancer, androgen-sensitive prostate cancer, chronic myelogenous leukemia and acute promyelocytic leukemia human cancer cell lines were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Human gingival fibroblast cells were used as a control. Results Our data showed that EtAc extract had the highest antimicrobial effect on Aggregatibacter actinomycetemcomitans (MIC: 1.562 mg/mL, MBC: 3.124 mg/mL) and Porphyromonas gingivalis (MIC: 0.781 mg/mL, MBC: 1.562 mg/mL). In antioxidant assays, EtAc extract exhibited also the highest radical scavenging activity [IC50=(30.0±0.3) µg/mL] and the highest inhibition [(74.35±0.30)%] against lineloic acide oxidation. The amount of phenolic content of it was also the highest [(162.5±1.2) µg/mg gallic acid]. In cytotoxic assay, only ethanol [IC50=(80.00±1.21) µg/mL] and EtAc extract [IC50=(70.0±0.9) µg/mL] were toxic on acute promyelocytic leukemia cells at 20-100 µg/mL (P<0.05). However, no toxic effect was observed on human gingival fibroblast cells. Conclusions According to our findings, owing to its antioxidant and cytotoxic potential, EtAc extract might include anticancer agents for acute promyelocytic leukemia. PMID:25183268

  19. 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. PMID:19711918

  20. 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. PMID:24279498

  1. 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. PMID:24906770

  2. Stability, antimicrobial activity, and effect of nisin on the physico-chemical properties of fruit juices.

    PubMed

    de Oliveira Junior, Adelson Alves; de Araújo Couto, Hyrla Grazielle Silva; Barbosa, Ana Andréa Teixeira; Carnelossi, Marcelo Augusto Guitierrez; de Moura, Tatiana Rodrigues

    2015-10-15

    Heat processing is the most commonly used hurdle for inactivating microorganisms in fruit juices. However, this preservation method could interfere with the organoleptic characteristics of the product. Alternative methods have been proposed and bacteriocins such as nisin are potential candidates. However, the approval of bacteriocins as food additives is limited, especially in foods from vegetal origin. We aimed to verify the stability, the effect on physico-chemical properties, and the antimicrobial activity of nisin in different fruit juices. Nisin remained stable in fruit juices (cashew, soursop, peach, mango, passion fruit, orange, guava, and cupuassu) for at least 30 days at room or refrigerated temperature and did not cause any significant alterations in the physico-chemical characteristics of the juices. Besides, nisin favored the preservation of vitamin C content in juices. The antimicrobial activity of nisin was tested against Alicyclobacillus acidoterrestris, Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes in cashew, soursop, peach, and mango juices. Nisin caused a 4-log reduction in viable cells of A. acidoterrestris in soursop, peach, and mango juices after 8h of incubation, and no viable cells were detected in cashew juices. After 24h of incubation in the presence of nisin, no viable cells were detected, independently of the juices. To S. aureus, at 24h of incubation in the presence of nisin, viable cells were only detected in mango juices, representing a 4-log decrease as compared with the control treatment. The number of viable cells of B. cereus at 24h of incubation in the presence of nisin represented at least a 4-log decrease compared to the control treatment. When the antimicrobial activity of nisin was tested against L. monocytogenes in cashew and soursop juices, no reduction in the viable cell number was observed compared to the control treatment after 24h of incubation. Viable cells were four and six times less than in the control treatment, in peach and mango juices respectively. The most sensitive microorganism to nisin was A. acidoterrestris and the least sensitive was L. monocytogenes. Still, a reduction of up to 90% of viable cells was observed in peach and mango juices inoculated with L. monocytogenes. These results indicate that the use of nisin could be an alternative in fruit juice processing. PMID:26162590

  3. Additive antimicrobial [corrected] effects of the active components of the essential oil of Thymus vulgaris--chemotype carvacrol.

    PubMed

    Iten, Felix; Saller, Reinhard; Abel, Gudrun; Reichling, Jürgen

    2009-09-01

    Herbal remedies are multicomponent mixtures by their nature as well as by pharmaceutical definition. Being a multicomponent mixture is not only a crucial property of herbal remedies, it also represents a precondition for interactions such as synergism or antagonism. Until now, only a few phytomedicines are accurately described concerning the interactions of their active components. The aim of this study was to search for interactions within such a naturally given multi-component mixture and to discuss the pharmaceutical and clinical impacts. The thyme oil chosen for the examination belongs to the essential oils with the most pronounced antimicrobial activity. Antibiotic activity of thyme oil and single active components were tested against six different strains of microorganisms. The checkerboard assay was used to search for interactions. The time-kill assay was used to verify the observed effects and to get information about the temporal resolution of the antimicrobial activity. The degree of the detected interactions corresponded with the demarcating FICI measure of 0.5, which separates the additive from the over-additive (synergistic) effects. Therefore, the observed effect was called a "borderline case of synergism" or, respectively, "partial synergism". Partial synergism was observed only in the presence of Klebsiella pneumoniae. Additive antimicrobial activity was observed for the combination of the two monosubstances carvacrol plus linalool and thymol plus linalool as well as with the combination of the two essential oils of the carvacrol and linalool chemotypes. An increase of the carvacrol oil concentration from one to two times the MIC resulted in a considerable acceleration of the kill-rate. Thyme oil is composed of several different components that show antimicrobial activity (at least: carvacrol, thymol and linalool). The antimicrobial activity of thyme oil is partly based on additive effects, which might especially enhance the rapidity of the antimicrobial action. In addition, a mixture of several active ingredients that varies in its composition from year to year and from lot to lot as is the case with herbal remedies may be more stable concerning the antimicrobial activity than mixtures containing just a single active component. PMID:19347798

  4. Effect of gamma irradiation on chemical composition, antimicrobial and antioxidant activities of Thymus vulgaris and Mentha pulegium essential oils

    NASA Astrophysics Data System (ADS)

    Zantar, Said; Haouzi, Rachid; Chabbi, Mohamed; Laglaoui, Amin; Mouhib, Mohammed; Mohammed Boujnah; Bakkali, Mohammed; Zerrouk, Mounir Hassani

    2015-10-01

    The effects of gamma irradiation doses (10, 20 and 30 kGy) on chemical composition, antimicrobial and antioxidant activities of Thymus vulgaris and Mentha pulegium essential oils (EOs) have been studied. The chromatographic analysis showed that the studied EOs were constituted mainly by carvacrol for T. vulgaris and pulegone for M. pulegium. Gamma irradiation on the studied doses, affects quantitatively and not qualitatively some components of the investigated oils. This effect was dose dependent. While the antioxidant activity remains stable at any dose applied for the plants studied, the antimicrobial activity increased in the irradiated samples for gram negative bacteria and did not change for gram+bacteria. This study supports that gamma irradiation employed at sterilizing doses did not compromise the biological activities of medicinal and aromatic plants.

  5. 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

  6. High antimicrobial effectiveness with low hemolytic and cytotoxic activity for PEG/quaternary copolyoxetanes.

    PubMed

    King, Allison; Chakrabarty, Souvik; Zhang, Wei; Zeng, Xiaomei; Ohman, Dennis E; Wood, Lynn F; Abraham, Sheena; Rao, Raj; Wynne, Kenneth J

    2014-02-10

    The alkyl chain length of quaternary ammonium/PEG copolyoxetanes has been varied to discern effects on solution antimicrobial efficacy, hemolytic activity and cytotoxicity. Monomers 3-((4-bromobutoxy)methyl)-3-methyloxetane (BBOx) and 3-((2-(2-methoxyethoxy)ethoxy)methyl)-3-methyloxetane (ME2Ox) were used to prepare precursor P[(BBOx)(ME2Ox)-50:50-4 kDa] copolyoxetane via cationic ring opening polymerization. The 1:1 copolymer composition and Mn (4 kDa) were confirmed by (1)H NMR spectroscopy. After C-Br substitution by a series of tertiary amines, ionic liquid Cx-50 copolyoxetanes were obtained, where 50 is the mole percent of quaternary repeat units and "x" is quaternary alkyl chain length (2, 6, 8, 10, 12, 14, or 16 carbons). Modulated differential scanning calorimetry (MDSC) studies showed Tgs between -40 and -60 °C and melting endotherms for C14-50 and C16-50. Minimum inhibitory concentrations (MIC) were determined for Escherichia coli , Staphylococcus aureus , and Pseudomonas aeruginosa . A systematic dependence of MIC on alkyl chain length was found. The most effective antimicrobials were in the C6-50 to C12-50 range. C8-50 had better overall performance with MICs of 4 μg/mL, E. coli ; 2 μg/mL, S. aureus ; and 24 μg/mL, P. aeruginosa . At 5 × MIC, C8-50 effected >99% kill in 1 h against S. aureus , E. coli , and P. aeruginosa challenges of 10(8) cfu/mL; log reductions (1 h) were 7, 3, and 5, respectively. To provide additional insight into polycation interactions with bacterial membranes, a geometric model based on the dimensions of E. coli is described that provides an estimate of the maximum number of polycations that can chemisorb. Chain dimensions were estimated for polycation C8-50 with a molecular weight of 5 kDa. Considering the approximations for polycation chemisorption (PCC), it is surprising that a calculation based on geometric considerations gives a C8-50 concentration within a factor of 2 of the MIC, 4.0 (±1.2) μg/mL for E. coli . Cx-50 copolyoxetane cytotoxicity was low for human red blood cells, human dermal fibroblasts (HDF), and human foreskin fibroblasts (HFF). Selectivities for bacterial kill over cell lysis were among the highest ever reported for polycations indicating good prospects for biocompatibility. PMID:24422429

  7. Antimicrobial and antiviral activity of hydrolysable tannins.

    PubMed

    Buzzini, Pietro; Arapitsas, Panagiotis; Goretti, Marta; Branda, Eva; Turchetti, Benedetta; Pinelli, Patrizia; Ieri, F; Romani, Annalisa

    2008-10-01

    Hydrolysable tannins (HTs), secondary metabolites widely distributed in the plant kingdom, are generally multiple esters of gallic acid with glucose. HTs have been shown to be effective antagonists against viruses, bacteria and eukaryotic microorganisms. The present review examines the antimicrobial and antiviral activity of HTs, the mechanism(s) of action, and some structure-activity relationships. PMID:18855732

  8. Antimicrobial and antiviral activity of hydrolysable tannins.

    TOXLINE Toxicology Bibliographic Information

    Buzzini P; Arapitsas P; Goretti M; Branda E; Turchetti B; Pinelli P; Ieri F; Romani A

    2008-10-01

    Hydrolysable tannins (HTs), secondary metabolites widely distributed in the plant kingdom, are generally multiple esters of gallic acid with glucose. HTs have been shown to be effective antagonists against viruses, bacteria and eukaryotic microorganisms. The present review examines the antimicrobial and antiviral activity of HTs, the mechanism(s) of action, and some structure-activity relationships.

  9. Effect of a single polymorphism in the Japanese quail NK-lysin gene on antimicrobial activity.

    PubMed

    Ishige, Taichiro; Hara, Hiromi; Hirano, Takashi; Kono, Tomohiro; Hanzawa, Kei

    2016-01-01

    NK-lysins are cationic peptides that play important roles in host protection, and are an important constituent of innate immunity. We identified nine single-nucleotide polymorphisms (SNPs) in the NK-lysin open reading frame (ORF) from 32 Japanese quails in six strains: A, B, ND, K, P, and Y. The G to A substitution at nucleotide position 272 in the ORF resulted in a Gly (G) to Asp (D) amino acid substitution (Cj31G and Cj31D alleles). The Cj31D allele was detected in P (frequency 0.76) and Y (frequency 0.03) strains. We compared the antimicrobial activities of four synthetic peptides from the helix 2-loop-helix 3 region of avian NK-lysins against Escherichia coli: Cj31G and Cj31D from quail and Gg29N and Gg29D from chicken. The antimicrobial activities of the four peptides decreased in the following order: Gg29N > Cj31G > Gg29D > Cj31D (P < 0.05). Although there were no differences in the predicted secondary structure of the Cj31G and Cj31D, the net charge of the Cj31G was higher than that of Cj31D. These data indicated that the antimicrobial activity of CjNKL is influenced by net charge, similar to that which has been observed in chicken. 2015 Japanese Society of Animal Science. PMID:26472627

  10. Effect of addition of 2% chlorhexidine or 10% doxycycline on antimicrobial activity of biodentine

    PubMed Central

    Nikhil, Vineeta; Madan, Molly; Agarwal, Charu; Suri, Navleen

    2014-01-01

    Aim: The purpose of this in vitro study was to determine whether the addition of 2% chlorhexidine gluconate or 10% doxycycline would enhance the antimicrobial activity of Biodentine against Staphylococcus aureus (ATCC-25923), Enterococcus faecalis (ATCC-29212), Candida albicans (ATCC-90028), and Streptococcus mutans (MTCC-497). Materials and Methods: Three wells of 4 mm diameter and 4 mm depth on each plate were prepared on the agar medium with standardized suspensions of each microorganism. Biodentine powder mixed with 2% chlorhexidine (0.06 g) or 10% doxycycline (0.30 g) in its liquid or liquid alone was placed to fill each well. Plates were incubated at 37°C as required for microbial growth. A blinded, independent observer measured zones of inhibition. The data were analyzed using independent “t” test to compare the differences among the three cement preparations for different micro-organisms. Results: All Biodentine samples inhibited microbial growth. The highest mean diameters of zone of inhibition for all the micro-organisms were found around Biodentine/chlorhexidine (13.417) followed by Biodentine alone (12.236) and Biodentine/doxycycline (11.25). Conclusion: In conclusion, adding 2% chlorhexidine gluconate in liquid of Biodentine enhanced the antimicrobial activity of Biodentine against all the tested micro-organisms except Candida albicans, while addition of 10% doxycycline decreased the antimicrobial activity of Biodentine. The differences were significant statistically (P < 0.05). PMID:24944453

  11. Effects of allspice, cinnamon, and clove bud essential oils in edible apple films on physical properties and antimicrobial activities.

    PubMed

    Du, W-X; Olsen, C W; Avena-Bustillos, R J; McHugh, T H; Levin, C E; Friedman, Mendel

    2009-09-01

    Essential oils (EOs) derived from plants are rich sources of volatile terpenoids and phenolic compounds. Such compounds have the potential to inactivate pathogenic bacteria on contact and in the vapor phase. Edible films made from fruits or vegetables containing EOs can be used commercially to protect food against contamination by pathogenic bacteria. EOs from cinnamon, allspice, and clove bud plants are compatible with the sensory characteristics of apple-based edible films. These films could extend product shelf life and reduce risk of pathogen growth on food surfaces. This study evaluated physical properties (water vapor permeability, color, tensile properties) and antimicrobial activities against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes of allspice, cinnamon, and clove bud oils in apple puree film-forming solutions formulated into edible films at 0.5% to 3% (w/w) concentrations. Antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor phase diffusion of the antimicrobial from the film to the bacteria. The antimicrobial activities against the 3 pathogens were in the following order: cinnamon oil > clove bud oil > allspice oil. The antimicrobial films were more effective against L. monocytogenes than against the S. enterica. The oils reduced the viscosity of the apple solutions and increased elongation and darkened the colors of the films. They did not affect water vapor permeability. The results show that apple-based films with allspice, cinnamon, or clove bud oils were active against 3 foodborne pathogens by both direct contact with the bacteria and indirectly by vapors emanating from the films. PMID:19895483

  12. Antimicrobial activity of lactic acid bacteria in dairy products and gut: effect on pathogens.

    PubMed

    Arqués, Juan L; Rodríguez, Eva; Langa, Susana; Landete, José María; Medina, Margarita

    2015-01-01

    The food industry seeks alternatives to satisfy consumer demands of safe foods with a long shelf-life able to maintain the nutritional and organoleptic quality. The application of antimicrobial compounds-producing protective cultures may provide an additional parameter of processing in order to improve the safety and ensure food quality, keeping or enhancing its sensorial characteristics. In addition, strong evidences suggest that certain probiotic strains can confer resistance against infection with enteric pathogens. Several mechanisms have been proposed to support this phenomenon, including antimicrobial compounds secreted by the probiotics, competitive exclusion, or stimulation of the immune system. Recent research has increasingly demonstrated the role of antimicrobial compounds as protective mechanism against intestinal pathogens and therefore certain strains could have an effect on both the food and the gut. In this aspect, the effects of the combination of different strains keep unknown. The development of multistrain probiotic dairy products with good technological properties and with improved characteristics to those shown by the individual strains, able to act not only as protective cultures in foods, but also as probiotics able to exert a protective action against infections, has gained increased interest. PMID:25861634

  13. Antimicrobial Activity of Lactic Acid Bacteria in Dairy Products and Gut: Effect on Pathogens

    PubMed Central

    Rodríguez, Eva; Landete, José María

    2015-01-01

    The food industry seeks alternatives to satisfy consumer demands of safe foods with a long shelf-life able to maintain the nutritional and organoleptic quality. The application of antimicrobial compounds-producing protective cultures may provide an additional parameter of processing in order to improve the safety and ensure food quality, keeping or enhancing its sensorial characteristics. In addition, strong evidences suggest that certain probiotic strains can confer resistance against infection with enteric pathogens. Several mechanisms have been proposed to support this phenomenon, including antimicrobial compounds secreted by the probiotics, competitive exclusion, or stimulation of the immune system. Recent research has increasingly demonstrated the role of antimicrobial compounds as protective mechanism against intestinal pathogens and therefore certain strains could have an effect on both the food and the gut. In this aspect, the effects of the combination of different strains keep unknown. The development of multistrain probiotic dairy products with good technological properties and with improved characteristics to those shown by the individual strains, able to act not only as protective cultures in foods, but also as probiotics able to exert a protective action against infections, has gained increased interest. PMID:25861634

  14. Antimicrobial activity against oral pathogens and immunomodulatory effects and toxicity of geopropolis produced by the stingless bee Melipona fasciculata Smith

    PubMed Central

    2011-01-01

    Background Native bees of the tribe Meliponini produce a distinct kind of propolis called geopropolis. Although many pharmacological activities of propolis have already been demonstrated, little is known about geopropolis, particularly regarding its antimicrobial activity against oral pathogens. The present study aimed at investigating the antimicrobial activity of M. fasciculata geopropolis against oral pathogens, its effects on S. mutans biofilms, and the chemical contents of the extracts. A gel prepared with a geopropolis extract was also analyzed for its activity on S. mutans and its immunotoxicological potential. Methods Antimicrobial activities of three hydroalcoholic extracts (HAEs) of geopropolis, and hexane and chloroform fractions of one extract, were evaluated using the agar diffusion method and the broth dilution technique. Ethanol (70%, v/v) and chlorhexidine (0.12%, w/w) were used as negative and positive controls, respectively. Total phenol and flavonoid concentrations were assayed by spectrophotometry. Immunotoxicity was evaluated in mice by topical application in the oral cavity followed by quantification of biochemical and immunological parameters, and macro-microscopic analysis of animal organs. Results Two extracts, HAE-2 and HAE-3, showed inhibition zones ranging from 9 to 13 mm in diameter for S. mutans and C. albicans, but presented no activity against L. acidophilus. The MBCs for HAE-2 and HAE-3 against S. mutans were 6.25 mg/mL and 12.5 mg/mL, respectively. HAE-2 was fractionated, and its chloroform fraction had an MBC of 14.57 mg/mL. HAE-2 also exhibited bactericidal effects on S. mutans biofilms after 3 h of treatment. Significant differences (p < 0.05) in total phenol and flavonoid concentrations were observed among the samples. Signs toxic effects were not observed after application of the geopropolis-based gel, but an increase in the production of IL-4 and IL-10, anti-inflammatory cytokines, was detected. Conclusions In summary, geopropolis produced by M. fasciculata can exert antimicrobial action against S. mutans and C. albicans, with significant inhibitory activity against S. mutans biofilms. The extract with the highest flavonoid concentration, HAE-2, presented the highest antimicrobial activity. In addition, a geopropolis-based gel is not toxic in an animal model and displays anti-inflammatory effect. PMID:22053900

  15. Antimicrobial activity of Viola tricolor herb.

    PubMed

    Witkowska-Banaszczak, Ewa; Bylka, Wiesława; Matławska, Irena; Goślińska, Olga; Muszyński, Zygmunt

    2005-07-01

    The antimicrobial activity of infusion, decoction, ethanol extract and fractions obtained by successive extraction of Viola tricolor herb with dichloromethane, ethyl acetate and methanol was evaluated. The infusion, decoction and ethanol extract were found to be most effective against the tested microorganisms. PMID:15893888

  16. Antimicrobial Activity of Commercial Nanoparticles

    NASA Astrophysics Data System (ADS)

    Gajjar, Priyanka; Pettee, Brian; Britt, David W.; Huang, Wenjie; Johnson, William P.; Anderson, Anne J.

    2009-07-01

    Engineered nanoparticles are finding increased use in applications ranging from biosensors to prophylactic antimicrobials embedded in socks. The release of heavy metal-containing nanoparticles (NP) into the environment may be harmful to the efficacy of beneficial microbes that function in element cycling, pollutant degradation, and plant growth. Antimicrobial activity of commercial NP of Ag, CuO, and ZnO is demonstrated here against the beneficial soil microbe, Pseudomonas putida KT2440, which was modified to serve as a bioluminescent sentinel organism. "As manufactured" preparations of nano- Ag, -CuO, and -ZnO caused rapid, dose dependent loss of light output in the biosensor. Bulk equivalents of these products showed no inhibitory activity, indicating that particle size was determinant in activity.

  17. Antimicrobial activity of carbon-based nanoparticles.

    PubMed

    Maleki Dizaj, Solmaz; Mennati, Afsaneh; Jafari, Samira; Khezri, Khadejeh; Adibkia, Khosro

    2015-03-01

    Due to the vast and inappropriate use of the antibiotics, microorganisms have begun to develop resistance to the commonly used antimicrobial agents. So therefore, development of the new and effective antimicrobial agents seems to be necessary. According to some recent reports, carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs) (especially single-walled carbon nanotubes (SWCNTs)) and graphene oxide (GO) nanoparticles show potent antimicrobial properties. In present review, we have briefly summarized the antimicrobial activity of carbon-based nanoparticles together with their mechanism of action. Reviewed literature show that the size of carbon nanoparticles plays an important role in the inactivation of the microorganisms. As major mechanism, direct contact of microorganisms with carbon nanostructures seriously affects their cellular membrane integrity, metabolic processes and morphology. The antimicrobial activity of carbon-based nanostructures may interestingly be investigated in the near future owing to their high surface/volume ratio, large inner volume and other unique chemical and physical properties. In addition, application of functionalized carbon nanomaterials as carriers for the ordinary antibiotics possibly will decrease the associated resistance, enhance their bioavailability and provide their targeted delivery. PMID:25789215

  18. Antimicrobial Activity of Carbon-Based Nanoparticles

    PubMed Central

    Maleki Dizaj, Solmaz; Mennati, Afsaneh; Jafari, Samira; Khezri, Khadejeh; Adibkia, Khosro

    2015-01-01

    Due to the vast and inappropriate use of the antibiotics, microorganisms have begun to develop resistance to the commonly used antimicrobial agents. So therefore, development of the new and effective antimicrobial agents seems to be necessary. According to some recent reports, carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs) (especially single-walled carbon nanotubes (SWCNTs)) and graphene oxide (GO) nanoparticles show potent antimicrobial properties. In present review, we have briefly summarized the antimicrobial activity of carbon-based nanoparticles together with their mechanism of action. Reviewed literature show that the size of carbon nanoparticles plays an important role in the inactivation of the microorganisms. As major mechanism, direct contact of microorganisms with carbon nanostructures seriously affects their cellular membrane integrity, metabolic processes and morphology. The antimicrobial activity of carbon-based nanostructures may interestingly be investigated in the near future owing to their high surface/volume ratio, large inner volume and other unique chemical and physical properties. In addition, application of functionalized carbon nanomaterials as carriers for the ordinary antibiotics possibly will decrease the associated resistance, enhance their bioavailability and provide their targeted delivery. PMID:25789215

  19. Antimicrobial Activities of Fidaxomicin

    PubMed Central

    Goldstein, Ellie J. C.; Babakhani, Farah; Citron, Diane M.

    2012-01-01

    Fidaxomicin is bactericidal against Clostridium difficile. The combined results of 8 in vitro studies of 1323 C. difficile isolates showed the minimum inhibitory concentration (MIC) range of fidaxomicin to be ≤0.001–1 μg/mL, with a maximum MIC for inhibition of 90% of organisms (MIC90) of 0.5 μg/mL. Isolates from 2 phase III clinical trials demonstrated that fidaxomicin MICs of baseline isolates did not predict clinical cure, failure, or recurrence of C. difficile infections. No resistance to fidaxomicin developed during treatment in either study, although a single strain recovered from a cured patient had an elevated MIC of 16 µg/mL at the time of recurrence. For 135 strains, OP-1118, a major metabolite, had an MIC for inhibition of 50% of organisms of 4 μg/mL and an MIC90 of 8 μg/mL. Changes in inoculum size (102–105 colony-forming units/spot) or cation concentrations of calcium or magnesium appeared to have no effect on fidaxomicin MICs. Fidaxomicin has little or no activity against gram-negative aerobes and anaerobes or yeast. PMID:22752863

  20. Antimicrobial activities of fidaxomicin.

    PubMed

    Goldstein, Ellie J C; Babakhani, Farah; Citron, Diane M

    2012-08-01

    Fidaxomicin is bactericidal against Clostridium difficile. The combined results of 8 in vitro studies of 1323 C. difficile isolates showed the minimum inhibitory concentration (MIC) range of fidaxomicin to be ≤ 0.001-1 μg/mL, with a maximum MIC for inhibition of 90% of organisms (MIC(90)) of 0.5 μg/mL. Isolates from 2 phase III clinical trials demonstrated that fidaxomicin MICs of baseline isolates did not predict clinical cure, failure, or recurrence of C. difficile infections. No resistance to fidaxomicin developed during treatment in either study, although a single strain recovered from a cured patient had an elevated MIC of 16 µg/mL at the time of recurrence. For 135 strains, OP-1118, a major metabolite, had an MIC for inhibition of 50% of organisms of 4 μg/mL and an MIC(90) of 8 μg/mL. Changes in inoculum size (10(2)-10(5) colony-forming units/spot) or cation concentrations of calcium or magnesium appeared to have no effect on fidaxomicin MICs. Fidaxomicin has little or no activity against gram-negative aerobes and anaerobes or yeast. PMID:22752863

  1. Effect of water-aging on the antimicrobial activities of an ORMOSIL-containing orthodontic acrylic resin

    PubMed Central

    Gong, Shi-qiang; Epasinghe, D. Jeevanie; Zhou, Bin; Niu, Li-na; Kimmerling, Kirk A.; Rueggeberg, Frederick A.; Yiu, Cynthia K.Y.; Mao, Jing; Pashley, David H.; Tay, Franklin R.

    2013-01-01

    Quaternary ammonium methacryloxy silicate (QAMS), an organically modified silicate (ORMOSIL) functionalized with polymerizable methacrylate groups and an antimicrobial agent with a long lipophilic alkyl chain quaternary ammonium group, was synthesized through a silane-based sol–gel route. By dissolving QAMS in methyl methacrylate monomer, this ORMOSIL molecule was incorporated into an auto-polymerizing, powder/liquid orthodontic acrylic resin system, yielding QAMS-containing poly (methyl methacrylate). The QAMS-containing acrylic resin showed a predominant contact-killing effect on Streptococcus mutans (ATCC 35668) and Actinomyces naeslundii (ATCC 12104) biofilms, while inhibiting adhesion of Candida albicans (ATCC 90028) on the acrylic surface. The antimicrobial activities of QAMS-containing acrylic resin were maintained after a 3 month water-aging period. Bromophenol blue assay showed minimal leaching of quaternary ammonium species when an appropriate amount of QAMS (<4 wt.%) was incorporated into the acrylic resin. The results suggest that QAMS is predominantly co-polymerized with the poly(methyl methacrylate) network, and only a minuscule amount of free QAMS molecules is present within the polymer network after water-aging. Acrylic resin with persistent antimicrobial activities represents a promising method for preventing bacteria- and fungus-induced stomatitis, an infectious disease commonly associated with the wearing of removable orthodontic appliances. PMID:23485857

  2. The antimicrobial efficiency of silver activated sorbents

    NASA Astrophysics Data System (ADS)

    Đolić, Maja B.; Rajaković-Ognjanović, Vladana N.; Štrbac, Svetlana B.; Rakočević, Zlatko Lj.; Veljović, Đorđe N.; Dimitrijević, Suzana I.; Rajaković, Ljubinka V.

    2015-12-01

    This study is focused on the surface modifications of the materials that are used for antimicrobial water treatment. Sorbents of different origin were activated by Ag+-ions. The selection of the most appropriate materials and the most effective activation agents was done according to the results of the sorption and desorption kinetic studies. Sorption capacities of selected sorbents: granulated activated carbon (GAC), zeolite (Z), and titanium dioxide (T), activated by Ag+-ions were following: 42.06, 13.51 and 17.53 mg/g, respectively. The antimicrobial activity of Ag/Z, Ag/GAC and Ag/T sorbents were tested against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and yeast C. albicans. After 15 min of exposure period, the highest cell removal was obtained using Ag/Z against S. aureus and E. coli, 98.8 and 93.5%, respectively. Yeast cell inactivation was unsatisfactory for all three activated sorbents. The antimicrobial pathway of the activated sorbents has been examined by two separate tests - Ag+-ions desorbed from the activated surface to the aqueous phase and microbial cell removal caused by the Ag+-ions from the solid phase (activated surface sites). The results indicated that disinfection process significantly depended on the microbial-activated sites interactions on the modified surface. The chemical state of the activating agent had crucial impact to the inhibition rate. The characterization of the native and modified sorbents was performed by X-ray diffraction technique, X-ray photoelectron spectroscopy and scanning electron microscope. The concentration of adsorbed and released ions was determined by inductively coupled plasma optical emission spectroscopy and mass spectrometry. The antimicrobial efficiency of activated sorbents was related not only to the concentration of the activating agent, but moreover on the surface characteristics of the material, which affects the distribution and the accessibility of the activating agent.

  3. Size and Aging Effects on Antimicrobial Efficiency of Silver Nanoparticles Coated on Polyamide Fabrics Activated by Atmospheric DBD Plasma.

    PubMed

    Zille, Andrea; Fernandes, Margarida M; Francesko, Antonio; Tzanov, Tzanko; Fernandes, Marta; Oliveira, Fernando R; Almeida, Luís; Amorim, Teresa; Carneiro, Noémia; Esteves, Maria F; Souto, António P

    2015-07-01

    This work studies the surface characteristics, antimicrobial activity, and aging effect of plasma-pretreated polyamide 6,6 (PA66) fabrics coated with silver nanoparticles (AgNPs), aiming to identify the optimum size of nanosilver exhibiting antibacterial properties suitable for the manufacture of hospital textiles. The release of bactericidal Ag(+) ions from a 10, 20, 40, 60, and 100 nm AgNPs-coated PA66 surface was a function of the particles' size, number, and aging. Plasma pretreatment promoted both ionic and covalent interactions between AgNPs and the formed oxygen species on the fibers, favoring the deposition of smaller-diameter AgNPs that consequently showed better immediate and durable antimicrobial effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. Surprisingly, after 30 days of aging, a comparable bacterial growth inhibition was achieved for all of the fibers treated with AgNPs <100 nm in size. The Ag(+) in the coatings also favored the electrostatic stabilization of the plasma-induced functional groups on the PA66 surface, thereby retarding the aging process. At the same time, the size-related ratio (Ag(+)/Ag(0)) of the AgNPs between 40 and 60 nm allowed for the controlled release of Ag(+) rather than bulk silver. Overall, the results suggest that instead of reducing the size of the AgNPs, which is associated with higher toxicity, similar long-term effects can be achieved with larger NPs (40-60 nm), even in lower concentrations. Because the antimicrobial efficiency of AgNPs larger than 30 nm is mainly ruled by the release of Ag(+) over time and not by the size and number of the AgNPs, this parameter is crucial for the development of efficient antimicrobial coatings on plasma-treated surfaces and contributes to the safety and durability of clothing used in clinical settings. PMID:26057400

  4. [Propolis' antimicrobial activity: what's new?].

    PubMed

    De Vecchi, Elena; Drago, Lorenzo

    2007-03-01

    Propolis is a hive product that bees manufacture from balsamic resins actively secreted by plants on leaf buds and barks. Propolis composition is highly variable, depending on the plant species and on the season of collection. However, propolis essentially contains resins, balsams, essential oils, flavonoids, vitamins, minerals and pollen, albeit at different concentrations. Although more than 300 constituents have been identified in propolis samples, biological activity is mainly due to few substances, such as flavonoids, terpens, caffeic, ferulic and cumaric acids and esters. Propolis is characterized by multifactorial activities, but only some of them have been substantiated by clinical and experimental evidence. It is widely acknowledged to exert antimicrobial activity against a wide range of microorganisms (bacteria, fungi and viruses), but also exerts antiinflammatory, anaesthetic, healing, vasoprotective, antioxidant, antitumoral, antiulcer and hepatoprotective activities. The wide spectrum of activities has led in recent years to the development of new technologies to improve propolis properties of the traditional hydroalcoholic extract. This paper reviews the antimicrobial properties of propolis, focusing on respiratory pathogens. These characteristics make propolis a valid option for therapy of upper respiratory tract infections. PMID:17515670

  5. Magnesium Based Materials and their Antimicrobial Activity

    NASA Astrophysics Data System (ADS)

    Robinson, Duane Allan

    The overall goals of this body of work were to characterize the antimicrobial properties of magnesium (Mg) metal and nano-magnesium oxide (nMgO) in vitro, to evaluate the in vitro cytotoxicity of Mg metal, and to incorporate MgO nanoparticles into a polymeric implant coating and evaluate its in vitro antimicrobial properties. In the course of this work it was found that Mg metal, Mg-mesh, and nMgO have in vitro antimicrobial properties that are similar to a bactericidal antibiotic. For Mg metal, the mechanism of this activity appears to be related to an increase in pH (i.e. a more alkaline environment) and not an increase in Mg2+. Given that Mg-mesh is a Mg metal powder, the assumption is that it has the same mechanism of activity as Mg metal. The mechanism of activity for nMgO remains to be elucidated and may be related to a combination of interaction of the nanoparticles with the bacteria and the alkaline pH. It was further demonstrated that supernatants from suspensions of Mg-mesh and nMgO had the same antimicrobial effect as was noted when the particles were used. The supernatant from Mg-mesh and nMgO was also noted to prevent biofilm formation for two Staphylococcus strains. Finally, poly-epsilon-caprolactone (PCL) composites of Mg-mesh (PCL+Mg-mesh) and nMgO (PCL+nMgO) were produced. Coatings applied to screws inhibited growth of Escherichia coli and Pseudomonas aeruginosa and in thin disc format inhibited the growth of Staphylococcus aureus in addition to the E. coli and P. aeruginosa. Pure Mg metal was noted to have some cytotoxic effect on murine fibroblast and osteoblast cell lines, although this effect needs to be characterized further. To address the need for an in vivo model for evaluating implant associated infections, a new closed fracture osteomyelitis model in the femur of the rat was developed. Magnesium, a readily available and inexpensive metal was shown to have antimicrobial properties that appear to be related to its corrosion products and that nMgO has similar effects. Incorporation of nMgO into a PCL composite was easily achieved and revealed similar, although not identical antimicrobial results. This work has provided a strong foundation and methodology for further evaluation of Mg based materials and their antimicrobial properties.

  6. Effects of hydrophobicity on the antifungal activity of alpha-helical antimicrobial peptides.

    PubMed

    Jiang, Ziqing; Kullberg, Bart Jan; van der Lee, Hein; Vasil, Adriana I; Hale, John D; Mant, Colin T; Hancock, Robert E W; Vasil, Michael L; Netea, Mihai G; Hodges, Robert S

    2008-12-01

    We utilized a series of analogs of D-V13K (a 26-residue amphipathic alpha-helical antimicrobial peptide, denoted D1) to compare and contrast the role of hydrophobicity on antifungal and antibacterial activity to the results obtained previously with Pseudomonas aeruginosa strains. Antifungal activity for zygomycota fungi decreased with increasing hydrophobicity (D-V13K/A12L/A20L/A23L, denoted D4, the most hydrophobic analog was sixfold less active than D1, the least hydrophobic analog). In contrast, antifungal activity for ascomycota fungi increased with increasing hydrophobicity (D4, the most hydrophobic analog was fivefold more active than D1). Hemolytic activity is dramatically affected by increasing hydrophobicity with peptide D4 being 286-fold more hemolytic than peptide D1. The therapeutic index for peptide D1 is 1569-fold and 62-fold better for zygomycota fungi and ascomycota fungi, respectively, compared with peptide D4. To reduce the hemolytic activity of peptide D4 and improve/maintain the antifungal activity of D4, we substituted another lysine residue in the center of the non-polar face (V16K) to generate D5 (D-V13K/V16K/A12L/A20L/A23L). This analog D5 decreased hemolytic activity by 13-fold, enhanced antifungal activity to zygomycota fungi by 16-fold and improved the therapeutic index by 201-fold compared with D4 and represents a unique approach to control specificity while maintaining high hydrophobicity in the two hydrophobic segments on the non-polar face of D5. PMID:19090916

  7. Effect of gamma irradiation on the antimicrobial and free radical scavenging activities of Glycyrrhiza glabra root

    NASA Astrophysics Data System (ADS)

    Fatima Khattak, Khanzadi; James Simpson, Thomas

    2010-04-01

    The efficacy of gamma irradiation as a method of decontamination for food and herbal materials is well established. In the present study, Glycyrrhiza glabra roots were irradiated at doses 5, 10, 15, 20 and 25 kGy in a cobalt-60 irradiator. The irradiated and un-irradiated control samples were evaluated for phenolic contents, antimicrobial activities and DPPH scavenging properties. The result of the present study showed that radiation treatment up to 20 kGy does not affect the antifungal and antibacterial activity of the plant. While sample irradiated at 25 kGy does showed changes in the antibacterial activity against some selected pathogens. No significant differences in the phenolic contents were observed for control and samples irradiated at 5, 10 and 15 kGy radiation doses. However, phenolic contents increased in samples treated with 20 and 25 kGy doses. The DPPH scavenging activity significantly ( p<0.05) increased in all irradiated samples of the plant.

  8. Antimicrobial preservative effectiveness of natural peptide antibiotics.

    PubMed

    Kamysz, Wojciech; Turecka, Katarzyna

    2005-01-01

    The constantly growing resistance of microbes to drugs and other substances which fight microbial infections leads to search for new antimicrobial substances. Among substances which attract the scientists attention are antimicrobial peptides. Such compounds are quite common in nature and belong to the most important elements of the innate immune system of all living organisms. Numerous antimicrobial peptides have been isolated from insects, amphibians, mammals, plants and bacterial species. In this study we investigated the in vitro activity of two animal peptides, citropin 1.1 and protegrin 1 alone and in combination against microbial strains proposed for the evaluation of preservatives: Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231, and Aspergillus niger ATCC 16404. The results of the antimicrobial preservative effectiveness were compared to the values received for benzalkonium chloride, popular preservative of medicines and cosmetics. PMID:16459482

  9. IN-VITRO ANTIMICROBIAL ACTIVITY OF BRONCHOSOL.

    PubMed

    Witkowska-Banaszczak, Ewa; Michalak, Anna; Kędzia, Anna

    2015-01-01

    Bronchosol is a traditional medicinal product in the form of syrup used in cough and impeded expectoration. The active ingredients that it contains include extracts from the herb of thyme, the root of primrose and thymol. It is recommended in disorders of the respiratory tract when expectoration is impeded and secretion of liquid mucus in bronchi is insufficient. Antimicrobial activity of the components of Bronchosol, especially thyme and thymol, has frequently been reported in the literature. To date, there have not been any studies to confirm such activity of Bronchosol, though. The results of our research are the first one to point to the great activity of Bronchosol against microorganisms causing infections of the respiratory tract. It has been demonstrated that this product displayed antimicrobial activity against reference strains as well as strains of anaerobic and aerobic bacteria and fungi isolated from patients. The confirmation of the antimicrobial activity of Bronchosol provides an explanation of its effectiveness in the therapy of the respiratory tract infections. PMID:26642688

  10. Antimicrobial activity of preparation Bioaron C.

    PubMed

    Gawron-Gzella, Anne; Michalak, Anna; Kędzia, Anna

    2014-01-01

    The antimicrobial activity of sirupus Bioaron C, a preparation, whose main ingredient is an extract from the leaves of Aloe arborescens, was tested against different microorganisms isolated from patients with upper respiratory tract infections. The experiments were performed on 40 strains: 20 strains of anaerobic bacteria, 13 strains of aerobic bacteria and 7 strains of yeast-like fungi from the genus Candida and on 18 reference strains (ATCC). The antimicrobial activity of Bioaron C (MBC and MFC) was determined at undiluted concentration. Bioaron C proved to be very effective against the microorganisms causing infections. At the concentration recommended by the producer, the preparation showed biocidal activity (MBC, MFC) against the strains of the pathogenic microorganisms, which cause respiratory infections most frequently, including, among others, Peptostreptococcus anaerobius, Parvimonas micra, Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus anginosus, Haemophilus influenzae, Moraxella catarrhalis, Pseudomonas aeruginosa and Candida albicans, already after 15 min. The MIC of Bioaron C against most of the tested microorganisms was 5 to 100 times lower than the usually applied concentration. The great antimicrobial activity means that the preparation may be used in the prevention and treatment of infections of the upper respiratory tract. Bioaron C may be an alternative or complement to classical therapy, especially in children. PMID:25362808

  11. Assessing the antimicrobial activities of Ocins

    PubMed Central

    Choyam, Shilja; Lokesh, Dhanashree; Kempaiah, Bettadaiah Bheemakere; Kammara, Rajagopal

    2015-01-01

    The generation of a zone of inhibition on a solid substrate indicates the bioactivity of antimicrobial peptides such as bacteriocin and enterocin. The indicator strain plays a significant role in bacteriocin assays. Other characteristics of bacteriocins, such as their dispersal ability and the different zymogram components, also affect bacteriocin assays. However, universal well diffusion assays for antimicrobials, irrespective of their ability to diffuse (bacteriocin and enterocin), do not exist. The ability of different zymography components to generate non-specific activities have rarely been explored in the literature. The purpose of the present work was to evaluate the impact of major factors (diffusion and rate of diffusion) in a solid substrate bioassay, and to document the adverse effects of sodium dodecyl sulfate in zymograms used to estimate the approximate molecular weight of bacteriocins. PMID:26441952

  12. Effective antimicrobial activity of Cbf-14, derived from a cathelin-like domain, against penicillin-resistant bacteria.

    PubMed

    Ma, Lingman; Wang, Yanrong; Wang, Mengxiao; Tian, Yuwei; Kang, Wei; Liu, Hanhan; Wang, Hui; Dou, Jie; Zhou, Changlin

    2016-05-01

    Cbf-14, a cationic peptide derived from a cathelin-like domain, was designed by inserting the highly α-helical sequence RLLR into an antibacterial sequence and deleting the inactive amino acids in Cbf-K16. Clinical penicillin-resistant isolates as well as NDM-1-carrying Escherichia coli and a correspondingly infected mice model were employed to evaluate Cbf-14 antibacterial activity. The results showed that Cbf-14 possessed potent antimicrobial effects with an MIC of 8-64 μg/ml, and killed almost all bacteria within 240 min. Cbf-14-treated mice achieved an 80% survival rate and approximate 2.5 log unit reduction in CFU in tissues; additionally, this peptide significantly suppressed the production of pro-inflammatory cytokines by the disaggregation of lipopolysaccharide (LPS), suggesting its anti-inflammatory effects. Furthermore, Cbf-14, concentration higher than 2 × MIC value, increased membrane uptake to NPN and PI dye by 96.2% and 63.7%, respectively, neutralised the negative zeta potential of LPS and bacteria surface, and induced 100% leakage of liposome-entrapped calcein and cytoplasmic membrane disruption of E. coli, indicating obvious membrane permeation. Finally, it bound to DNA and respectively evoked 85.0% and 63.3% inhibition of gene replication and protein expression of NDM-1 at sub-MIC concentration in E. coli BL21 (DE3)-NDM-1. These data indicated that Cbf-14 possessed effective antimicrobial activity against penicillin-resistant bacteria in vitro/vivo through membrane disruption, DNA binding, down-regulating NDM-1 expression by plasmid replication inhibition, and anti-inflammatory activity by LPS disaggregation, suggesting a potential anti-infective clinical agent. PMID:26897538

  13. Antimicrobial activity of garlic against oral streptococci.

    PubMed

    Groppo, F C; Ramacciato, J C; Motta, R H L; Ferraresi, P M; Sartoratto, A

    2007-05-01

    The antimicrobial activity of two garlic clones' (1: purple and 2: white) crude extracts against oral microbiota was evaluated in vitro (study 1) and in vivo (study 2). Study 1 consisted of the evaluation of minimum inhibitory (MIC) and bactericidal (MBC) concentrations against nine streptococci strains. In study 2, a 2.5% garlic (clone 2) solution was used as a mouthwash in a 5-week study by 30 subjects. Blood agar and Mitis Salivarius Bacitracin agar were inoculated with subjects' saliva to quantify oral microorganisms and mutans streptococci. Study 1 showed MIC ranging from 0.5 to 32.0 mg ml(-1) for clone 2 and from 8 to 64.0 mg ml(-1) for clone 1. MBC ranged from 1.0 to 128.0 mg ml(-1) and from 8.0 to 128.0 mg ml(-1) regarding clones 2 and 1 respectively. Study 2 showed that 2.5% garlic mouthwash solution had good antimicrobial activity against mutans streptococci and oral microorganisms. Maintenance of reduced salivary levels of streptococci was observed after 2 weeks at the end of mouthwash use. Unpleasant taste (100%), halitosis (90%) and nausea (30%) were reported by subjects after the end of the study. It was concluded that the garlic clones have antimicrobial properties in vitro against streptococci and anticariogenic properties against oral microorganism in spite of its adverse effects. PMID:17461963

  14. [Comparative evaluation of antimicrobial activity of root canal irrigation agents].

    PubMed

    Dmitrieva, N A; Krechina, E K; Iarygina, L B; Efremov, N V

    2013-01-01

    A comparative study of the antimicrobial activity of different antiseptics for root canal irrigation: chlorhexidine bigluconate solution in 6 concentrations (2.0-1.0-0.5-0.2-0.1-0.02%), two sodium hypochlorite formulations: "Parcan" (France) and "Hypochloran-3" (Russia), and stabilized EDTA solution (EDTA Solutions (Korea)) was carried out. The results indicate that the level of antimicrobial activity of chlorhexidine is directly proportional to its concentration. Sodium hypochlorite tends to be more effective in compare with chlorhexidine. EDTA Solutions has a pronounced antimicrobial activity against all strains. PMID:24300699

  15. Antimicrobial effect of extracts of cruciferous vegetables.

    PubMed

    Hu, Shu-Hui; Wang, Jinn-Chyi; Kung, Hsien-Feng; Wang, Jih-Terng; Lee, Wei-Lun; Yang, Yi-Hsin

    2004-12-01

    The cruciferous vegetables cauliflower, broccoli, cabbage, Chinese radish, Chinese kale, and Chinese kitam were used in this study to prepare water-soluble and methanol-water extracts. Crude protein extracts were also obtained by diethylaminoethyl (DEAE) anion exchange chromatography. Water-soluble polysaccharides were prepared by ethanol precipitation followed by ultrafiltration. The antimicrobial effects of all these extracts were evaluated against Gram-positive bacteria, Gram-negative bacteria, and yeast. Crude protein extracts exhibited the greatest antimicrobial activity in monoculture experiments. The antimicrobial effects of cruciferous vegetables were also studied by steeping beef, carrot, and celery in chlorine (10 ppm) or citric acid solution (1%) containing the crude protein extract (500 ppm) for different time periods. Total aerobic plate counts and coliform counts on these foods decreased significantly after 10 minutes in all steeping solutions (p < 0.05). PMID:15696789

  16. 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

  17. ANTIMICROBIAL EFFECT OF INTRACANAL SUBSTANCES

    PubMed Central

    Carreira, Cláudia de Moura; dos Santos, Silvana Soléo Ferreira; Jorge, Antônio Olavo Cardoso; Lage-Marques, José Luiz

    2007-01-01

    In some situations, endodontic infections do not respond to therapeutic protocol. In these cases, it is suggested the administration of an alternative intracanal medication that presents a wide spectrum of action and has an in-depth effect on the root canal system. The purpose of this study was to assess the antimicrobial action of ciprofloxacin, metronidazole and polyethylene glycol and natrosol vehicles with different associations and concentrations. The minimum inhibitory concentration (MIC) was determined by using the agar dilution method. The culture media (Müller-Hinton agar) were prepared containing antimicrobial agents at multiple two-fold dilutions of 0.25 to 16 µg/mL, and with the vehicles at the concentrations of 50, 45, 40, 35, 30 and 25%. Twenty-three microbial strains were selected for the study. Metronidazole was not capable of eliminating any of the tested microorganisms. The association of ciprofloxacin with metronidazole resulted in a reduction of the MIC. The vehicle polyethylene glycol inhibited the growth of 100% of the tested strains, while natrosol inhibited 18% of the strains. Ciprofloxacin formulations with polyethylene glycol presented better effects than those of formulations to which metronidazole was added. It was possible to conclude that ciprofloxacin presented antimicrobial action against all tested bacterial strains, and its association with metronidazole was synergic. The vehicle polyethylene glycol showed antimicrobial effect and the ciprofloxacin/polyethylene glycol association was the most effective combination for reducing the tested bacteria and yeasts. PMID:19089178

  18. Chemical composition, cytotoxicity effect and antimicrobial activity of Ceratonia siliqua essential oil with preservative effects against Listeria inoculated in minced beef meat.

    PubMed

    Hsouna, Anis Ben; Trigui, Mohamed; Mansour, Riadh Ben; Jarraya, Raoudha Mezghani; Damak, Mohamed; Jaoua, Samir

    2011-07-15

    The present study describes the phytochemical profile and the protective effects of Ceratonia siliqua pods essential oil (CsEO), a food and medicinal plant widely distributed in Tunisia. Twenty five different components were identified in the CsEO. Among them, the major detected components were: Nonadecane, Heneicosane , Naphthalene, 1,2-Benzenedicarboxylic acid dibutylester, Heptadecane, Hexadecanoic acid, Octadecanoic acid, 1,2-Benzenedicarboxylic acid, Phenyl ethyl tiglate, Eicosene, Farnesol 3, Camphor, Nerolidol and n-Eicosane. The antimicrobial activity of CsEO was evaluated against a panel of 13 bacteria and 8 fungal strains using agar diffusion and broth microdilution methods. Results have shown that CsEO exhibited moderate to strong antimicrobial activity against the tested species. In addition, the inhibitory effect of this CsEO was evaluated in vivo against a foodborne pathogens Listeria monocytogenes, experimentally inoculated in minced beef meat (2×10(2) CFU/g of meat) amended with different concentrations of the CsEO and stored at 7 °C for 10 days. The antibacterial activity of CsEO in minced beef meat was clearly evident and its presence led to a strong inhibitory effect against the pathogens at 7 °C. On the other hand, the cytotoxic effects of the essential oil against two tumoral human cell lines HeLa and MCF-7 were examined by MTT assay. The CsEO showed an inhibition of both cell lines with significantly stronger activity against HeLa cells. The IC(50) values were 210 and 800 μg/ml for HeLa and MCF-7 cells, respectively. Overall, results presented here suggest that the EO of C. siliqua possesses antimicrobial and cytotoxic properties, and is therefore a potential source of active ingredients for food and pharmaceutical industry. PMID:21601302

  19. 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. PMID:20060120

  20. Hurdle Effect of Antimicrobial Activity Achieved by Time Differential Releasing of Nisin and Chitosan Hydrolysates from Bacterial Cellulose.

    PubMed

    Hsiao, Hui-Ling; Lin, Shih-Bin; Chen, Li-Chen; Chen, Hui-Huang

    2016-05-01

    We investigated the combined antimicrobial effect of nisin and chitosan hydrolysates (CHs) by regulating the antimicrobial reaction order of substances due to differential releasing rate from hydroxypropylmethylcellulose-modified bacterial cellulose (HBC). The minimum inhibitory concentration of nisin against Staphylococcus aureus and that of CHs against Escherichia coli were 6 IU and 200 μg/mL, respectively. Hurdle and additive effects in antimicrobial tests were observed when nisin was used 6 h before CH treatment against S. aureus; similar effects were observed when CH was used before nisin treatment against E. coli. Simultaneously combined treatment of nisin and CHs exhibited the low antimicrobial effect. HBC was then selected as the carrier for the controlled release of nisin and CHs. A 90% inhibition in the growth of S. aureus and E. coli was achieved when 30 IU-nisin-containing HBC and 62.5 μg/mL-CH-containing HBC were used simultaneously. The controlled release of nisin and CHs by using HBC minimized the interaction between nisin and CHs as well as increased the number of microbial targets. PMID:27074534

  1. In Vitro Antimicrobial Activity and Effect on Biofilm Production of a White Grape Juice (Vitis vinifera) Extract

    PubMed Central

    Filocamo, Angela; Bisignano, Carlo; Mandalari, Giuseppina; Navarra, Michele

    2015-01-01

    Background. The aim of the present study was to evaluate the antimicrobial effect of a white grape juice extract (WGJe) against a range of Gram-positive and Gram-negative bacteria, yeasts, and the fungus Aspergillus niger. WGJe was also tested on the production of bacterial biofilms in vitro. Results. WGJe inhibited in vitro most Gram-positive bacteria tested, Staphylococcus aureus ATCC 6538P being the most sensitive strain (MIC values of 3.9 μg/mL). The effect was bactericidal at the concentration of 500 μg/mL. Amongst the Gram-negative bacteria, Escherichia coli was the only susceptible strain (MIC and MBC of 2000 μg/mL). No effect on the growth of Candida sp. and the fungus Aspergillus niger was detected (MIC values > 2000 μg/mL). WGJe inhibited the biofilms formation of E. coli and Pseudomonas aeruginosa with a dose-dependent effect. Conclusions. WGJe exerted both bacteriostatic and bactericidal activity in vitro. The presented results could be used to develop novel strategies for the treatment of skin infections and against potential respiratory pathogens. PMID:26770255

  2. In Vitro Antimicrobial Activity and Effect on Biofilm Production of a White Grape Juice (Vitis vinifera) Extract.

    PubMed

    Filocamo, Angela; Bisignano, Carlo; Mandalari, Giuseppina; Navarra, Michele

    2015-01-01

    Background. The aim of the present study was to evaluate the antimicrobial effect of a white grape juice extract (WGJe) against a range of Gram-positive and Gram-negative bacteria, yeasts, and the fungus Aspergillus niger. WGJe was also tested on the production of bacterial biofilms in vitro. Results. WGJe inhibited in vitro most Gram-positive bacteria tested, Staphylococcus aureus ATCC 6538P being the most sensitive strain (MIC values of 3.9 μg/mL). The effect was bactericidal at the concentration of 500 μg/mL. Amongst the Gram-negative bacteria, Escherichia coli was the only susceptible strain (MIC and MBC of 2000 μg/mL). No effect on the growth of Candida sp. and the fungus Aspergillus niger was detected (MIC values > 2000 μg/mL). WGJe inhibited the biofilms formation of E. coli and Pseudomonas aeruginosa with a dose-dependent effect. Conclusions. WGJe exerted both bacteriostatic and bactericidal activity in vitro. The presented results could be used to develop novel strategies for the treatment of skin infections and against potential respiratory pathogens. PMID:26770255

  3. Evaluation of Persistent Antimicrobial Effects of an Antimicrobial Formulation

    PubMed Central

    Ferrara, Michael S.; Courson, Ron; Paulson, Daryl S.

    2011-01-01

    Context: Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is becoming more prevalent in healthy athletic populations. Various preventive measures have been proposed, but few researchers have evaluated the protective effects of a prophylactic application of a commercially available product. Objective: To compare the persistent antimicrobial properties of a commercially available antimicrobial product containing 4% chlorhexidine gluconate (Hibiclens) with those of a mild, nonmedicated soap (Dr. Bronner's Magic Soap). Design: Cross-sectional study. Setting: Microbiology laboratory, contract research organization. Patients or Other Participants: Twenty healthy human volunteers. Intervention(s): The test and control products were randomly assigned and applied to both forearms of each participant. Each forearm was washed for 2 minutes with the test or control product, rinsed, and dried. At, 1, 2, and 4 hours after application, each forearm was exposed to MRSA for approximately 30 minutes. Main Outcome Measure(s): Differences in numbers of MRSA recovered from each forearm, test and control, at each postapplication time point were compared. Results: Fewer MRSA (P < .0001) were recovered from the forearms treated with the test product (4% chlorhexidine gluconate) than from the forearms treated with the control product (nonmedicated soap). Conclusions: The 4% chlorhexidine gluconate product demonstrated persistent bactericidal activity versus MRSA for up to 4 hours after application. PMID:22488188

  4. The effects of silver nanoparticles on antimicrobial activity of ProRoot mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM)

    PubMed Central

    Jonaidi-Jafari, Nematollah; Izadi, Morteza

    2016-01-01

    Background Although, mineral trioxide aggregate (MTA) and new experimental cement (CEM) are good root filling cements, but had no or low antimicrobial activities. The aim of this study was to evaluate the effects of addition of silver nanoparticles (SNP) to these two cements on antimicrobial effects against five most dental infection related microorganisms. Material and Methods Two suspensions of 100 and 200 ppm of SNP were prepared and 180 μl of microbial suspension with 1.5 × 108 CFU/ml of each respected microorganisms were re-suspended in deionized water or each of SNP suspensions. After that, 60 μg of MTA and CEM were added to each tube. In one tube, the mixture of all above mentioned microorganisms were added as a source of microorganism. Colonies were counted after 0, 24, 48, 72 and 96 hours intervals of incubation at 35°C on blood agar for evaluation of antimicrobial efficacy. Results MTA and CEM had antibacterial activities on all microorganisms’ strains except for Enterococcus faecalis and mixture group. MTA had better antibacterial activity than CEM but the difference was not significant (p<0.05). The combination of SNP with two cements resulted in significantly higher antimicrobial activities (p<0.05). Also, there was no statistically significant difference between two SNP concentrations (p>0.05). Conclusions Mixture of MTA and CEM with different concentrations of SNP significantly increased the antibacterial activity. Key words:Mineral trioxide aggregate, calcium-enriched mixture, silver nanoparticle, antimicrobial activity. PMID:26855701

  5. Investigating the antimicrobial activity of natural honey and its effects on the pathogenic bacterial infections of surgical wounds and conjunctiva.

    PubMed

    Al-Waili, Noori S

    2004-01-01

    Antimicrobial activities of 10-100% (wt/vol) concentrations of new honey, stored honey, heated honey, ultraviolet-exposed honey, and heated stored honey were tested against common human pathogens, including Escherichia coli, Entrobacter cloacae, Pseudomonas aeruginosa, Shigella dysenteriae, Klebsiella sp., Haemophilus influenzae, Proteus sp., Staphylococcus aureus, Streptococcus hemolyticus group B, and Candida albicans. Antimicrobial activity of honey was tested in acidic, neutral, or alkaline media. These were compared with similar concentrations of glucose in nutrient broth. Surgical wounds were made on the dorsum of mice and infected with S. aureus or Klebsiella sp. The wounds were treated with local application of honey four times a day or appropriate antibiotics and compared with control values. Bacterial conjunctivitis due to E. coli, Proteus sp., S. aureus, Klebsiella sp., and P. aeruginosa was induced in rats. Conjunctival application of honey four times a day or appropriate antibiotics was used for treatment and compared with control values. Growth of all the isolates was completely inhibited by 30-100% honey concentrations. The most sensitive microbes were E. coli, P. aeruginosa, and H. influenzae. Glucose showed less antimicrobial activity than honey, and many microbes showed positive culture even in 100% glucose. Heating to 80 degrees C for 1 hour decreased antimicrobial activity of both new and stored honey. Storage of honey for 5 years decreased its antimicrobial activity, while ultraviolet light exposure increased its activity against some of the microorganisms. Antimicrobial activity of honey was stronger in acidic media than in neutral or alkaline media. Single doses of honey used to prepare the 60% concentration in nutrient broth were bacteriocidal for P. aeruginosa and bacteriostatic for S. aureus and Klebsiella sp. during certain periods. Local application of raw honey on infected wounds reduced redness, swelling, time for complete resolution of lesion, and time for eradication of bacterial infection due to S. aureus or Klebsiella sp. Its potency was comparable to that of local antibiotics. Honey application into infective conjunctivitis reduced redness, swelling, pus discharge, and time for eradication of bacterial infections due to all the isolates tested. PMID:15298770

  6. Effects of exercise intensity on salivary antimicrobial proteins and markers of stress in active men.

    PubMed

    Allgrove, Judith E; Gomes, Elisa; Hough, John; Gleeson, Michael

    2008-04-01

    In the present study, we assessed the effects of exercise intensity on salivary immunoglobulin A (s-IgA) and salivary lysozyme (s-Lys) and examined how these responses were associated with salivary markers of adrenal activation. Using a randomized design, 10 healthy active men participated in three experimental cycling trials: 50% maximal oxygen uptake (VO2max), 75%VO2max, and an incremental test to exhaustion. The durations of the trials were the same as for a preliminary incremental test to exhaustion (22.3 min, sx = 0.8). Timed, unstimulated saliva samples were collected before exercise, immediately after exercise, and 1 h after exercise. In the incremental exhaustion trial, the secretion rates of both s-IgA and s-Lys were increased. An increase in s-Lys secretion rate was also observed at 75%VO2max. No significant changes in saliva flow rate were observed in any trial. Cycling at 75%VOmax and to exhaustion increased the secretion of alpha-amylase and chromogranin A immediately after exercise; higher cortisol values at 75%VO2max and in the incremental exhaustion trial compared with 50%VO2max were observed 1 h immediately after exercise only. These findings suggest that short-duration, high-intensity exercise increases the secretion rate of s-IgA and s-Lys despite no change in the saliva flow rate. These effects appear to be associated with changes in sympathetic activity and not the hypothalamic - pituitary - adrenal axis. PMID:18344136

  7. Temporin L: antimicrobial, haemolytic and cytotoxic activities, and effects on membrane permeabilization in lipid vesicles.

    PubMed Central

    Rinaldi, Andrea C; Mangoni, Maria Luisa; Rufo, Anna; Luzi, Carla; Barra, Donatella; Zhao, Hongxia; Kinnunen, Paavo K J; Bozzi, Argante; Di Giulio, Antonio; Simmaco, Maurizio

    2002-01-01

    The temporins are a family of small, linear antibiotic peptides with intriguing biological properties. We investigated the antibacterial, haemolytic and cytotoxic activities of temporin L (FVQWFSKFLGRIL-NH2), isolated from the skin of the European red frog Rana temporaria. The peptide displayed the highest activity of temporins studied to date, against both human erythrocytes and bacterial and fungal strains. At variance with other known temporins, which are mainly active against Gram-positive bacteria, temporin L was also active against Gram-negative strains such as Pseudomonas aeruginosa A.T.C.C. 15692 and Escherichia coli D21 at concentrations comparable with those that are microbiocidal to Gram-positive bacteria. In addition, temporin L was cytotoxic to three different human tumour cell lines (Hut-78, K-562 and U-937), causing a necrosis-like cell death, although sensitivity to the peptide varied markedly with the specific cell line tested. A study of the interaction of temporin L with liposomes of different lipid compositions revealed that the peptide causes perturbation of bilayer integrity of both neutral and negatively charged membranes, as revealed by the release of a vesicle-encapsulated fluorescent marker, and that the action of the peptide is modulated to some extent by membrane lipid composition. In particular, the presence of negatively charged lipids in the model bilayer inhibits the lytic power of temporin L. We also show that the release of fluorescent markers caused by temporin L is size-dependent and that the peptide does not have a detergent-like effect on the membrane, suggesting that perturbation of bilayer organization takes place on a local scale, i.e. through the formation of pore-like openings. PMID:12133008

  8. Access to effective antimicrobials: a worldwide challenge.

    PubMed

    Laxminarayan, Ramanan; Matsoso, Precious; Pant, Suraj; Brower, Charles; Røttingen, John-Arne; Klugman, Keith; Davies, Sally

    2016-01-01

    Recent years have seen substantial improvements in life expectancy and access to antimicrobials, especially in low-income and lower-middle-income countries, but increasing pathogen resistance to antimicrobials threatens to roll back this progress. Resistant organisms in health-care and community settings pose a threat to survival rates from serious infections, including neonatal sepsis and health-care-associated infections, and limit the potential health benefits from surgeries, transplants, and cancer treatment. The challenge of simultaneously expanding appropriate access to antimicrobials, while restricting inappropriate access, particularly to expensive, newer generation antimicrobials, is unique in global health and requires new approaches to financing and delivering health care and a one-health perspective on the connections between pathogen transmission in animals and humans. Here, we describe the importance of effective antimicrobials. We assess the disease burden caused by limited access to antimicrobials, attributable to resistance to antimicrobials, and the potential effect of vaccines in restricting the need for antibiotics. PMID:26603918

  9. In vitro screening of mare's milk antimicrobial effect and antiproliverative activity.

    PubMed

    Guri, Anilda; Paligot, Michele; Crèvecoeur, Sebastien; Piedboeuf, Benoit; Claes, Jonathan; Daube, Georges; Corredig, Milena; Griffiths, M W; Delcenserie, Veronique

    2016-01-01

    The aims of this study were to examine the effect of mare's milk on virulence gene expression of Salmonella Typhimurium and observe its potential activity on proliferation of adenocarcinoma Caco-2 cells. Different supernatants of mare's milk, raw or heat-treated at 65°C for 15 s or 30 min, were studied. The changes in hilA gene expression of Salmonella Typhimurium in presence of mare's milk supernatants were assessed using a reporter luminescent strain. A significant decrease in hilA gene expression was observed with all tested supernatants. Virulence gene expression was then assessed using qPCR on a wild-type strain of Salmonella Typhimurium. A significant decrease of hilA and ssrB2 gene expression was observed with raw milk supernatants but not with heat-treated supernatants. The same supernatants were administered to Caco-2 cells to measure their proliferation rate. A significant reduction of proliferative effect was observed only with raw milk supernatants. This study reports that raw mare's milk was able to modulate virulence gene expression of Salmonella Typhimurium and exerts antiproliferative effects on Caco-2 cells. These results may offer new approaches for promoting gastrointestinal health. PMID:26656278

  10. Natural cinnamic acids, synthetic derivatives and hybrids with antimicrobial activity.

    PubMed

    Guzman, Juan David

    2014-01-01

    Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC) of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships. PMID:25429559

  11. Protease inhibitors from plants with antimicrobial activity.

    PubMed

    Kim, Jin-Young; Park, Seong-Cheol; Hwang, Indeok; Cheong, Hyeonsook; Nah, Jae-Woon; Hahm, Kyung-Soo; Park, Yoonkyung

    2009-06-01

    Antimicrobial proteins (peptides) are known to play important roles in the innate host defense mechanisms of most living organisms, including plants, insects, amphibians and mammals. They are also known to possess potent antibiotic activity against bacteria, fungi, and even certain viruses. Recently, the rapid emergence of microbial pathogens that are resistant to currently available antibiotics has triggered considerable interest in the isolation and investigation of the mode of action of antimicrobial proteins (peptides). Plants produce a variety of proteins (peptides) that are involved in the defense against pathogens and invading organisms, including ribosome-inactivating proteins, lectins, protease inhibitors and antifungal peptides (proteins). Specially, the protease inhibitors can inhibit aspartic, serine and cysteine proteinases. Increased levels of trypsin and chymotrypsin inhibitors correlated with the plants resistance to the pathogen. Usually, the purification of antimicrobial proteins (peptides) with protease inhibitor activity was accomplished by salt-extraction, ultrafiltration and C(18) reverse phase chromatography, successfully. We discuss the relation between antimicrobial and anti-protease activity in this review. Protease inhibitors from plants potently inhibited the growth of a variety of pathogenic bacterial and fungal strains and are therefore excellent candidates for use as the lead compounds for the development of novel antimicrobial agents. PMID:19582234

  12. Antimicrobial activity of different Finnish monofloral honeys against human pathogenic bacteria

    PubMed Central

    Huttunen, Sanna; Riihinen, Kaisu; Kauhanen, Jussi; Tikkanen-Kaukanen, Carina

    2013-01-01

    The antimicrobial activity and phenolic compounds of five Finnish honey products against important human pathogens Streptococcus pneumoniae, S. pyogenes, Staphylococcus aureus, and methicillin-resistant S. aureus were analyzed. Microbroth dilution method and HPLC-DAD were used in antimicrobial testing and phenolic compound determination, respectively. Significant antimicrobial activity (p < 0.01) against all the tested pathogens was found from willow herb (Epilobium angustifolium), heather (Calluna vulgaris), and buckwheat (Fagopyrum esculentum) honeys. This is the first report on antimicrobial activity of Finnish monofloral honeys against streptococcal and staphylococcal bacteria. To our knowledge this is also the first report on the antimicrobial effect of honey against S. pneumoniae. PMID:23278378

  13. Multidrug Pump Inhibitors Uncover Remarkable Activity of Plant Antimicrobials

    PubMed Central

    Tegos, George; Stermitz, Frank R.; Lomovskaya, Olga; Lewis, Kim

    2002-01-01

    Plant antimicrobials are not used as systemic antibiotics at present. The main reason for this is their low level of activity, especially against gram-negative bacteria. The reported MIC is often in the range of 100 to 1,000 μg/ml, orders of magnitude higher than those of common broad-spectrum antibiotics from bacteria or fungi. Major plant pathogens belong to the gram-negative bacteria, which makes the low level of activity of plant antimicrobials against this group of microorganisms puzzling. Gram-negative bacteria have an effective permeability barrier, comprised of the outer membrane, which restricts the penetration of amphipathic compounds, and multidrug resistance pumps (MDRs), which extrude toxins across this barrier. It is possible that the apparent ineffectiveness of plant antimicrobials is largely due to the permeability barrier. We tested this hypothesis in the present study by applying a combination of MDR mutants and MDR inhibitors. A panel of plant antimicrobials was tested by using a set of bacteria representing the main groups of plant pathogens. The human pathogens Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica serovar Typhimurium were also tested. The results show that the activities of the majority of plant antimicrobials were considerably greater against the gram-positive bacteria Staphylococcus aureus and Bacillus megaterium and that disabling of the MDRs in gram-negative species leads to a striking increase in antimicrobial activity. Thus, the activity of rhein, the principal antimicrobial from rhubarb, was potentiated 100- to 2,000-fold (depending on the bacterial species) by disabling the MDRs. Comparable potentiation of activity was observed with plumbagin, resveratrol, gossypol, coumestrol, and berberine. Direct measurement of the uptake of berberine, a model plant antimicrobial, confirmed that disabling of the MDRs strongly increases the level of penetration of berberine into the cells of gram-negative bacteria. These results suggest that plants might have developed means of delivering their antimicrobials into bacterial cells. These findings also suggest that plant antimicrobials might be developed into effective, broad-spectrum antibiotics in combination with inhibitors of MDRs. PMID:12234835

  14. Antimicrobial and antibiofilm activity of pleurocidin against cariogenic microorganisms.

    PubMed

    Tao, Rui; Tong, Zhongchun; Lin, Yuan; Xue, Yunpeng; Wang, Wei; Kuang, Rong; Wang, Ping; Tian, Yu; Ni, Longxing

    2011-08-01

    Dental caries is a common oral bacterial infectious disease of global concern. Prevention and treatment of caries requires control of the dental plaque formed by pathogens such as Streptococcus mutans and Streptococcus sobrinus. Pleurocidin, produced by Pleuronectes americanus, is an antimicrobial peptide that exerts broad-spectrum activity against pathogenic bacteria and fungi. Moreover, pleurocidin shows less hemolysis and is less toxic than other natural peptides. In the present study, we investigated whether pleurocidin is an effective antibiotic peptide against common cariogenic microorganisms and performed a preliminary study of the antimicrobial mechanism. We assayed minimal inhibitory concentration (MIC), minimal bactericide concentration (MBC) and bactericidal kinetics and performed a spot-on-lawn assay. The BioFlux system was used to generate bacterial biofilms under controllable flow. Fluorescence microscopy and confocal laser scanning microscopy (CLSM) were used to analyze and observe biofilms. Scanning electron microscopy was used to observe the bacterial membrane. MIC and MBC results showed that pleurocidin had different antimicrobial activities against the tested oral strains. Although components of saliva could affect antimicrobial activity, pleurocidin dissolved in saliva still showed antimicrobial effects against oral microorganisms. Furthermore, pleurocidin showed a favorable killing effect against BioFlux flow biofilms in vitro. Our findings suggest that pleurocidin has the potential to kill dental biofilms and prevent dental caries. PMID:21703317

  15. Antimicrobial activity of caO nanoparticles.

    PubMed

    Roy, Arup; Gauri, Samiran S; Bhattacharya, Madhusmita; Bhattacharya, Jayanta

    2013-09-01

    The high degree of microbial diseases and their multidrug resistant properties make the researchers to develop new class of antimicrobial agents. A modern and innovative approach of drug development is the use of metallic nanoparticles as new formulations of antimicrobial agents. In this study, microwave irradiated CaO nanoparticles (CaO-NPs) were used to determine their antimicrobial efficacy against gram negative and gram positive bacteria, as well as pathogenic yeast. The physiochemical properties of CaO-NPs were characterized by means of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The nanoparticles consist of well dispersed agglomerates of grains with a narrow size distribution of 14-24 nm. The prepared CaO-NPs showed much higher antimicrobial activity against Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus epidermidis (MTCC 435) in comparision to Candida tropicalis (NCIM 3110). The minimum inhibitory concentration (MIC) value of CaO-NPs was found within the range of 2-8 mM for all the above tested strains. This bioactive nanoparticle also inhibits the biofilm formation and may have future applications cheap and non toxic as antimicrobial drug for skin care product development. PMID:23980504

  16. Combination Effects of Antimicrobial Peptides.

    PubMed

    Yu, Guozhi; Baeder, Desiree Y; Regoes, Roland R; Rolff, Jens

    2016-01-01

    Antimicrobial peptides (AMPs) are ancient and conserved across the tree of life. Their efficacy over evolutionary time has been largely attributed to their mechanisms of killing. Yet, the understanding of their pharmacodynamics both in vivo and in vitro is very limited. This is, however, crucial for applications of AMPs as drugs and also informs the understanding of the action of AMPs in natural immune systems. Here, we selected six different AMPs from different organisms to test their individual and combined effects in vitro. We analyzed their pharmacodynamics based on the Hill function and evaluated the interaction of combinations of two and three AMPs. Interactions of AMPs in our study were mostly synergistic, and three-AMP combinations displayed stronger synergism than two-AMP combinations. This suggests synergism to be a common phenomenon in AMP interaction. Additionally, AMPs displayed a sharp increase in killing within a narrow dose range, contrasting with those of antibiotics. We suggest that our results could lead a way toward better evaluation of AMP application in practice and shed some light on the evolutionary consequences of antimicrobial peptide interactions within the immune system of organisms. PMID:26729502

  17. Combination Effects of Antimicrobial Peptides

    PubMed Central

    Yu, Guozhi; Baeder, Desiree Y.; Regoes, Roland R.

    2016-01-01

    Antimicrobial peptides (AMPs) are ancient and conserved across the tree of life. Their efficacy over evolutionary time has been largely attributed to their mechanisms of killing. Yet, the understanding of their pharmacodynamics both in vivo and in vitro is very limited. This is, however, crucial for applications of AMPs as drugs and also informs the understanding of the action of AMPs in natural immune systems. Here, we selected six different AMPs from different organisms to test their individual and combined effects in vitro. We analyzed their pharmacodynamics based on the Hill function and evaluated the interaction of combinations of two and three AMPs. Interactions of AMPs in our study were mostly synergistic, and three-AMP combinations displayed stronger synergism than two-AMP combinations. This suggests synergism to be a common phenomenon in AMP interaction. Additionally, AMPs displayed a sharp increase in killing within a narrow dose range, contrasting with those of antibiotics. We suggest that our results could lead a way toward better evaluation of AMP application in practice and shed some light on the evolutionary consequences of antimicrobial peptide interactions within the immune system of organisms. PMID:26729502

  18. Antimicrobial activities of Indian Berberis species.

    PubMed

    Singh, Meenakshi; Srivastava, Sharad; Rawat, A K S

    2007-12-01

    The antimicrobial activity of hydroalcoholic extracts of four Berberis species viz. Berberis aristata, Berberis asiatica, Berberis chitria and Berberis lycium were tested against eleven bacterial and eight fungal strains. B. aristata root extract gave low MICs values against Bacillus cereus, Escherichia coli, Staphylococcus aureus and Aspergillus flavus while stem extract against B. cereus and Streptococcus pneumoniae. PMID:17583443

  19. Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria

    PubMed Central

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

    2015-01-01

    Analysis of a Selected Set of Antimicrobial Peptides The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Aeromonas salmonicida, Listeria monocytogenes, Campylobacter jejuni, Flavobacterium psychrophilum, Salmonella typhimurium and Yersinia ruckeri by minimal inhibitory concentration (MIC) determinations. Additional characteristics such as cytotoxicity, thermo and protease stability were measured and compared among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants. Cap18 Shows a High Broad Spectrum Antimicrobial Activity Of all the tested AMPs, Cap18 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria. In addition, Cap18 is highly thermostable and showed no cytotoxic effect in a hemolytic assay, measured at the concentration used. However, Cap18 is, as most of the tested AMPs, sensitive to proteolytic digestion in vitro. Thus, Cap18 is an excellent candidate for further development into practical use; however, modifications that should reduce the protease sensitivity would be needed. In addition, our findings from analyzing LPS mutant strains suggest that the core oligosaccharide of the LPS molecule is not essential for the antimicrobial activity of cationic AMPs, but in fact has a protective role against AMPs. PMID:26656394

  20. Antimicrobial Activity and Stability of Electron Beam Irradiated Dental Irrigants

    PubMed Central

    Geethashri, A; Palaksha, K.J.; Sridhar, K. R.; Sanjeev, Ganesh

    2014-01-01

    Background: The electron beam (e-beam) radiation is considered as an effective means of sterilization of healthcare products as well as to induce the structural changes in the pharmaceutical agents/drug molecules. In addition to structural changes of pharmaceutical it also induces the formation of low molecular weight compounds with altered microbiological, physicochemical and toxicological properties. Among the several known medicaments, sodium hypochlorite (NaOCl) and chlorhexidine digluconate (CHX) are used as irrigants in dentistry to kill the pathogenic microorganisms like Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans and Candida albicans inhabiting the oral cavity. Objectives: The aim of this study was to evaluate the antimicrobial activity and stability of e-beam irradiated dental irrigants, NaOCl and CHX. Materials and Methods: Two dental irrigants NaOCl (1.25% and 2.5%) and CHX (1% and 2%) were exposed to various doses of e-beam radiation. The antimicrobial activities of e-beam irradiated irrigants were compared with the non-irradiated (control) irrigants against E. faecalis, S. aureus, S. mutans and C. albicans by disc diffusion method. Following the storage, physico-chemical properties of the irrigants were recorded and the cytotoxic effect was evaluated on human gingival fibroblast cells. Result: The irrigants, 1.25% NaOCl and 1% CHX showed significantly increased antimicrobial activity against both E. faecalis, (16+0.0) and S. aureus (25+0.0) after irradiation with 1 kGy e-beam. Whereas, 2.5% NaOCl and 2% CHX showed slightly increased antimicrobial activity only against S. aureus (28+0.0). The significant difference was noticed in the antimicrobial activity and cytotoxicity of irradiated and non-irradiated irrigants following the storage for 180 d at 40C. Conclusion: The e-beam irradiation increased the antimicrobial activity of irrigants without altering the biocompatibility. PMID:25584220

  1. Poisson Parameters of Antimicrobial Activity: A Quantitative Structure-Activity Approach

    PubMed Central

    Sestraş, Radu E.; Jäntschi, Lorentz; Bolboacă, Sorana D.

    2012-01-01

    A contingency of observed antimicrobial activities measured for several compounds vs. a series of bacteria was analyzed. A factor analysis revealed the existence of a certain probability distribution function of the antimicrobial activity. A quantitative structure-activity relationship analysis for the overall antimicrobial ability was conducted using the population statistics associated with identified probability distribution function. The antimicrobial activity proved to follow the Poisson distribution if just one factor varies (such as chemical compound or bacteria). The Poisson parameter estimating antimicrobial effect, giving both mean and variance of the antimicrobial activity, was used to develop structure-activity models describing the effect of compounds on bacteria and fungi species. Two approaches were employed to obtain the models, and for every approach, a model was selected, further investigated and found to be statistically significant. The best predictive model for antimicrobial effect on bacteria and fungi species was identified using graphical representation of observed vs. calculated values as well as several predictive power parameters. PMID:22606039

  2. Antimicrobial activity of Aspilia latissima (Asteraceae)

    PubMed Central

    Souza, Jeana M.E.; Chang, Marilene R.; Brito, Daniela Z.; Farias, Katyuce S.; Damasceno-Junior, Geraldo A.; Turatti, Izabel C.C.; Lopes, Norberto P.; Santos, Edson A.; Carollo, Carlos A.

    2015-01-01

    Abstract We evaluated the antimicrobial activity of Aspilia latissima - an abundant plant from the Brazilian Pantanal region - against Candida albicans, Candida parapsilosis, Candida krusei, Candida tropicalis, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli and Staphylococcus aureus. The crude extracts and fractions showed activity in all tested microorganisms. The chloroform fraction of the leaves and roots showed the most antimicrobial activity against S. aureus, with an MIC of 500 μg/mL. This fraction was submitted to bioautographic assays to characterize the activity of the compounds. Two bands from the leaves (L-A and L-B) and three bands from the roots (R-C, R-D and R-E) were bioactive. Within the root-derived bands, the terpene derivatives stigmasterol, kaurenoic acid and kaura-9(11), 16-dien-18-oic acid were identified. Antibiotic activity of A. latissima is reported for the first time. PMID:26691468

  3. Antimicrobial activity of Aspilia latissima (Asteraceae).

    PubMed

    Souza, Jeana M E; Chang, Marilene R; Brito, Daniela Z; Farias, Katyuce S; Damasceno-Junior, Geraldo A; Turatti, Izabel C C; Lopes, Norberto P; Santos, Edson A; Carollo, Carlos A

    2015-12-01

    We evaluated the antimicrobial activity of Aspilia latissima - an abundant plant from the Brazilian Pantanal region - against Candida albicans, Candida parapsilosis, Candida krusei, Candida tropicalis, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli and Staphylococcus aureus. The crude extracts and fractions showed activity in all tested microorganisms. The chloroform fraction of the leaves and roots showed the most antimicrobial activity against S. aureus, with an MIC of 500 μg/mL. This fraction was submitted to bioautographic assays to characterize the activity of the compounds. Two bands from the leaves (L-A and L-B) and three bands from the roots (R-C, R-D and R-E) were bioactive. Within the root-derived bands, the terpene derivatives stigmasterol, kaurenoic acid and kaura-9(11), 16-dien-18-oic acid were identified. Antibiotic activity of A. latissima is reported for the first time. PMID:26691468

  4. Antimicrobial and Antioxidant Activities of Pycnocycla spinosa Extracts

    PubMed Central

    Mahboubi, Mohaddese; Taghizadeh, Mohsen; Kazempour, Nastaran

    2014-01-01

    Background: Pycnocycla spinosa (P. spinosa) a member of the Umbelliferae family is traditionally used for treatment of different ailments. Objectives: This study aimed to evaluate the total phenolic and flavonoid content of P. spinosa extracts (methanol, ethanol and aqueous) and their antioxidant and antimicrobial effects. Materials and Methods: The antimicrobial activity of different extracts of P. spinosa was evaluated using micro broth dilution. Total phenolic and flavonoid contents were measured. Their antioxidant effect was evaluated using DPPH assay and β-carotene linoleic acid test. Results: P. spinosa ethanol extract with higher-level phenolic and flavonoid contents showed the highest antioxidant and antimicrobial effects, in comparison with the other extracts. Bacillus sp. and Streptococcus sp. showed higher sensitivity to P. spinosa ethanol extract. Conclusions: P. spinosa ethanol extract can be used as a mouthwash for treatment of the oral infections. More clinical and toxicological studies are required for providing its efficacy. PMID:25237641

  5. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

    PubMed Central

    Shalavi, S; Yazdizadeh, M

    2012-01-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial. PMID:23323217

  6. Antimicrobial activity of syringic acid against Cronobacter sakazakii and its effect on cell membrane.

    PubMed

    Shi, Chao; Sun, Yi; Zheng, Zhiwei; Zhang, Xiaorong; Song, Kaikuo; Jia, Zhenyu; Chen, Yifei; Yang, Miaochun; Liu, Xin; Dong, Rui; Xia, Xiaodong

    2016-04-15

    Syringic acid (SA) has been reported to exhibit antibacterial ability against various microorganisms, but little work has been done on its effect on Cronobacter sakazakii. In this study, minimum inhibitory concentrations (MICs) of SA against various C. sakazakii strains were determined. Moreover, changes in intracellular ATP concentration, intracellular pH (pHin), membrane potential and membrane integrity were measured to evaluate the influence of SA on cell membrane. Finally, field emission scanning electron microscope (FESEM) was used to assess the morphological changes of bacterial cells caused by SA. It was shown that the MICs of SA against all tested C. sakazakii strains were 5mg/mL. SA retarded bacterial growth, and caused cell membrane dysfunction, which was evidenced by intracellular ATP concentration decrease, pHin reduction, cell membrane hyperpolarization and changes in cellular morphology. These findings indicated that SA has potential to be developed as a natural preservative to control C. sakazakii in foods associated with this pathogen and prevent related infections. PMID:26616929

  7. Morphology and oxygen incorporation effect on antimicrobial activity of silver thin films

    NASA Astrophysics Data System (ADS)

    Rebelo, Rita; Manninen, N. K.; Fialho, Luísa; Henriques, Mariana; Carvalho, Sandra

    2016-05-01

    Ag and AgxO thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering, respectively, with the final propose of functionalizing the SS316L substrate with antibacterial properties. The coatings were characterized chemically, physically and structurally. The coatings nanostructure was assessed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the coatings morphology was determined by scanning electron microscopy (SEM). The XRD and XPS analyses suggested that Ag thin film is composed by metallic Ag, which crystallizes in fcc-Ag phase, while the AgxO thin film showed both metallic Ag and Agsbnd O bonds, which crystalize in fcc-Ag and silver oxide phases. The SEM results revealed that Ag thin film formed a continuous layer, while AgxO layer was composed of islands with hundreds of nanometers surrounded by small nanoparticles with tens of nanometers. The surface wettability and surface tension parameters were determined by contact angle measurements, being found that Ag and AgxO surfaces showed very similar behavior, with all the surfaces showing a hydrophobic character. In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. Ag coatings did not show antibacterial behavior, contrarily to AgxO coating, which presented antibacterial properties against the studied bacteria. The presence of silver oxide phase along with the development of different morphology was pointed as the main factors in the origin of the antibacterial effect found in AgxO thin film. The present study demonstrated that AgxO coating presented antibacterial behavior and its application in cardiovascular stents is promising.

  8. Molybdenum doped titanium dioxide photocatalytic coatings for use as hygienic surfaces: the effect of soiling on antimicrobial activity.

    PubMed

    Fisher, L; Ostovapour, S; Kelly, P; Whitehead, K A; Cooke, K; Storgrds, E; Verran, J

    2014-09-01

    Titanium dioxide (TiO2) surfaces doped with molybdenum (Mo) were investigated to determine if their photocatalytic ability could enhance process hygiene in the brewery industry. Doping TiO2 with Mo showed a 5-log reduction in bacterial counts within 4 to 24?h and a 1-log reduction in yeast numbers within 72?h. The presence of a dilute brewery soil on the surface did not interfere with antimicrobial activity. The TiO2-Mo surface was also active in the dark, showing a 5-log reduction in bacteria within 4 to 24?h and a 1-log reduction in yeast numbers within 72?h, suggesting it could have a novel dual function, being antimicrobial and photocatalytic. The study suggests the TiO2-Mo coating could act as a secondary barrier in helping prevent the build-up of microbial contamination on surfaces within the brewery industry, in particular in between cleaning/disinfection regimes during long production runs. PMID:25184432

  9. Inhibitory effects of Na7PMo11CuO40 on mushroom tyrosinase and melanin formation and its antimicrobial activities.

    PubMed

    Xing, Rui; Wang, Fang; Dong, Le; Zheng, A-Ping; Wang, Li; Su, Wen-Jin; Lin, Ting

    2016-04-15

    Keggin-type Cu-substituted phosphomolybdic acid (Na7PMo11CuO40, abbreviated as PMo11Cu) was synthesized and characterized. The inhibitory effects of PMo11Cu on mushroom tyrosinase and melanin formation in B16 melanoma cells were studied. The results showed that PMo11Cu could strongly inhibit the activity of tyrosinase, and it was reversible and competitive inhibitor. The IC50 value was estimated to be 0.48 mM for diphenolase activity. PMo11Cu also exhibited inhibitory effects on cell viability, cellular tyrosinase activity and melanin formation in B16 melanoma cells at concentrations ranging from 0 to 200 μM for 24 h. Furthermore, the antimicrobial activities of PMo11Cu against Sarcina lutea, Staphylococcus aureus, Bacillus subtilis and Escherichia coli were investigated. The results showed that PMo11Cu had an obvious antimicrobial activities, and it was more effective against two kinds of coccus than two kinds of bacillus. This study may provide theoretical basis for designing novel effective mushroom tyrosinase inhibitors and extend the use of polyoxometalates in the fields of food preservation and depigmentation. PMID:26616942

  10. Antimicrobial Activity of Sodium n-Alkylsalicylates

    PubMed Central

    Buckley, D.; Thomas, J.

    1971-01-01

    The activities are reported of sodium salts of several n-alkylsalicylic acids against Staphylococcus aureus, Pseudomonas aeruginosa, Mycobacterium phlei, and Candida albicans. The acids had alkyl substituents of 1 to 18 carbon atoms in the 3, 4, or 5 positions relative to the carboxyl group of salicylic acid. Generally, the antimicrobial properties were typical of anionic surface-active agents although the salicylates are more potent than most of these, particularly against S. aureus. PMID:4995846

  11. Antimicrobial Peptide from the Wild Bee Hylaeus signatus Venom and Its Analogues: Structure-Activity Study and Synergistic Effect with Antibiotics.

    PubMed

    Nešuta, Ondřej; Hexnerová, Rozálie; Buděšínský, Miloš; Slaninová, Jiřina; Bednárová, Lucie; Hadravová, Romana; Straka, Jakub; Veverka, Václav; Čeřovský, Václav

    2016-04-22

    Venoms of hymenopteran insects have attracted considerable interest as a source of cationic antimicrobial peptides (AMPs). In the venom of the solitary bee Hylaeus signatus (Hymenoptera: Colletidae), we identified a new hexadecapeptide of sequence Gly-Ile-Met-Ser-Ser-Leu-Met-Lys-Lys-Leu-Ala-Ala-His-Ile-Ala-Lys-NH2. Named HYL, it belongs to the category of α-helical amphipathic AMPs. HYL exhibited weak antimicrobial activity against several strains of pathogenic bacteria and moderate activity against Candida albicans, but its hemolytic activity against human red blood cells was low. We prepared a set of HYL analogues to evaluate the effects of structural modifications on its biological activity and to increase its potency against pathogenic bacteria. This produced several analogues exhibiting significantly greater activity compared to HYL against strains of both Staphylococcus aureus and Pseudomonas aeruginosa even as their hemolytic activity remained low. Studying synergism of HYL peptides and conventional antibiotics showed the peptides act synergistically and preferentially in combination with rifampicin. Fluorescent dye propidium iodide uptake showed the tested peptides were able to facilitate entrance of antibiotics into the cytoplasm by permeabilization of the outer and inner bacterial cell membrane of P. aeruginosa. Transmission electron microscopy revealed that treatment of P. aeruginosa with one of the HYL analogues caused total disintegration of bacterial cells. NMR spectroscopy was used to elucidate the structure-activity relationship for the effect of amino acid residue substitution in HYL. PMID:26998557

  12. ANTIMICROBIAL ACTIVITY OF EXTRACTS FROM ECUADORIAN LICHENS.

    PubMed

    Matvieieva, N A; Pasichnyk, L A; Zhytkevych, N V; Jacinto, Pabn Garcs Galo; Pidgorskyi, V S

    2015-01-01

    Antimicrobial activity of the ethanolic, isopropanolic, acetone, DMSO and aqueous extracts of the two lichen species from Ecuadorian highland, Usnea sp. and Stereocaulon sp. were explored in vitro against bacteria Bacillus subtilis, Escherichia coli and Staphylococcus aureus by the disc-diffusion method. Also the minimal inhibitory concentration (MIC) was determined. The strongest antimicrobial activity was found in DMSO extract of Usnea sp. compared to antibacterial activity of ciprfloxacin and cefazolin antibiotics. The inhibition zone was 28 mm, 30 mm, 31mm (DMSO extract, ciprfloxacin and cefazolin respectively) in case of B. subtilis usage as the test bacteria. MIC value for Usnea sp. and Stereocaulon sp. DMSO extracts was 0.4 mg/ml. E. coli was resistant to all kinds of extracts. The S. aureus sensitivity to lichen DMSO extracts was comparable to sensitivity of these microorganisms to tetracycline and vancomycin. Thereby, most kinds of extracts (ethanol, isopropanol, hexane, DMSO and acetone solvents) from Ecuadorian lichens Usnea sp. and Stereocaulon sp. with the exception of aqueous Stereocaulon sp. extracts possessed antibacterial activity against B. subtilis. DMSO lichen extracts had also antimicrobial activity against S. aureus. At the same time the extracts studied didn't demonstrate antibacterial activity against the representatives of the most common and harmful phytopathogenic bacteria tested. Further investigations of Ecuadorian lichens especially study of plants collected from extremal highland biotops can be very important in study of possibility of treatment of numerous diseases caused by pathogenic microorganisms. PMID:26214895

  13. Effects of antimicrobial peptides (AMPs) on blood biochemical parameters, antioxidase activity, and immune function in the common carp (Cyprinus carpio).

    PubMed

    Dong, Xiao-Qing; Zhang, Dong-Ming; Chen, Yu-Ke; Wang, Qiu-Ju; Yang, Yi-Yu

    2015-11-01

    Antibiotic use in livestock feed additives has resulted in harmful residue accumulation and spread of drug-resistance. We examined the use of antimicrobial peptides (AMPs) as a safer alternative to antibiotics in feeding the common carp. AMPs were added to common carp basal diets (Control) as additives at four concentrations: 100 mg kg(-1) (B1), 200 mg kg(-1) (B2), 400 mg kg(-1) (B3), 600 mg kg(-1) (B4) by dry weight of basal diet. After a 60-day feeding experiment, the final weight, DG and SGR of carps on B1, B2 and B3 diet were significantly higher than the control (p < 0.05). The FCR of carps on B1, B2 and B3 diet were significantly lower than the control (p < 0.05). Carps on B2, B3, and B4 diets showed significantly lower (p < 0.05) levels of triglyceride than the control. B4-fed carps showed significantly lower (p < 0.05) levels of total protein, albumin, and total cholesterol than the control. However there was no remarkable difference (p > 0.05) in levels of uric ammonia, globulin, glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase, lactic dehydrogenase and blood glucose in all groups. The serum superoxide dismutase and catalase activity of B1-fed carps was significantly higher (p < 0.05) than the control and B4-fed carps. The serum alkaline phosphate activity of carps on B1 diets was significantly higher (p < 0.05) than B4-fed carps. The serum acid phosphatase activity of B1-fed carps was significantly higher (p < 0.05) than the control and other antimicrobial peptide-fed groups. The serum lysozyme activity of carps on B1, B2, and B3 diets was significantly higher (p < 0.05) than the control- and B4-fed carps. Regarding immune factors in serum, the levels of immunoglobulin (Ig) and interleukin (IL)-1β in B1-fed carps were significantly higher (p < 0.05) than the control and other groups, while IL-1α levels in B1-fed carps was significantly higher (p < 0.05) than the control-, B2-, and B3-fed carps. Furthermore, there were no significant differences in the content of MHC among the five groups. In conclusion, antimicrobial peptide can reduce triglyceride levels in serum, enrich oxidation resistance, and improve immunity of the common carp. It showed that appropriate concentration of antibacterial peptide as supplements in diets for common carp increased the final weight, DG, SGR and decreased the FCR. PMID:26386195

  14. Antimicrobial silver: An unprecedented anion effect

    PubMed Central

    Swathy, J. R.; Sankar, M. Udhaya; Chaudhary, Amrita; Aigal, Sahaja; Anshup; Pradeep, T.

    2014-01-01

    Silver is an indispensable metal but its use has to be minimised for sustainable growth. Much of the silver lost during use is unrecoverable; an example being its use as an antimicrobial agent, a property known since ages. While developing methods to create an affordable drinking water purifier especially for the developing world, we discovered that 50 parts per billion (ppb) of Ag+ released continuously from silver nanoparticles confined in nanoscale cages is enough to cause antimicrobial activity in conditions of normal water. Here we show that the antibacterial and antiviral activities of Ag+ can be enhanced ~1,000 fold, selectively, in presence of carbonate ions whose concentration was maintained below the drinking water norms. The protective layers of the organisms were affected during the carbonate-assisted antimicrobial activity. It is estimated that ~1,300 tons of silver can be saved annually using this new way to enhance its antimicrobial activity. PMID:25418185

  15. Antimicrobial silver: An unprecedented anion effect

    NASA Astrophysics Data System (ADS)

    Swathy, J. R.; Sankar, M. Udhaya; Chaudhary, Amrita; Aigal, Sahaja; Anshup; Pradeep, T.

    2014-11-01

    Silver is an indispensable metal but its use has to be minimised for sustainable growth. Much of the silver lost during use is unrecoverable; an example being its use as an antimicrobial agent, a property known since ages. While developing methods to create an affordable drinking water purifier especially for the developing world, we discovered that 50 parts per billion (ppb) of Ag+ released continuously from silver nanoparticles confined in nanoscale cages is enough to cause antimicrobial activity in conditions of normal water. Here we show that the antibacterial and antiviral activities of Ag+ can be enhanced ~1,000 fold, selectively, in presence of carbonate ions whose concentration was maintained below the drinking water norms. The protective layers of the organisms were affected during the carbonate-assisted antimicrobial activity. It is estimated that ~1,300 tons of silver can be saved annually using this new way to enhance its antimicrobial activity.

  16. Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species

    PubMed Central

    Mitrović, Tatjana; Stamenković, Slaviša; Cvetković, Vladimir; Tošić, Svetlana; Stanković, Milan; Radojević, Ivana; Stefanović, Olgica; Čomić, Ljiljana; Đačić, Dragana; Ćurčić, Milena; Marković, Snežana

    2011-01-01

    The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA)/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru)/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+) bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells. PMID:21954369

  17. Antioxidant, antimicrobial and antiproliferative activities of five lichen species.

    PubMed

    Mitrović, Tatjana; Stamenković, Slaviša; Cvetković, Vladimir; Tošić, Svetlana; Stanković, Milan; Radojević, Ivana; Stefanović, Olgica; Comić, Ljiljana; Dačić, Dragana; Curčić, Milena; Marković, Snežana

    2011-01-01

    The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA)/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru)/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+) bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells. PMID:21954369

  18. Antimicrobially active isoquinoline alkaloids from Litsea cubeba.

    PubMed

    Feng, Tao; Xu, Yan; Cai, Xiang-Hai; Du, Zhi-Zhi; Luo, Xiao-Dong

    2009-01-01

    Bioassay-guided fractionation of the alkaloidal extract of the aerial part of Litsea cubeba led to the isolation of two new isoquinoline alkaloids, (+)- N-(methoxycarbonyl)-N-norboldine (1) and (+)-isoboldine beta-N-oxide (2), together with 11 known analogues (3-13). Their structures were established by extensive spectroscopic techniques and by comparing spectroscopic data with those in the literature. Compounds 1 and 4 showed antimicrobial activities. This is the first report on the presence of compounds 1, 2, 6, 8, 9, 11, and 12 in this plant and on the antimicrobial activities of 1 and 4. The bioactivities of isoquinoline alkaloids are also at least partly responsible for the pharmacological function of the folk medicinal plant Litsea cubeba. PMID:18991207

  19. Salvia officinalis L. essential oils: effect of hydrodistillation time on the chemical composition, antioxidant and antimicrobial activities.

    PubMed

    Miguel, G; Cruz, C; Faleiro, M L; Simões, M T F; Figueiredo, A C; Barroso, J G; Pedro, L G

    2011-03-01

    Salvia officinalis L. oils were isolated from the plant's commercial dried aerial parts, by hydrodistillation, with different distillation times. The essential oils were analysed by gas chromatography and gas chromatography-mass spectrometry. The antioxidant ability was measured using a free radical scavenging activity assay using 2,2-diphenyl-1-picrylhydrazyl (DPPH), a thiobarbituric acid reactive substances (TBARS) assay, a deoxyribose assay for the scavenging of hydroxyl radical, an assay for site-specific actions and a 5-lipoxygenase assay. Antibacterial activity was determined by the agar diffusion method. 1,8-Cineole, α-pinene and camphor were the dominant components of all the essential oils. The different hydrodistillation times did not affect the oil yield nor the relative amount of the oil components. The time of hydrodistillation influenced the antioxidant activity. With the DPPH method, the oils isolated for 2 and 3 h were stronger free radical scavengers, while with the TBARS method, the highest antioxidant values were obtained in the oils isolated for 30 min, 2 and 3 h. Hydroxyl radical scavenging and lipoxygenase activity assays showed the best results with oils isolated for 1 and 3 h. With the deoxyribose method, sage oils at concentrations <1000 mg L(-1) showed better activity than mannitol. The essential oil of S. officinalis showed very weak antimicrobial activity. PMID:21391115

  20. Antimicrobial activity of nerolidol and its derivatives against airborne microbes and further biological activities.

    PubMed

    Krist, Sabine; Banovac, Daniel; Tabanca, Nurhayat; Wedge, David E; Gochev, Velizar K; Wanner, Jürgen; Schmidt, Erich; Jirovetz, Leopold

    2015-01-01

    Nerolidol and its derivatives, namely cis-nerolidol, O-methyl-nerolidol, O-ethyl-nerolidol, (-)-α-bisabolol, trans,trans-farnesol and its main natural source cabreuva essential oil, were tested for their antimicrobial activity against airborne microbes and antifungal properties against plant pathogens. Among the tested compounds, α-bisabolol was the most effective antimicrobial agent and trans,trans-farnesol showed the best antifungal activity. PMID:25920237

  1. Antimicrobials

    PubMed Central

    Murphy, Eileen F.; Clarke, Siobhan F.; Marques, Tatiana M.; Hill, Colin; Stanton, Catherine; Ross, R. Paul; O’Doherty, Robert M.; Shanahan, Fergus; Cotter, Paul D.

    2013-01-01

    Obesity is associated with a number of serious health consequences, including type 2 diabetes, cardiovascular disease and a variety of cancers among others and has been repeatedly shown to be associated with a higher risk of mortality. The relatively recent discovery that the composition and metabolic activity of the gut microbiota may affect the risk of developing obesity and related disorders has led to an explosion of interest in this distinct research field. A corollary of these findings would suggest that modulation of gut microbial populations can have beneficial effects with respect to controlling obesity. In this addendum, we summarize our recent data, showing that therapeutic manipulation of the microbiota using different antimicrobial strategies may be a useful approach for the management of obesity and metabolic conditions. In addition, we will explore some of the mechanisms that may contribute to microbiota-induced susceptibility to obesity and metabolic diseases. PMID:23018760

  2. Effect of disulphide bond position on salt resistance and LPS-neutralizing activity of α-helical homo-dimeric model antimicrobial peptides.

    PubMed

    Nan, Yong Hai; Shin, Song Yub

    2011-11-01

    To investigate the effects of disulphide bond position on the salt resistance and lipopolysaccharide (LPS)-neutralizing activity of α-helical homo-dimeric antimicrobial peptides (AMPs), we synthesized an α-helical model peptide (K6L4W1) and its homo-dimeric peptides (di-K(6)L(4)W(1)-N, di-K(6)L(4)W(1)-M, and di-K(6)L(4)W(1)-C) with a disulphide bond at the N-terminus, the central position, and the C-terminus of the molecules, respectively. Unlike (6)L(4)W(1) and di-K(6)L(4)W(1)-M, the antimicrobial activity of di-K(6)L(4)W(1)-N and di-K(6)L(4)W(1)-C was unaffected by 150 mM NaCl. Both di-K(6)L(4)W(1)-N and di-K(6)L(4)W(1)-C caused much greater inhibitory effects on nitric oxide (NO) release in LPS-induced mouse macrophage RAW 264.7 cells, compared to di-K(6)L(4)W(1)-M. Taken together, our results indicate that the presence of a disulphide bond at the N- or C-terminus of the molecule, rather than at the central position, is more effective when designing salt-resistant α-helical homo-dimeric AMPs with potent antimicrobial and LPS-neutralizing activities. [BMB reports 2011; 44(11): 747-752]. PMID:22118542

  3. Antioxidant, antimicrobial and neutrophil-modulating activities of herb extracts.

    PubMed

    Denev, Petko; Kratchanova, Maria; Ciz, Milan; Lojek, Antonin; Vasicek, Ondrej; Blazheva, Denitsa; Nedelcheva, Plamena; Vojtek, Libor; Hyrsl, Pavel

    2014-01-01

    The present study provides a comprehensive data on the antioxidant, antimicrobial and neutrophil-modulating activities of extracts from six medicinal plants--blackberry (Rubus fruticosus) leaves, chokeberry (Aronia melanocarpa) leaves, hawthorn (Crataegus monogyna) leaves, lady's mantle (Alchemilla glabra) aerial parts, meadowsweet (Filipendula ulmaria) aerial parts and raspberry (Rubus idaeus) leaves. In order to analyze the antioxidant activity of the herbs, several methods (ORAC, TRAP, HORAC and inhibition of lipid peroxidation) were used. Blackberry leaves and meadowsweet extracts revealed the highest antioxidant activities via all methods. All extracts studied blocked almost completely the opsonized zymosan particle-activated ROS production by neutrophils from human whole blood. On the other hand, the effect of extracts on phorbol myristate acetate-activated ROS production was much milder and even nonsignificant in the case of chokeberry leaves. This latter result suggests that extracts (apart from their antioxidative activity) interfere with the signaling cascade of phagocyte activation upstream of the protein kinase C activation. The antimicrobial activity of the investigated extracts against 11 human pathogens was investigated using three different methods. Meadowsweet and blackberry leaves extracts had the highest antimicrobial effect and the lowest minimal inhibiting concentrations (MICs) against the microorganisms tested. PMID:24945135

  4. 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. PMID:26687790

  5. Destabilization of α-Helical Structure in Solution Improves Bactericidal Activity of Antimicrobial Peptides: Opposite Effects on Bacterial and Viral Targets

    PubMed Central

    Morris, Christopher J.; Fox, Marc A.; Gumbleton, Mark; Beck, Konrad

    2016-01-01

    We have previously examined the mechanism of antimicrobial peptides on the outer membrane of vaccinia virus. We show here that the formulation of peptides LL37 and magainin-2B amide in polysorbate 20 (Tween 20) results in greater reductions in virus titer than formulation without detergent, and the effect is replicated by substitution of polysorbate 20 with high-ionic-strength buffer. In contrast, formulation with polysorbate 20 or high-ionic-strength buffer has the opposite effect on bactericidal activity of both peptides, resulting in lesser reductions in titer for both Gram-positive and Gram-negative bacteria. Circular dichroism spectroscopy shows that the differential action of polysorbate 20 and salt on the virucidal and bactericidal activities correlates with the α-helical content of peptide secondary structure in solution, suggesting that the virucidal and bactericidal activities are mediated through distinct mechanisms. The correlation of a defined structural feature with differential activity against a host-derived viral membrane and the membranes of both Gram-positive and Gram-negative bacteria suggests that the overall helical content in solution under physiological conditions is an important feature for consideration in the design and development of candidate peptide-based antimicrobial compounds. PMID:26824944

  6. Chemical Composition, Antioxidant and Antimicrobial Activities of Thymus capitata Essential Oil with Its Preservative Effect against Listeria monocytogenes Inoculated in Minced Beef Meat.

    PubMed

    El Abed, Nariman; Kaabi, Belhassen; Smaali, Mohamed Issam; Chabbouh, Meriem; Habibi, Kamel; Mejri, Mondher; Marzouki, Mohamed Nejib; Ben Hadj Ahmed, Sami

    2014-01-01

    The chemical composition, antioxidant and antimicrobial activities, and the preservative effect of Thymus capitata essential oil against Listeria monocytogenes inoculated in minced beef meat were evaluated. The essential oil extracted was chemically analyzed by gas chromatography-mass spectrometry. Nineteen components were identified, of which carvacrol represented (88.89%) of the oil. The antioxidant activity was assessed in vitro by using both the DPPH and the ABTS assays. The findings showed that the essential oil exhibited high antioxidant activity, which was comparable to the reference standards (BHT and ascorbic acid) with IC50 values of 44.16 and 0.463 μ g/mL determined by the free-radical scavenging DPPH and ABTS assays, respectively. Furthermore, the essential oil was evaluated for its antimicrobial activity using disc agar diffusion and microdilution methods. The results demonstrated that the zone of inhibition varied from moderate to strong (15-80 mm) and the minimum inhibition concentration values ranged from 0.32 to 20 mg/mL. In addition, essential oil evaluated in vivo against Listeria monocytogenes showed clear and strong inhibitory effect. The application of 0.25 or 1% (v/w) essential oil of T. capitata to minced beef significantly reduced the L. monocytogenes population when compared to those of control samples (P-value  <0.01). PMID:24719640

  7. Chemical Composition, Antioxidant and Antimicrobial Activities of Thymus capitata Essential Oil with Its Preservative Effect against Listeria monocytogenes Inoculated in Minced Beef Meat

    PubMed Central

    El Abed, Nariman; Kaabi, Belhassen; Smaali, Mohamed Issam; Chabbouh, Meriem; Habibi, Kamel; Mejri, Mondher; Marzouki, Mohamed Nejib; Ben Hadj Ahmed, Sami

    2014-01-01

    The chemical composition, antioxidant and antimicrobial activities, and the preservative effect of Thymus capitata essential oil against Listeria monocytogenes inoculated in minced beef meat were evaluated. The essential oil extracted was chemically analyzed by gas chromatography-mass spectrometry. Nineteen components were identified, of which carvacrol represented (88.89%) of the oil. The antioxidant activity was assessed in vitro by using both the DPPH and the ABTS assays. The findings showed that the essential oil exhibited high antioxidant activity, which was comparable to the reference standards (BHT and ascorbic acid) with IC50 values of 44.16 and 0.463 μg/mL determined by the free-radical scavenging DPPH and ABTS assays, respectively. Furthermore, the essential oil was evaluated for its antimicrobial activity using disc agar diffusion and microdilution methods. The results demonstrated that the zone of inhibition varied from moderate to strong (15–80 mm) and the minimum inhibition concentration values ranged from 0.32 to 20 mg/mL. In addition, essential oil evaluated in vivo against Listeria monocytogenes showed clear and strong inhibitory effect. The application of 0.25 or 1% (v/w) essential oil of T. capitata to minced beef significantly reduced the L. monocytogenes population when compared to those of control samples (P-value  <0.01). PMID:24719640

  8. Destabilization of α-Helical Structure in Solution Improves Bactericidal Activity of Antimicrobial Peptides: Opposite Effects on Bacterial and Viral Targets.

    PubMed

    Ulaeto, David O; Morris, Christopher J; Fox, Marc A; Gumbleton, Mark; Beck, Konrad

    2016-04-01

    We have previously examined the mechanism of antimicrobial peptides on the outer membrane of vaccinia virus. We show here that the formulation of peptides LL37 and magainin-2B amide in polysorbate 20 (Tween 20) results in greater reductions in virus titer than formulation without detergent, and the effect is replicated by substitution of polysorbate 20 with high-ionic-strength buffer. In contrast, formulation with polysorbate 20 or high-ionic-strength buffer has the opposite effect on bactericidal activity of both peptides, resulting in lesser reductions in titer for both Gram-positive and Gram-negative bacteria. Circular dichroism spectroscopy shows that the differential action of polysorbate 20 and salt on the virucidal and bactericidal activities correlates with the α-helical content of peptide secondary structure in solution, suggesting that the virucidal and bactericidal activities are mediated through distinct mechanisms. The correlation of a defined structural feature with differential activity against a host-derived viral membrane and the membranes of both Gram-positive and Gram-negative bacteria suggests that the overall helical content in solution under physiological conditions is an important feature for consideration in the design and development of candidate peptide-based antimicrobial compounds. PMID:26824944

  9. Ocular Surface Expression and In Vitro Activity of Antimicrobial Peptides

    PubMed Central

    Huang, Ling C.; Jean, Daniele; Proske, Rita J.; Reins, Rose Y.; McDermott, Alison M.

    2008-01-01

    Purpose Human ocular surface epithelia express four antimicrobial peptides (APs): β-defensin (hBD) 1-3 and LL-37. Here the expression of additional APs (hBD 4-6, HE2β1; histatin-1, -3; liver expressed antimicrobial peptide-1, -2; macrophage inflammatory protein (MIP)-3α, and thymosin (T)β-4) was sought and activity against common ocular pathogens studied. Methods AP expression was determined in human corneal and conjunctival epithelial cells (HCEC, HCjEC) by RT-PCR and in corneal sections by immunostaining. Antimicrobial assays were performed to assess peptide (hBD 1-3, LL-37, MIP-3α, and Tβ4) activity against Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), and Staphylococcus epidermidis (SE) in the presence of NaCl or tears. Results HCEC and HCjEC expressed MIP-3α and Tβ4. hBD 1-3, MIP-3α, and Tβ4 showed activity against PA. hBD-3 had potent activity against SA and SE, whereas hBD-2, MIP-3α and Tβ4 had moderate activity and hBD-1 had none. NaCl markedly attenuated, and tears almost completely inhibited the activity of hBD 1-2 and Tβ4, but not that of hBD-3. Conclusions The ocular surface epithelia additionally express MIP-3α and Tβ4 which have moderate antimicrobial activity. The current data support a role for hBD-3 as an antimicrobial peptide in vivo, but call in to question the effectiveness of some other APs. However, further study is required to conclusively elucidate the physiological role of each AP. PMID:17852183

  10. Antimicrobial Activity of Indigofera suffruticosa

    PubMed Central

    Leite, Sônia Pereira; Vieira, Jeymesson Raphael Cardoso; de Medeiros, Paloma Lys; Leite, Roberta Maria Pereira; de Menezes Lima, Vera Lúcia; Xavier, Haroudo Satiro; de Oliveira Lima, Edeltrudes

    2006-01-01

    Various organic and aqueous extracts of leaves of Indigofera suffruticosa Mill (Fabaceae) obtained by infusion and maceration were screened for their antibacterial and antifungal activities. The extracts were tested against 5 different species of human pathogenic bacteria and 17 fungal strains by the agar-solid diffusion method. Most of the extracts were devoid of antifungal and antibacterial activities, except the aqueous extract of leaves of I. suffruticosa obtained by infusion, which showed strong inhibitory activity against the Gram-positive bacteria Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 5000 µg ml−1. The MIC values to dermatophyte strains were 2500 µg ml−1 against Trichophyton rubrum (LM-09, LM-13) and Microsporum canis. This study suggests that aqueous extracts of leaves of I. suffruticosa obtained by infusion can be used in the treatment of skin diseases caused by dermatophytes. PMID:16786057

  11. Antimicrobial activity of Antarctic bryozoans: an ecological perspective with potential for clinical applications.

    PubMed

    Figuerola, Blanca; Sala-Comorera, Laura; Angulo-Preckler, Carlos; Vázquez, Jennifer; Jesús Montes, M; García-Aljaro, Cristina; Mercadé, Elena; Blanch, Anicet R; Avila, Conxita

    2014-10-01

    The antimicrobial activity of Antarctic bryozoans and the ecological functions of the chemical compounds involved remain largely unknown. To determine the significant ecological and applied antimicrobial effects, 16 ether and 16 butanol extracts obtained from 13 different bryozoan species were tested against six Antarctic (including Psychrobacter luti, Shewanella livingstonensis and 4 new isolated strains) and two bacterial strains from culture collections (Escherichia coli and Bacillus cereus). Results from the bioassays reveal that all ether extracts exhibited antimicrobial activity against some bacteria. Only one butanol extract produced inhibition, indicating that antimicrobial compounds are mainly lipophilic. Ether extracts of the genus Camptoplites inhibited the majority of bacterial strains, thus indicating a broad-spectrum of antimicrobial activity. Moreover, most ether extracts presented activities against bacterial strains from culture collections, suggesting the potential use of these extracts as antimicrobial drugs against pathogenic bacteria. PMID:25232675

  12. [Antimicrobial activity of orthodontic band cements].

    PubMed

    Pavic, J; Arriagada, M; Elgueta, J; García, C

    1990-01-01

    The prevalence of enamel decalcification and caries beneath orthodontic bands, has indicated the need for a new enamel binding adhesive orthodontic cement. The purpose of this study was to evaluate the antimicrobial activity, in vitro, on Streptococcus mutans and Lactobacillus, acidophillus, of three materials used to cements the orthodontic bands. The cements studied were: Zinc phosphate cement, Glass-ionomer cement, and Policarboxylate cement. Thirty petri plates were seeded with S. mutans, and thirty with L. acidophillus; on each plate three pellet were placed, one of each cement studied. Petri plates were incubated under microaerophilic conditions at 37 C, and checked at 72 hrs. for Streptococcus, mutans, and four days for Lactobacillus acidophillus to evaluate the inhibition zone. The results were tabulated for each material. It was demonstrated that exists important variations in the antimicrobial properties of the materials studied, as in the microbial sensitivity to these cements. PMID:2135908

  13. Antimicrobial activity of the metals and metal oxide nanoparticles.

    PubMed

    Dizaj, Solmaz Maleki; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad Hossein; Adibkia, Khosro

    2014-11-01

    The ever increasing resistance of pathogens towards antibiotics has caused serious health problems in the recent years. It has been shown that by combining modern technologies such as nanotechnology and material science with intrinsic antimicrobial activity of the metals, novel applications for these substances could be identified. According to the reports, metal and metal oxide nanoparticles represent a group of materials which were investigated in respect to their antimicrobial effects. In the present review, we focused on the recent research works concerning antimicrobial activity of metal and metal oxide nanoparticles together with their mechanism of action. Reviewed literature indicated that the particle size was the essential parameter which determined the antimicrobial effectiveness of the metal nanoparticles. Combination therapy with the metal nanoparticles might be one of the possible strategies to overcome the current bacterial resistance to the antibacterial agents. However, further studies should be performed to minimize the toxicity of metal and metal oxide nanoparticles to apply as proper alternatives for antibiotics and disinfectants especially in biomedical applications. PMID:25280707

  14. Review of antimicrobial and antioxidative activities of chitosans in food.

    PubMed

    Friedman, Mendel; Juneja, Vijay K

    2010-09-01

    Interest in chitosan, a biodegradable, nontoxic, non-antigenic, and biocompatible biopolymer isolated from shellfish, arises from the fact that chitosans are reported to exhibit numerous health-related beneficial effects, including strong antimicrobial and antioxidative activities in foods. The extraordinary interest in the chemistry and application in agriculture, horticulture, environmental science, industry, microbiology, and medicine is attested by about 17,000 citations on this subject in the Scopus database. A special need exists to develop a better understanding of the role of chitosans in ameliorating foodborne illness. To contribute to this effort, this overview surveys and interprets our present knowledge of the chemistry and antimicrobial activities of chitosan in solution, as powders, and in edible films and coating against foodborne pathogens, spoilage bacteria, and pathogenic viruses and fungi in several food categories. These include produce, fruit juices, eggs and dairy, cereal, meat, and seafood products. Also covered are antimicrobial activities of chemically modified and nanochitosans, therapeutic properties, and possible mechanisms of the antimicrobial, antioxidative, and metal chelating effects. Further research is suggested in each of these categories. The widely scattered data on the multifaceted aspects of chitosan microbiology, summarized in the text and in 10 tables and 8 representative figures, suggest that low-molecular-weight chitosans at a pH below 6.0 presents optimal conditions for achieving desirable antimicrobial and antioxidative-preservative effects in liquid and solid foods. We are very hopeful that the described findings will be a valuable record and resource for further progress to improve microbial food safety and food quality. PMID:20828484

  15. Repurposing the Antihistamine Terfenadine for Antimicrobial Activity against Staphylococcus aureus

    PubMed Central

    2015-01-01

    Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure–activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics. PMID:25238555

  16. Antimicrobial activity of bone cements embedded with organic nanoparticles

    PubMed Central

    Perni, Stefano; Thenault, Victorien; Abdo, Pauline; Margulis, Katrin; Magdassi, Shlomo; Prokopovich, Polina

    2015-01-01

    Infections after orthopedic surgery are a very unwelcome outcome; despite the widespread use of antibiotics, their incidence can be as high as 10%. This risk is likely to increase as antibiotics are gradually losing efficacy as a result of bacterial resistance; therefore, novel antimicrobial approaches are required. Parabens are a class of compounds whose antimicrobial activity is employed in many cosmetic and pharmaceutical products. We developed propylparaben nanoparticles that are hydrophilic, thus expanding the applicability of parabens to aqueous systems. In this paper we assess the possibility of employing paraben nanoparticles as antimicrobial compound in bone cements. The nanoparticles were embedded in various types of bone cement (poly(methyl methacrylate) [PMMA], hydroxyapatite, and brushite) and the antimicrobial activity was determined against common causes of postorthopedic surgery infections such as: Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, and Acinetobacter baumannii. Nanoparticles at concentrations as low as 1% w/w in brushite bone cement were capable of preventing pathogens growth, 5% w/w was needed for hydroxyapatite bone cement, while 7% w/w was required for PMMA bone cement. No detrimental effect was determined by the addition of paraben nanoparticles on bone cement compression strength and cytocompatibility. Our results demonstrate that paraben nanoparticles can be encapsulated in bone cement, providing concentration-dependent antimicrobial activity; furthermore, lower concentrations are needed in calcium phosphate (brushite and hydroxyapatite) than in acrylic (PMMA) bone cements. These nanoparticles are effective against a wide spectrum of bacteria, including those already resistant to the antibiotics routinely employed in orthopedic applications, such as gentamicin. PMID:26487803

  17. Lipid-Based Liquid Crystals As Carriers for Antimicrobial Peptides: Phase Behavior and Antimicrobial Effect.

    PubMed

    Boge, Lukas; Bysell, Helena; Ringstad, Lovisa; Wennman, David; Umerska, Anita; Cassisa, Viviane; Eriksson, Jonny; Joly-Guillou, Marie-Laure; Edwards, Katarina; Andersson, Martin

    2016-05-01

    The number of antibiotic-resistant bacteria is increasing worldwide, and the demand for novel antimicrobials is constantly growing. Antimicrobial peptides (AMPs) could be an important part of future treatment strategies of various bacterial infection diseases. However, AMPs have relatively low stability, because of proteolytic and chemical degradation. As a consequence, carrier systems protecting the AMPs are greatly needed, to achieve efficient treatments. In addition, the carrier system also must administrate the peptide in a controlled manner to match the therapeutic dose window. In this work, lyotropic liquid crystalline (LC) structures consisting of cubic glycerol monooleate/water and hexagonal glycerol monooleate/oleic acid/water have been examined as carriers for AMPs. These LC structures have the capability of solubilizing both hydrophilic and hydrophobic substances, as well as being biocompatible and biodegradable. Both bulk gels and discrete dispersed structures (i.e., cubosomes and hexosomes) have been studied. Three AMPs have been investigated with respect to phase stability of the LC structures and antimicrobial effect: AP114, DPK-060, and LL-37. Characterization of the LC structures was performed using small-angle X-ray scattering (SAXS), dynamic light scattering, ζ-potential, and cryogenic transmission electron microscopy (Cryo-TEM) and peptide loading efficacy by ultra performance liquid chromatography. The antimicrobial effect of the LCNPs was investigated in vitro using minimum inhibitory concentration (MIC) and time-kill assay. The most hydrophobic peptide (AP114) was shown to induce an increase in negative curvature of the cubic LC system. The most polar peptide (DPK-060) induced a decrease in negative curvature while LL-37 did not change the LC phase at all. The hexagonal LC phase was not affected by any of the AMPs. Moreover, cubosomes loaded with peptides AP114 and DPK-060 showed preserved antimicrobial activity, whereas particles loaded with peptide LL-37 displayed a loss in its broad-spectrum bactericidal properties. AMP-loaded hexosomes showed a reduction in antimicrobial activity. PMID:27033359

  18. Green synthesis of biogenic silver nanomaterials using Raphanus sativus extract, effects of stabilizers on the morphology, and their antimicrobial activities.

    PubMed

    Khan, Mohammad Naved; Khan, Tabrez Alam; Khan, Zaheer; Al-Thabaiti, Shaeel Ahmed

    2015-12-01

    The present study explores the reducing and capping potentials of aqueous Raphanus sativus root extract for the synthesis of silver nanomaterials for the first time in the absence and presence of two stabilizers, namely, water-soluble starch and cetyltrimethylammonium bromide (CTAB). The surface properties of silver nanoparticles (AgNPs) were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy dispersion X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) techniques. The mean size of AgNPs, ranging from 3.2 to 6.0 nm, could be facilely controlled by merely varying the initial [extract], [CTAB], [starch], and [Ag(+)] ions. The agglomeration number, average number of silver atoms per nanoparticle, and changes in the fermi potentials were calculated and discussed. The AgNPs were evaluated for their antimicrobial activities against different pathogenic organisms. The inhibition action was due to the structural changes in the protein cell wall. PMID:26458821

  19. [Antimicrobial activity of stable silver nanoparticles of a certain size].

    PubMed

    Mukha, Iu P; Eremenko, A M; Smirnova, N P; Mikhienkova, A I; Korchak, G I; Gorchev, V F; Chunikhin, A Iu

    2013-01-01

    Conditions for obtaining stable silver nanoparticles smaller than 10 nm were developed using a binary stabilizer polyvinylpyrrolidone/sodium dodecylsulphate in optimal ratio. Optical spectra, morphology and dependence of size of the nanoparticles on the amount of reducing agent were studied. Colloidal solutions of nanosilver showed a high bactericidal activity against strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and fungicidal activity against Candida albicans. The mechanism of action of nanosized silver on microbial cell was examined by laser scanning confocal microscope using fluorescent label. First step of antimicrobial effect on microorganisms was membrane damage and penetration of silver nanoparticles into the cell. Prolonged stability of nanoparticles and their antimicrobial activity over the past two years were showed. PMID:23795483

  20. Screening of Brazilian basidiomycetes for antimicrobial activity.

    PubMed

    Rosa, Luiz Henrique; Machado, Ktia M Gomes; Jacob, Camila Cristina; Capelari, Marina; Rosa, Carlos Augusto; Zani, Carlos Leomar

    2003-10-01

    A total of 103 isolates of basidiomycetes, representing 84 species from different Brazilian ecosystems, were evaluated for their antifungal and antibacterial activity in a panel of pathogenic and non-pathogenic microorganisms. Tissue plugs of the fruiting bodies were cultivated in liquid media and the whole culture extracted with ethyl acetate. Crude extracts from Agaricus cf. nigrecentulus, Agrocybe perfecta, Climacodon pulcherrimus, Gloeoporus thelephoroides, Hexagonia hydnoides, Irpex lacteus, Leucoagaricus cf. cinereus, Marasmius cf. bellus, Marasmius sp., Nothopanus hygrophanus, Oudemansiella canarii, Pycnoporus sanguineus, Phellinus sp., and Tyromyces duracinus presented significant activity against one or more of the target microorganisms. Eight isolates were active only against bacteria while three inhibited exclusively the growth of fungi. Two extracts presented wide antimicrobial spectrum and were active against both fungi and bacteria. Differences in the bioactivity of extracts obtained from isolates from the same species were observed. PMID:14762527

  1. Synthesis and antimicrobial activity of novel tetrahydrobenzothienopyrimidines.

    PubMed

    Eissa, Amal Abdel Haleem Mohamed; Moneer, Ashraf Ahmed

    2004-09-01

    Due to the rapidly growing number of resistant strains of bacteria, the search for antibacterial agents with new modes of action will always remain an important and challenging task. Thus, the reaction of 2-substituted or unsubstituted-4-(4-acetylanilino)-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-d]pyrimidine derivatives 1-3 with the hydrazine derivatives, semi and/or thiosemicarbazides, provided the corresponding hydrazones 4-6 and semi and/or thiosemicarbazones 7-9. Claisen-Schmidt condensation of compounds 1 or 2 with the appropriate aldehyde yielded the chalcones 10, 11 which, when treated with hydroxylamine hydrochloride gave rise to the isoxazoline-containing compounds 12, 13. Furthermore, reacting the respective chalcones 10, 11 with different hydrazines, urea and/or thiourea, furnished compounds 14, 15, 16, and 17 respectively. Representative compounds were tested for their antimicrobial activity against Candida albicans and certain gram-positive and gram-negative bacteria. Their MICs were then determined. Compound 15e, showed a broad spectrum of activity while most of the other compounds showed varying antimicrobial activity. PMID:15473655

  2. Antimicrobial Activity of Nanoemulsion on Cariogenic Planktonic and Biofilm Organisms

    PubMed Central

    Amaechi, Bennett T.; Rawls, H Ralph; Valerie, A Lee

    2011-01-01

    Introduction Nanoemulsions (NE) are a unique class of disinfectants produced by mixing a water immiscible liquid phase into an aqueous phase under high shear forces. NE have antimicrobial properties and are also effective anti-biofilm agents. Materials and Methods The effectiveness of nanoemulsion and its components was determined against Streptococcus mutans and Lactobacillus casei by live/dead staining. In vitro antimicrobial effectiveness of nanoemulsion against planktonic Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus, Candida albicans and mixed culture was determined by a serial dilution technique to obtain minimum inhibitory concentration and minimum bactericidal concentration (MIC/MBC). In addition, efficacy was investigated by kinetics of killing, adherence and biofilm assays. Results Compared to its components, nanoemulsion showed notable antimicrobial activity against biofilm organisms, up to 83.0% kill within 1 min. NE dilutions ranging from 243 to 19683 were effective against planktonic S. mutans, L. casei, A. viscosus, C. albicans and mixed culture of these four strains as shown through MIC/MBC assays. NE showed antimicrobial activity against planktonic cells at high dilutions, confirmed by time kill studies. The level of adhesion on glass surface was reduced by 94.2 to 99.5 % in nanoemulsion treated groups (p < 0.001). 4-day-old S. mutans, L. casei, A. viscosus, C. albicans and mixed cultures biofilms treated with NE showed reductions of bacterial counts with decreasing dilutions (p < 0.001). Conclusion These results suggest that nanoemulsion has effective anti-cariogenic activity against cariogenic microorganisms and may be a useful medication in the prevention of caries. PMID:21807359

  3. Antimicrobial Activity of Some Higher Amine Salts of Carboxylic Acids

    PubMed Central

    Borick, Paul M.; Bratt, Martin

    1961-01-01

    Various higher amine salts of dicarboxylic and tricarboxylic acids were prepared and tested for antimicrobial activity in vitro. Although activity was present in all compounds tested, tetradecylammonium malonate showed the greatest activity with the widest spectrum. This compound was effective against gram-negative as well as gram-positive microorganisms, yeast, and fungi. A high order of microbiological activity was demonstrated with various higher amine salts of dicarboxylic and tricarboxylic acids, e.g., tetradecylammonium oxalate, tetradecylammonium citrate, and so forth. Compounds tested exhibited a low order of toxicity. PMID:13871338

  4. Antimicrobial activities of some Euphorbia species.

    PubMed

    Kirbag, Sevda; Erecevit, Pınar; Zengin, Fikriye; Guvenc, Ayşe Nilay

    2013-01-01

    In this study, the antimicrobial activities of methanolic extracts and latex of some Euphorbia species used for medical purposes in Turkey were investigated. The extracts of Euphorbia aleppica L., Euphorbia szovitsii Fisch.&Mey. var. harputensis Aznav. ex M. S. Khan, Euphorbia falcata L. sub. falcata var. falcata, Euphorbia denticulata Lam., Euphorbia macroclada Boiss., Euphorbia cheiradenia Boiss.&Hohen, Euphorbia virgata Waldst.&Kit., Euphorbia petiolata Banks&Sol. were prepared with methanol. The antimicrobial activities of these extracts were examined on test microorganisms as follows: Staphylococcus aureus COWAN 1, Bacillus megaterium DSM 32, Proteus vulgaris FMC 1, Klebsiella pneumonia FMC 5, Escherichia coli ATCC 25922, Pseudomonas aeruginosa DSM 50071, Candida albicans FMC 17, Candida glabrata ATCC 66032, Epidermophyton sp. and Trichophyton sp. by the disc diffusion methods and well agar method. The MIC values of extracts were determined according to the broth microdulitions method. Results indicated that extracts of Euphorbia species inhibited the growth of tested microorganisms in the different ratio. Also, the MIC values of extracts were determined as 31,2-1000 µg. PMID:24311840

  5. Antimicrobial Properties and Membrane-Active Mechanism of a Potential α-Helical Antimicrobial Derived from Cathelicidin PMAP-36

    PubMed Central

    Lv, Yinfeng; Wang, Jiajun; Gao, He; Wang, Zeyun; Dong, Na; Ma, Qingquan; Shan, Anshan

    2014-01-01

    Antimicrobial peptides (AMPs), which present in the non-specific immune system of organism, are amongst the most promising candidates for the development of novel antimicrobials. The modification of naturally occurring AMPs based on their residue composition and distribution is a simple and effective strategy for optimization of known AMPs. In this study, a series of truncated and residue-substituted derivatives of antimicrobial peptide PMAP-36 were designed and synthesized. The 24-residue truncated peptide, GI24, displayed antimicrobial activity comparable to the mother peptide PMAP-36 with MICs ranging from 1 to 4 µM, which is lower than the MICs of bee venom melittin. Although GI24 displayed high antimicrobial activity, its hemolytic activity was much lower than melittin, suggesting that GI24 have optimal cell selectivity. In addition, the crucial site of GI24 was identified through single site-mutation. An amino acid with high hydrophobicity at position 23 played an important role in guaranteeing the high antimicrobial activity of GI24. Then, lipid vesicles and whole bacteria were employed to investigate the membrane-active mechanisms. Membrane-simulating experiments showed that GI24 interacted strongly with negatively charged phospholipids and weakly with zwitterionic phospholipids, which corresponded well with the data of its biological activities. Membrane permeabilization and flow cytometry provide the evidence that GI24 killed microbial cells by permeabilizing the cell membrane and damaging membrane integrity. GI24 resulted in greater cell morphological changes and visible pores on cell membrane as determined using scanning electron microscopy (SEM) and transmission electron microscope (TEM). Taken together, the peptide GI24 may provide a promising antimicrobial agent for therapeutic applications against the frequently-encountered bacteria. PMID:24466055

  6. Antimicrobial activity of some medicinal barks used in Peruvian Amazon.

    PubMed

    Kloucek, P; Svobodova, B; Polesny, Z; Langrova, I; Smrcek, S; Kokoska, L

    2007-05-01

    The aim of this study was to evaluate the antimicrobial activity of six barks traditionally used in Callería District (Ucayali Department, Peru) for treating conditions likely to be associated with microorganisms. Ethanol extracts of stem barks of Abuta grandifolia (Menispermaceae), Dipteryx micrantha (Leguminosae), Cordia alliodora (Boraginaceae), Naucleopsis glabra (Moraceae), Pterocarpus rohrii (Leguminosae), and root bark of Maytenus macrocarpa (Celastraceae) were tested against nine bacteria and one yeast using the broth microdilution method. All plants possessed significant antimicrobial effect, however, the extract of Naucleopsis glabra exhibited the strongest activity against Gram-positive bacteria (MICs ranging from 62.5 to 125 microg/ml), while the broadest spectrum of action was shown by the extract of Maytenus macrocarpa, which inhibited all the strains tested with MICs ranging from 125 to 250 microg/ml. PMID:17178202

  7. The antiviral and antimicrobial activities of licorice, a widely-used Chinese herb

    PubMed Central

    Wang, Liqiang; Yang, Rui; Yuan, Bochuan; Liu, Ying; Liu, Chunsheng

    2015-01-01

    Licorice is a common herb which has been used in traditional Chinese medicine for centuries. More than 20 triterpenoids and nearly 300 flavonoids have been isolated from licorice. Recent studies have shown that these metabolites possess many pharmacological activities, such as antiviral, antimicrobial, anti-inflammatory, antitumor and other activities. This paper provides a summary of the antiviral and antimicrobial activities of licorice. The active components and the possible mechanisms for these activities are summarized in detail. This review will be helpful for the further studies of licorice for its potential therapeutic effects as an antiviral or an antimicrobial agent. PMID:26579460

  8. Impact of interspecific interactions on antimicrobial activity among soil bacteria

    PubMed Central

    Tyc, Olaf; van den Berg, Marlies; Gerards, Saskia; van Veen, Johannes A.; Raaijmakers, Jos M.; de Boer, Wietse; Garbeva, Paolina

    2014-01-01

    Certain bacterial species produce antimicrobial compounds only in the presence of a competing species. However, little is known on the frequency of interaction-mediated induction of antibiotic compound production in natural communities of soil bacteria. Here we developed a high-throughput method to screen for the production of antimicrobial activity by monocultures and pair-wise combinations of 146 phylogenetically different bacteria isolated from similar soil habitats. Growth responses of two human pathogenic model organisms, Escherichia coli WA321 and Staphylococcus aureus 533R4, were used to monitor antimicrobial activity. From all isolates, 33% showed antimicrobial activity only in monoculture and 42% showed activity only when tested in interactions. More bacterial isolates were active against S. aureus than against E. coli. The frequency of interaction-mediated induction of antimicrobial activity was 6% (154 interactions out of 2798) indicating that only a limited set of species combinations showed such activity. The screening revealed also interaction-mediated suppression of antimicrobial activity for 22% of all combinations tested. Whereas all patterns of antimicrobial activity (non-induced production, induced production and suppression) were seen for various bacterial classes, interaction-mediated induction of antimicrobial activity was more frequent for combinations of Flavobacteria and alpha- Proteobacteria. The results of our study give a first indication on the frequency of interference competitive interactions in natural soil bacterial communities which may forms a basis for selection of bacterial groups that are promising for the discovery of novel, cryptic antibiotics. PMID:25389421

  9. Antityrosinase and antimicrobial activities from Thai medicinal plants.

    PubMed

    Dej-Adisai, Sukanya; Meechai, Imron; Puripattanavong, Jindaporn; Kummee, Sopa

    2014-04-01

    Various dermatological disorders and microbial skin infection can cause hyperpigmentation. Therefore, screenings for whitening and antimicrobial agents from Thai medicinal plants have been of research interest. Seventy-seven ethanol plant extracts were investigated for antityrosinase activity, eleven samples showed the tyrosinase inhibition more than 50 % were further preliminary screening for antimicrobial activity by agar disc diffusion and broth micro-dilution methods. Artocarpus integer (Thunb.) Merr. (Moraceae) root extract, which showed the potential of tyrosinase inhibition with 90.57 ± 2.93 % and antimicrobial activity against Staphylococcus aureus, S. epidermidis, Propionibacterium acnes and Trichophyton mentagophytes with inhibition zone as 9.10 ± 0.00, 10.67 ± 0.09, 15.25 ± 0.05 and 6.60 ± 0.17 mm, respectively was selected for phytochemical investigation. Three pure compounds were isolated as artocarpin, cudraflavone C and artocarpanone. And artocarpanone exhibited anti-tyrosinase effect; artocarpin and cudraflavone C also showed the potential of antibacterial activity against S. aureus, S. epidermidis and P. acnes with MIC at 2, 4 and 2 μg/ml, respectively and MBC at 32 μg/ml for these bacteria. So, these pure compounds are interesting for further study in order to provide possibilities of new whitening and antibacterial development. This will be the first report of phytochemical investigation of A. integer root. PMID:23835832

  10. Antimicrobial activity of grapefruit seed and pulp ethanolic extract.

    PubMed

    Cvetnić, Zdenka; Vladimir-Knezević, Sanda

    2004-09-01

    Antibacterial and antifungal activity of ethanolic extract of grapefruit (Citrus paradisi Macf., Rutaceae) seed and pulp was examined against 20 bacterial and 10 yeast strains. The level of antimicrobial effects was established using an in vitro agar assay and standard broth dilution susceptibility test. The contents of 3.92% of total polyphenols and 0.11% of flavonoids were determined spectrometrically in crude ethanolic extract. The presence of flavanones naringin and hesperidin in the extract was confirmed by TLC analysis. Ethanolic extract exibited the strongest antimicrobial effect against Salmonella enteritidis (MIC 2.06%, m/V). Other tested bacteria and yeasts were sensitive to extract concentrations ranging from 4.13% to 16.50% (m/V). PMID:15610620

  11. The antimicrobial activity of Prevention mouthrinse.

    PubMed

    Drake, D R; Wefel, J S; Dunkerson, D; Hogle, K

    1993-10-01

    Prevention mouthrinse was designed to serve as a vital supplement to normal oral hygiene procedures. To determine the antimicrobial potency of this mouthrinse, minimal inhibitory concentrations (MICs), bactericidal kinetics, and short-term exposure studies were conducted. A spectrum of oral microorganisms was employed in this investigation: Streptococcus sanguis, Streptococcus anginosus, Streptococcus mutans, Actinomyces viscosus, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Eikenella corrodens, Porphyromonas gingivalis, Serratia marcescens and Candida albicans. Microorganisms were cultured in standard enriched media and under appropriate atmospheric conditions. Inhibition assays were conducted in tubes, with each mouthrinse dilution assayed in triplicate. MIC determinations revealed that all of the microorganisms studied were highly susceptible to Prevention mouthrinse, with MICs ranging from 16-fold to 128-fold dilutions. Bactericidal kinetics assays showed rapid killing of the test organisms in the presence of the mouthrinse. Brief (5-minute) exposure of S. mutans to 8-fold diluted mouthrinse resulted in a substantial delay in growth. Under the constraints of this type of study, Prevention mouthrinse exhibited potent antimicrobial activity against all of the microorganisms studied. We support the notion that Prevention mouthrinse may be a valuable supplement to normal oral hygiene procedures. A 6-month clinical trial assessing the in vivo efficacy of Prevention mouthrinse is currently being conducted. PMID:7880467

  12. Antimicrobial activity of hydroxytyrosol: a current controversy.

    PubMed

    Medina-Martínez, María S; Truchado, Pilar; Castro-Ibáñez, Irene; Allende, Ana

    2016-04-01

    This study focus on the main factors that affect the antimicrobial capacity of hydroxytyrosol, including the concentration (200, 400, and 1000 μg/mL), target strains, and the culture media (nutrient-rich and less-rich culture media). The potential HT degradation was also evaluated by HPLC-PAD. Kinetic parameters from growth curves showed that HT concentrations produced a doses-dependent shift when compared to the untreated control. In most of the cases, the highest tested dose (1000 μg/mL) was needed to inhibit growth of the selected strains. However, all the strains were able to grow even at the highest HT dose when cultivated in nutrient-rich culture media. It was observed that HT concentrations were reduced by about 15%, except for Escherichia coli 533 and 679 in Muller Hinton broth, where HT was reduced up to 35%. The results showed a limited antimicrobial activity, contrary to information previously published in some research papers. PMID:26679750

  13. Antimicrobial metallopeptides with broad nuclease and ribonuclease activity.

    PubMed

    Joyner, Jeff C; Hodnick, W F; Cowan, Ada S; Tamuly, Deepika; Boyd, Rachel; Cowan, J A

    2013-03-14

    Metallopeptides containing both the complex Cu(2+)-glycyl-glycyl-histidine (Cu-GGH) and the sequence WRWYCR were shown to possess antimicrobial activity against a variety of pathogenic bacteria, as well as bind to and cleave a variety of nucleic acids, suggesting potential mechanisms for antimicrobial activity that involve binding and/or irreversible cleavage of bacterial nucleic acids. PMID:23380915

  14. 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. PMID:16730921

  15. Effects of Allspice, Cinnamon, and Clove Bud Essential Oils in Edible Apple Films on Physical Properties and Antimicrobial Activities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The results of the present study show that allspice, cinnamon and clove bud essential oils can be used to prepare apple-based antimicrobial edible films with good physical properties for food applications by both direct contact and indirectly by vapors emanating from the films. Application of the a...

  16. Aedesin: Structure and Antimicrobial Activity against Multidrug Resistant Bacterial Strains

    PubMed Central

    Padilla, André; Hamel, Rodolphe; Luplertlop, Natthanej; Chauffour, Aurélie; Vittecoq, Marion; Hoh, François; Thomas, Frédéric; Sougakoff, Wladimir; Lionne, Corinne; Yssel, Hans; Missé, Dorothée

    2014-01-01

    Multidrug resistance, which is acquired by both Gram-positive and Gram-negative bacteria, causes infections that are associated with significant morbidity and mortality in many clinical settings around the world. Because of the rapidly increasing incidence of pathogens that have become resistant to all or nearly all available antibiotics, there is a need for a new generation of antimicrobials with a broad therapeutic range for specific applications against infections. Aedesin is a cecropin-like anti-microbial peptide that was recently isolated from dengue virus-infected salivary glands of the Aedes aegypti mosquito. In the present study, we have refined the analysis of its structural characteristics and have determined its antimicrobial effects against a large panel of multidrug resistant bacterial strains, directly isolated from infected patients. Based the results from nuclear magnetic resonance spectroscopy analysis, Aedesin has a helix-bend-helix structure typical for a member of the family of α-helix anti-microbial peptides. Aedesin efficiently killed Gram-negative bacterial strains that display the most worrisome resistance mechanisms encountered in the clinic, including resistance to carbapenems, aminoglycosides, cephalosporins, 4th generation fluoroquinolones, folate inhibitors and monobactams. In contrast, Gram-positive strains were insensitive to the lytic effects of the peptide. The anti-bacterial activity of Aedesin was found to be salt-resistant, indicating that it is active under physiological conditions encountered in body fluids characterized by ionic salt concentrations. In conclusion, because of its strong lytic activity against multidrug resistant Gram-negative bacterial strains displaying all types of clinically relevant resistance mechanisms known today, Aedesin might be an interesting candidate for the development of alternative treatment for infections caused by these types of bacteria. PMID:25162372

  17. Spectroscopic characterization of the effect of gamma radiation on the physical parameters of biosynthesized silver/chitosan nano-particles and their antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Osman, Mohamed E.; Eid, May M.; Khattab, Om kolthoum H.; El-Hallouty, Salwa M.; El-Marakby, Seham M.; Mahmoud, Doaa A.

    2015-09-01

    Studying the effect of pH on the biosynthesis of silver/chitosan nanoparticles (Ag/CS NPs) using Aspergillus deflectus and Penicillium pinophilum as reducing agents, showed very weak surface plasmon resonance (SPR) of Ag/CS NPs at certain pH. In this paper, the effect of irradiation on the synthesis of Ag/CS at non-optimum pH was evaluated and thereby, the antimicrobial effect of the biosynthesized Ag/CS NPs. The SPR of the AgNPs was analyzed by UV-visible spectroscopy. The active groups responsible for the reduction and capping of the AgNPs were analyzed by Fourier transform infrared (FTIR), and their shape and size were determined via high resolution transmission electron microscopy (HRTEM) and the dynamic light scattering (DLS) technique. UV/Visible spectroscopy confirmed the appearance of AgNPs’ SPR. Additionally, the FTIR spectroscopy confirmed the Ag/CS NP formation. Data also revealed that increasing both the pH and irradiation dose resulted in a decrease of the Ag/CS NPs’ size. DLS and HRTEM results showed that the best pH for biosynthesis of Ag/Cs is 7.5 at 50 kGy considering the particle size and crystallinity. Also, pH 8.5 gave the best antimicrobial activity of the Ag/CS NPs from Penicillium against both S. aureus and E. coli, while 8.5 and 7.5 were the best in the same order, for Ag/CS from Aspergillus.

  18. Composition and Antimicrobial Activity of Euphrasia rostkoviana Hayne Essential Oil.

    PubMed

    Novy, Pavel; Davidova, Hana; Serrano-Rojero, Cecilia Suqued; Rondevaldova, Johana; Pulkrabek, Josef; Kokoska, Ladislav

    2015-01-01

    Eyebright, Euphrasia rostkoviana Hayne (Scrophulariaceae), is a medicinal plant traditionally used in Europe for the treatment of various health disorders, especially as eyewash to treat eye ailments such as conjunctivitis and blepharitis that can be associated with bacterial infections. Some Euphrasia species have been previously reported to contain essential oil. However, the composition and bioactivity of E. rostkoviana oil are unknown. Therefore, in this study, we investigated the chemical composition and antimicrobial activity of the eyebright essential oil against some organisms associated with eye infections: Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, and Candida albicans. GC-MS analysis revealed more than 70 constituents, with n-hexadecanoic acid (18.47%) as the main constituent followed by thymol (7.97%), myristic acid (4.71%), linalool (4.65%), and anethole (4.09%). The essential oil showed antimicrobial effect against all organisms tested with the exception of P. aeruginosa. The best activity was observed against all Gram-positive bacteria tested with the minimum inhibitory concentrations of 512 µg/mL. This is the first report on the chemical composition of E. rostkoviana essential oil and its antimicrobial activity. PMID:26000025

  19. Composition and Antimicrobial Activity of Euphrasia rostkoviana Hayne Essential Oil

    PubMed Central

    Novy, Pavel; Davidova, Hana; Serrano-Rojero, Cecilia Suqued; Rondevaldova, Johana; Pulkrabek, Josef

    2015-01-01

    Eyebright, Euphrasia rostkoviana Hayne (Scrophulariaceae), is a medicinal plant traditionally used in Europe for the treatment of various health disorders, especially as eyewash to treat eye ailments such as conjunctivitis and blepharitis that can be associated with bacterial infections. Some Euphrasia species have been previously reported to contain essential oil. However, the composition and bioactivity of E. rostkoviana oil are unknown. Therefore, in this study, we investigated the chemical composition and antimicrobial activity of the eyebright essential oil against some organisms associated with eye infections: Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, and Candida albicans. GC-MS analysis revealed more than 70 constituents, with n-hexadecanoic acid (18.47%) as the main constituent followed by thymol (7.97%), myristic acid (4.71%), linalool (4.65%), and anethole (4.09%). The essential oil showed antimicrobial effect against all organisms tested with the exception of P. aeruginosa. The best activity was observed against all Gram-positive bacteria tested with the minimum inhibitory concentrations of 512 µg/mL. This is the first report on the chemical composition of E. rostkoviana essential oil and its antimicrobial activity. PMID:26000025

  20. Antimicrobial activity of toothpastes containing natural extracts, chlorhexidine or triclosan.

    PubMed

    De Rossi, Andiara; Ferreira, Danielly Cunha Araújo; da Silva, Raquel Assed Bezerra; de Queiroz, Alexandra Mussolino; da Silva, Léa Assed Bezerra; Nelson-Filho, Paulo

    2014-01-01

    The objective of this in vitro study was to evaluate the antimicrobial effect of toothpastes containing natural extracts, chlorhexidine or triclosan. The effectiveness of toothpastes containing natural extracts (Parodontax®), 0.12% chlorhexidine (Cariax®), 0.3% triclosan (Sanogil®) or fluoride (Sorriso®, control) was evaluated against yeasts, Gram-positive and Gram-negative bacteria using the disk diffusion method. Water was used as a control. Disks impregnated with the toothpastes were placed in Petri dishes containing culture media inoculated with 23 indicative microorganisms by the pour plate method. After incubation, the inhibition growth halos were measured and statistical analyses (α=0.05) were performed. The results indicated that all formulations, except for conventional toothpaste (Sorriso®), showed antimicrobial activity against Gram-positive bacteria and yeasts. The toothpaste containing natural extracts (Parodontax®) was the only product able to inhibit the growth of Pseudomonas aeruginosa. The toothpastes containing chlorhexidine, triclosan or natural extracts presented antimicrobial activity against Gram-positive bacteria and yeasts. PMID:25252251

  1. Effects of Egg Shell Membrane Hydrolysates on Anti-Inflammatory, Anti-Wrinkle, Anti-Microbial Activity and Moisture-Protection

    PubMed Central

    Yoo, Jinhee; Park, Kimoon; Yoo, Youngji; Kim, Jongkeun; Yang, Heejin; Shin, Youngjae

    2014-01-01

    This study was conducted to examine the effects of eggshell membrane hydrolysates (ESMH) on the anti-inflammatory, anti-wrinkle, anti-microbial activity, and moisture-protection for cosmetic use. Whole ESMH (before fractionation), and fraction I (>10 kDa), fraction II (3-10 kDa), and fraction III (<3 kDa) of the hydrolysates were assessed in this experiment. As lipopolysaccharide (LPS) and IFN-γ caused the inflammation on Raw264.7 cell, whole ESMH and fraction I showed to be effective in inhibiting the induction of cell inflammation depending on the concentration, and also showed outstanding effect to suppress the skin inflammation. Fraction I inhibited collagenase and elastase activities to a greater extent than the other fractions, while all fractions had antibiotic effects at concentrations of 10 mg/disc and 20 mg/disc. In addition, it showed the moisture protection effects of skin on the holding amount and losing amount of moisture in upper-inner arm of the human body with a relatively low loss rate in skin, which confirmed that the hydrolyzed fractions of ESM helps to form the superior protective layer of moisture. It was concluded that ESMH fractions with different molecular weights, especially the 10 kDa fraction, have anti-lipopolysaccharide, anti-IFN-γ-induced inflammation, anti- collagenase and elastase activities, and thus can be used as a cosmetic agent to protect skin. PMID:26760742

  2. Novel Antimicrobial Peptides with High Anticancer Activity and Selectivity

    PubMed Central

    Chen, Kuan-Hao; Yu, Hui-Yuan; Chih, Ya-Han; Cheng, Hsi-Tsung; Chou, Yu-Ting; Cheng, Jya-Wei

    2015-01-01

    We describe a strategy to boost anticancer activity and reduce normal cell toxicity of short antimicrobial peptides by adding positive charge amino acids and non-nature bulky amino acid β-naphthylalanine residues to their termini. Among the designed peptides, K4R2-Nal2-S1 displayed better salt resistance and less toxicity to hRBCs and human fibroblast than Nal2-S1 and K6-Nal2-S1. Fluorescence microscopic studies indicated that the FITC-labeled K4R2-Nal2-S1 preferentially binds cancer cells and causes apoptotic cell death. Moreover, a significant inhibition in human lung tumor growth was observed in the xenograft mice treated with K4R2-Nal2-S1. Our strategy provides new opportunities in the development of highly effective and selective antimicrobial and anticancer peptide-based therapeutics. PMID:25970292

  3. Lactoferrin: Antimicrobial activity and therapeutic potential.

    PubMed

    Embleton, Nicholas D; Berrington, Janet E; McGuire, William; Stewart, Chris J; Cummings, Stephen P

    2013-03-15

    Lactoferrin is a highly conserved protein from an evolutionary perspective, with a wide range of roles related to protection from infection and promotion of nutritional status. Infection, malnutrition and intestinal pathologies are key inter-related problems, represent important threats to survival and are associated with adverse long-term health outcomes after preterm birth. Lactoferrin is available as a commercial extract from bovine milk and offers potential as a therapeutic intervention for preterm infants modulating infections and intestinal pathologies. In this review we explore the structure, direct antimicrobial effects, modification of host immune function and gastrointestinal effects of lactoferrin. Current trial data are reviewed, and research priorities and challenges identified and discussed. PMID:23507150

  4. Antimicrobial activity of natural Respitol-B and its main components against poultry microorganisms.

    PubMed

    Mahboubi, Mohaddese; Kazempour, Nastaran; Valian, Mahdi

    2013-10-01

    Poultries are infected to different kinds of microbial infections during their growth. For prevent of these diseases, many farmers use the synthetic antimicrobial agents. Whereas, the poultries participate in food cycle of human, the residues of these agents enter in human and cause many undesired side effects. In this study, the antimicrobial activity of Respitol-B and its main components (eucalyptus oil and menthol) was evaluated on different kinds of microorganisms including gram positive, gram negative bacteria, yeast and fungi in vitro conditions by disc diffusion and micro broth dilution assays. The gram positive bacteria, yeast and fungi is more sensitive than Gram negative ones to Respitol-B. Pseudomonas aeruginosa, Escherichia coli and Salmonella typhimurium is less sensitive to Respitol-B. Evaluation of menthol and eucalyptus oil for their antimicrobial activities exhibited that the antimicrobial activity of menthol is higher than that of eucalyptus oil. Eucalyptus oil had the best effect on Vibrio cholerae, Staphylococcus aureus, Aspergillus flavus but had no effect on others. The antimicrobial activity of menthol is observable and its presence in Respitol-B enhances the antimicrobial activity of Respitol-B. Respitol-B as a 100% herbal drug has antimicrobial effect and can be used as alternative therapy for preventing and controlling of infections. PMID:24502173

  5. Biologically Active and Antimicrobial Peptides from Plants

    PubMed Central

    Salas, Carlos E.; Badillo-Corona, Jesus A.; Ramírez-Sotelo, Guadalupe; Oliver-Salvador, Carmen

    2015-01-01

    Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application. PMID:25815307

  6. Biologically active and antimicrobial peptides from plants.

    PubMed

    Salas, Carlos E; Badillo-Corona, Jesus A; Ramírez-Sotelo, Guadalupe; Oliver-Salvador, Carmen

    2015-01-01

    Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application. PMID:25815307

  7. Effect of postharvest UV-C treatment on the bacterial diversity of Ataulfo mangoes by PCR-DGGE, survival of E. coli and antimicrobial activity

    PubMed Central

    Fernández-Suárez, Rocío; Ramírez-Villatoro, Guadalupe; Díaz-Ruiz, Gloria; Eslava, Carlos; Calderón, Montserrat; Navarro-Ocaña, Arturo; Trejo-Márquez, Andrea; Wacher, Carmen

    2013-01-01

    Since Mexico is the second largest exporter of mangoes, its safety assurance is essential. Research in microbial ecology and knowledge of complex interactions among microbes must be better understood to achieve maximal control of pathogens. Therefore, we investigated the effect of UV-C treatments on bacterial diversity of the Ataulfo mangoes surface using PCR-DGGE analysis of variable region V3 of 16S rRNA genes, and the survival of E. coli, by plate counting. The UV-C irradiation reduced the microbial load on the surface of mangoes immediately after treatment and the structure of bacterial communities was modified during storage. We identified the key members of the bacterial communities on the surface of fruits, predominating Enterobacter genus. Genera as Lactococcus and Pantoea were only detected on the surface of non-treated (control) mangoes. This could indicate that these genera were affected by the UV-C treatment. On the other hand, the treatment did not have a significant effect on survival of E. coli. However, genera that have been recognized as antagonists against foodborne pathogens were identified in the bands patterns. Also, phenolic compounds were determined by HPLC and antimicrobial activity was assayed according to the agar diffusion method. The main phenolic compounds were chlorogenic, gallic, and caffeic acids. Mango peel methanol extracts (UV-C treated and control mangoes) showed antimicrobial activity against strains previously isolated from mango, detecting significant differences (P < 0.05) among treated and control mangoes after 4 and 12 days of storage. Ps. fluorescens and Ps. stutszeri were the most sensitive. PMID:23761788

  8. Antimicrobial activity of prodigiosin isolated from Serratia marcescens UFPEDA 398.

    PubMed

    Lapenda, J C; Silva, P A; Vicalvi, M C; Sena, K X F R; Nascimento, S C

    2015-02-01

    Prodigiosin is an alkaloid and natural red pigment produced by Serratia marcescens. Prodigiosin has antimicrobial, antimalarial and antitumor properties and induces apoptosis in T and B lymphocytes. These properties have piqued the interest of researchers in the fields of medicine, pharmaceutics and different industries. The aim of the present study was to evaluate the antimicrobial activity of prodigiosin against pathogenic micro-organisms. The red pigments produced by S. marcescens exhibited absorption at 534 nm, Rf of 0.59 and molecular weight of 323 m/z. Antimicrobial activity was tested against oxacillin-resistant Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes, Acinetobacter sp. and oxacillin-resistant S. aureus. The standard antibiotics employed were ampicillin, chloramphenicol, gentamicin and oxacillin. The disc-diffusion tests demonstrated significant inhibition zones for S. aureus (35 ± 0.6), E. faecalis (22 ± 1.0) and S. pyogenes (14 ± 0.6). However, prodigiosin showed resistance to E. coli, P. aeruginosa and acinetobacter, where no significant formation of inhibitory halos were observed. We determined the inhibitory minimum concentrations and bactericidal for 20 strains of oxacillin-resistant S. aureus (ORSA). The pattern was the antibiotic oxacillin. The minimum inhibitory concentrations observed ranged from 1, 2 and 4.0 μg/mL, respectively, while the minimum bactericidal concentrations ranged from 2, 4, 8 and 16 μg/mL. The S. marcescens prodigiosin produced by showed bactericidal and bacteriostatic effect showing promising antimicrobial activity and suggesting future studies regarding its applicability in antibiotics therapies directed ORSA. PMID:25549906

  9. Prediction of Antimicrobial Activity of Synthetic Peptides by a Decision Tree Model

    PubMed Central

    Lira, Felipe; Perez, Pedro S.; Baranauskas, José A.

    2013-01-01

    Antimicrobial resistance is a persistent problem in the public health sphere. However, recent attempts to find effective substitutes to combat infections have been directed at identifying natural antimicrobial peptides in order to circumvent resistance to commercial antibiotics. This study describes the development of synthetic peptides with antimicrobial activity, created in silico by site-directed mutation modeling using wild-type peptides as scaffolds for these mutations. Fragments of antimicrobial peptides were used for modeling with molecular modeling computational tools. To analyze these peptides, a decision tree model, which indicated the action range of peptides on the types of microorganisms on which they can exercise biological activity, was created. The decision tree model was processed using physicochemistry properties from known antimicrobial peptides available at the Antimicrobial Peptide Database (APD). The two most promising peptides were synthesized, and antimicrobial assays showed inhibitory activity against Gram-positive and Gram-negative bacteria. Colossomin C and colossomin D were the most inhibitory peptides at 5 μg/ml against Staphylococcus aureus and Escherichia coli. The methods described in this work and the results obtained are useful for the identification and development of new compounds with antimicrobial activity through the use of computational tools. PMID:23455341

  10. Chemical properties and antioxidant and antimicrobial activities of Slovenian propolis.

    PubMed

    Mavri, Ana; Abramovič, Helena; Polak, Tomaž; Bertoncelj, Jasna; Jamnik, Polona; Smole Možina, Sonja; Jeršek, Barbara

    2012-08-01

    The chemical composition as well as the antioxidant and antimicrobial activities of two EtOH extracts of propolis (PEEs) from Slovenia were determined. EtOH was used as extracting solvent at 70 and 96%, providing the extracts PEE70 and PEE96, respectively. The extraction with 70% EtOH was more efficient than that with 96% EtOH, as the PEE70 was richer in total phenolic compounds than the PEE96. The Slovenian propolis was characterized by different phenolic acids and flavonoids. The PEE96 was slightly richer in three specific compounds, i.e., caffeic acid, ferulic acid, and luteolin, while all other substances detected showed higher contents in the PEE70. The PEE70 showed a stronger reducing power and ability to scavenge free radicals and metal ions than the PEE96. Both PEEs were in the main more effective against Gram-positive bacteria than against fungi and Gram-negative bacteria like Salmonella and Escherichia coli, with the exception of Campylobacter. The PEE96 decreased the intracellular oxidation in Saccharomyces cerevisiae in a dose-dependent manner. The antimicrobial activities and antioxidant properties were related to the total phenolic contents. The two PEEs have the potential for use as natural antimicrobial and antioxidant additives in foods. PMID:22899615

  11. Antimicrobial use in swine production and its effect on the swine gut microbiota and antimicrobial resistance.

    PubMed

    Holman, Devin B; Chénier, Martin R

    2015-11-01

    Antimicrobials have been used in swine production at subtherapeutic levels since the early 1950s to increase feed efficiency and promote growth. In North America, a number of antimicrobials are available for use in swine. However, the continuous administration of subtherapeutic, low concentrations of antimicrobials to pigs also provides selective pressure for antimicrobial-resistant bacteria and resistance determinants. For this reason, subtherapeutic antimicrobial use in livestock remains a source of controversy and concern. The swine gut microbiota demonstrates a number of changes in response to antimicrobial administration depending on the dosage, duration of treatment, age of the pigs, and gut location that is sampled. Both culture-independent and -dependent studies have also shown that the swine gut microbiota contains a large number of antimicrobial resistance determinants even in the absence of antimicrobial exposure. Heavy metals, such as zinc and copper, which are often added at relatively high doses to swine feed, may also play a role in maintaining antimicrobial resistance and in the stability of the swine gut microbiota. This review focuses on the use of antimicrobials in swine production, with an emphasis on the North American regulatory context, and their effect on the swine gut microbiota and on antimicrobial resistance determinants in the gut microbiota. PMID:26414105

  12. Antimicrobial activity of chicken NK-lysin against Eimeria sporozoites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    NK-lysin is an antimicrobial and antitumor polypeptide that is considered to play an important role during innate immunity. Chicken NK-lysin is a member of the saposin-like protein family and exhibits potent antitumor cell activity. To evaluate the antimicrobial properties of chicken NK-lysin, we ex...

  13. Antimicrobial effects of Quercus ilex L. extract.

    PubMed

    Güllüce, M; Adigüzel, A; Oğütçü, H; Sengül, M; Karaman, I; Sahin, F

    2004-03-01

    The antimicrobial activities of the methanol extract of Quercus ilex L. (Pirnal oak) leaves were tested in vitro against a wide range of human and plant-associated microorganisms. A total of 132 microbial organisms belonging to 55 bacteria and five fungi and yeast species were studied using a disc-diffusion method and microdilution assays. The results were evaluated as inhibition zones around the disc impregnated with Q. ilex extract at a concentration of 300 micro L/mL. The results showed that Q. ilex did not have any antifungal activities against Alterneria alternata, Aspergillus flavus, Fusarium oxysporum, Penicillum spp., whereas there were inhibition effects on the growth of all Candida albicans isolates. In total 97 bacterial strains (74%) were found to be resistant to Q. ilex extract. The remaining 35 (27%) strains of seven different bacteria genera including Brucella, Bacillus, Enterobacter, Neisseria, Pseudomonas and Escherichia were susceptible to the extract tested. The minimum inhibitory concentrations (MIC) of the extract ranged from 125 to 500 micro L/mL. These results suggest that Q. ilex possesses compounds with antibacterial and anticandidal properties. PMID:15103667

  14. Studies on Anticancer Activities of Antimicrobial Peptides

    PubMed Central

    Hoskin, David W.; Ramamoorthy, Ayyalusamy

    2008-01-01

    In spite of great advances in cancer therapy, there is considerable current interest in developing anticancer agents with a new mode of action because of the development of resistance by cancer cells towards current anticancer drugs. A growing number of studies have shown that some of the cationic antimicrobial peptides (AMPs), which are toxic to bacteria but not to normal mammalian cells, exhibit a broad spectrum of cytotoxic activity against cancer cells. Such studies have considerably enhanced the significance of AMPs, both synthetic and from natural sources, which have been of importance both for an increased understanding of the immune system and for their potential as clinical antibiotics. The electrostatic attraction between the negatively charged components of bacterial and cancer cells and the positively charged AMPs is believed to play a major role in the strong binding and selective disruption of bacterial and cancer cell membranes, respectively. However, it is unclear why some host defense peptides are able to kill cancer cells when others do not. In addition, it is not clear whether the molecular mechanism(s) underlying the antibacterial and anticancer activities of AMPs are the same or different. In this article, we review various studies on different AMPs that exhibit cytotoxic activity against cancer cells. The suitability of cancer cell-targeting AMPs as cancer therapeutics is also discussed. PMID:18078805

  15. Antimicrobial activity of fermented Theobroma cacao pod husk extract.

    PubMed

    Santos, R X; Oliveira, D A; Sodré, G A; Gosmann, G; Brendel, M; Pungartnik, C

    2014-01-01

    Theobroma cacao L. contains more than 500 different chemical compounds some of which have been traditionally used for their antioxidant, anti-carcinogenic, immunomodulatory, vasodilatory, analgesic, and antimicrobial activities. Spontaneous aerobic fermentation of cacao husks yields a crude husk extract (CHE) with antimicrobial activity. CHE was fractioned by solvent partition with polar solvent extraction or by silica gel chromatography and a total of 12 sub-fractions were analyzed for chemical composition and bioactivity. CHE was effective against the yeast Saccharomyces cerevisiae and the basidiomycete Moniliophthora perniciosa. Antibacterial activity was determined using 6 strains: Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis (Gram-positive) and Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella choleraesuis (Gram-negative). At doses up to 10 mg/mL, CHE was not effective against the Gram-positive bacteria tested but against medically important P. aeruginosa and S. choleraesuis with a minimum inhibitory concentration (MIC) of 5.0 mg/mL. Sub-fractions varied widely in activity and strongest antibacterial activity was seen with CHE8 against S. choleraesuis (MIC of 1.0 mg/mL) and CHE9 against S. epidermidis (MIC of 2.5 mg/mL). All bioactive CHE fractions contained phenols, steroids, or terpenes, but no saponins. Fraction CHE9 contained flavonoids, phenolics, steroids, and terpenes, amino acids, and alkaloids, while CHE12 had the same compounds but lacked flavonoids. PMID:25299086

  16. Antidiarrhoeal and antimicrobial activity of Calpurnia aurea leaf extract

    PubMed Central

    2013-01-01

    Background In Ethiopia, Calpurnia aurea is used for the treatment of syphilis, malaria, rabies, diabetes, hypertension, diarrhoea, leishmaniasis, trachoma, elephantiasis, fungal diseases and different swellings. However, despite its traditional usage as an antidiarrhoeal and antimicrobial agent, there is limited or no information regarding its effectiveness and mode of action in diarrhoea which may be caused by Shigella flexneri, Staphylococcus aureus, Escherichia coli and Salmonella typhi. Hence, we evaluated the 80% methanol (MeOH) extract of dried and powdered leaves of C. aurea for its antidiarrhoeal and antimicrobial activities. Methods Swiss albino mice of either sex were divided into five groups (five/group): Group I served as control and received vehicle (1% Tween 80) at a dose of 10 ml/kg orally; Group II served as standard and received loperamide at the dose of 3 mg/kg orally; Groups III, IV and V served as test groups and received the 80% MeOH leaf extract of C. aurea at doses of 100, 200 and 400 mg/kg orally, respectively. Diarrhoea was induced by oral administration of 0.5 ml castor oil to each mouse, 1 h after the above treatments. During an observation period of 4 h, time of onset of diarrhea, total number of faecal output (frequency of defecation) and weight of faeces excreted by the animals were recorded. Data were analyzed using one way analysis of variance followed by Tukey post test. Antimicrobial activity test was conducted using agar well diffusion assay. Clinical isolates tested were Salmonella typhi, Salmonella paratyphi, Salmonella typhimurium, Shigella species, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Results In castor oil induced diarrhea model, the 80% methanol leaf extract of C. aurea at 100, 200 and 400 mg/kg and the standard drug loperamide (3 mg/kg) significantly reduced the time of onset of diarrhea, the frequency of defecation (total number of faecal output) and weight of faeces. C. aurea leaf extract also showed good antimicrobial activity against all tested organisms. Conclusions C. aurea possesses good antidiarrhoeal and antimicrobial activity which support the traditional use of the plant in the treatment of diarrhea in Ethiopia. PMID:23351272

  17. Antimicrobial and cytotoxic effects of Mexican medicinal plants.

    PubMed

    Jacobo-Salcedo, Maria del Rosario; Alonso-Castro, Angel Josabad; Salazar-Olivo, Luis A; Carranza-Alvarez, Candy; González-Espíndola, Luis Angel; Domínguez, Fabiola; Maciel-Torres, Sandra Patricia; García-Lujan, Concepción; González-Martínez, Marisela del Rocio; Gómez-Sánchez, Maricela; Estrada-Castillón, Eduardo; Zapata-Bustos, Rocio; Medellin-Milán, Pedro; García-Carrancá, Alejandro

    2011-12-01

    The antimicrobial effects of the Mexican medicinal plants Guazuma ulmifolia, Justicia spicigera, Opuntia joconostle, O. leucotricha, Parkinsonia aculeata, Phoradendron longifolium, P. serotinum, Psittacanthus calyculatus, Tecoma stans and Teucrium cubense were tested against several human multi-drug resistant pathogens, including three Gram (+) and five Gram (-) bacterial species and three fungal species using the disk-diffusion assay. The cytotoxicity of plant extracts on human cancer cell lines and human normal non-cancerous cells was also evaluated using the MTT assay. Phoradendron longifolium, Teucrium cubense, Opuntia joconostle, Tecoma stans and Guazuma ulmifolia showed potent antimicrobial effects against at least one multidrug-resistant microorganism (inhibition zone > 15 mm). Only Justicia spicigera and Phoradendron serotinum extracts exerted active cytotoxic effects on human breast cancer cells (IC50 < or = 30 microg/mL). The results showed that Guazuma ulmifolia produced potent antimicrobial effects against Candida albicans and Acinetobacter lwoffii, whereas Justicia spicigera and Phoradendron serotinum exerted the highest toxic effects on MCF-7 and HeLa, respectively, which are human cancer cell lines. These three plant species may be important sources of antimicrobial and cytotoxic agents. PMID:22312741

  18. Antimicrobial activities of Saudi honey against Pseudomonas aeruginosa

    PubMed Central

    Al-Nahari, Alaa A.M.; Almasaudi, Saad B.; Abd El-Ghany, El Sayed M.; Barbour, Elie; Al Jaouni, Soad K.; Harakeh, Steve

    2015-01-01

    Five types of imported and local honey were screened for both their bacteriocidal/bacteriostatic activities against both Imipenem resistant and sensitive Pseudomonas aeruginosa in both Brain Heart infusion broth and Mueller–Hinton agar. The results indicated that the effect was concentration and type of honey dependant. All types of honey tested exerted a full inhibition of bacterial growth at the highest concentration tested of 50% at 24 h of contact. The inhibitory effect of honey on bacterial growth was clear with concentrations of 20% and 10% and this effect was most evident in the case of Manuka honey as compared to Nigella sativa honey and Seder honey. Manuka honey UMF +20 showed a bacteriocidal activity on both Imipenem resistant and sensitive P. aeruginosa, while Seder honey and N. sativa honey exerted only a bacteriostatic effect. Manuka honey UMF +10 showed most effect on antimicrobial resistance. Manuka honey UMF +10 had an effect on modulation of Imipenem resistant P. aeruginosa. Conclusion: The results indicated that various types of honey affected the test organisms differently. Modulation of antimicrobial resistance was seen in the case Manuka honey UMF +10. PMID:26288553

  19. Antimicrobial activity of nanodispersed thymol in tryptic soy broth.

    PubMed

    Shah, Bhavini; Davidson, P Michael; Zhong, Qixin

    2013-03-01

    Food safety is a continuing challenge for the food industry due to sporadic illness outbreaks caused by foodborne pathogens. Plant essential oils have been studied extensively as natural antimicrobials to control foodborne pathogens. However, their hydrophobic nature makes application in foods difficult because of their low water solubility, adverse impact on sensory quality, and binding with food components, which can interfere with antimicrobial efficacy. The objective of this study was to characterize antimicrobial activities of transparent nanodispersions of thymol encapsulated in whey protein isolate-maltodextrin conjugates, with comparison to free thymol. Tests were conducted for Escherichia coli O157:H7 strains ATCC 43889 and 43894, Salmonella Typhimurium strain 2576, Listeria monocytogenes strains Scott A and 101, and Staphylococcus aureus strains 27708 and SA113 in tryptic soy broth at various pHs and temperatures. Results indicate that the MIC for nanodispersed and free thymol against all strains of both gram-negative and gram-positive pathogens tested was 500 ppm at pH 6.8 and at the optimal growth temperature, with the exception of E. coli O157:H7 and L. monocytogenes strain Scott A, which were inhibited by 300 ppm of free thymol. Nanodispersed thymol was further tested at 500 ppm for inhibition of E. coli O157:H7 and L. monocytogenes at 35, 32, 25, and 4°C in tryptic soy broth adjusted to pH 5.5 and 3.5. At pH 5.5, L. monocytogenes was completely inhibited after 3 h, and E. coli O157:H7 showed a reduction of 1.0 to 3.0 log CFU/ml after 48 h. At pH 3.5, L. monocytogenes controls did not grow, but E. coli O157:H7 survived. At both pH 5.5 and 3.5, no significant effect of temperature on antimicrobial activity was observed at 500 mg/ml nanodispersed thymol. The present study demonstrated that transparent nanodispersions of thymol have promising antimicrobial activity against a broad spectrum of foodborne pathogens. PMID:23462081

  20. Synergistic Antimicrobial Activity of Camellia sinensis and Juglans regia against Multidrug-Resistant Bacteria

    PubMed Central

    Farooqui, Amber; Khan, Adnan; Borghetto, Ilaria; Kazmi, Shahana U.; Rubino, Salvatore; Paglietti, Bianca

    2015-01-01

    Synergistic combinations of antimicrobial agents with different mechanisms of action have been introduced as more successful strategies to combat infections involving multidrug resistant (MDR) bacteria. In this study, we investigated synergistic antimicrobial activity of Camellia sinensis and Juglans regia which are commonly used plants with different antimicrobial agents. Antimicrobial susceptibility of 350 Gram-positive and Gram-negative strains belonging to 10 different bacterial species, was tested against Camellia sinensis and Juglans regia extracts. Minimum inhibitory concentrations (MICs) were determined by agar dilution and microbroth dilution assays. Plant extracts were tested for synergistic antimicrobial activity with different antimicrobial agents by checkerboard titration, Etest/agar incorporation assays, and time kill kinetics. Extract treated and untreated bacteria were subjected to transmission electron microscopy to see the effect on bacterial cell morphology. Camellia sinensis extract showed higher antibacterial activity against MDR S. Typhi, alone and in combination with nalidixic acid, than to susceptible isolates.” We further explore anti-staphylococcal activity of Juglans regia that lead to the changes in bacterial cell morphology indicating the cell wall of Gram-positive bacteria as possible target of action. The synergistic combination of Juglans regia and oxacillin reverted oxacillin resistance of methicillin resistant Staphylococcus aureus (MRSA) strains in vitro. This study provides novel information about antimicrobial and synergistic activity of Camellia sinensis and Juglans regia against MDR pathogens PMID:25719410

  1. Antimicrobial activity and stability of weakly acidified chlorous acid water.

    PubMed

    Horiuchi, Isanori; Kawata, Hiroyuki; Nagao, Tamiko; Imaohji, Haruyuki; Murakami, Kazuya; Kino, Yasuhiro; Yamasaki, Hisashi; Koyama, A Hajime; Fujita, Yatsuka; Goda, Hisataka; Kuwahara, Tomomi

    2015-01-01

    The antimicrobial activity of weakly acidified chlorous acid water (WACAW) against Staphylococcus aureus, non-pathogenic Escherichia coli, enterohemorrhagic E. coli (EHEC O157:H7), Candida albicans, and spore-forming Bacillus and Paenibacillus species was evaluated in vitro. The antiviral activity was also examined using feline calicivirus (FCV). Diluted WACAW (>100 ppm) effectively reduced the number of non-spore-forming bacteria (>4 log10 CFU reductions) within 5 min. Treatment with this sanitizer at 400 ppm for 30 min achieved>5 log10 CFU reductions in spore-forming Bacillus and Paenibacillus species while an equivalent concentration of sodium hypochlorite (NaClO) resulted in only a 0.98 and 2.72 log10 CFU reduction, respectively. The effect of this sanitizer against FCV was equivalent to that of NaClO. Immersion in WACAW (400 ppm) achieved >4 and 2.26 log10 CFU reductions in Campylobacter jejuni and EHEC, respectively, on artificially contaminated broiler carcass pieces. Finally, theantimicrobial activity of this sanitizer was shown to be maintained for at least 28 d when in contact with nonwoven fabric (100% cotton). This study showed that pH control of chlorous acid is expected to modify its antimicrobial activity and stability. WACAW is expected to have applications in various settings such as the food processing and healthcare industries. PMID:25817812

  2. Antimicrobial effect of silver-impregnated cellulose: potential for antimicrobial therapy

    PubMed Central

    2009-01-01

    Background Silver has long been known to have antimicrobial activity. To incorporate this property into multiple applications, a silver-impregnated cellulose (SIC) with low cytotoxicity to human cells was developed. SIC differs from other silver treatment methods in that the leaching of silver particles is non-existent and the release of ionic silver is highly controlled. Results Candida albicans, Micrococcus luteu, Pseudomonas putida, and Escherichia coli were used for antimicrobial testing. No microbial cells were able to grow in the presence of SIC at concentrations above 0.0035 Ag w/v %. Even at a concentration of 0.00035 Ag w/v %, P. putida and M. luteu failed to grow, and C. albicans and E. coli exhibited diminished growth. To determine the cytotoxic effect of silver on human cells, five different concentrations of SIC were tested on human fibroblasts. In SIC concentrations of 0.035 Ag w/v % and below, no cytotoxicity was observed. Conclusion The optimal concentration of SIC for a broad range of anti-microbial activity and low or negligible cytotoxicity was 0.0035 Ag w/v %. Although the highly controlled releasing characteristics of SIC would prove a substantial improvement over current technologies, further investigation for genotoxicity and other biocompatibility test will be required. PMID:19961601

  3. 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. PMID:23551508

  4. Antimicrobial activities of three species of family mimosaceae.

    PubMed

    Mahmood, Adeel; Mahmood, Aqeel; Qureshi, Rizwana Aleem

    2012-01-01

    The antimicrobial activities of crude methanolic extract of leaves of Acacia nilotica L., Albizia lebbeck L. and Mimosa himalayana Gamble belonging to family mimosaceae were investigated in this research work. Antibacterial activity was studied by agar well diffusion method against one gram-positive Bacillus subtilis and three gram-negative Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumonia. Crude extract of all plants showed best activity against gram-negative bacterial strains while minor inhibition zones were found against gram positive bacterial strains. Antifungal activity of crude plant extract was screened by agar tube dilution method against Aspergillus nigar and Aspergillus flavus. These results showed that these plants extracts have potential against bacterias, while against fungi their activity is not much effective. PMID:22186331

  5. Rational design of tryptophan-rich antimicrobial peptides with enhanced antimicrobial activities and specificities.

    PubMed

    Yu, Hui-Yuan; Huang, Kuo-Chun; Yip, Bak-Sau; Tu, Chih-Hsiang; Chen, Heng-Li; Cheng, Hsi-Tsung; Cheng, Jya-Wei

    2010-11-01

    Trp-rich antimicrobial peptides play important roles in the host innate defense mechanism of many plants and animals. A series of short Trp-rich peptides derived from the C-terminal region of Bothrops asper myothoxin II, a Lys49 phospholipase A(2) (PLA(2)), were found to reproduce the antimicrobial activities of their parent molecule. Of these peptides, KKWRWWLKALAKK-designated PEM-2-was found to display improved activity against both Gram-positive and Gram-negative bacteria. To improve the antimicrobial activity of PEM-2 for potential clinical applications further, we determined the solution structure of PEM-2 bound to membrane-mimetic dodecylphosphocholine (DPC) micelles by two-dimensional NMR methods. The DPC micelle-bound structure of PEM-2 adopts an α-helical conformation and the positively charged residues are clustered together to form a hydrophilic patch. The surface electrostatic potential map indicates that two of the three tryptophan residues are packed against the peptide backbone and form a hydrophobic face with Leu7, Ala9, and Leu10. A variety of biophysical and biochemical experiments, including circular dichroism, fluorescence spectroscopy, and microcalorimetry, were used to show that PEM-2 interacted with negatively charged phospholipid vesicles and efficiently induced dye release from these vesicles, suggesting that the antimicrobial activity of PEM-2 could be due to interactions with bacterial membranes. Potent analogues of PEM-2 with enhanced antimicrobial and less pronounced hemolytic activities were designed with the aid of these structural studies. PMID:20865718

  6. Antimicrobial Activity of Bacteriophage Endolysin Produced in Nicotiana benthamiana Plants.

    PubMed

    Kovalskaya, Natalia; Foster-Frey, Juli; Donovan, David M; Bauchan, Gary; Hammond, Rosemarie W

    2016-01-28

    The increasing spread of antibiotic-resistant pathogens has raised the interest in alternative antimicrobial treatments. In our study, the functionally active gram-negative bacterium bacteriophage CP933 endolysin was produced in Nicotiana benthamiana plants by a combination of transient expression and vacuole targeting strategies, and its antimicrobial activity was investigated. Expression of the cp933 gene in E. coli led to growth inhibition and lysis of the host cells or production of trace amounts of CP933. Cytoplasmic expression of the cp933 gene in plants using Potato virus X-based transient expression vectors (pP2C2S and pGR107) resulted in death of the apical portion of experimental plants. To protect plants against the toxic effects of the CP933 protein, the cp933 coding region was fused at its Nterminus to an N-terminal signal peptide from the potato proteinase inhibitor I to direct CP933 to the delta-type vacuoles. Plants producing the CP933 fusion protein did not exhibit the severe toxic effects seen with the unfused protein and the level of expression was 0.16 mg/g of plant tissue. Antimicrobial assays revealed that, in contrast to gram-negative bacterium E. coli (BL21(DE3)), the gram-positive plant pathogenic bacterium Clavibacter michiganensis was more susceptible to the plant-produced CP933, showing 18% growth inhibition. The results of our experiments demonstrate that the combination of transient expression and protein targeting to the delta vacuoles is a promising approach to produce functionally active proteins that exhibit toxicity when expressed in plant cells. PMID:26403819

  7. Silver activation on thin films of Ag-ZrCN coatings for antimicrobial activity.

    PubMed

    Ferreri, I; Calderon V, S; Escobar Galindo, R; Palacio, C; Henriques, M; Piedade, A P; Carvalho, S

    2015-10-01

    Nowadays, with the increase of elderly population and related health problems, knee and hip joint prosthesis are being widely used worldwide. However, failure of these invasive devices occurs in a high percentage thus demanding the revision of the chirurgical procedure. Within the reasons of failure, microbial infections, either hospital or subsequently-acquired, contribute in high number to the statistics. Staphylococcus epidermidis (S. epidermidis) has emerged as one of the major nosocomial pathogens associated with these infections. Silver has a historic performance in medicine due to its potent antimicrobial activity, with a broad-spectrum on the activity of different types of microorganisms. Consequently, the main goal of this work was to produce Ag-ZrCN coatings with antimicrobial activity, for the surface modification of hip prostheses. Thin films of ZrCN with several silver concentrations were deposited onto stainless steel 316 L, by DC reactive magnetron sputtering, using two targets, Zr and Zr with silver pellets (Zr+Ag target), in an atmosphere containing Ar, C2H2 and N2. The antimicrobial activity of the modified surfaces was tested against S. epidermidis and the influence of an activation step of silver was assessed by testing samples after immersion in a 5% (w/v) NaClO solution for 5 min. The activation procedure revealed to be essential for the antimicrobial activity, as observed by the presence of an inhibition halo on the surface with 11 at.% of Ag. The morphology analysis of the surface before and after the activation procedure revealed differences in silver distribution indicating segregation/diffusion of the metallic element to the film's surface. Thus, the results indicate that the silver activation step is responsible for an antimicrobial effect of the coatings, due to silver oxidation and silver ion release. PMID:26117788

  8. Endophytic Fungi Isolated from Coleus amboinicus Lour Exhibited Antimicrobial Activity

    PubMed Central

    Astuti, Puji; Sudarsono, Sudarsono; Nisak, Khoirun; Nugroho, Giri Wisnu

    2014-01-01

    Purpose: Coleus amboinicus is a medicinal plant traditionally used to treat various diseases such as throat infection, cough and fever, diarrhea, nasal congestion and digestive problems. The plant was explored for endophytic fungi producing antimicrobial agents. Methods: Screening for endophytic fungi producing antimicrobial agents was conducted using agar plug method and antimicrobial activity of promising ethyl acetate extracts was determined by disc diffusion assay. Thin layer chromatography (TLC) - bioautography was performed to localize the bioactive components within the extract. TLC visualization detection reagents were used to preliminary analyze phytochemical groups of the bioactive compounds. Results: Three endophytic fungi were obtained, two of them showed promising potential. Agar diffusion method showed that endophytic fungi CAL-2 exhibited antimicrobial activity against P. aeruginosa, B. subtilis, S. aureus and S. thypi, whilst CAS-1 inhibited the growth of B. subtilis. TLC bioautography of ethyl acetate extract of CAL-2 revealed at least three bands exhibited antimicrobial activity and at least two bands showed inhibition of B. subtilis growth. Preliminary analysis of the crude extracts suggests that bioactive compounds within CAL-2 extract are terpenoids, phenolics and phenyl propanoid compounds whilst the antimicrobial agents within CAS-1 extract are terpenoids, propylpropanoids, alkaloids or heterocyclic nitrogen compounds. Conclusion: These data suggest the potential of endophytic fungi of C. amboinicus as source for antimicrobial agents. PMID:25671195

  9. Size-Dependent Antimicrobial Effects of Novel Palladium Nanoparticles

    PubMed Central

    Adams, Clara P.; Walker, Katherine A.; Obare, Sherine O.; Docherty, Kathryn M.

    2014-01-01

    Investigating the interactions between nanoscale materials and microorganisms is crucial to provide a comprehensive, proactive understanding of nanomaterial toxicity and explore the potential for novel applications. It is well known that nanomaterial behavior is governed by the size and composition of the particles, though the effects of small differences in size toward biological cells have not been well investigated. Palladium nanoparticles (Pd NPs) have gained significant interest as catalysts for important carbon-carbon and carbon-heteroatom reactions and are increasingly used in the chemical industry, however, few other applications of Pd NPs have been investigated. In the present study, we examined the antimicrobial capacity of Pd NPs, which provides both an indication of their usefulness as target antimicrobial compounds, as well as their potency as potential environmental pollutants. We synthesized Pd NPs of three different well-constrained sizes, 2.00.1 nm, 2.50.2 nm and 3.10.2 nm. We examined the inhibitory effects of the Pd NPs and Pd2+ ions toward gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) bacterial cultures throughout a 24 hour period. Inhibitory growth effects of six concentrations of Pd NPs and Pd2+ ions (2.510?4, 10?5, 10?6, 10?7, 10?8, and 10?9 M) were examined. Our results indicate that Pd NPs are generally much more inhibitory toward S. aureus than toward E. coli, though all sizes are toxic at ?10?5 M to both organisms. We observed a significant difference in size-dependence of antimicrobial activity, which differed based on the microorganism tested. Our work shows that Pd NPs are highly antimicrobial, and that fine-scale (<1 nm) differences in size can alter antimicrobial activity. PMID:24465824

  10. Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

    PubMed Central

    Chen, Meiwan; Yang, Zhiwen; Wu, Hongmei; Pan, Xin; Xie, Xiaobao; Wu, Chuanbin

    2011-01-01

    Purpose The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel) on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Patients and methods This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria. The cell morphology of normal and treated bacteria cells was assessed by transmission electron microscopy (TEM), and the effects of S-T-Gel on genome DNA of bacterial cells were evaluated by agarose gel electrophoresis. Results S-T-Gel showed promising activity against Staphylococcus aureus and moderate activity against Escherichia coli and Pseudomonas aeruginosa. The observation with TEM suggested that S-T-Gel may destroy the structure of bacterial cell membranes in order to enter the bacterial cell. S-T-Gel then condensed DNA and combined and coagulated with the cytoplasm of the damaged bacteria, resulting in the leakage of the cytoplasmic component and the eventual death of these three bacteria. In addition, the analysis of agarose gel electrophoresis demonstrated that S-T-Gel could increase the decomposability of genome DNA. Conclusion These results about promising antimicrobial activity and mechanism of S-T-Gel may be useful for further research and development in in-vivo studies. PMID:22131833

  11. Antimicrobial activities of indole alkaloids from Tabernaemontana catharinensis.

    PubMed

    Medeiros, Maria Rita Furquini; Prado, Luiz Afonso de Melo; Fernandes, Vanessa Colnaghi; Figueiredo, Sérgio Souza; Coppede, Juliana; Martins, Juliana; Fiori, Giovana Maria Lanchoti; Martinez-Rossi, Nilce Maria; Beleboni, Rene Oliveira; Contini, Silvia Helena Taleb; Pereira, Paulo Sérgio; Fachin, Ana Lúcia

    2011-02-01

    Tabernaemontana catharinensis root bark ethanol extract, EB2 fraction and the MMV alkaloid (12-methoxy-4-methylvoachalotine) were evaluated for their antimicrobial activities. T. catharinensis ethanol extract was effective against both strains of the dermatophyte Trichophyton rubrum at concentrations of 2.5 mg/mL (wild strain) and 1.25 mg/mL (mutant strain), while the EB2 fraction and MMV alkaloid showed a strong antifungal activity against wild and mutant strains with MIC values of <0.02 and 0.16 mg/mL, respectively. The EB2 fraction showed a strong antibacterial activity against ATCC strains of S. aureus, S. epidermidis, E. coli and P. aeruginosa with MICs from <0.02 to 0.04 mg/mL, as well as against resistant clinical isolates species of Enterococcus sp, Klebsiella oxytoca, Citrobacter, K. pneumoniae, P. mirabilis, S. aureus, S. epidermidis, E. coli and P. aeruginosa with MIC values ranging from 0.04 to 0.08 mg/mL. The MMV alkaloid presented a MIC of 0.16 mg/mL against the strains of S. aureus and E. coli ATCC. For the resistant clinical isolates Enterococcus sp, Citrobacter, S. aureus, S. epidermidis, E. coli and P. aeruginosa the MIC of MMV ranged from 0.08 to 0.31 mg/mL. The chromatography analysis of the EB2 fraction revealed the presence of indole alkaloids, including MMV, possibly responsible for the observed antimicrobial activity. PMID:21425672

  12. 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

  13. Synergistic Effects of Antimicrobial Peptides and Antibiotics against Clostridium difficile

    PubMed Central

    Nuding, Sabine; Frasch, Tina; Schaller, Martin; Stange, Eduard F.

    2014-01-01

    Accelerating rates of health care-associated infections caused by Clostridium difficile, with increasing recurrence and rising antibiotic resistance rates, have become a serious problem in recent years. This study was conducted to explore whether a combination of antibiotics with human antimicrobial peptides may lead to an increase in antibacterial activity. The in vitro activities of the antimicrobial peptides HBD1 to HBD3, HNP1, HD5, and LL-37 and the antibiotics tigecycline, moxifloxacin, piperacillin-tazobactam, and meropenem alone or in combination against 10 toxinogenic and 10 nontoxinogenic C. difficile strains were investigated. Bacterial viability was determined by flow cytometry and toxin production by enzyme-linked immunosorbent assay (ELISA). When combined at subinhibitory concentrations, antimicrobial peptides and antibiotics generally led to an additive killing effect against toxinogenic and nontoxinogenic C. difficile strains. However, LL-37 and HBD3 acted in synergism with all the antibiotics that were tested. Electron microscopy revealed membrane perturbation in bacterial cell walls by HBD3. In 3 out of 10 toxinogenic strains, HBD3, LL-37, piperacillin-tazobactam, and meropenem administration led to an increased toxin release which was not neutralized by the addition of HNP1. Antimicrobial peptides increase the bacterial killing of antibiotics against C. difficile regardless of the antibiotics' mode of action. Membrane perturbation in or pore formation on the bacterial cell wall may enhance the uptake of antibiotics and increase their antibacterial effect. Therefore, a combination of antibiotics with antimicrobial peptides may represent a promising novel approach to the treatment of C. difficile infections. PMID:25022581

  14. Effect of antimicrobial proteins from porcine leukocytes on Staphylococcus aureus and Escherichia coli in comminuted meats.

    PubMed

    Wang, Feng-Sheng

    2003-09-01

    Study is aimed to elucidate the effect of porcine leukocyte antimicrobial protein on the proliferation of Staphylococcus aureus and Escherichia coli inoculated in ground meats. The antimicrobial proteins were isolated from porcine blood using 0.2 M sodium acetate extraction and cation-exchange column chromatography. Antimicrobial protein preparation consisted predominantly of 7.5 and 6 kDa molecules. Immunoblotting demonstrated that the 7.5 kDa molecule displayed defensin immuno-reactivity, a unique blood granulocyte antimicrobial protein. Both 7.5 and 6 kDa molecules could decrease apparent proliferation of test cultures. Sterilization (121 °C, 30 min) and proteolytic enzymes (pepsin, trypsin, and chymotrypsin) could significantly decrease bacteriocidal activities of antimicrobial protein preparation. Furthermore, antimicrobial protein preparation enhanced exposure of intercellular nucleotide of test cultures. Antimicrobial protein preparation inhibition of S. aureus and E. coli growth was concentration and time dependence. Adding 160 μg/g antimicrobial protein preparation to ground ham meat and sausage mince could significantly (P<0.05) hurdle viable colony formation of test cultures at 6 and 12 h, respectively. Taken together, porcine leukocyte antimicrobial protein preparation has potential to inhibit proliferation of S. aureus and E. coli inoculated in ground meat via induction of bacterolysis, suggesting this antimicrobial protein preparation be an alternative natural bio-preservation source for ground meat products. PMID:22063256

  15. Poly(anhydride-esters) comprised exclusively of naturally occurring antimicrobials and EDTA: antioxidant and antibacterial activities.

    PubMed

    Carbone-Howell, Ashley L; Stebbins, Nicholas D; Uhrich, Kathryn E

    2014-05-12

    Carvacrol, thymol, and eugenol are naturally occurring phenolic compounds known to possess antimicrobial activity against a range of bacteria, as well as antioxidant activity. Biodegradable poly(anhydride-esters) composed of an ethylenediaminetetraacetic acid (EDTA) backbone and antimicrobial pendant groups (i.e., carvacrol, thymol, or eugenol) were synthesized via solution polymerization. The resulting polymers were characterized to confirm their chemical composition and understand their thermal properties and molecular weight. In vitro release studies demonstrated that polymer hydrolytic degradation was complete after 16 days, resulting in the release of free antimicrobials and EDTA. Antioxidant and antibacterial assays determined that polymer release media exhibited bioactivity similar to that of free compound, demonstrating that polymer incorporation and subsequent release had no effect on activity. These polymers completely degrade into components that are biologically relevant and have the capability to promote preservation of consumer products in the food and personal care industries via antimicrobial and antioxidant pathways. PMID:24702678

  16. Polymer-Ag nanocomposites with enhanced antimicrobial activity against bacterial infection.

    PubMed

    Mei, Lin; Lu, Zhentan; Zhang, Xinge; Li, Chaoxing; Jia, Yanxia

    2014-09-24

    Herein, a nontoxic nanocomposite is synthesized by reduction of silver nitrate in the presence of a cationic polymer displaying strong antimicrobial activity against bacterial infection. These nanocomposites with a large concentration of positive charge promote their adsorption to bacterial membranes through electrostatic interaction. Moreover, the synthesized nanocomposites with polyvalent and synergistic antimicrobial effects can effectively kill both Gram-positive and Gram-negative bacteria without the emergence of bacterial resistance. Morphological changes obtained by transmission electron microscope observation show that these nanocomposites can cause leakage and chaos of intracellular contents. Analysis of the antimicrobial mechanism confirms that the lethal action of nanocomposites against the bacteria started with disruption of the bacterial membrane, subsequent cellular internalization of the nanoparticles, and inhibition of intracellular enzymatic activity. This novel antimicrobial material with good cytocompatibility promotes healing of infected wounds in diabetic rats, and has a promising future in the treatment of other infectious diseases. PMID:25170799

  17. Phytochemical profiles, antioxidant and antimicrobial activities of three Potentilla species

    PubMed Central

    2013-01-01

    Background Extracts from Potentilla species have been applied in traditional medicine and exhibit antioxidant, hypoglycemic, anti-inflammatory, antitumor and anti-ulcerogenic properties, but little has been known about the diversity of phytochemistry and pharmacology on this genus. This study investigated and compared the phytochemical profiles, antioxidant and antimicrobial activities of leaf extracts from three Potentilla species (Potentilla fruticosa, Potentilla glabra and Potentilla parvifolia) in order to discover new resources for lead structures and pharmaceutical products. Methods Chemical composition and content of six phenolic compounds were evaluated and determined by RP-HPLC; Total phenolic and total flavonoid content were determined using Folin-Ciocalteau colourimetric method and sodium borohydride/chloranil-based method (SBC); Antioxidant activities were determined using DPPH, ABTS and FRAP assays; Antimicrobial properties were investigated by agar dilution and mycelial growth rate method. Results The results showed hyperoside was the predominant phenolic compound in three Potentilla species by RP-HPLC assay, with the content of 8.86 (P. fruticosa), 2.56 (P. glabra) and 2.68 mg/g (P. parvifolia), respectively. The highest content of total identified phenolic compounds (hyperoside, (+)-catechin, caffeic acid, ferulic acid, rutin and ellagic acid) was observed in P. parvifolia (14.17 mg/g), follow by P. fruticosa (10.01 mg/g) and P. glabra (7.01 mg/g). P. fruticosa possessed the highest content of total phenolic (84.93 ± 0.50 mmol gallic acid equivalent/100 g) and total flavonoid (84.14 ± 0.03 mmol quercetin equivalent/100 g), which were in good correlation with its significant DPPHIC50 (16.87 μg/mL), ABTS (2763.48 μmol Trolox equivalent/g) and FRAP (1398.70 μmol Trolox equivalent/g) capacities. Furthermore, the effective methodology to distinguish the different species of Potentilla was also established by chromatographic fingerprint analysis for the first time. The results of antimicrobial activities showed P. fruticosa exhibited the strongest inhibition aganist Gram-positive bacteria, Pseudomonas aeruginosa and Candida albicans with MIC values of 0.78–6.25 mg/mL. P. parvifolia possessed antibacterial and antifungal activities against all the microorganisms tested, with EC50 and MIC values of 20.52–47.02 mg/mL and 0.78–50 mg/mL, respectively. Conclusions These results indicated that leaf extracts from three Potentilla species could become useful supplement for pharmaceutical products as a new antioxidant and antimicrobial agents. PMID:24252124

  18. Diverse antimicrobial activity from Enterococcus faecium NRRL B-30746 bacteriocin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibiotic therapy to resolve bacterial disease has been compromised by the increased prevalence and magnitude of bacterial antibiotic resistance. In our efforts to identify new effective antimicrobials, bacteria isolated from poultry intestinal contents were screened for bacteriocin synthesis again...

  19. Antimicrobial activity and membrane-active mechanism of tryptophan zipper-like β-hairpin antimicrobial peptides.

    PubMed

    Xu, Lin; Chou, Shuli; Wang, Jiajun; Shao, Changxuan; Li, Weizhong; Zhu, Xin; Shan, Anshan

    2015-11-01

    Antimicrobial peptides (AMPs) with amphipathic β-hairpin structures have been demonstrated to possess potent antimicrobial activities and great cell selectivities. However, our understanding of β-hairpin antimicrobial peptides lags behind that of α-helices, mainly because it is difficult for short peptides to form robust β-hairpin structures. Tryptophan zipper (trpzip) peptides are among the most stable β-hairpin peptides known to fold spontaneously without requiring covalent disulfide constraint or metal binding. To develop model β-hairpin AMPs with small size and remarkable stability, a series of amphiphilic linear peptides were designed based on the trpzip motif. The sequence of designed peptides is (WK) n (D) PG(KW) n -NH2 (n = 1, 2, 3, 4, 5), and the antimicrobial activity and membrane interaction mechanism of the peptides were evaluated. The results showed that these peptides readily fold into β-hairpin structures in aqueous and membrane-mimicking environments and exhibit broad-spectrum antimicrobial activities against both gram-positive and gram-negative bacteria. The antibacterial potency of the peptides initially increased and then decreased with increasing chain length. WK3, a 14-residue peptide, displayed excellent antimicrobial activity with minimal hemolytic activity and cytotoxicity, suggesting that it possesses great cell selectivity. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectroscopy, and flow cytometry indicated that representative peptides WK3 and WK4 exert their activities by permeabilizing the microbial membrane and damaging cell membrane integrity. This study reveals the application potential of the designed peptides as promising antimicrobial agents for the control of infectious diseases, and it also provides new insights into the design and optimization of highly stable β-hairpin AMPs with great antimicrobial activities and cell selectivities. PMID:26088720

  20. Antimicrobial activity of fresh garlic juice: An in vitro study

    PubMed Central

    Yadav, Seema; Trivedi, Niyati A.; Bhatt, Jagat D.

    2015-01-01

    Introduction: Antimicrobial resistance has been a global concern. Currently, interest has been focused on exploring antimicrobial properties of plants and herbs. One such botanical is Allium sativum (garlic). Aim: To evaluate the antimicrobial activity of fresh juice of garlic. Materials and Methods: Varying concentrations of fresh garlic juice (FGJ) were tested for their antimicrobial activity against common pathogenic organisms isolated at SSG Hospital, Vadodara, using well diffusion method. Moreover, minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of FGJ were tested using broth dilution method. Sensitivity pattern of the conventional antimicrobials against common pathogenic bacteria was tested using disc diffusion method. Results: FGJ produced dose-dependent increase in the zone of inhibition at a concentration of 10% and higher. MIC of FGJ against the pathogens ranged from 4% to 16% v/v whereas MLC value ranged from 4% to 32% v/v with Escherichia coli and Staphylococcus aureus spp. showed highest sensitivity. Conclusion: FGJ has definite antimicrobial activity against common pathogenic organisms isolated at SSG Hospital, Vadodara. Further studies are needed to find out the efficacy, safety, and kinetic data of its active ingredients. PMID:27011724

  1. Nutrient composition and antimicrobial activity of sorrel drinks (soborodo).

    PubMed

    Oboh, G; Elusiyan, C A

    2004-01-01

    Aqueous extracts (1,200 mL) of roselle calyx (40 g), fortified with either orange juice or pineapple juice as sweetener and lemon grass as flavorant (sorrel drink), were analyzed with regard to their mineral composition (Na, Fe, Zn, Cu, Pb, Mn, and Ca), vitamin C content, and sensory evaluation. While the medicinal potentials were determined with respect to their inhibitory effect on the growth of Bacillus sp., Pseudomonas aeruginosa, Lactobacillus sp., and Corynebacterium sp. The results revealed that the roselle extract fortified with orange juice had higher vitamin C content than did those fortified with pineapple juice, while those fortified with pineapple juice had the best general acceptability. Zn, Na, and Ca were generally high in all the drinks; however, fortification with either pineapple or orange juice reduced the mineral content of the roselle extract. However, Pb, Cu, and Mn (toxic metals) were not detected. The antimicrobial effect of the unfortified roselle extract was low against the entire organism; however, fortification with pineapple juice and lemon grass greatly enhanced the inhibition of the growth of those organisms. They all had their highest inhibitory effect on the growth of P. aeruginosa. In view of the high Zn, Ca, Fe, Na, and vitamin C content as well as the antimicrobial activity, this cheaply produced drink from purely local materials could serve as a good replacement for expensive carbonated drinks. PMID:15383229

  2. Antimicrobial activity of rice bran extracts for diarrheal disease.

    TOXLINE Toxicology Bibliographic Information

    Kondo S; Teongtip R; Srichana D; Itharat A

    2011-12-01

    BACKGROUND: Rice bran showed antioxidative, antimutagenic, carcinogenic and antibacterial activities in previous reports. The rice bran has been recently used as a natural source of health food for several diseases such as diabetes, atherosclerosis and cancer. Severe diarrheal disease due to food-borne contamination of bacteria resulted from the bacteria have become resistant to many antibiotics. Hence, early treatment of diarrhea using natural food containing antibacterial activity to prevent progression of severe symptoms will be beneficial.OBJECTIVE: To investigate antimicrobial activity of rice bran extracts against bacteria causing diarrheal disease.MATERIAL AND METHOD: Bacterial strains isolated from patients include Vibrio cholerae, Vibrio vulnificus, Salmonella spp, Shigella spp, Escherichia coli (ETEC, EHEC, EAEC, EPEC, EIEC) and Stahylococcus aureus. Rice bran was extracted by five different extraction techniques. The antimicrobial activity was performed by disk diffusion and broth dilution methods.RESULTS: The results showed that rice bran extracts using different techniques of extraction were able to inhibit the growth of test strains. Rice bran extracts exhibited the most effective antibacterial activity against V. cholerae O139 with MIC value of 0.976 mg/ml. Using ethanol and supercritical techniques, Sang-Yod rice bran showed better antibacterial activity than Jasmine rice bran. In the present study, the MIC values of rice bran extracts against all tested strains except V. cholerae O139 and S. aureus were between 7.812 to 31.25 mg/ml.CONCLUSION: The results of present study provide insighful basic knowledge which would lead to develop rice bran extracts for effective treatment of diarrheal disease causing by bacteria including resistant strains. The rice bran extracts used against bacterial infection will be an alternative remedy in order to reduce the incidence of antibiotic resistance in future.

  3. Copper(II) complexes with cyanoguanidine and o-phenanthroline: Theoretical studies, in vitro antimicrobial activity and alkaline phosphatase inhibitory effect

    NASA Astrophysics Data System (ADS)

    Martínez Medina, Juan J.; Islas, María S.; López Tévez, Libertad L.; Ferrer, Evelina G.; Okulik, Nora B.; Williams, Patricia A. M.

    2014-01-01

    Calculations based on density functional methods are carried out for two Cu(II) complexes with cyanoguanidine (cnge) and o-phenanthroline (o-phen): [Cu(o-phen)2(cnge)](NO3)2ṡ2H2O (1) and [Cu(o-phen)(cnge)(H2O)(NO3)2] (2). The calculated geometrical parameters are in agreement with the experimental values. The results of Atoms in Molecules (AIM) topological analysis of the electron density indicate that the Cu-N(phen) bonds in complex (1) have lower electron density, suggesting that those bonds are stronger in complex (2). Moreover, the ionic character of the Cu-N bond in the complex (1) is slightly stronger than that in the complex (2) and this situation would explain the fact that only complex (2) was stable in water solution. For this reason, the antimicrobial and enzymatic assays were performed using complex (2). It is well known that the increased use of antibiotics has resulted in the development of resistant bacterial and fungal strains. In this context, the study of novel antimicrobial agents has an enormous importance and metal complexes represent an interesting alternative for the treatment of infectious diseases. The aim of this work is to prove the modification of some biological properties like antimicrobial activity or alkaline phosphatase inhibitory activity upon copper complexation.

  4. Antimicrobial activity of Uncaria tomentosa against oral human pathogens.

    PubMed

    Ccahuana-Vasquez, Renzo Alberto; Santos, Silvana Soléo Ferreira dos; Koga-Ito, Cristiane Yumi; Jorge, Antonio Olavo Cardoso

    2007-01-01

    Uncaria tomentosa is considered a medicinal plant used over centuries by the peruvian population as an alternative treatment for several diseases. Many microorganisms usually inhabit the human oral cavity and under certain conditions can become etiologic agents of diseases. The aim of the present study was to evaluate the antimicrobial activity of different concentrations of Uncaria tomentosa on different strains of microorganisms isolated from the human oral cavity. Micropulverized Uncaria tomentosa was tested in vitro to determine the minimum inhibitory concentration (MIC) on selected microbial strains. The tested strains were oral clinical isolates of Streptococcus mutans, Staphylococcus spp., Candida albicans, Enterobacteriaceae and Pseudomonas aeruginosa. The tested concentrations of Uncaria tomentosa ranged from 0.25-5% in Müeller-Hinton agar. Three percent Uncaria tomentosa inhibited 8% of Enterobacteriaceae isolates, 52% of S. mutans and 96% of Staphylococcus spp. The tested concentrations did not present inhibitory effect on P. aeruginosa and C. albicans. It could be concluded that micropulverized Uncaria tomentosa presented antimicrobial activity on Enterobacteriaceae, S. mutans and Staphylococcus spp. isolates. PMID:17426895

  5. 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

  6. 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. PMID:26457111

  7. Antimicrobial activity of some macrophytes from Lake Manzalah (Egypt).

    PubMed

    Fareed, M F; Haroon, A M; Rabeh, S A

    2008-11-01

    The antimicrobial activities of aqueous and organic solvents (chloroform, ethanol and methanol) extracts of four plants Ceratophyllum demersum L., Eichhornia crassipes, Potamogeton crispus and Potamogeton pectinatus were tested in vitro against seventeen different microorganisms including Gram-positive and Gram-negative bacteria and fungi. Nine of these identified organisms were obtained from different sources, Bacillus subtilis 1020, Bacillus cereus 1080, Staphylococcus aureus, Erwinia carotovora NCPPB 312, Candida albicans, Candida tropicalis, Aspergillus niger, Fusarium oxysporum and Penicillium italicum. The other eight organisms were isolated from Manzalah lake water and identified using API 20E strip system (BioMereux). One hundred pathogenic bacterial isolates representing eight genera were identified to species level. These organisms are Escherichia coli (20%), Pseudomonas aeruginosa (16%), Klebsiella pneumoniae (14%), Salmonella colerasuis (13%), Shigella sp. (11%), Serratia liquefaciens (10%), Proteus vulgaris (9%) and Brenneria nigrifluens (7%). The extracts of all tested plants demonstrated antimicrobial activity against the used organisms. The efficiency of the extracts varied with, solvent used in the extraction as well as plant species and the part of plant used. The aqueous extract appeared to be the highly effective extract against all tested organisms especially Fusarium oxysporum causing inhibition zone 48 +/- 0.01 mm, Pseudomonas aeruginosa 59 +/- 0.02 mm and Salmonella cholerasuis 55 +/- 0.01 mm when using P. crispus, P. pectinatus and C. demersum, respectively. Ethanol extracts of C. demersum, P. crispus and E. crassipes root showed antimicrobial activities against all tested organisms except Aspergillus niger. At the same time the extract of P. pectinatus had no effect also on Fusarium oxysporum and the extract of E. crassipes leaves have no effect on Penicillium italicum. On using chloroform extracts Escherichia coli, Aspergillus niger and Penicillium italicum showed resistance. Comparing the effect of different plants extracts C. demersum appeared to be the most effective followed by P. pectinatus. Furthermore, the extracts of E. crassipes leaves being more effective than that, of its roots. Elemental analysis were also takes place in water and plant samples and the results revealed the presence of Mn and Pb in higher concentration in P. pectinatus (Mn 603 +/- 4.243 ppm and Pb 44 +/- 2.828 ppm), at the same time the highest values of Fe 1680 +/- 2.2 ppm, Zn 31.5 +/- 2.1 ppm and Cu 26.5 +/- 2.1 ppm were recorded for C. demersum. Comparing the two parts of E. crassipes (leaves and roots), the roots have the highest values of all studied metals. PMID:19205264

  8. 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

  9. Antimicrobial activity of Eucalyptus globulus oil, xylitol and papain: a pilot study.

    PubMed

    Mota, Valéria de Siqueira; Turrini, Ruth Natalia Teresa; Poveda, Vanessa de Brito

    2015-01-01

    OBJECTIVE To evaluate the in vitro antimicrobial activity of the Eucalyptus globulus essential oil, and of the xylitol and papain substances against the following microorganisms: Pseudomonas aeruginosa; Samonella sp.; Staphylococus aureus; Proteus vulgaris; Escherichia coli and Candida albicans. METHOD The in vitro antimicrobial evaluation was used by means of the agar diffusion test and evaluation of the inhibition zone diameter of the tested substances. Chlorhexidine 0.5% was used as control. RESULTS The Eucalyptus globulus oil showed higher inhibition than chlorhexidine when applied to Staphylococcus aureus, and equal inhibition when applied to the following microorganisms: Escherichia coli, Proteus vulgaris and Candida albicans. Papain 10% showed lower antimicrobial effect than chlorhexidine in relation to Candida albicans. Xylitol showed no inhibition of the tested microorganisms. CONCLUSION The Eucalyptus globulus oil has antimicrobial activity against different microorganisms and appears to be a viable alternative as germicidal agent hence, further investigation is recommended. PMID:25992819

  10. Identification and antimicrobial activity detection of lactic Acid bacteria isolated from corn stover silage.

    PubMed

    Li, Dongxia; Ni, Kuikui; Pang, Huili; Wang, Yanping; Cai, Yimin; Jin, Qingsheng

    2015-05-01

    A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC 43971(T), Micrococcus luteus ATCC 4698(T) and Escherichia coli ATCC 11775(T) were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at 100°C), but the antimicrobial activity was eliminated after treatment at 121°C for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory. PMID:25924957

  11. Identification and Antimicrobial Activity Detection of Lactic Acid Bacteria Isolated from Corn Stover Silage

    PubMed Central

    Li, Dongxia; Ni, Kuikui; Pang, Huili; Wang, Yanping; Cai, Yimin; Jin, Qingsheng

    2015-01-01

    A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC 43971T, Micrococcus luteus ATCC 4698T and Escherichia coli ATCC 11775T were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at 100°C), but the antimicrobial activity was eliminated after treatment at 121°C for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory. PMID:25924957

  12. Antimicrobial activity of Ulva reticulata and its endophytes

    NASA Astrophysics Data System (ADS)

    Dhanya, K. I.; Swati, V. I.; Vanka, Kanth Swaroop; Osborne, W. J.

    2016-04-01

    Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy (GC-MS) revealed the existence of phenol, 3, 5-bis (1, 1-dimethylethyl) in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas stutzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.

  13. Influence of montmorillonite on antimicrobial activity of tetracycline and ciprofloxacin

    NASA Astrophysics Data System (ADS)

    Lv, Guocheng; Pearce, Cody W.; Gleason, Andrea; Liao, Libing; MacWilliams, Maria P.; Li, Zhaohui

    2013-11-01

    Antibiotics are used not only to fight infections and inhibit bacterial growth, but also as growth promotants in farm livestock. Farm runoff and other farm-linked waste have led to increased antibiotic levels present in the environment, the impact of which is not completely understood. Soil, more specifically clays, that the antibiotic contacts may alter its effectiveness against bacteria. In this study a swelling clay mineral montmorillonite was preloaded with antibiotics tetracycline and ciprofloxacin at varying concentrations and bioassays were conducted to examine whether the antibiotics still inhibited bacterial growth in the presence of montmorillonite. Escherichia coli was incubated with montmorillonite or antibiotic-adsorbed montmorillonite, and then the number of viable bacteria per mL was determined. The antimicrobial activity of tetracycline was affected in the presence of montmorillonite, as the growth of non-resistant bacteria was still found even when extremely high TC doses were used. Conversely, in the presence of montmorillonite, ciprofloxacin did inhibit E. coli bacterial growth at high concentrations. These results suggest that the effectiveness of antimicrobial agents in clayey soils depends on the amount of antibiotic substance present, and on the interactions between the antibiotic and the clays in the soil, as well.

  14. Cholesterol suppresses antimicrobial effect of statins

    PubMed Central

    Haeri, Mohammad Reza; White, Kenneth; Qharebeglou, Mohammad; Ansar, Malek Moein

    2015-01-01

    Objective(s): Isoprenoid biosynthesis is a key metabolic pathway to produce a wide variety of biomolecules such as cholesterol and carotenoids, which target cell membranes. On the other hand, it has been reported that statins known as inhibitors of isoprenoid biosynthesis and cholesterol lowering agents, may have a direct antimicrobial effect on the some bacteria. The exact action of statins in microbial metabolism is not clearly understood. It is possible that statins inhibit synthesis or utilization of some sterol precursor necessary for bacterial membrane integrity. Accordingly, this study was designed in order to examine if statins inhibit the production of a compound, which can be used in the membrane, and whether cholesterol would replace it and rescue bacteria from toxic effects of statins. Materials and Methods: To examine the possibility we assessed antibacterial effect of statins with different classes; lovastatin, simvastatin, and atorvastatin, alone and in combination with cholesterol on two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria using gel diffusion assay. Results: Our results showed that all of the statins except for lovastatin had significant antibacterial property in S. aureus, E. coli, and Enter. faecalis. Surprisingly, cholesterol nullified the antimicrobial action of effective statins in statin-sensitive bacteria. Conclusion: It is concluded that statins may deprive bacteria from a metabolite responsible for membrane stability, which is effectively substituted by cholesterol. PMID:26877857

  15. Structure-Activity Relationship of Benzophenanthridine Alkaloids from Zanthoxylum rhoifolium Having Antimicrobial Activity

    PubMed Central

    Tavares, Luciana de C.; Zanon, Graciane; Weber, Andréia D.; Neto, Alexandre T.; Mostardeiro, Clarice P.; Da Cruz, Ivana B. M.; Oliveira, Raul M.; Ilha, Vinicius; Dalcol, Ionara I.; Morel, Ademir F.

    2014-01-01

    Zanthoxylum rhoifolium (Rutaceae) is a plant alkaloid that grows in South America and has been used in Brazilian traditional medicine for the treatment of different health problems. The present study was designed to evaluate the antimicrobial activity of the steam bark crude methanol extract, fractions, and pure alkaloids of Z. rhoifolium. Its stem bark extracts exhibited a broad spectrum of antimicrobial activity, ranging from 12.5 to 100 µg/mL using bioautography method, and from 125 to 500 µg/mL in the microdilution bioassay. From the dichloromethane basic fraction, three furoquinoline alkaloids (1–3), and nine benzophenanthridine alkaloids (4–12) were isolated and the antimicrobial activity of the benzophenanthridine alkaloids is discussed in terms of structure-activity relationships. The alkaloid with the widest spectrum of activity was chelerythrine (10), followed by avicine (12) and dihydrochelerythrine (4). The minimal inhibitory concentrations of chelerythrine, of 1.50 µg/mL for all bacteria tested, and between 3.12 and 6.25 µg/mL for the yeast tested, show this compound to be a more powerful antimicrobial agent when compared with the other active alkaloids isolated from Z. rhoifolium. To verify the potential importance of the methylenedioxy group (ring A) of these alkaloids, chelerythrine was selected to represent the remainder of the benzophenanthridine alkaloids isolated in this work and was subjected to a demethylation reaction giving derivative 14. Compared to chelerythrine, the derivative (14) was less active against the tested bacteria and fungi. Kinetic measurements of the bacteriolytic activities of chelerythrine against the bacteria Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) were determined by optical density based on real time assay, suggesting that its mechanism of action is not bacteriolytic. The present study did not detect hemolytic effects of chelerythrine on erythrocytes and found a protective effect considering the decrease in TBARS and AOPP (advanced oxidized protein products) levels when compared to the control group. PMID:24824737

  16. Defensins and cathelicidins in inflammatory lung disease: beyond antimicrobial activity.

    PubMed

    Hiemstra, P S

    2006-04-01

    Innate immunity provides an effective first line of defence against infections. This is of particular importance in the lung, an organ that is exposed to a large number of pathogens that are inhaled. Antimicrobial peptides play an important role in the defence against these pathogens as effector molecules of innate immunity. These peptides are mainly produced by phagocytes and epithelial cells, and kill a wide range of micro-organisms: gram-negative and gram-positive bacteria, fungi and (enveloped) viruses. However, it is increasingly evident that these peptides not only act as endogenous antibiotics, but also display a range of other functions, including activities that are involved in regulating immune responses and inflammation, and wound repair. In this review, these activities are highlighted and their role in inflammatory lung disorders is discussed. PMID:16545093

  17. Antimicrobial activity of Ammodaucus leucotrichus fruit oil from Algerian Sahara.

    PubMed

    El-Haci, Imad Abdelhamid; Bekhechi, Chahrazed; Atik-Bekkara, Fewzia; Mazari, Wissame; Gherib, Mohamed; Bighelli, Ange; Casanova, Joseph; Tomi, Félix

    2014-05-01

    Three fruit oil samples of Ammodaucus leucotrichus Cosson & Durieu from Algerian Sahara were obtained by hydrodistillation and analyzed by GC(RI), GC-MS and 13C NMR spectroscopy. The main compounds were perillaldehyde (87.0-87.9%) and limonene (7.4-8.2%). The antimicrobial effect of the essential oil was evaluated against bacteria, yeasts and filamentous fungi. High antibacterial activity was observed against Escherichia coli, Staphylococcus aureus. Enterobacter cloaceae, Bacillus cereus and Salmonella typhimurium, with MIC values between 0.5-1.0 microL/mL. Fungal strains were also sensitive to the essential oil (MIC values: 0.25-0.75 microL/mL).The most potent activity was observed against the filamentous fungi, Fusarium oxysporum and Aspergillusflavus (0.25-0.50 microL/mL). PMID:25026729

  18. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity

    PubMed Central

    2012-01-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics. PMID:22625664

  19. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Ashraf, Sumaira; Akhtar, Nasrin; Ghauri, Muhammad Afzal; Rajoka, Muhammad Ibrahim; Khalid, Zafar M.; Hussain, Irshad

    2012-05-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics.

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

    PubMed

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

    2014-05-01

    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 a 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 the antimicrobial activity of RNase 7. Using RNA isolated from non-infected human bladder and kidney tissue, quantitative real-time polymerase chain reaction 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

  1. Antimicrobial activity of ibuprofen: new perspectives on an "Old" non-antibiotic drug.

    PubMed

    Obad, Jelena; Šušković, Jagoda; Kos, Blaženka

    2015-04-25

    Pharmaceutical industry has been encountering antimicrobial activity of non-antibiotics during suitability tests carried out prior to routine pharmacopoeial microbiological purity analysis of finished dosage forms. These properties are usually ignored or perceived as a nuisance during pharmaceutical analysis. The aim of this study was: (i) to compare the available data to our method suitability test results carried out on products containing ibuprofen, i.e. to demonstrate that method suitability can be a valuable tool in identifying new antimicrobials, (ii) to demonstrate the antimicrobial activity of ibuprofen and ibuprofen lysine. Microbiological purity method suitability testing was carried out according to European Pharmacopoeia (EP), chapters 2.6.12. and 2.6.13. Antimicrobial activity of ibuprofen and ibuprofen lysine was demonstrated by a disk diffusion method, a modification of the European Committee for Antimicrobial Susceptibility Testing method (EUCAST), against test microorganisms recommended in the EP. It was confirmed that ibuprofen may be responsible for the broad spectrum of antimicrobial activity of the tested products, and that method suitability tests according to the EP can indeed be exploited by the scientific community in setting guidelines towards future research of new antimicrobials. In the disk diffusion assay, inhibition zones were obtained with more than 62.5 μg and 250 μg for Staphylococcus aureus, 125 μg and 250 μg for Bacillus subtilis, 31.3 μg and 125 μg for Candidaalbicans, 31.3 μg and 62.5 μg for Aspergillusbrasiliensis, of ibuprofen/disk, and ibuprofen lysine/disk, respectively. For Escherichiacoli, Pseudomonasaeruginosa and Salmonellatyphimurium inhibition zones were not obtained. Antimicrobial activity of ibuprofen is considered merely as a side effect, and it is not mentioned in the patient information leaflets of ibuprofen drugs. As such, for the patient, it could represent an advantage, but, it could also introduce additional risks during usage. Further microbiological, pharmacological and clinical trials are of great importance. PMID:25708941

  2. 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.

  3. Effect of Selectively Introducing Arginine and D-Amino Acids on the Antimicrobial Activity and Salt Sensitivity in Analogs of Human Beta-Defensins

    PubMed Central

    Olli, Sudar; Rangaraj, Nandini; Nagaraj, Ramakrishnan

    2013-01-01

    We have examined the antimicrobial activity of C-terminal analogs of human β-defensins HBD-1and-3 wherein lysines have been selectively replaced by L- and D-arginines and L-isoleucine substituted with its D-enantiomer. The analogs exhibited antibacterial and antifungal activities. Physiological concentration of NaCl did not attenuate the activity of the peptides against Gram-negative bacteria considerably, while some attenuation of activity was observed against S. aureus. Variable attenuation of activity was observed in the presence of Ca2+ and Mg2+. Introduction of D-amino acids abrogated the need for a disulfide bridge for exhibiting activity. Confocal images of carboxyfluorescein (CF) labeled peptides indicated initial localization on the membrane and subsequent translocation into the cell. Analogs corresponding to cationic rich segments of human defensins substituted with L- and D-arginine, could be attractive candidates for development as future therapeutic drugs. PMID:24086767

  4. Effect of potassium sorbate on antimicrobial and physical properties of starch-clay nanocomposite films.

    PubMed

    Barzegar, Hassan; Azizi, Mohammad Hossein; Barzegar, Mohsen; Hamidi-Esfahani, Zohreh

    2014-09-22

    Using fresh foods which undergo the least processing operations developed widely in recent years. Active packaging is a novel method for preserving these products. Active starch-clay nanocomposite films which contained potassium sorbate (PS) at a level of 0, 5, 7.5 and 10 g PS/100 g starch were produced and their physical, mechanical and antimicrobial properties were evaluated. In order to evaluate antimicrobial properties of films Aspergillus niger was used. The results showed that 5% of the PS did not produce antimicrobial property in the film, but by increasing the content of the additive in film formulation, antimicrobial effect increased. PS increased water permeability and elongation at break of the films, but decreased tensile strength. The rate of PS migration into the semi-solid medium in starch-nanocomposites was lower than starch films. This shows that nanocomposite films could retain their antimicrobial property for longer time. PMID:24906724

  5. Peptides from the scorpion Vaejovis punctatus with broad antimicrobial activity.

    PubMed

    Ramírez-Carreto, Santos; Jiménez-Vargas, Juana María; Rivas-Santiago, Bruno; Corzo, Gerardo; Possani, Lourival D; Becerril, Baltazar; Ortiz, Ernesto

    2015-11-01

    The antimicrobial potential of two new non-disulfide bound peptides, named VpAmp1.0 (LPFFLLSLIPSAISAIKKI, amidated) and VpAmp2.0 (FWGFLGKLAMKAVPSLIGGNKSSSK) is here reported. These are 19- and 25-aminoacid-long peptides with +2 and +4 net charges, respectively. Their sequences correspond to the predicted mature regions from longer precursors, putatively encoded by cDNAs derived from the venom glands of the Mexican scorpion Vaejovis punctatus. Both peptides were chemically synthesized and assayed against a variety of microorganisms, including pathogenic strains from clinical isolates and strains resistant to conventional antibiotics. Two shorter variants, named VpAmp1.1 (FFLLSLIPSAISAIKKI, amidated) and VpAmp2.1 (FWGFLGKLAMKAVPSLIGGNKK), were also synthesized and tested. The antimicrobial assays revealed that the four synthetic peptides effectively inhibit the growth of both Gram-positive (Staphylococcus aureus and Streptococcus agalactiaea) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, with MICs in the range of 2.5-24.0 μM; yeasts (Candida albicans and Candida glabrata) with MICs of 3.1-50.0 μM; and two clinically isolated strains of Mycobacterium tuberculosis-including a multi-drug resistant one- with MICs in the range of 4.8-30.5 μM. A comparison between the activities of the original peptides and their derivatives gives insight into the structural/functional role of their distinctive residues. PMID:26352292

  6. Minidefensins: antimicrobial peptides with activity against HIV-1.

    PubMed

    Cole, Alexander M; Lehrer, Robert I

    2003-01-01

    Over 80 different alpha-defensin or beta-defensin peptides are expressed by the leukocytes and epithelial cells of birds and mammals. Although their broad spectrum antimicrobial properties makes them candidates for therapeutic development, technical limitations related to their size (typically 30-45 residues) and complex structure have impeded such development. The minidefensins covered in this review are antimicrobial peptides with 16-18 residues, approximately half the number found in alpha-defensins. The theta-defensins are evolutionarily related toalpha- and beta-defensins, but other minidefensins probably arose independently. Like alpha- or beta-defensins, minidefensin molecules have a net positive charge and a largely beta-sheet structure that is stabilized by intramolecular disulfide bonds. Whereas alpha-defensins are found only in mammals and theta-defensins only in nonhuman primates, the other minidefensins come from widely divergent species, including horseshoe crabs, spiders, and pigs. Several alpha-defensins and minidefensins are effective inhibitors of HIV-1 infection in vitro, and recent evidence implicates alpha-defensins in resistance to HIV-1 progression in vivo. This review compares defensins and minidefensins with respect to their activity against HIV-1. It pays special attention to retrocyclins - the ancestral theta-defensins of humans, and their extant counterparts in rhesus monkeys. In addition to describing critical elements of their structure and unusual mode of formation, we will venture some predictions about using theta-defensins as antiviral agents. PMID:12769726

  7. Fractionation of Mastic Gum in Relation to Antimicrobial Activity

    PubMed Central

    Sharifi, Mohammad Sharif; Hazell, Stuart Loyd

    2009-01-01

    Mastic gum is a viscous light-green liquid obtained from the bark of Pistacia lentiscus var. chia. which belongs to the Anacardiaceae family. The gum has been fractionated to investigate the antimicrobial activity of the whole gum and its fractions against various strains of Helicobacter pylori. The polymeric gum fraction was separated from the essential oil and the resin (trunk exudates without essential oil) to assess and compare the anti-H. pylori activity of the polymer fraction against lower molecular weight fractions, the gum itself and masticated gum. The polymer fraction was also oxidized and assessed for antimicrobial activity.

  8. Effect of floral sources on the antioxidant, antimicrobial, and anti-inflammatory activities of honeys in Taiwan.

    PubMed

    Liu, Je-Ruei; Ye, Yi-Ling; Lin, Ting-Yu; Wang, Yun-Wen; Peng, Chi-Chung

    2013-08-15

    We evaluated the antioxidant, antibacterial, and anti-inflammatory activities of honey made from different floral sources, including the medicinal herb Bidens pilosa, fruit trees, Dimocarpus longan, Litchi chinensis, and Citrus maxima, the Taiwanese endemic plant Aglaia formosana, and a multifloral forest. The total phenolic and flavonoid contents of the honey made from B. pilosa were significantly higher than those of the other honeys. The honey from B. pilosa also had significantly greater scavenging activities for 1,1-diphenyl-2-picrylhydrazyl (DPPH·) and hydroxyl radical, and substantially more reducing power. In addition, the honey from B. pilosa showed greater antibacterial activity against gram-positive and gram-negative bacteria. However, B. pilosa honey showed little inhibitory activity against IL-8 secretion, whereas the other honeys did. These findings suggest that the levels of antioxidant and antibacterial activities are attributable to the total phenolic and flavonoid contents of honeys, while the IL-8 inhibition is attributable to components other than phenols. PMID:23561193

  9. Improvement of the antimicrobial and antioxidant activities of camel and bovine whey proteins by limited proteolysis.

    PubMed

    Salami, Maryam; Moosavi-Movahedi, Ali Akbar; Ehsani, Mohammad Reza; Yousefi, Reza; Haertlé, Thomas; Chobert, Jean-Marc; Razavi, Seyed Hadi; Henrich, Robert; Balalaie, Saeed; Ebadi, Seyed Ahmad; Pourtakdoost, Samineh; Niasari-Naslaji, Amir

    2010-03-24

    The compositions and structures of bovine and camel milk proteins are different, which define their functional and biological properties. The aim of this study was to investigate the effects of enzymatic hydrolysis of camel and bovine whey proteins (WPs) on their antioxidant and antimicrobial properties. After enzymatic treatment, both the antioxidant and the antimicrobial activities of bovine and camel WPs were improved. The significantly higher antioxidant activity of camel WPs and their hydrolysates as compared with that of bovine WPs and their hydrolysates may result from the differences in amounts and/or in accessibilities of antioxidant amino acid residues present in their primary structures and from the prevalence of alpha-lactalbumin and beta-lactoglobulin as proteolytic substrates in camel and bovine whey, respectively. The results of this study reveal differences in antimicrobial and antioxidant activities between WP hydrolysates of bovine and camel milk and the effects of limited proteolysis on these activities. PMID:20175528

  10. Antimicrobial effect of garlic (Allium sativum).

    PubMed

    Goncagul, Gulsen; Ayaz, Erol

    2010-01-01

    Medicinal plants like pumpkin seed, thyme, onion, Nigella sativa, lemon balm, and stinging nettle are used extensively today. One of these plants used most intensively and widespread is garlic. In this context, fresh shape, powder state and oil of garlic have been used all around the world, especially in Far East for centuries. It is scientifically proven that garlic is effectively used in cardiovascular diseases as a regulator of blood pressure, with dropper effects on glycaemia and high blood cholesterol, against bacterial, viral, mycotic and parasitic infections. It's also known that garlic is a wonderful plant having the properties of empowering immune system, anti-tumour and antioxidant effects. In this article, the summary of properties of garlic and its use against bacterial diseases is given. This article is a short review of recent patents on antimicrobial effect of garlic. PMID:19929845

  11. 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. PMID:24951887

  12. Antimicrobial, antibiofilm and cytotoxic activities of Hakea sericea Schrader extracts

    PubMed Central

    Luís, Ângelo; Breitenfeld, Luiza; Ferreira, Susana; Duarte, Ana Paula; Domingues, Fernanda

    2014-01-01

    Background: Hakea sericea Schrader is an invasive shrub in Portuguese forests. Objective: The goal of this work was to evaluate the antimicrobial activity of H. sericea extracts against several strains of microorganisms, including the ability to inhibit the formation of biofilms. Additionally the cytotoxic properties of these extracts, against human cells, were assessed. Materials and Methods: The antimicrobial activity of the methanolic extracts of H. sericea was assessed by disk diffusion assay and Minimum Inhibitory Concentration (MIC) value determination. The antibiofilm activity was determined by quantification of total biofilm biomass with crystal violet. Cytotoxicity was evaluated by hemolysis assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Results: For Gram-positive bacteria, MIC values of H. sericea methanolic extracts ranged between 0.040 and 0.625 mg/mL, whereas the fruits extract yielded the lowest MIC for several strains of microorganisms, namely, S. aureus, B. cereus, L. monocytogenes and clinical methicillin-resistant S. aureus (MRSA). Stems and fruits extract at 2.5 mg/mL effectively eradicated the biofilm of S. aureus ATCC 25923, SA 01/10 and MRSA 12/10. Regarding leaves extract, hemolysis was not observed, and in the case of stems and fruits, hemolysis was verified only for higher concentrations, suggesting its low toxicity. Fruits extract presented no toxic effect to normal human dermal fibroblasts (NHDF) cells however for concentrations of 0.017 and 0.008 mg/mL this extract was able to decrease human breast adenocarcinoma cells (MCF-7) viability in about 60%, as MTT test results had confirmed. This is a clearly demonstrator of the cytotoxicity of this extract against MCF-7 cells. PMID:24914310

  13. A screening for antimicrobial activities of Caribbean herbal remedies

    PubMed Central

    2013-01-01

    Background The TRAMIL program aims to understand, validate and expand health practices based on the use of medicinal plants in the Caribbean, which is a “biodiversity hotspot” due to high species endemism, intense development pressure and habitat loss. The antibacterial activity was examined for thirteen plant species from several genera that were identified as a result of TRAMIL ethnopharmacological surveys or were reported in ethnobotanical accounts from Puerto Rico. The aim of this study was to validate the traditional use of these plant species for the treatment of bacterial infections, such as conjunctivitis, fever, otitis media and furuncles. Methods An agar disc diffusion assay was used to examine five bacterial strains that are associated with the reported infections, including Staphylococcus saprophyticus (ATCC 15305), S. aureus (ATCC 6341), Escherichia coli (ATCC 4157), Haemophilus influenzae (ATCC 8142), Pseudomonas aeruginosa (ATCC 7700) and Proteus vulgaris (ATCC 6896), as well as the fungus Candida albicans (ATCC 752). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined for each of the extracts that showed inhibitory activity. Results The decoctions of Pityrogramma calomelanos, Tapeinochilus ananassae, and Syzygium jambos, as well as the juice of Gossypium barbadense, showed > 20% growth inhibition against several bacteria relative to the positive control, which was the antibiotic Streptomycin. Extracts with the best antimicrobial activities were S. jambos that showed MIC = 31 μg/mL and MBC = 1.0 mg/mL against P. vulgaris and T. ananassae that showed MIC = 15 μg/mL against S. aureus. Conclusion This report confirms the traditional use of P. calomelanos for the treatment of kidney infections that are associated with stones, as well as the antimicrobial and bactericidal effects of T. ananassae against P. vulgaris and S. saprophyticus and the effects of S. jambos against S. aureus and S. saprophyticus. PMID:23731467

  14. In vitro evaluation of the antimicrobial activity of endodontic sealers.

    PubMed

    Miyagak, Daniela Cristina; de Carvalho, Elaine Manso Oliveira Franco; Robazza, Carlos Roberto Colombo; Chavasco, Jorge Kleber; Levorato, Gustavo Labegalline

    2006-01-01

    The purpose of this study is to evaluate the antimicrobial activity of the endodontic sealers: N-Rickert, Sealapex, AH Plus, Mineral Trioxide Aggregate (MTA) and portland cement. The Agar diffusion method was used in plates previously inoculated with the following microorganisms: C. albicans, S. aureus, E. faecalis, E. coli. The diameters of microbial inhibition zones were measured after 24 hours of incubation in kiln at 37 degrees C. According to the methodology used, it was possible to conclude that only the sealers AH Plus and N-Rickert presented antimicrobial activity against C. albicans, S. aureus, and E. coli; no antimicrobial activity in MTA, Sealapex and portland cement was observed. N-Rickert presented the largest inhibition zones varying from 8 to 18 mm, and the microorganism E. faecalis was resistant against all sealers tested. PMID:17242789

  15. Chemical composition and antimicrobial activity of Polish herbhoneys.

    PubMed

    Isidorov, V A; Bagan, R; Bakier, S; Swiecicka, I

    2015-03-15

    The present study focuses on samples of Polish herbhoneys (HHs), their chemical composition and antimicrobial activity. A gas chromatography-mass spectrometry (GC-MS) method was used to analyse eight samples of herbal honeys and three samples of nectar honeys. Their antimicrobial activities were tested on selected Gram-positive (Bacillus cereus, Staphylococcus aureus, Staphylococcus schleiferi) and Gram-negative (Escherichia coli) bacteria, as well as on pathogenic fungi Candida albicans. Ether extracts of HHs showed significant differences in composition but the principal groups found in the extracts were phenolics and aliphatic hydroxy acids typical of royal jelly and unsaturated dicarboxylic acids. In spite of the differences in chemical composition, antimicrobial activity of the extracts of HHs against all the tested microorganisms except E. coli was observed. PMID:25308646

  16. Phytochemical and antimicrobial activities of Himalayan Cordyceps sinensis (Berk.) Sacc.

    PubMed

    Mamta; Mehrotra, Shubhi; Amitabh; Kirar, Vandana; Vats, Praveen; Nandi, Shoma Paul; Negi, P S; Misra, Kshipra

    2015-01-01

    This study evaluated the phytochemical and antimicrobial activities and also quantified bioactive nucleoside using high performance thin layer chromatography (HPTLC) of five extracts of Indian Himalayan Cordyceps sinensis prepared with different solvents employing accelerated solvent extraction (ASE) technique. The phytochemical potential of these extracts was quantified in terms of total phenolic and total flavonoid content while antioxidant activities were determined by 1,1-diphenyl-2-pycryl-hydrazyl (DPPH) and 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and ferric-reducing antioxidant power (FRAP) assays. Total reducing power (TRP) was determined by converting iron (III) into iron (II) reduction assay. CS(50%Alc) (15.1 ± 0.67mg/g of dry extract) and CS(100%Alc) (19.3 ± 0.33 mg/g of dry extract) showed highest phenolic and flavonoid content, respectively while CS(Aq) extract showed maximum antioxidant activity and the highest concentration of the three nucleosides (adenine 12.8 ± 0.49 mg/g, adenosine 0.36 ± 0.28 mg/g and uracil 0.14 ± 0.36 mg/g of dry extract) determined by HPTLC. The evaluation of extracts for antimicrobial activity against gram-negative and gram-positive bacterial strains showed CS(25%Alc), CS(75%Alc) and CS(100%Alc) extract to be more effective against E. coli, P. aerugenosa and B. subtilis giving 9, 7 and 6.5 mm of zone of inhibition (ZOI) in 93.75, 93.75 and 45 μg concentration, respectively, whereas CS(Aq) extract showed minimal inhibition against these. PMID:25675710

  17. Antimicrobial and antioxidant activities of alcoholic extracts obtained from vegetative organs of A. retroflexus.

    PubMed

    Marinaş, Ioana Cristina; Chifiriuc, Carmen; Oprea, Eliza; Lazăr, Veronica

    2014-01-01

    In vitro antimicrobial and antioxidant activities of Amaranthus retroflexus leaves and inflorescence alcoholic (ethanol 70%) extracts of various concentrations ranging from 0.78 to 400 μL/ml were analyzed on different clinical and reference bacterial strains (Staphylococcus aureus, Bacillus subtills, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii) and fungal strains (Candida albicans, C. famata, C. utilis, Saccharomyces cerevisiae) using agar disk diffusion method and broth dilution method (MIC determination) for antimicrobial activity and TEAC (Trolox capacity) assay for the evaluation of the antioxidant activity. The adapted diffusion method was used to test the antimicrobial effect of the extracts separately and in combination with a range of standard antibiotics, in order to evidence any synergic effects of A. retroflexus extracts on the antibiotics activity. The extracts showed the highest inhibitory effect against K. pneumoniae and B. subtilis with no activity against S. aureus among the bacterial strains, while in case of the fungal strains the most intensive effect was exhibited against C. famata by both extracts. The A. retroflexus leaves extract improved the ciprofloxacin and ticarcillin-clavulanic acid activity towards the P. aeruginosa clinical strain. The inflorescences extract significantly increased chloramphenicol activity on B. subtilis strain. The antioxidant activity assay showed that the studied extracts exhibited the ability to neutralize the free radicals leading to the conclusion that the tested extracts bear compounds with a broad spectrum of antimicrobial and antioxidant activity that could represent a potential alternative for treating various infectious diseases. PMID:25518569

  18. 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%). PMID:22459760

  19. Antimicrobial activity of submerged cultures of Chilean basidiomycetes.

    PubMed

    Aqueveque, Pedro; Anke, Timm; Saéz, Katia; Silva, Mario; Becerra, José

    2010-10-01

    This study is part of a screening program aimed at searching for bioactive metabolites from Chilean basidiomycetes. Submerged cultivation of fungal mycelia in liquid media was evaluated for antimicrobial activity. A total of 148 strains were obtained in vitro. The extracts produced from submerged cultures were evaluated against bacteria and fungi. In the primary antimicrobial assay, approximately 60% of the extracts presented positive biological activity. The highest frequencies of active strains were from the orders Agaricales (31.0%), Polyporales (20.6%), Sterales (18.3%), Boletales (11.4%), and Cortinariales (9.1%). Antifungal activity was more pronounced than antibacterial activity. Twelve extracts that exhibited strong antimicrobial activity showed minimum inhibitory concentration (MIC) values of 50 µL/mL against Bacillus brevis and 25∼50 µL/mL against Penicillium notatum and Paecilomyces variotii. The biological activity of some strains did not vary considerably, regardless of the substrate or collection site whereas, for others, it showed marked variations. Differences in antimicrobial activities observed in the different fungal genera suggested that the ability to produce bioactive compounds is not homogenously distributed among basidiomycetes. The information obtained from this study reveals that Chilean basidiomycetes are able to generate small and/or large variations in the normal pathway of compounds production. Thus, it is necessary to evaluate this biological and chemical wealth, which could be an unsuspected reservoir of new and potentially useful molecules. PMID:20425689

  20. 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. PMID:25305209

  1. The Synthesis and Antimicrobial Activity of Heterocyclic Derivatives of Totarol

    PubMed Central

    2012-01-01

    The synthesis and antimicrobial activity of heterocyclic analogues of the diterpenoid totarol are described. An advanced synthetic intermediate with a ketone on the A-ring is used to attach fused heterocycles, and a carbon-to-nitrogen atom replacement is made on the B-ring by de novo synthesis. A-ring analogues with an indole attached exhibit, for the first time, enhanced antimicrobial activity relative to the parent natural product. Preliminary experiments demonstrate that the indole analogues do not target the bacterial cell division protein FtsZ as had been hypothesized for totarol. PMID:23119123

  2. Structure-antimicrobial activity relationship between pleurocidin and its enantiomer

    PubMed Central

    Lee, Juneyoung

    2008-01-01

    To develop novel antibiotic peptides useful as therapeutic drugs, the enantiomeric analogue of pleurocidin (Ple), which is a well known 25-mer antimicrobial peptide, was designed for proteolytic resistance by D-amino acids substitution. The proteolytic resistance was confirmed by using HPLC after the digestion with various proteases. To investigate the antibiotic effect of L- and D-Ple, the antibacterial activity and hemolytic effect were tested against human erythrocytes. The D-Ple showed a decreased antibacterial activity and a dramatically decreased hemolytic activity compared with L-Ple. The hemolytic effect of analogue was further confirmed by using calcein leakage measurement with liposome. To elucidate these results, the secondary structure of the peptides was investigated by using circular dichroism spectroscopy. The results revealed that D-Ple, as well as L-Ple, had typical ?-helical structures which were mirror images, with a different helicity. These results suggested that the discrepancy of the structure between the two peptides made their antibacterial activity distinct. PMID:18779649

  3. Synthesis and antimicrobial activity of gold/silver-tellurium nanostructures.

    PubMed

    Chang, Hsiang-Yu; Cang, Jinshun; Roy, Prathik; Chang, Huan-Tsung; Huang, Yi-Cheng; Huang, Chih-Ching

    2014-06-11

    Gold-tellurium nanostructures (Au-Te NSs), silver-tellurium nanostructures (Ag-Te NSs), and gold/silver-tellurium nanostructures (Au/Ag-Te NSs) have been prepared through galvanic reactions of tellurium nanotubes (Te NTs) with Au(3+), Ag(+), and both ions, respectively. Unlike the use of less environmentally friendly hydrazine, fructose as a reducing agent has been used to prepare Te NTs from TeO2 powders under alkaline conditions. The Au/Ag-Te NSs have highly catlaytic activity to convert nonfluorescent Amplex Red to form fluorescent product, revealing their great strength of generating reactive oxygen species (ROS). Au/Ag-Te NSs relative to the other two NSs exhibit greater antimicrobial activity toward the growth of E. coli, S. enteritidis, and S. aureus; the minimal inhibitory concentration (MIC) values of Au/Ag-Te NSs were much lower (>10-fold) than that of Ag-Te NSs and Au-Te NSs. The antibacterial activity of Au/Ag-Te NSs is mainly due to the release of Ag(+) ions and Te-related ions and also may be due to the generated ROS which destroys the bacteria membrane. In vitro cytotoxicity and hemolysis analyses have revealed their low toxicity in selected human cell lines and insignificant hemolysis in red blood cells. In addition, inhibition zone measurements using a Au/Ag-Te NSs-loaded konjac jelly film have suggested that it has great potential in practial application such as wound dressing for reducing bacterial wound infection. Having great antibacterial activitiy and excellent biocompatibility, the low-cost Au/Ag-Te NSs hold great potential as effective antimicrobial drugs. PMID:24832728

  4. The effect of pH and chloride concentration on the stability and antimicrobial activity of chlorine-based sanitizers.

    PubMed

    Waters, Brian W; Hung, Yen-Con

    2014-04-01

    Chlorinated water and electrolyzed oxidizing (EO) water solutions were made to compare the free chlorine stability and microbicidal efficacy of chlorine-containing solutions with different properties. Reduction of Escherichia coli O157:H7 was greatest in fresh samples (approximately 9.0 log CFU/mL reduction). Chlorine loss in "aged" samples (samples left in open bottles) was greatest (approximately 40 mg/L free chlorine loss in 24 h) in low pH (approximately 2.5) and high chloride (Cl(-) ) concentrations (greater than 150 mg/L). Reduction of E. coli O157:H7 was also negatively impacted (<1.0 log CFU/mL reduction) in aged samples with a low pH and high Cl(-) . Higher pH values (approximately 6.0) did not appear to have a significant effect on free chlorine loss or numbers of surviving microbial cells when fresh and aged samples were compared. This study found chloride levels in the chlorinated and EO water solutions had a reduced effect on both free chlorine stability and its microbicidal efficacy in the low pH solutions. Greater concentrations of chloride in pH 2.5 samples resulted in decreased free chlorine stability and lower microbicidal efficacy. PMID:24621341

  5. [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. PMID:26137678

  6. Nanocolloidal carriers of isotretinoin: antimicrobial activity against Propionibacterium acnes and dermatokinetic modeling.

    PubMed

    Raza, Kaisar; Singh, Bhupinder; Singla, Saloni; Wadhwa, Sheetu; Garg, Babita; Chhibber, Sanjay; Katare, Om Prakash

    2013-05-01

    Acne, a common skin disease in teenagers, is caused by Propionibacterium acnes (P. acnes). Isotretinoin (ITR) is though reported to have immense antiacne potential, yet there are hardly any reports vouching its antimicrobial activity. The present study, therefore, was undertaken to study the antimicrobial activity of ITR and evaluate the effect of its encasement in nanocarriers on its minimum inhibitory concentration (MIC). The nanocarriers were also evaluated for the skin transport characteristics. MICs of pure drug and entrapped drug in nanolipid carriers (ITR-NLCs) and in solid lipid nanoparticles (ITR-SLNs) were determined by broth dilution method against clindamycin phosphate as the reference antibiotic. It was observed that ITR possessed marked antimicrobial activity against anaerobic pathogen, P. acnes. Nanocarriers loaded with ITR, that is, SLNs and NLCs, enhanced the antimicrobial activity even at lower concentrations vis--vis the drug alone and improved drug transport potential vis--vis the commercial gel. The unique findings could be the result of effective adhesion of ITR-loaded nanocarriers to the bacterial membranes and release of drug directly to the target. Besides establishing ITR as an antimicrobial agent against acne-causing bacteria, the current work ratifies immense potential of nanocolloidal carriers like SLNs and NLCs to treat acne in a more efficient manner. PMID:23544848

  7. Effects of antimicrobial peptide L-K6, a temporin-1CEb analog on oral pathogen growth, Streptococcus mutans biofilm formation, and anti-inflammatory activity.

    PubMed

    Shang, Dejing; Liang, Hao; Wei, Shi; Yan, Xin; Yang, Qingzu; Sun, Yue

    2014-10-01

    Dental caries and periodontitis are common bacterial mouth infections. As a potentially attractive substitute for conventional antibiotics, antimicrobial peptides have been widely tested and used for controlling bacterial infections. In this study, we tested the efficacy of the peptides from the skin secretions of Rana chensinensis for killing several major cariogenic and periodontic pathogens as well as Candida albicans. L-K6, a temporin-1CEb analog, exhibited high antimicrobial activity against the tested oral pathogens and was able to inhibit Streptococcus mutans biofilm formation and reduce 1-day-old S. mutans biofilms with a minimum biofilm inhibitory concentration and reducing concentration of 3.13 and 6.25 μM, respectively. The results of confocal laser scanning microscopy demonstrated that the peptide significantly reduced cell viability within oral biofilms. Furthermore, as little as 5 μM L-K6 significantly inhibited lipopolysaccharide (LPS)- and interleukin-1β-induced productions of interleukin-8 and tumor necrosis factor-α from THP-1 monocytic cells. This anti-inflammatory activity is associated with the binding of L-K6 to LPS and neutralizing LPS-induced proinflammatory responses in THP-1 cells, as well as dissociating LPS aggregates. Our results suggest that L-K6 may have potential clinical applications in treating dental caries by killing S. mutans within dental plaque and acting as anti-inflammatory agents in infected tissues. PMID:25056289

  8. Inducible ASABF-Type Antimicrobial Peptide from the Sponge Suberites domuncula: Microbicidal and Hemolytic Activity in Vitro and Toxic Effect on Molluscs in Vivo†

    PubMed Central

    Wiens, Matthias; Schröder, Heinz C.; Korzhev, Michael; Wang, Xiao-Hong; Batel, Renato; Müller, Werner E. G.

    2011-01-01

    Since sponges, as typical filter-feeders, are exposed to a high load of attacking prokaryotic and eukaryotic organisms, they are armed with a wide arsenal of antimicrobial/cytostatic low-molecular-weight, non-proteinaceous bioactive compounds. Here we present the first sponge agent belonging to the group of ASABF-type antimicrobial peptides. The ASABF gene was identified and cloned from the demosponge Suberites domuncula. The mature peptide, with a length of 64 aa residues has a predicted pI of 9.24, and comprises the characteristic CSα β structural motif. Consequently, the S. domuncula ASABF shares high similarity with the nematode ASABFs; it is distantly related to the defensins. The recombinant peptide was found to display besides microbicidal activity, anti-fungal activity. In addition, the peptide lyses human erythrocytes. The expression of ASABF is upregulated after exposure to the apoptosis-inducing agent 2,2′-dipyridyl. During the process of apoptosis of surface tissue of S. domuncula, grazing gastropods (Bittium sp.) are attracted by quinolinic acid which is synthesized through the kynurenine pathway by the enzyme 3-hydroxyanthranilate 3,4-dioxygenase (HAD). Finally, the gastropods are repelled from the sponge tissue by the ASABF. It is shown that the effector peptide ASABF is sequentially expressed after the induction of the HAD gene and a caspase, as a central enzyme executing apoptosis. PMID:22073005

  9. 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

  10. [Antimicrobially effective compounded medications. Clinical value and critical comments].

    PubMed

    Eifler-Bollen, R; Fluhr, J W

    2005-08-01

    Triphenyl-methan dyes, traditionally used in dermatology should be reevaluated with caution. Their use should be limited due to the uncertain pharmacological-toxicological risk-benefit ratio and the lack of pharmacological quality of the raw substances. Sometimes antimicrobial activity is insufficient and the cytotoxic effects, along with the inhibition of wound healing, make these dyes less suitable for topical treatment in dermatology. Chinolinolsulfat (Chinosol) and Clioquinol should be used in low concentrations and only on small areas. Due to their negative benefit-risk profile ethracidinlactate-monohydrate (Rivanol) and phenylmercuri-borate (Mercuchrom) should not be used as topical antimicrobial substances. The present publication is intended to give practical recommendations on compounded medications for topical antimicrobial use. Even though some of the cited compounds must be considered critically, we recommend the topical use of chlorhexidine salts, polihexanide, triclosan, polyvidone iodide and silver compounds. Useful standardised compounded formulations containing these four groups are listed in the NRF (Neues Rezeptur Formularium: New German Pharmacopoeia for compounded medication). PMID:15933865

  11. Antimicrobial effect of nylon fiber immersed with nano-silver

    NASA Astrophysics Data System (ADS)

    Haryono, Agus; Harmami, Sri Budi; Sondari, Dewi

    2010-05-01

    The development of new products based on the immobilization of nanoparticles on fibers has recently received a growing interest from both the academic and industrial sectors. A wide range of nanoparticles and nano-structures can be immobilized on fibers, which brings new properties to the final product. In the present work, silver nanoparticle was immobilized on nylon fibers by immersed deposition method as an antimicrobial agent. Silver colloid was produced by chemical reduction of silver salt (silver nitrate) solution, in the presence of sodium citrate. Synthesis of silver colloid was carried out by using chemical reduction method at temperature of 95 and 100°C. The mixture was heated until color changed into pale yellow. UV-Vis spectrometry indicated formation of silver nanoparticles. UV-Vis analysis was reported that the absorption spectrum of silver nanoparticles showed a maximum between 420 and 450 nm. Characterization of silver nanoparticles was conducted using Fourier Transformed Infra Red (FTIR) spectroscopy, UV-Vis spectroscopy, particle size analyzer (PSA), and scanning electron microscope (SEM). It was found that silver nanoparticles forms aggregates on the surface of fiber, during deposition process. The size of aggregates varied from 19.9 +/- 4.8 nm to 49.5 +/- 12.5 nm. To evaluate the antimicrobial effects against microorganisms, we used representative microorganisms S. aureus. Silver nanoparticles showed antimicrobial activity reducing bacterial growth.

  12. Structure and antimicrobial activity relationship of royalisin, an antimicrobial peptide from royal jelly of Apis mellifera.

    PubMed

    Bílikova, Katarina; Huang, Sheng-Chang; Lin, I-Ping; Šimuth, Jozef; Peng, Chi-Chung

    2015-06-01

    Royalisin is a 5.5-kDa antibacterial peptide isolated from the royal jelly of the honeybee (Apis mellifera). The antimicrobial activity of royalisin against fungi, Gram-positive and Gram-negative bacteria has been revealed. Compared with another insect antibacterial peptide, there is an extra stretch of 11 amino acid residues at the C-terminus of royalisin. In this study, a recombinant shortened form of royalisin named as royalisin-D, was constructed without the 11 amino acid residues at the C-terminal of royalisin and linked to the C-terminal of oleosin by an inteinS fragment. The recombinant protein was overexpressed in Escherichia coli, purified by artificial oil body system and subsequently released through self-splicing of inteinS induced by the changes of temperature. The antibacterial activity of royalisin-D was compared with royalisin via minimal inhibitory concentration (MIC) assay, minimal bactericidal concentration (MBC) assay, microbial adhesion to solvents (MATS) methods, and cell membrane permeability. Furthermore, the recombinant royalisin and royalisin-D have also been treated with the reducing agent of disulfide bonds, dithiothreitol (DTT), to investigate the importance of the intra-disulfide bond in royalisin. In our results, royalisin-D exhibited similar antimicrobial activity to royalisin. Royalisin and royalisin D lost their antimicrobial activities when the intra-disulfide bonds were reduced by DDT. The intra-disulfide bond plays a more important role than the extra stretch of 11 amino acid residues at the C-terminus of royalisin in terms of the antimicrobial properties of the native royalisin. PMID:25784287

  13. 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. PMID:26788316

  14. Foeniculum vulgare essential oils: chemical composition, antioxidant and antimicrobial activities.

    PubMed

    Miguel, Maria Graça; Cruz, Cláudia; Faleiro, Leonor; Simões, Mariana T F; Figueiredo, Ana Cristina; Barroso, José G; Pedro, Luis G

    2010-02-01

    The essential oils from Foeniculum vulgare commercial aerial parts and fruits were isolated by hydrodistillation, with different distillation times (30 min, 1 h, 2 h and 3 h), and analyzed by GC and GC-MS. The antioxidant ability was estimated using four distinct methods. Antibacterial activity was determined by the agar diffusion method. Remarkable differences, and worrying from the quality and safety point of view, were detected in the essential oils. trans-Anethole (31-36%), alpha-pinene (14-20%) and limonene (11-13%) were the main components of the essentials oil isolated from F. vulgare dried aerial parts, whereas methyl chavicol (= estragole) (79-88%) was dominant in the fruit oils. With the DPPH method the plant oils showed better antioxidant activity than the fruits oils. With the TBARS method and at higher concentrations, fennel essential oils showed a pro-oxidant activity. None of the oils showed a hydroxyl radical scavenging capacity > 50%, but they showed an ability to inhibit 5-lipoxygenase. The essential oils showed a very low antimicrobial activity. In general, the essential oils isolated during 2 h were as effective, from the biological activity point of view, as those isolated during 3 h. PMID:20334152

  15. Antimicrobial Activity of Bacteriocins and Their Applications

    NASA Astrophysics Data System (ADS)

    Drosinos, Eleftherios H.; Mataragas, Marios; Paramithiotis, Spiros

    Bacteriocins are peptides or proteins that exert an antimicrobial action against a range of microorganisms. Their production can be related to the antagonism within a certain ecological niche, as the producer strain, being itself immune to its action, generally gains a competitive advantage. Many Gram-positive and Gram-negative microorganisms have been found to produce bacteriocins. The former, and especially the ones produced by lactic acid bacteria, has been the field of intensive research during the last decades mainly due to their properties that account for their suitability in food preservation and the benefits arising from that, and secondarily due to the broader inhibitory spectrum compared to the ones produced by Gramnegative microorganisms.

  16. Synthesis and Antimicrobial activity of some new Schiff bases

    NASA Astrophysics Data System (ADS)

    G, Karamunge K.; B, Vibhute Y.

    2013-04-01

    New Schiff bases derived from 4iodoaniline, 4-chloroniline, p- toluidine and halogenohydroxy substituted acetophenone have been synthesized. All the compounds have been characterized by IR, H1NMR and mass spectral, halogen, nitrogen analysis. The synthesized compounds have been screened for antimicrobial activity.

  17. Antimicrobial activity of six constituents of essential oil from Salvia.

    PubMed

    Sonboli, Ali; Babakhani, Babak; Mehrabian, Ahmad Reza

    2006-01-01

    The antimicrobial activity of three Salvia species, i.e. S. santolinifolia, S. hydrangea and S. mirzayanii, essential oils were investigated. The essential oils were obtained from the aerial parts of plants and analyzed by GC-MS. The main constituents of aforementioned species were alpha-pinene (72.4%), beta-pinene (6.6%) and limonene (5.3%); beta-caryophyllene (25.1%), 1,8-cineol (15.2%) and caryophyllene oxide (11.5%); alpha-terpinenyl acetate (22.6%), 1,8-cineol (21.2%) and linalool (8.9%), respectively. Bioassays exhibited that the property of the oil of S. myrzayanii was superior to others. The antimicrobial activity of essential oil from Salvia species may well be due to the presence of synergy between six tested compounds (linalool, 1,8-cineol, alpha-pinene, beta-pinene, beta-caryophyllene and limonene) and other constituents of the oils with various degrees of antimicrobial activity. Among these, linalool and 1,8-cineol had the highest antimicrobial activity. PMID:16729570

  18. Antimicrobial activity of aqueous and organic extracts of a Saudi medicinal plant: Rumex nervosus

    PubMed Central

    Al-Asmari, Abdul Rahman K.; Siddiqui, Yunus M.; Athar, Md. Tanwir; Al-Buraidi, Ahmed; Al-Eid, A. S.; Horaib, Ghalib B.

    2015-01-01

    Objective: The antimicrobial effect of aerial part of Rumex nervosus obtained from the Southern region of Saudi Arabia was evaluated on bacterial strains Staphylococcus aureus, methicillin resistant S. aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas Aeruginosa, and fungal strain Candida albicans. Materials and Methods: The solvents used for the extraction were aqueous, hexane, and methanol. The in vitro antimicrobial activity was performed by agar diffusion and disk diffusion methods and the confirmation of this activity was done by the enumeration of colony forming units (CFU). Results: The aqueous extract showed the growth inhibitory effect on Gram-positive bacteria while the Gram-negative P. aeruginosa was the most sensitive microorganism as determined by the agar diffusion technique. Surprisingly, the extract showed little antibacterial activity on other Gram-negative bacteria (E. coli) by this technique. Ethanolic extract was also found to be inhibitory to the growth of microorganisms. Hexane extract was relatively low in antimicrobial activity on Gram-negative E. coli and P. aeruginosa, while both the organic extracts were inhibitory to the growth of the fungus, C. albicans. Hexane gave no conclusive results with agar or disk diffusion methods, but showed the microbial growth inhibition in CFU enumeration. The antibacterial activity of active extracts was compared with vancomycin while antifungal activity of was compared with amphotericin B. Conclusion: The results obtained in the present study suggest that R. nervosus showed a marked antimicrobial activity with the test organisms. PMID:26681888

  19. Radical scavenging, antioxidant and antimicrobial activities of halophytic species.

    PubMed

    Meot-Duros, Laetitia; Le Floch, Gaëtan; Magné, Christian

    2008-03-01

    For the first time, both antioxidant and antimicrobial activities are simultaneously reported in halophytic plants, particularly on polar fractions. Chloroformic and methanolic extracts of the halophytes Eryngium maritimum L., Crithmum maritimum L. and Cakile maritima Scop. were tested for their antimicrobial activities against 12 bacterial and yeast strains. In addition, radical scavenging and antioxidant activities were assessed, as well as total phenol contents. Only one bacterial strain (Listeria monocytogenes) was not inhibited by plants extracts, and apolar (chloroformic) fractions were generally more active than polar (methanolic) ones. Eryngium maritimum presented the weakest radical scavenging activity (ABTS IC(50)=0.28 mg ml(-1)), as well as the lowest total phenol content (16.4 mg GAE g(-1) DW). However, the three halophytic species had relatively strong total antioxidant activities (from 32.7 to 48.6 mg ascorbate equivalents g (-1) DW). Consequences on the potential use of these plants in food or cosmetic industry are discussed. PMID:18164885

  20. Antimicrobial activity of a compound isolated from an oil-macerated garlic extract.

    PubMed

    Yoshida, H; Iwata, N; Katsuzaki, H; Naganawa, R; Ishikawa, K; Fukuda, H; Fujino, T; Suzuki, A

    1998-05-01

    A compound showing antimicrobial activity was isolated from an oil-macerated garlic extract by silica gel column chromatography and preparative TLC. On basis of the results of NMR and MS analyses, it was identified as Z-4,5,9-trithiadeca-1,6-diene-9-oxide (Z-10-devinylajoene; Z-10-DA). Z-10-DA exhibited a broad spectrum of antimicrobial activity against such microorganisms as gram-positive and gram-negative bacteria and yeasts. The antimicrobial activity of Z-10-DA was comparable to that of Z-ajoene, but was superior to that of E-ajoene. Z-10-DA and Z-ajoene are different in respect of substitution of the allyl group by the methyl group flanking a sulfinyl group. This result suggests that substitution by the methyl group would also be effective for the inhibition of microbial growth. PMID:9648236

  1. Antioxidant and antimicrobial activities of rosemary extracts linked to their polyphenol composition.

    PubMed

    Moreno, Silvia; Scheyer, Tamara; Romano, Catalina S; Vojnov, Adrián A

    2006-02-01

    Rosmarinus officinalis extracts were investigated by a combination of bioassays and biochemical analysis to identify bioactive compounds. The 2,2-diphenyl-2-picrylhydracyl hydrate (DPPH) radical scavenging method, Folin-Ciocaulteau method and HPLC chromatography were used to study the distribution and levels of antioxidants (AOXs). Antimicrobial activity analysis was carried out using the disk diffusion and broth dilution techniques. A good correlation between the AOX activities and total phenol content in the extracts was found. Although all rosemary extracts showed a high radical scavenging activity, a different efficacy as antimicrobial agent was observed. Methanol extract containing 30% of carnosic acid, 16% of carnosol and 5% of rosmarinic acid was the most effective antimicrobial against Gram positive bacteria (minimal inhibition concentration, MIC, between 2 and 15 mug/ml), Gram negative bacteria (MIC between 2 and 60 mug/ml) and yeast (MIC of 4 mug/ml). By contrast, water extract containing only 15% of rosmarinic acid showed a narrow activity. MIC value of the methanol and water extracts is in a good correlation with the values obtained with pure carnosic acid and rosmarinic acid, respectively. Therefore, our results suggested that the antimicrobial rosemary extracts efficacy was associated with their specific phenolic composition. Carnosic acid and rosmarinic acid may be the main bioactive antimicrobial compounds present in rosemary extracts. From a practical point of view, rosemary extract may be a good candidate for functional foods as well as for pharmaceutical plant-based products. PMID:16390832

  2. 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.

  3. Comparison of the antimicrobial activity of deactivated human macrophages challenged with Aspergillus fumigatus and Listeria monocytogenes.

    PubMed

    Meier-Osusky, I; Schoedon, G; Bluer, F; Schneemann, M; Schaffner, A

    1996-09-01

    The anticonidial activity of human monocytes deactivated by cytokines interleukin (IL)-4 and IL-10 and the hormone dexamethasone was studied and compared with antilisterial activity. Dexamethasone had the largest effect on the anticonidial activity and suppressed germination-inhibiting activity and elimination of ingested spores by macrophages more than the cytokines did. Maximally active concentrations of IL-10 had a similar but significantly smaller deactivating effect. IL-4, in contrast to IL-10 and dexamethasone, did not reduce anticonidial activity. However, IL-4 and IL- 10 were equally potent in deactivating human macrophages against Listeria monocytogenes, whereas dexamethasone was significantly less potent in the Listeria model. These observations indicate that all three mediators lessen antimicrobial activity but that this effect depends on the test organism studied and is apparently mediated through regulation of different antimicrobial systems operating against a particular microorganism. PMID:8769631

  4. Antimicrobial activity of some new thioureides derived from 2-(4-chlorophenoxymethyl)benzoic acid.

    PubMed

    Limban, Carmen; Chifiriuc, Mariana-Carmen Balotescu; Missir, Alexandru-Vasile; Chiriţă, Ileana Cornelia; Bleotu, Coralia

    2008-01-01

    We report here the characterisation of eight newly synthesized thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid and the evaluation of the in vitro antimicrobial activity of the new compounds against Gram-positive [Listeria monocytogenes,Staphylococcus aureus, Bacillus subtilis], Gram-negative [Psedomonas aeruginosa,Escherichia coli, Salmonella enteritidis], as well as Candida spp., using both reference and clinical multidrug resistant strains to establish the minimal inhibitory concentration (MIC)values. Our results showed that the tested compounds exhibited specific antimicrobial activities, both concerning the spectrum of antimicrobial activity and the corresponding MIC values, which ranged widely between 1024 and 32 mug/mL, depending on the nature and position of the substituents on the benzene ring. The most active compounds were N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(2,6-dichlorophenyl)-thiourea (5 g) and N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(4-bromophenyl)-thiourea (5h), which showed a broad spectrum of antimicrobial activity against enterobacterial strains (E. coli and S. enteritidis),P. aeruginosa, S. aureus and Candida spp. All the tested compounds except 5f were highly active against S. aureus (MIC=32 mug/mL), suggesting their possible use in the treatment of MRSA infections. Four of compounds also exhibited antifungal activity (MIC =256-32 microg/mL) against C. albicans, but L. monocytogenes as well as B. subtilis were resistant to all tested compounds. Our studies thus demonstrated that among other biological activities,the thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid also exhibit selective and effective antimicrobial properties that could lead to the selection and use of these compounds as efficient antimicrobial agents, especially for the treatment of multidrug resistant infections. PMID:18463566

  5. The Toxic Effect on Leukocyte Lineage of Antimicrobial Therapy in Urinary and Respiratory Infections

    PubMed Central

    Junuzovic, Dzelaludin; Zunic, Lejla; Dervisefendic, Melika; Skopljak, Amira; Pasagic, Almir; Masic, Izet

    2014-01-01

    Introduction: Antimicrobials are widely used in infectious diseases. Only the timely intervention will contribute to the positive outcome of the disease. Unjustified use of antimicrobial prophylaxis may have adverse effects, i.e., result in bacterial resistance to existing antimicrobials, as well as toxic effects on leukocyte lineage and other parameters of the blood. Goal: The goal of this study was to confirm that the antimicrobial therapy of urinary, gynecological and respiratory infections has a toxic effect on leukocyte lineage. Followed by lowered immunity and the emergence of risk for health complications especially in oncology and other immunodeficient patients for whom to apply pharmacotherapy it is necessary to have adequate immunity, or white blood cell count that is greater than 4.0x109/L. Material and methods: A prospective-retrospective study was conducted on a sample of 30 patients in a Primary Health Care Center in Gracanica during the period from March 01, 2013 until April 01, 2014. Testing of this sample was conducted by survey on health status and treatment, or on taking of antimicrobial therapy and other treatment regimens, with the referral diagnosis and determination of leukocytes count in by hematology counter SYSMEX. Results of leukocytes below and close to the lower reference values were statistically analyzed by Students t-test. Results: Mean WBC count in the group treated with antimicrobial therapy was 3.687±0.83 x109/L, in the group which during repeated infection did not use the antimicrobial therapy 5.09±1.04 x109/L, and in the control group of healthy subjects 7.178±1.038 x109/L. Statistical analysis with Student’s t test indicate highly significant differences between group of patients that used antimicrobial therapy with the group of patient that did not used antimicrobial during repeated infection (t=6.091; p=0.0001), as well as significant differences in mean WBC count of both of these groups and the controls (t=4.984; p=0.0001, and t=8.402, p=0.0001). Conclusion: Use of antimicrobial drugs leads to serious toxic reactions, or leukopenia. Indications for the use of antimicrobial therapy must be strictly followed, because banal, frequent infections are not indication for antimicrobial therapy. It is necessary to know the types of infection causes. Important is the proper and timely selection of antimicrobial therapy. When selecting the drug we should bear in mind its antimicrobial activity, pharmacokinetic and toxic properties, as well as patient health status. Possible is also the application of preventive medicine as well as other manner of solving infection. PMID:25568526

  6. [Current animal feeds with antimicrobial activity].

    PubMed

    Drumev, D

    1981-01-01

    Among the growth-promoting substances and factors contributing to fodder utilization in growing farm animals, also called nutritive, ergotropic means, the antibiotics and some synthetic chemotherapeutics have acquired special importance. To avoid the hazardous effect in humans consuming products of animal origin there should be no residual amounts of these stimulating agents in such products. That is why it has been assumed in a number of countries to use for the same purpose only nutritive means that are not applied as therapeutic agents. Such means should neither induce resistence to antibiotics and chemotherapeutics in microorganism nor should they be resorbed by the alimentary tract (or resorption should be negligible) or they are rapidly eliminated from the animal body, leaving no residual amounts. They should likewise act chiefly against gram-positive organisms, inducing no allergic reactions in the animals. Described are the following nutritive antibiotics: flavophospholipol (bambermycin, menomycin--flavomycin, producing a nutritive effect also in ruminants with a developed forestomach, and rebuilds sensitivity in antibiotic-resistant organisms belonging to Enterobacteriaceae), avoparcin (avotan--also active in ruminants with a developed forestomach), virginiamycin (staphylomycin--escalin, stafac), zincbacitracin (bacipharmin, baciferm), grisin (kormogrisin, of a road spectrum, with an antimycotic effect, raising the fertilization rate and activating phagocitosis), vitamycin-A (vitamycin--active also at retinol deficiency, lambdamycin, nosiheptide (primofax), efrotomycin. Due consideration is given to such chemotherapeutics as nitrovin (payson, paison), carbadox (mecadox, fortigro, of a broad spectrum retained for a longer period in the body of pigs), olaquindox (bio-N-celbar--of a broad spectrum, particularly with regard to gram-negative organisms, applied at present as a therapeutic and prophylactic preparation), cyadox (with a broad sprectrum). The following polyether ionophoric antibiotics are mentioned: monensine (rumensine, elancoban), lassalocide (avatek, lasotek), slinomycin(eustin, ustin, coxistac), lonomycin (emercide), harasine. Dosage rates and other data are given characterising the respective preparations. PMID:7046217

  7. Antimicrobial activities of Ferulago essential oils.

    PubMed

    Demirci, F; Işcan, G; Güven, K; Kirimer, N; Demirci, B; Başer, K H

    2000-01-01

    Essential oils from Ferulago asparagifolia Boiss., F. galbanifera (Miller) W. Koch, F. humilis Boiss. (Endemic), F. trachycarpa Boiss. growing in Turkey were evaluated against 15 microorganisms for their antifungal and antibacterial activity using an agar tube dilution and microdilution broth susceptibility assay, respectively. The essential oil compositions were investigated by GC/MS. Inhibitory effects against Escherichia coli, Enterobacter aerogenes, Candida albicans, Gaeumannomyces graminis var. tritici, Sclerotium rolfsii and Fusarium moniliforme were remarkable. Results are discussed in comparison with the chemical composition of the essential oils. PMID:11204191

  8. Extraction, antioxidant and antimicrobial activities of Epimedium acuminatum Franch. polysaccharide.

    PubMed

    Cheng, Haoran; Feng, Shiling; Shen, Shian; Zhang, Li; Yang, Ruiwu; Zhou, Yonghong; Ding, Chunbang

    2013-07-01

    Polysaccharides from Epimedium acuminatum were extracted by hot water and optimized with response surface methodology. The optimal conditions of the extraction were determined to be the ratio of water to raw material of 29.61, extraction temperature of 85.67°C and extraction time of 3.57 h. Under these optimal conditions, the yield of polysaccharide was 8.21%, which was well matched with the predictive yield (8.23%). Moreover, three purified fractions (EAP40-1, EAP60-1 and EAP80-2) were obtained for further chemical analysis, antioxidant activity analysis and antimicrobial activity analysis. EAP40-1 with molecular weight of 138,884 Da showed the best radical scavenging activity. Meanwhile, EAP60-1 with molecular weight of 114,667 Da was found to exhibit significant antihemolytic activity and antimicrobial activity. PMID:23688459

  9. Antimicrobial activity of Amazonian oils against Paenibacillus species.

    PubMed

    Santos, Roberto Christ Vianna; dos Santos Alves, Camilla Filippi; Schneider, Taiane; Lopes, Leonardo Quintana Soares; Aurich, Carlos; Giongo, Janice Luehring; Brandelli, Adriano; de Almeida Vaucher, Rodrigo

    2012-03-01

    The Gram-positive, spore-forming bacterium Paenibacillus larvae is the primary bacterial pathogen of honeybee brood and the causative agent of American foulbrood disease (AFB). One of the feasible alternative treatments being used for their control of this disease is essential oils. In this study in vitro antimicrobial activity of Andiroba and Copaíba essential oils against Paenibacillus species, including P. larvae was evaluated. Minimal inhibitory concentration (MIC) in Mueller-Hinton broth by the microdilution method was assessed. Andiroba registered MIC values of 1.56-25%, while the MICs values obtained for Copaíba oil were of 1.56-12.5%. In order to determine the time-response effect of essential oils on P. larvae, this microorganism was exposed to the oils for up to 48 h. After 24 h treatment with Andiroba oil and after 48 h treatment with Copaíba oil no viable cells of P. larvae ATCC 9545 were observed. The possible toxic effect of essential oils were assessed by the spraying application method of the same concentrations of MICs. Bee mortality was evident only in treatment with Andiroba oil and the Copaíba oil shows no toxic effects after 10 days of observation. Taking together ours results showed for the first time that these oils presented a high activity against Paenibacillus species showing that Copaíba oil may be a candidate for the treatment or prevention of AFB. PMID:22200645

  10. In-silico docking based design and synthesis of [1H,3H] imidazo[4,5-b] pyridines as lumazine synthase inhibitors for their effective antimicrobial activity

    PubMed Central

    Harer, Sunil L.; Bhatia, Manish S.

    2014-01-01

    Purpose: The imidazopyridine moiety is important pharmacophore that has proven to be useful for a number of biologically relevant targets, also reported to display antibacterial, antifungal, antiviral properties. Riboflavin biosynthesis involving catalytic step of Lumazine synthase is absent in animals and human, but present in microorganism, one of marked advantage of this study. Still, this path is not exploited as antiinfective target. Here, we proposed different interactions between [1H,3H] imidazo[4,5-b] pyridine test ligands and target protein Lumazine synthase (protein Data Bank 2C92), one-step synthesis of title compounds and further evaluation of them for in vitro antimicrobial activity. Materials and Methods: Active pocket of the target protein involved in the interaction with the test ligands molecules was found using Biopredicta tools in VLifeMDS 4.3 Suite. In-silico docking suggests H-bonding, hydrophobic interaction, charge interaction, aromatic interaction, and Vanderwaal forces responsible for stabilizing enzyme-inhibitor complex. Disc diffusion assay method was used for in vitro antimicrobial screening. Results and Discussion: Investigation of possible interaction between test ligands and target lumazine synthase of Mycobacterium tuberculosis suggested 1i and 2f as best fit candidates showing hydrogen bonding, hydrophobic, aromatic and Vanderwaal's forces. Among all derivatives 1g, 1j, 1k, 1l, 2a, 2c, 2d, 2e, 2h, and 2j exhibited potent activities against bacteria and fungi compared to the standard Ciprofloxacin and Fluconazole, respectively. The superiority of 1H imidazo [4,5-b] pyridine compounds having R’ = Cl >No2 > NH2 at the phenyl/aliphatic moiety resident on the imidazopyridine, whereas leading 3H imidazo[4,5-b] pyridine compounds containing R/Ar = Cl > No2 > NH2> OCH3 substituents on the 2nd position of imidazole. PMID:25400412

  11. Antimicrobial activity in the cuticle of the American lobster, Homarus americanus.

    PubMed

    Mars Brisbin, Margaret; McElroy, Anne E; Pales Espinosa, Emmanuelle; Allam, Bassem

    2015-06-01

    American lobster, Homarus americanus, continues to be an ecologically and socioeconomically important species despite a severe decline in catches from Southern New England and Long Island Sound (USA) and a high prevalence of epizootic shell disease in these populations. A better understanding of lobster immune defenses remains necessary. Cuticle material collected from Long Island Sound lobsters was found to be active against a broad spectrum of bacteria, including Gram-negative and -positive species. The antimicrobial activity was characterized by boiling, muffling, and size fractioning. Boiling did not significantly reduce activity, while muffling did have a significant effect, suggesting that the active component is organic and heat stable. Size fractioning with 3 and 10 kDa filters did not significantly affect activity. Fast protein liquid chromatography fractions were also tested for antimicrobial activity, and fractions exhibiting protein peaks remained active. MALDI mass spectrometry revealed peptide peaks at 1.6, 2.8, 4.6, and 5.6 kDa. The data presented suggest that one or several antimicrobial peptides contribute to antimicrobial activity present in the American lobster cuticle. PMID:25804485

  12. Dissociation of antimicrobial and hemolytic activities of gramicidin S through N-methylation modification.

    PubMed

    Li, Yangmei; Bionda, Nina; Yongye, Austin; Geer, Phaedra; Stawikowski, Maciej; Cudic, Predrag; Martinez, Karina; Houghten, Richard A

    2013-11-01

    β-Sheet antimicrobial peptides (AMPs) are well recognized as promising candidates for the treatment of multidrug-resistant bacterial infections. To dissociate antimicrobial activity and hemolytic effect of β-sheet AMPs, we hypothesize that N-methylation of the intramolecular hydrogen bond(s)-forming amides could improve their specificities for microbial cells over human erythrocytes. We utilized a model β-sheet antimicrobial peptide, gramicidin S (GS), to study the N-methylation effects on the antimicrobial and hemolytic activities. We synthesized twelve N-methylated GS analogues by replacement of residues at the β-strand and β-turn regions with N-methyl amino acids, and tested their antimicrobial and hemolytic activities. Our experiments showed that the HC50 values increased fivefold compared with that of GS, when the internal hydrogen-bonded leucine residue was methylated. Neither hemolytic effect nor antimicrobial activity changed when proline alone was replaced with N-methylalanine in the β-turn region. However, analogues containing N-methylleucine at β-strand and N-methylalanine at β-turn regions exhibited a fourfold increase in selectivity index compared to GS. We also examined the conformation of these N-methylated GS analogues using (1)H NMR and circular dichroism (CD) spectroscopy in aqueous solution, and visualized the backbone structures and residue orientations using molecular dynamics simulations. The results show that N-methylation of the internal hydrogen bond-forming amide affected the conformation, backbone shape, and side chain orientation of GS. PMID:24023000

  13. Study of the nanomaterials and their antimicrobial activities

    NASA Astrophysics Data System (ADS)

    Ramadi, Muntaha

    In the last decade, the world faced huge problems associated with the spread of antimicrobial resistant infections that are essentially untreatable such as methicillin resistant Staphylococcus aureus (MRSA) infection. These infections have begun to occur in both hospital and community environments. Developing new antimicrobial surface coatings can hold a great promise to minimize and control various problems that associated with the spreading of infections and biofilms formation, these coatings can be used in medicine where medical devices associated with severe infections, in construction industry and the in food packaging industry. It has been established that single-walled CNTs exhibit a strong antimicrobial activity and can pierce bacterial cell walls. Recently, nanomaterial structures that made from pure carbon such as CNTs have been seen as promising candidates for many potential applications in Biotechnology and bioscience due to the combination of their extraordinary properties that arise from surface area, light weight, strength, flexibility, unique electrical conductivity and many more novel physical and chemical properties at nanoscale level. CNTs have been used widely in biomedical field including drug delivery, gene therapy and creating new biomedical devices with novel properties. Researchers have now made a first step to add carbon nanotubes to antimicrobial agents list. There are two types of CNTs have been used in biomedical research. The first one is a single-walled carbon nanotube (SWNT) and the second is a multi-walled carbon nanotube (MWNT). Recent in vitro studies suggest that carbon nanotubes have antimicrobial activity and coating CNTs with nickel nanoparticle could enhance the antimicrobial activity of cabon nanotubes. In order to test this hypothesis, nickel nanoparticles were deposited on carbon nanotubes (CNTs) by electrochemical deposition. The carbon nanotubes used in this study were XD-CNTs, SWNTs and Ni-coated CNTs. The structure and the morphology of Ni-coated CNTs were investigated by scanning electron microscopy (SEM), dispersive x-ray analysis (EDX) and thermo gravimetric analysis (TGA). The SEM results revealed that CNTs provide an excellent surface for electrochemical deposition of nanomaterials. Ni nanoparticles were homogeneously electrodeposited on the surfaces of SWNTs. Antimicrobial activity of CNTs was determined by broth dilution method using six different bacterial strains, three strains of gram negative and three strains of gram positive bacteria. The gram positive bacteria include Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis . The gram negative bacteria include Eshericia coli, Klebsiella pneumonia and Pseudomonas aerugenosa. Bactericidal rate was calculated. Based on the results Ni-coated CNTs show much stronger bactericidal property comparing to SWNTs and XD-grade CNTs.

  14. Antimicrobial activity of different tea varieties available in Pakistan.

    PubMed

    Zakir, Muhammad; Sultan, Khush Bakht; Khan, Haroon; Ihsaanullah; Khan, Murad Ali; Fazal, Hina; Rauf, Abdur

    2015-11-01

    In this antimicrobial study, various extracts of Green and Black tea (Camellia sinensis) and Lemon grass (Cymbopogon citrates) were evaluated for antimicrobial activities against six bacterial strains including both human pathogenic bacteria (Escherichia coli, Pseudomonas aeuroginosa, Staphylococcus aureus and Salmonella typhi) and plant pathogenic bacteria (Erwinia carotovora, Agro bacterium tumifaciens) and one fungal strain Candida albicans by disc diffusion susceptibility method. Of human pathogens, P. aeruginosa was most susceptible to all three different tea varieties; though rest of the strains also demonstrated prominent sensitivity. In comparison, black tea extracts were less activities than green tea and lemon grass. However, all the three tea varieties illustrated profound activity against plant pathogenic bacteria. Similarly, when extracts of tea were tested against C. albicans, green tea and lemon grass exhibited significant activity while black tea was mostly inactive. PMID:26639502

  15. Antimicrobial and antiproliferative activity of Athamanta sicula L. (Apiaceae)

    PubMed Central

    Stefano, Vita Di; Pitonzo, Rosa; Schillaci, Domenico

    2011-01-01

    Background: Athamanta sicula L., a member of Apiaceae, is an annual perennial herb and it is known in Sicilian popular medicine with the name of “spaccapietre” (rock splitters), because fresh roots infusions are indicated as diuretic and used in the treatment of diseases of the urinary tract, and to dissolve kidney stones. Materials and Methods: Acetone extracts of leaves, flowers, and stems of A. sicula L. were investigated in vitro for antibacterial and cytotoxic activities. Antimicrobial activity was carried out against bacterial and fungal strains and antiproliferative activity against a group of human cancer cell lines (K-562, NCI-H460, and MCF-7). Results: All acetone extracts, apiol and myristicin, resulted inactive as antimicrobial agents at the maximum tested concentration of 200 μg/mL, but they induced significant antiproliferative activity on the tested cancer cell lines. Conclusions: Our study show that both apiol and myristicin could be tested as novel treatment in cancer chemotherapy. PMID:21472076

  16. Linalool production from the leaves of Bursera aloexylon and its antimicrobial activity.

    PubMed

    Queiroga, Carmen Lucia; Duarte, Marta Cristina Teixeira; Ribeiro, Bruna Baesa; de Magalhães, Pedro Melillo

    2007-06-01

    The oil of the leaves of Bursera aloexylon was found to contain a high linalool level (96.7 %). The antimicrobial activity tests indicated that the oil was effective against Rhodococcus equi (0.60 mg/ml) and Staphylococcus epidermides (0.15 mg/ml). PMID:17482377

  17. In vitro and in vivo activities of antimicrobials against Nocardia brasiliensis.

    PubMed

    Gomez-Flores, Alejandra; Welsh, Oliverio; Said-Fernández, Salvador; Lozano-Garza, Gerardo; Tavarez-Alejandro, Roman Erick; Vera-Cabrera, Lucio

    2004-03-01

    In Mexico mycetomas are mostly produced by Nocardia brasiliensis, which can be isolated from about 86% of cases. In the present work, we determined the sensitivities of 30 N. brasiliensis strains isolated from patients with mycetoma to several groups of antimicrobials. As a first screening step we carried out disk diffusion assays with 44 antimicrobials, including aminoglycosides, cephalosporins, penicillins, quinolones, macrolides, and some others. In these assays we observed that some antimicrobials have an effect on more than 66% of the strains: linezolid, amikacin, gentamicin, isepamicin, netilmicin, tobramycin, minocycline, amoxicillin-clavulanic acid, piperacillin-tazobactam, nitroxolin, and spiramycin. Drug activity was confirmed quantitatively by the broth microdilution method. Amoxicillin-clavulanic acid, linezolid, and amikacin, which have been used to treat patients, were tested in an experimental model of mycetoma in BALB/c mice in order to validate the in vitro results. Linezolid showed the highest activity in vivo, followed by the combination amoxicillin-clavulanic acid and amikacin. PMID:14982772

  18. In Vitro and In Vivo Activities of Antimicrobials against Nocardia brasiliensis

    PubMed Central

    Gomez-Flores, Alejandra; Welsh, Oliverio; Said-Fernández, Salvador; Lozano-Garza, Gerardo; Tavarez-Alejandro, Roman Erick; Vera-Cabrera, Lucio

    2004-01-01

    In Mexico mycetomas are mostly produced by Nocardia brasiliensis, which can be isolated from about 86% of cases. In the present work, we determined the sensitivities of 30 N. brasiliensis strains isolated from patients with mycetoma to several groups of antimicrobials. As a first screening step we carried out disk diffusion assays with 44 antimicrobials, including aminoglycosides, cephalosporins, penicillins, quinolones, macrolides, and some others. In these assays we observed that some antimicrobials have an effect on more than 66% of the strains: linezolid, amikacin, gentamicin, isepamicin, netilmicin, tobramycin, minocycline, amoxicillin-clavulanic acid, piperacillin-tazobactam, nitroxolin, and spiramycin. Drug activity was confirmed quantitatively by the broth microdilution method. Amoxicillin-clavulanic acid, linezolid, and amikacin, which have been used to treat patients, were tested in an experimental model of mycetoma in BALB/c mice in order to validate the in vitro results. Linezolid showed the highest activity in vivo, followed by the combination amoxicillin-clavulanic acid and amikacin. PMID:14982772

  19. In Vitro Antimicrobial and Antiproliferative Activity of Amphipterygium adstringens

    PubMed Central

    Rodriguez-Garcia, A.; Peixoto, I. T. A.; Verde-Star, M. J.; De la Torre-Zavala, S.; Aviles-Arnaut, H.; Ruiz, A. L. T. G.

    2015-01-01

    Amphipterygium adstringens is a plant widely used in Mexican traditional medicine for its known anti-inflammatory and antiulcer properties. In this work, we evaluated the in vitro antimicrobial and antiproliferative activities of the methanolic extract of A. adstringens against oral pathogens such as Streptococcus mutans, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Candida albicans, and Candida dubliniensis, using microdilution (MIC) and agar diffusion methods (MBC), and the antiproliferative activity evaluating total growth inhibition (TGI) by staining the protein content with sulforhodamine B (SRB), using nine human cancer cell lines. Crude extract (CE) of A. adstringens showed some degree of activity against one or more of the strains with a MIC from 0.125 mg/mL to 63 mg/mL and MBC from 1.6 to 6.3 mg/mL and cytotoxic activity, particularly against NCI-ADR/RES, an ovarian cell line expressing multiple resistance drugs phenotype. The CE is a complex mixture of possible multitarget metabolites that could be responsible for both antimicrobial and antiproliferative activities, and further investigation is required to elucidate the identity of active compounds. Nevertheless the CE itself is useful in the development of new antimicrobial treatment based on natural products to prevent oral diseases and as alternative natural source for cancer treatment and prevention. PMID:26451151

  20. [Antimicrobial activity of human colostrum against enteropathogens. Preliminary study].

    PubMed

    Solórzano-Santos, F; Castellanos-Cruz, R C; Echaniz-Avilés, G; Arredondo-García, J L

    1993-01-01

    The antimicrobial activity of the colostrum serum from ten women has been evaluated. The activity against Escherichia coli, Shigella sonnei and Klebsiella pneumonia at three different bacterial populations was determined (1 x 10(4), 1 x 10(5) and 1 x 10(6) UFC/ml). Antimicrobial activity against the three strains was found. Bactericidal activity was observed to inocula of 1 x 10(4) UFC/ml in 8/10 sera against E. coli, in 6/10 sera against S. sonnei, and in 3/10 sera against K. pneumonia; in the rest of the cases, sera were bacteriostatic. With inocula of 1 x 10(5) UFC/ml there was bactericidal activity in 4/10 sera against E. coli and S. sonnei and in 1/10 against K. pneumonia. Lastly, with inocula of 1 x 10(6) UFC/ml there was bactericidal activity in 4/10 sera against E. coli, 1/10 against S. sonnei and none against K. pneumoniae. The results suggest that because of the antimicrobial properties of human milk the risk of intestinal infections by enteropathogens is less. PMID:8140329

  1. Factors Affecting the Antimicrobial Activity of Vitamin K51

    PubMed Central

    Merrifield, Larry S.; Yang, H. Y.

    1965-01-01

    Pure cultures of Escherichia coli, Bacillus subtilis, Proteus vulgaris, Staphylococcus aureus, and Pseudomonas fluorescens were used in this investigation. The bactericidal concentrations of vitamin K5 required for E. coli, B. subtilis, P. vulgaris, S. aureus, and P. fluorescens; the effect of an absence of oxygen; the effect of contact time with E. coli and S. aureus; and the effect of initial counts per milliliter of E. coli were studied. The bactericidal concentrations ranged from 60 ppm of K5 for S. aureus to 220 ppm for E. coli, with an initial count of 160,000 to 200,000 cells per milliliter and a contact time of 12 hr in nutrient broth. The gram-positive bacteria tested were more susceptible to the antimicrobial activity of vitamin K5 than the gram-negative bacteria. In the studies conducted under nitrogen atmosphere, the per cent inhibition showed an inverse relationship to the bactericidal concentrations required for complete inhibition in studies conducted under air atmosphere. This finding suggested that there might be different factors responsible for inhibition depending on the species of bacteria being tested, and it also might help explain the difference in concentrations necessary for inhibition. Cells of E. coli and S. aureus were not inhibited immediately on coming into contact with vitamin K5; 50% inhibition occurred after 25 and 32 min, respectively. A rapid inhibition rate was maintained until approximately 90% inhibition occurred, after whch a rapid decrease in the rate was noted. PMID:4956243

  2. In Vitro Antimicrobial Activities of Bakuchiol against Oral Microorganisms

    PubMed Central

    Katsura, Harumi; Tsukiyama, Ryo-Ichi; Suzuki, Akiko; Kobayashi, Makio

    2001-01-01

    Bakuchiol was isolated from the seeds of Psoralea corylifolia, a tree native to China with various uses in traditional medicine, followed by extraction with ether and column chromatography combined with silica gel and octyldecyl silane. In this study, the antimicrobial activities of bakuchiol against some oral microorganisms were evaluated in vitro. The cell growth of Streptococcus mutans was inhibited in a bakuchiol concentration-dependent manner, and growth of S. mutans was completely prevented by 20 μg of bakuchiol per ml. The bactericidal effect of bakuchiol on S. mutans was dependent on temperature and stable under the following conditions: sucrose, 0 to 10% (wt/vol); pH, 3.0 to 7.0; organic acids (3% [wt/vol] citric and malic acids). Bakuchiol showed bactericidal effects against all bacteria tested, including S. mutans, Streptococcus sanguis, Streptococcus salivarius, Streptococcus sobrinus, Enterococcus faecalis, Enterococcus faecium, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus plantarum, Actinomyces viscosus, and Porphyromonas gingivalis, with MICs ranging from 1 to 4 μg/ml and the sterilizing concentration for 15 min ranging from 5 to 20 μg/ml. Furthermore, bakuchiol was also effective against adherent cells of S. mutans in water-insoluble glucan in the presence of sucrose and inhibited the reduction of pH in the broth. Thus, bakuchiol would be a useful compound for development of antibacterial agents against oral pathogens and has great potential for use in food additives and mouthwash for preventing and treating dental caries. PMID:11600349

  3. A demonstration of the antimicrobial effectiveness of various copper surfaces

    PubMed Central

    2013-01-01

    Background Bacterial contamination on touch surfaces results in increased risk of infection. In the last few decades, work has been done on the antimicrobial properties of copper and its alloys against a range of micro-organisms threatening public health in food processing, healthcare and air conditioning applications; however, an optimum copper method of surface deposition and mass structure has not been identified. Results A proof-of-concept study of the disinfection effectiveness of three copper surfaces was performed. The surfaces were produced by the deposition of copper using three methods of thermal spray, namely, plasma spray, wire arc spray and cold spray The surfaces were then inoculated with meticillin-resistant Staphylococcus aureus (MRSA). After a two hour exposure to the surfaces, the surviving MRSA were assayed and the results compared. The differences in the copper depositions produced by the three thermal spray methods were examined in order to explain the mechanism that causes the observed differences in MRSA killing efficiencies. The cold spray deposition method was significantly more effective than the other methods. It was determined that work hardening caused by the high velocity particle impacts created by the cold spray technique results in a copper microstructure that enhances ionic diffusion, and copper ions are principally responsible for antimicrobial activity. Conclusions This test showed significant microbiologic differences between coatings produced by different spray techniques and demonstrates the importance of the copper application technique. The cold spray technique shows superior anti-microbial effectiveness caused by the high impact velocity imparted to the sprayed particles which results in high dislocation density and high ionic diffusivity. PMID:23537176

  4. Chemical constituents of Solanum coagulans and their antimicrobial activities.

    PubMed

    Qin, Xu-Jie; Lunga, Paul-Keilah; Zhao, Yun-Li; Liu, Ya-Ping; Luo, Xiao-Dong

    2016-04-01

    The present study aimed at determining the chemical constituents of Solanum coagulans and their antimicrobial activities. The compounds were isolated by various chromatographic techniques and their structures were elucidated on the basis of extensive spectroscopic analysis, chemical methods, and comparison with reported spectroscopic data. One new phenolic glycoside, methyl salicylate 2-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1), together with 12 known compounds (2-13), were isolated from the aerial parts of Solanum coagulans. Compound 1 was a new phenolic glycoside, and 2-6 were isolated from Solanum genus for the first time. The antimicrobial activities of the isolated compounds were also evaluated. Compound 7 showed remarkable antifungal activity against T. mentagrophytes, M. gypseum and E. floccosum with MIC values being 3.13, 1.56 and 3.13 μg·mL(-1), respectively. PMID:27114320

  5. Evaluating the antimicrobial activity of Nisin, Lysozyme and Ethylenediaminetetraacetate incorporated in starch based active food packaging film.

    PubMed

    Bhatia, Sugandha; Bharti, Anoop

    2015-06-01

    The pleothera of micro organisms obtained from contaminated food cultured in a starch broth was effectively tested against antibacterial agents, i.e. nisin, lysozyme and chelating agent EDTA. A variety of combination treatments of these antimicrobial agents and their incorporation in Starch based active packaging film according to their permissibility standards was done. 4 variables of Nisin concentration (ranging from 0 to 750 IU/ml), 3 variables of lysozyme concentration (ranging from 0 to 500 IU/ml) and 3 variables of EDTA concentration from (0 to 20 μM) were chosen. Bacterial inhibition by combination of different levels of different factors without antimicrobial films was evaluated using a liquid incubation method. The samples were assayed for turbidity at interval of 2, 4 and 24 h to check effectiveness of combined effects of antimicrobial agents which proved a transitory bactericidal effect for short incubation times. Zone of Inhibition was observed in the antimicrobial films prepared by agar diffusion method. Statistical analysis of experimental data for their antimicrobial spectrum was carried out by multi regression analysis and ANOVA using Design-Expert software to plot the final equation in terms of coded factors as antimicrobial agents. The experimental data indicated that the model was highly significant. Results were also evaluated graphically using response surface showing interactions between two factors, keeping other factor fixed at values at the center of domain. Synergy was also determined among antibacterial agents using the fractional inhibitory concentration (FIC) index which was observed to be 0.56 supporting the hypothesis that nisin and EDTA function as partial synergistically. The presented work aimed to screen in quick fashion the combinatorial effect of three antimicrobial agents and evaluating their efficacy in anti microbial film development. PMID:26028732

  6. Antioxidant, antimicrobial and anticancer activity of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis

    PubMed Central

    2011-01-01

    Background The aim of this study is to investigate in vitro antioxidant, antimicrobial and anticancer activity of the acetone extracts of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis. Methods Antioxidant activity was evaluated by five separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method against six species of bacteria and ten species of fungi. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. Results Of the lichens tested, Lecanora atra had largest free radical scavenging activity (94.7% inhibition), which was greater than the standard antioxidants. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. Extract of Cladonia furcata was the most active antimicrobial agent with minimum inhibitory concentration values ranging from 0.78 to 25 mg/mL. All extracts were found to be strong anticancer activity toward both cell lines with IC50 values ranging from 8.51 to 40.22 μg/mL. Conclusions The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial and anticancer effects. That suggest that lichens may be used as as possible natural antioxidant, antimicrobial and anticancer agents to control various human, animal and plant diseases. PMID:22013953

  7. Antioxidant, antimicrobial and wound healing activities of Boesenbergia rotunda.

    PubMed

    Jitvaropas, Rungrat; Saenthaweesuk, Suphaket; Somparn, Nuntiya; Thuppia, Amornnat; Sireeratawong, Seewaboon; Phoolcharoen, Waranyoo

    2012-07-01

    The ethanolic extract of Boesenbergia rotunda (L.) Mansf was studied for its wound-healing potential. Since wound healing is interrelated with microbial infection and reactive oxygen species (ROS), this study was conducted to evaluate the antimicrobial and antioxidant activity of B. rotunda. The antimicrobial activity of B. rotunda was studied against six bacterial and two yeast strains using disc diffusion, minimum inhibitory concentration (MIC), and minimum microbicidal concentration (MMC). The B. rotunda extract displayed potential antimicrobial and antifungal activities by inhibiting the Gram-positive bacteria Staphylococcus aureus (ATCC 25923), S. epidermidis, and Bacillus subtilis (ATCC 6633), and the yeasts Candida albicans (ATCC 10231), and Saccharomyces cerevisiae. MIC and MMC values varied from 0.04 to 25 mg/mL and from 0.16 to 25 mg/mL, respectively. The antioxidant activity of B. rotunda was evaluated by measuring the Ferric Reducing/Antioxidant Power (FRAP) and DPPH free radical scavenging activity. The FRAP and DPPH values were 22.2 microM/microg and 76.3 mg/mL, respectively. In the wound-healing studies, the topical application of the B. rotunda extract indicated a significantly increased percentage of wound contraction on day 12 compared with the control group. Histological studies showed the complete epidermis and found collagen fibers and hair follicles in the dermis. The results of the present study support the continued and expanded utilization of B. rotunda in Thai folk medicine. PMID:22908579

  8. Antimicrobial activity of UV-induced phenylamides from rice leaves.

    PubMed

    Park, Hye Lin; Yoo, Youngchul; Hahn, Tae-Ryong; Bhoo, Seong Hee; Lee, Sang-Won; Cho, Man-Ho

    2014-01-01

    Rice produces a wide array of phytoalexins in response to pathogen attacks and UV-irradiation. Except for the flavonoid sakuranetin, most phytoalexins identified in rice are diterpenoid compounds. Analysis of phenolic-enriched fractions from UV-treated rice leaves showed that several phenolic compounds in addition to sakuranetin accumulated remarkably in rice leaves. We isolated two compounds from UV-treated rice leaves using silica gel column chromatography and preparative HPLC. The isolated phenolic compounds were identified as phenylamide compounds: N-trans-cinnamoyltryptamine and N-p-coumaroylserotonin. Expression analysis of biosynthetic genes demonstrated that genes for arylamine biosynthesis were upregulated by UV irradiation. This result suggested that phenylamide biosynthetic pathways are activated in rice leaves by UV treatment. To unravel the role of UV-induced phenylamides as phytoalexins, we examined their antimicrobial activity against rice fungal and bacterial pathogens. N-trans-Cinnamoyltryptamine inhibited the growth of rice brown spot fungus (Bipolaris oryzae). In addition to the known antifungal activity to the blast fungus, sakuranetin had antimicrobial activity toward B. oryzae and Rhizoctonia solani (rice sheath blight fungus). UV-induced phenylamides and sakuranetin also had antimicrobial activity against rice bacterial pathogens for grain rot (Burkholderia glumae), blight (Xanthomonas oryzae pv. oryzae) and leaf streak (X. oryzae pv. oryzicola) diseases. These findings suggested that the UV-induced phenylamides in rice are phytoalexins against a diverse array of pathogens. PMID:25383752

  9. Antimicrobial Activities of Isothiocyanates Against Campylobacter jejuni Isolates

    PubMed Central

    Dufour, Virginie; Alazzam, Bachar; Ermel, Gwennola; Thepaut, Marion; Rossero, Albert; Tresse, Odile; Baysse, Christine

    2012-01-01

    Food-borne human infection with Campylobacter jejuni is a medical concern in both industrialized and developing countries. Efficient eradication of C. jejuni reservoirs within live animals and processed foods is limited by the development of antimicrobial resistances and by practical problems related to the use of conventional antibiotics in food processes. We have investigated the bacteriostatic and bactericidal activities of two phytochemicals, allyl-isothiocyanate (AITC), and benzyl isothiocyanate (BITC), against 24 C. jejuni isolates from chicken feces, human infections, and contaminated foods, as well as two reference strains NCTC11168 and 81-176. AITC and BITC displayed a potent antibacterial activity against C. jejuni. BITC showed a higher overall antibacterial effect (MIC of 1.25–5 μg mL−1) compared to AITC (MIC of 50–200 μg mL−1). Both compounds are bactericidal rather than bacteriostatic. The sensitivity levels of C. jejuni isolates against isothiocyanates were neither correlated with the presence of a GGT (γ-Glutamyl Transpeptidase) encoding gene in the genome, with antibiotic resistance nor with the origin of the biological sample. However the ggt mutant of C. jejuni 81-176 displayed a decreased survival rate compared to wild-type when exposed to ITC. This work determined the MIC of two ITC against a panel of C. jejuni isolates, showed that both compounds are bactericidal rather than bacteriostatic, and highlighted the role of GGT enzyme in the survival rate of C. jejuni exposed to ITC. PMID:22919644

  10. Antimicrobial and antibiofilm activity of cathelicidins and short, synthetic peptides against Francisella.

    PubMed

    Amer, Lilian S; Bishop, Barney M; van Hoek, Monique L

    2010-05-28

    Francisella infects the lungs causing pneumonic tularemia. Focusing on the lung's host defense, we have examined antimicrobial peptides as part of the innate immune response to Francisella infection. Interest in antimicrobial peptides, such as the cathelicidins, has grown due their potential therapeutic applications and the increasing problem of bacterial resistance to commonly used antibiotics. Only one human cathelicidin, LL-37, has been characterized. Helical cathelicidins have also been discovered in snakes including the Chinese King Cobra, Naja atra (NA-CATH). Four synthetic 11-residue peptides (ATRA-1, -2, -1A and -1P) containing variations of a repeated motif within NA-CATH were designed. We hypothesized that these smaller synthetic peptides could have excellent antimicrobial effectiveness with shorter length (and less cost), making them strong potential candidates for development into broad-spectrum antimicrobial compounds. We tested the susceptibility of F. novicida to four ATRA peptides, LL-37, and NA-CATH. Two of the ATRA peptides had high antimicrobial activity (microM), while the two proline-containing ATRA peptides had low activity. The ATRA peptides did not show significant hemolytic activity even at high peptide concentration, indicating low cytotoxicity against host cells. NA-CATH killed Francisella bacteria more quickly than LL-37. However, LL-37 was the most effective peptide against F. novicida (EC50=50 nM). LL-37 mRNA was induced in A549 cells by Francisella infection. We recently demonstrated that F. novicida forms in vitro biofilms. LL-37 inhibited F. novicida biofilm formation at sub-antimicrobial concentrations. Understanding the properties of these peptides, and their endogenous expression in the lung could lead to potential future therapeutic interventions for this lung infection. PMID:20399752

  11. Bifidobacterium strains from resident infant human gastrointestinal microflora exert antimicrobial activity

    PubMed Central

    Lievin, V; Peiffer, I; Hudault, S; Rochat, F; Brassart, D; Neeser, J; Servin, A

    2000-01-01

    BACKGROUND AND AIMS—The gastrointestinal microflora exerts a barrier effect against enteropathogens. The aim of this study was to examine if bifidobacteria, a major species of the human colonic microflora, participates in the barrier effect by developing antimicrobial activity against enterovirulent bacteria.
METHODS—Antibacterial activity was examined in vitro against a wide range of Gram negative and Gram positive pathogens. Inhibition of Salmonella typhimurium SL1334 cell association and cell invasion was investigated in vitro using Caco-2 cells. Colonisation of the gastrointestinal tract in vivo by bifidobacteria was examined in axenic C3/He/Oujco mice. Antimicrobial activity was examined in vivo in axenic C3/He/Oujco mice infected by the lethal S typhimurium C5 strain.
RESULTS—Fourteen human bifidobacterium strains isolated from infant stools were examined for antimicrobial activity. Two strains (CA1 and F9) expressed antagonistic activity against pathogens in vitro, inhibited cell entry, and killed intracellular S typhimurium SL1344 in Caco-2 cells. An antibacterial component(s) produced by CA1 and F9 was found to be a lipophilic molecule(s) with a molecular weight of less than 3500. In the axenic C3/He/Oujco mice, CA1 and F9 strains colonised the intestinal tract and protected mice against S typhimurium C5 lethal infection.
CONCLUSION—Several bifidobacterium strains from resident infant human gastrointestinal microflora exert antimicrobial activity, suggesting that they could participate in the "barrier effect" produced by the indigenous microflora.


Keywords: bifidobacteria; infant microflora; gastrointestinal infection; antimicrobial; microbial infection; intestinal cells PMID:11034580

  12. [Antimicrobial activity of Actinomycetale isolated from the lagoon in Algeria].

    PubMed

    Alliouch-Kerboua, Chérifa; Gacemi Kirane, Djamila; La Scola, Bernard

    2015-01-01

    In the aim of the study of the taxonomy and the antimicrobial activity, a strain of actinomycete SM2/2GF which was isolated from sediment of the lagoon El-Mellah which is situated in the city of El-Kala in the Northeast of Algeria, was tested against diverse pathogenic microorganisms and against a Gram-negative bacterium Pseudomonas alcaliphila which was isolated from water of the lagoon El-Mellah. The phenotypic and the molecular characteristics show that the isolate SM2/2GF belongs to the kind Streptomyces. This strain showed an antimicrobial activity against a Gram-negative bacterium Pseudomonas alcaliphila and the positive-Gram bacteria as Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus subtilis, Enterococcus faecalis, as well as the yeast Candida albicans. It has no activity against Pseudomonas aeruginosa. The interesting antimicrobial activity of the strain SM2/2GF against the pathogenic microorganisms could encourage further researches on one or several bioactive molecules which it secretes. PMID:25847739

  13. Trigona laeviceps propolis from Thailand: antimicrobial, antiproliferative and cytotoxic activities.

    PubMed

    Umthong, Supawadee; Puthong, Songchan; Chanchao, Chanpen

    2009-01-01

    Propolis is one of the natural bee products which has long been used as a crude preventative and prophylactic medicine, and has been reported to possess antibacterial, antiviral, anti-inflammatory, antioxidative and anticancer properties. Propolis of the stingless bee, Trigona laeviceps, was extracted by water or methanol at 35% (w/v) yielding a crude water or a methanolic extract at 60 and 80 mg/ml, respectively, which is 17.1 and 22.9% (w/w) of the total propolis, respectively. The antimicrobial activity of both crude extracts was assayed on four selected pathogenic microbes by using the agar well diffusion method. The results suggested that both water and methanolic crude extracts have some antimicrobial activities, water extract has greater antimicrobial activity than methanolic extract. The relative order of sensitivity of the four microbes were, however, the same between the two extracts from the most to least sensitive, S. aureus > E. coli > C. albicans > A. niger, with indeed no observed growth inhibition of A. niger at all. Antiproliferative and cytotoxic affects were tested on the colon carcinoma cell line, SW620, using the three parameters: (1) MTT assay; (2) cell morphology; and (3) the fragmentation of genomic DNA. The water extract of propolis showed a higher antiproliferative activity than that of methanolic extract to SW620 cells, additionally both appeared to cause cell death by necrosis. PMID:19885946

  14. 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

  15. Chemical composition, cytotoxicity, antimicrobial and antifungal activity of several essential oils.

    PubMed

    Cannas, Sara; Usai, Donatella; Tardugno, Roberta; Benvenuti, Stefania; Pellati, Federica; Zanetti, Stefania; Molicotti, Paola

    2016-01-01

    Essential oils (EOs) are known and used for their biological, antibacterial, antifungal and antioxidant properties. Numerous studies have shown that EOs exhibit a large spectrum of biological activities in vitro. The incidence of drug-resistant pathogens and the toxicity of antibiotics have drawn attention to the antimicrobial activity of natural products, encouraging the development of alternative treatments. The aim of this study was to analyse the phytochemical and the cytotoxic characteristic of 36 EOs; we then evaluated the antimicrobial activity of the less-toxic EOs on Gram-positive, Gram-negative and fungi strains. The results showed low cytotoxicity in seven EOs and good activity against Gram-negative and Candida spp. strains. Based on our results, EOs could be proposed as a novel group of therapeutic agents. Further experiments are necessary to confirm their pharmacological effectiveness, and to determine potential toxic effects and the mechanism of their activity in in vivo models. PMID:26214364

  16. 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. PMID:25114180

  17. Antimicrobial activity and partial characterization of bacteriocin-like inhibitory substances produced by Lactobacillus spp. isolated from artisanal Mexican cheese.

    PubMed

    Heredia-Castro, Priscilia Y; Méndez-Romero, José I; Hernández-Mendoza, Adrián; Acedo-Félix, Evelia; González-Córdova, Aarón F; Vallejo-Cordoba, Belinda

    2015-12-01

    Lactobacillus spp. from Mexican Cocido cheese were shown to produce bacteriocin-like substances (BLS) active against Staphylococcus aureus,Listeria innocua,Escherichia coli, andSalmonella typhimurium by using the disk diffusion method. Crude extracts of Lactobacillus fermentum showed strong inhibitory activity against Staph. aureus, L. innocua, E. coli, and Salmonella cholerae. Complete inactivation of antimicrobial activity was observed after treatment of crude extracts with proteinase K, pronase, papain, trypsin, and lysozyme, confirming their proteinaceous nature. However, antimicrobial activity was partly lost for some of the crude extracts when treated with α-amylase, indicating that carbohydrate moieties were involved. The antimicrobial activity of the crude extracts was stable at 65°C for 30min over a wide pH range (2-8), and addition of potassium chloride, sodium citrate, ethanol, and butanol did not affect antibacterial activity. However, antimicrobial activity was lost after heating at 121°C for 15min, addition of methanol or Tween 80. Fourteen out of 18 Lactobacillus spp. showed antimicrobial activity against different test microorganisms, and 12 presented bacteriocin-like substances. Generation time and growth rate parameters indicated that the antimicrobial activity of crude extracts from 3 different strains was effective against the 4 indicator microorganisms. One of the crude extracts showed inhibition not only against gram-positive but also against gram-negative bacteria. Bacteriocin-like substances produced by this specific Lactobacillus strain showed potential for application as a food biopreservative. PMID:26476937

  18. Antimicrobial activity and chemical investigation of Brazilian Drosera.

    PubMed

    Ferreira, Dalva Trevisan; Andrei, César Cornélio; Saridakis, Halha Ostrensky; Faria, Terezinha de Jesus; Vinhato, Elisângela; Carvalho, Kátia Eliane; Daniel, Juliana Feijó Souza; Machado, Sílvio Luiz; Saridakis, Dennis Panayotis; Braz-Filho, Raimundo

    2004-11-01

    The antimicrobial activity of three different extracts (hexanic, ethyl acetate, methanol) obtained from Brazilian Drosera species (D. communis, D. montana var. montana, D. brevifolia, D. villosa var. graomogolensis, D. villosa var. villosa, Drosera sp. 1, and Drosera sp. 2 ) were tested against Staphylococcus aureus (ATCC 25923), Enterococcus faecium (ATCC23212), Pseudomonas aeruginosa (ATCC27853), Escherichia coli (ATCC11229), Salmonella choleraesuis (ATCC10708), Klebsiella pneumoniae (ATCC13883), and Candida albicans (a human isolate). Better antimicrobial activity was observed with D. communis and D. montana var. montana ethyl acetate extracts. Phytochemical analyses from D. communis, D. montana var. montana and D. brevifolia yielded 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin); long chain aliphatic hydrocarbons were isolated from D. communis and from D. villosa var. villosa, a mixture of long chain aliphatic alcohols and carboxylic acids, was isolated from D. communis and 3b-O-acetylaleuritolic acid from D. villosa var. villosa. PMID:15654434

  19. Antimicrobial activity of Guinea-Bissau traditional remedies.

    PubMed

    Silva, O; Duarte, A; Cabrita, J; Pimentel, M; Diniz, A; Gomes, E

    1996-01-01

    The ethanolic extracts of twelve plants selected through ethnomedical survey in Guinea-Bissau were investigated for their in vitro antimicrobial properties over ten bacteria and Candida albicans, using agar diffusion and dilution methods. All the tested extracts showed some activity against at least one of the bacteria. Most of the extracts (79%) showed activity against Staphylococcus aureus and only one (Cryptolepis sanguinolenta) against Escherichia coli. Cryptolepis sanguinolenta and Terminalia macroptera root extracts showed some activity against Candida albicans as well as showing an interesting profile of activity against most of the enteropathogen microorganisms. Inhibition zones against Staphylococcus aureus were localised on extract chromatograms by bioautographic techniques. PMID:8778508

  20. Antimicrobial activity of Bridelia ferruginea leaves extracts.

    PubMed

    Talla, E; Djamen, D; Djould, D; Tatsadjeu, L; Tantoh, D; Mbafor, J T; Fomum, Z T

    2002-07-01

    Methanol, ethyl acetate, and hexane extracts of Bridelia ferruginea leaves exhibited significant activity against Pseudomonas frutescens, Bacillus subtilis, Echerichia coli, Staphylococcus aureus and Streptococcus faecalis. PMID:12234581

  1. 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

  2. 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

  3. In vitro antimicrobial activity of Romanian medicinal plants hydroalcoholic extracts on planktonic and adhered cells.

    PubMed

    Stanciuc, A M; Gaspar, A; Moldovan, L; Saviuc, C; Popa, M; Măruţescu, L

    2011-01-01

    The aim of this study was to assess the antibacterial and antifungal potential of some Romanian medicinal plants, arnica--Arnica montana, wormwood--Artemisia absinthium and nettle--Urtica dioica. In order to perform this antimicrobial screening, we obtained the vegetal extracts and we tested them on a series of Gram-positive and Gram-negative bacteria, and also against two fungal strains. The vegetal extracts showed antimicrobial activity preferentially directed against the planktonic fungal and bacterial growth, while the effect against biofilm formation and development was demonstrated only against S. aureus and C. albicans. Our in vitro assays indicate that the studied plant extracts are a significant source of natural alternatives to antimicrobial therapy, thus avoiding antibiotic therapy, the use of which has become excessive in recent years. PMID:21717806

  4. 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. PMID:23488765

  5. Semisynthesis and antimicrobial activity of novel guttiferone-A derivatives.

    PubMed

    Dias, Kris S T; Januário, Jaqueline P; D' Dego, Jéssica Lopes; Dias, Amanda L T; dos Santos, Marcelo H; Camps, Ihosvany; Coelho, Luiz Felipe L; Viegas, Claudio

    2012-04-15

    Six derivatives of guttiferone-A (LFQM-79, 80, 81, 82, 113 and 114) were synthesized and evaluated for their antimicrobial activity against the opportunistic or pathogenic fungi Candida albicans (ATCC 09548), Candida glabrata (ATCC 90030), Candida krusei (ATCC 6258), Candida parapsilosis (ATCC 69548), Candida tropicalis (ATCC 750), Cryptococcus neoformans (ATCC 90012), Trichophyton tonsurans, Microsporum gypseum and also against the opportunistic and pathogenic Gram-positive bacteria Staphylococcus aureus (ATCC 6538), Staphylococcus epidermidis (ATCC 12228), Bacillus cereus (ATCC 11778) and Gram-negative Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 9027), Salmonella typhimurium (ATCC 14028), Proteus mirabilis (ATCC 25933). The antimicrobial activities of derivatives were compared with guttiferone-A and they presented to be more potent than the original molecule and sometimes greater than standard drugs established in therapeutics. The current study showed that derivatives of guttiferone-A possess potent antimicrobial activity and are relatively non-cytotoxic, which reveal these new molecules as promising new drug prototype candidates, with innovative structural pattern. PMID:22401914

  6. Biocompatible cellulose-based superabsorbent hydrogels with antimicrobial activity.

    PubMed

    Peng, Na; Wang, Yanfeng; Ye, Qifa; Liang, Lei; An, Yuxing; Li, Qiwei; Chang, Chunyu

    2016-02-10

    Current superabsorbent hydrogels commercially applied in the disposable diapers have disadvantages such as weak mechanical strength, poor biocompatibility, and lack of antimicrobial activity, which may induce skin allergy of body. To overcome these hassles, we have developed novel cellulose based hydrogels via simple chemical cross-linking of quaternized cellulose (QC) and native cellulose in NaOH/urea aqueous solution. The prepared hydrogel showed superabsorbent property, high mechanical strength, good biocompatibility, and excellent antimicrobial efficacy against Saccharomyces cerevisiae. The presence of QC in the hydrogel networks not only improved their swelling ratio via electrostatic repulsion of quaternary ammonium groups, but also endowed their antimicrobial activity by attraction of sections of anionic microbial membrane into internal pores of poly cationic hydrogel leading to the disruption of microbial membrane. Moreover, the swelling properties, mechanical strength, and antibacterial activity of hydrogels strongly depended on the contents of quaternary ammonium groups in hydrogel networks. The obtained data encouraged the use of these hydrogels for hygienic application such as disposable diapers. PMID:26686105

  7. Screening antimicrobial activity of various extracts of Urtica dioica.

    PubMed

    Modarresi-Chahardehi, Amir; Ibrahim, Darah; Fariza-Sulaiman, Shaida; Mousavi, Leila

    2012-12-01

    Urtica dioica or stinging nettle is traditionally used as an herbal medicine in Western Asia. The current study represents the investigation of antimicrobial activity of U. dioica from nine crude extracts that were prepared using different organic solvents, obtained from two extraction methods: the Soxhlet extractor (Method I), which included the use of four solvents with ethyl acetate and hexane, or the sequential partitions (Method II) with a five solvent system (butanol). The antibacterial and antifungal activities of crude extracts were tested against 28 bacteria, three yeast strains and seven fungal isolates by the disc diffusion and broth dilution methods. Amoxicillin was used as positive control for bacteria strains, vancomycin for Streptococcus sp., miconazole nitrate (30 microg/mL) as positive control for fungi and yeast, and pure methanol (v/v) as negative control. The disc diffusion assay was used to determine the sensitivity of the samples, whilst the broth dilution method was used for the determination of the minimal inhibition concentration (MIC). The ethyl acetate and hexane extract from extraction method I (EA I and HE I) exhibited highest inhibition against some pathogenic bacteria such as Bacillus cereus, MRSA and Vibrio parahaemolyticus. A selection of extracts that showed some activity was further tested for the MIC and minimal bactericidal concentrations (MBC). MIC values of Bacillus subtilis and Methicillin-resistant Staphylococcus aureus (MRSA) using butanol extract of extraction method II (BE II) were 8.33 and 16.33mg/mL, respectively; while the MIC value using ethyl acetate extract of extraction method II (EAE II) for Vibrio parahaemolyticus was 0.13mg/mL. Our study showed that 47.06% of extracts inhibited Gram-negative (8 out of 17), and 63.63% of extracts also inhibited Gram-positive bacteria (7 out of 11); besides, statistically the frequency of antimicrobial activity was 13.45% (35 out of 342) which in this among 21.71% belongs to antimicrobial activity extracts from extraction method I (33 out of 152 of crude extracts) and 6.82% from extraction method II (13 out of 190 of crude extracts). However, crude extracts from method I exhibited better antimicrobial activity against the Gram-positive bacteria than the Gram-negative bacteria. The positive results on medicinal plants screening for antibacterial activity constitutes primary information for further phytochemical and pharmacological studies. Therefore, the extracts could be suitable as antimicrobial agents in pharmaceutical and food industry. PMID:23342511

  8. Synthesis, characterization, antimicrobial activity and carbonic anhydrase enzyme inhibitor effects of salicilaldehyde-N-methyl p-toluenesulfonylhydrazone and its Palladium(II), Cobalt(II) complexes

    NASA Astrophysics Data System (ADS)

    Alyar, Saliha; Adem, Şevki

    2014-10-01

    We report the synthesis of the ligand, salicilaldehyde-N-methyl p-toluenesulfonylhydrazone (salptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Pd(II) and Co(II) metal complexes were synthesized for the first time. The structure of the ligand and their complexes were investigated using elemental analysis, magnetic susceptibility, molar conductance and spectral (IR, NMR and LC-MS) measurements. Salptsmh has also been characterized by single crystal X-ray diffraction. 1H and 13C shielding tensors for crystal structure were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The complexes were found to have general composition [ML2]. The results of elemental analysis showed 1:2 (metal/ligand) stoichiometry for all the complex. Magnetic and spectral data indicate a square planar geometry for Pd(II) complex and a distorted tetrahedral geometry for Co(II) complexes. The ligand and its metal chelates have been screened for their antimicrobial activities using the disk diffusion method against the selected Gram positive bacteria: Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Gram negative bacteria: Eschericha coli, Pseudomonas aeruginosa, Klebsiella pneumonia. The inhibition activities of these compounds on carbonic anhydrase II (CA II) and carbonic anhydrase I (CA I) have been investigated by comparing IC50 and Ki values and it has been found that Pd(II) complex have more enzyme inhibition efficiency than salptsmh and Co(II) complex.

  9. Antimicrobial and antitumor activities of chitosan from shiitake stipes, compared to commercial chitosan from crab shells.

    PubMed

    Chien, Rao-Chi; Yen, Ming-Tsung; Mau, Jeng-Leun

    2016-03-15

    Chitosan was prepared by alkaline N-deacetylation of chitin obtained from shiitake stipes and crab shells and its antimicrobial and antitumor activities were studied. Chitosan from shiitake stipes and crab shells exhibited excellent antimicrobial activities against eight species of Gram positive and negative pathogenic bacteria with inhibition zones of 11.4-26.8mm at 0.5mg/ml. Among chitosan samples, shiitake chitosan C120 was the most effective with inhibition zones of 16.4-26.8mm at 0.5mg/ml. In addition, shiitake and crab chitosan showed a moderate anti-proliferative effect on IMR 32 and Hep G2 cells. At 5mg/ml, the viability of IMR 32 cells incubated with chitosan was 68.8-85.0% whereas that of Hep G2 cells with chitosan was 60.4-82.9%. Overall, shiitake chitosan showed slightly better antimicrobial and antitumor activities than crab chitosan. Based on the results obtained, shiitake and crab chitosan were strong antimicrobial agents and moderate antitumor agents. PMID:26794761

  10. Characterization and antimicrobial activity of sweetpotato starch-based edible film containing origanum (Thymus capitatus) oil.

    PubMed

    Ehivet, Fabienne E; Min, Byungjin; Park, Mi-Kyung; Oh, Jun-Hyun

    2011-01-01

    The objectives of this research were to characterize the mechanical and barrier properties of sweetpotato starch (SPS)-based film (SPSF) and to investigate the antimicrobial activity of SPSF containing origanum oil (OG) against foodborne pathogenic bacteria. The SPSF was fabricated with the SPS extracted from commercial sweetpotato roots. Tensile strength (TS), percent elongation at break (E), and water vapor permeability (WVP) were determined to characterize the SPSF fabricated with selected SPS concentrations, plasticizers, and the concentrations of plasticizers. The agar diffusion assay was used to determine the antimicrobial activity of SPSF containing selective concentrations of OG against Salmonella Enteritidis, Escherichia coli O157:H7, and Listeria monocytogenes. The SPSF fabricated with 2.5% SPS exhibited the greatest TS (4.58 MPa). The TS, E, and WVP of SPSF plasticized with 40% sorbitol exhibited 7.96 MPa, 77.92%, 0.212 ng m/m(2) S Pa, respectively. Therefore, the SPSF fabricated with 2.5% SPS and 40% sorbitol was determined as the optimum film. The antimicrobial activity of the SPSF containing OG increased as the concentration of OG increased. And the SPSF containing OG exhibited greater inhibitory effects against the gram-negative bacteria such as S. Enteritidis and E. coli O157:H7 than the gram-positive L. monocytogenes. The greatest antimicrobial activity was observed against S. Enteritidis when the SPSF containing 2% OG was applied, and the maximum square of zone width was 18.43 mm(2). PMID:21535647

  11. Antimicrobial activity of essential oil and various extracts of fruits of greater cardamom.

    PubMed

    Agnihotri, Supriya; Wakode, S

    2010-09-01

    Greater cardamom (Amomum subulatum Roxb. Zingiberaceae) commonly known as "Bari ilaichi" is a well known plant used in Ayurvedic and Unani medicine. It has been used for the treatment of various diseases and disorders like gastric ulcer. Therefore antimicrobial activity of petroleum ether, methanol and aqueous extracts from leaves and roots, essential oil and isolated vasicine from A. vasica were tested against various microorganisms. Antimicrobial activity was done by disc diffusion method. The zone of inhibition observed was compared with that of standard drugs, ciprofloxacin and fluconazole. Minimum inhibitory concentration was determined against microorganisms used in the study. The results of this study reveal that methanol extract of fruits of A. subulatum shows remarkable antimicrobial activity against Escherichia coli whereas in case of other microorganisms used it was found inferior to the standard drug used. Methanol extract of rind showed good antimicrobial activity against Staphylococcus aureus. It was found that the essential oil isolated was effective against majority of microorganisms used viz. Bacillus pumilus, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Saccharomyces cerevisiae. PMID:21695005

  12. 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. PMID:25475328

  13. Antimicrobial activity of new porphyrins of synthetic and natural origin

    NASA Astrophysics Data System (ADS)

    Gyulkhandanyan, Grigor V.; Ghazaryan, Robert K.; Paronyan, Marina H.; Ulikhanyan, Ghukas I.; Gyulkhandanyan, Aram G.; Sahakyan, Lida A.

    2012-03-01

    Antimicrobial photodynamic inactivation has been successfully used against Gram (+) microorganisms, but most of the photosensitizers (PSs) on Gram (-) bacteria acts weakly. PSs are the natural or synthetic origin dyes, mainly porphyrins. We have synthesized more than 100 new cationic porphyrins and metalloporphyrins with different functional groups (hydroxyethyl, butyl, allyl, methallyl) and metals (cobalt, iron, copper, zinc, silver and other); from the nettle have also been purified pheophytin (a+b) and pheophytin (a) and have synthesized their Ag-and Zn-metalloporphyrins. It was found that in the dark (cytotoxic) mode, the most highly efficiency against microorganisms showed Agmetalloporphyrins of both types of porphyrins (synthetic and natural). Metalloporphyrin of natural origin Ag-pheophytin (a + b) is a strong antibacterial agent and causes 100% death as the Gram (+) microorganisms (St. aureus and MRSA) and the Gram (-) microorganisms (E.coli and Salmonella). It is established that for the destruction of Gram (+) and Gram (-) microorganisms in photodynamic mode cationic water-soluble synthetic metalloporphyrins, especially Zn-TBut4PyP, many times more effective than pheophytins. In vivo conditions on mice established that the best therapeutic activity against various strains of the microorganism St. aureus has the synthetic metalloporphyrin Ag-TBut4PyP. It is significantly more efficient than known drug "Chlorophyllipt" (2.5-3 times) and leads the survival rate of animals up to 50-60%.

  14. Extracellular Streptomyces lividans vesicles: composition, biogenesis and antimicrobial activity

    PubMed Central

    Schrempf, Hildgund; Merling, Philipp

    2015-01-01

    We selected Streptomyces lividans to elucidate firstly the biogenesis and antimicrobial activities of extracellular vesicles that a filamentous and highly differentiated Gram-positive bacterium produces. Vesicle types range in diameter from 110 to 230 nm and 20 to 60 nm, respectively; they assemble to clusters, and contain lipids and phospholipids allowing their in situ imaging by specific fluorescent dyes. The presence of the identified secondary metabolite undecylprodigiosin provokes red fluorescence of a portion of the heterogeneous vesicle populations facilitating in vivo monitoring. Protuberances containing vesicles generate at tips, and alongside of substrate hyphae, and enumerate during late vegetative growth to droplet-like exudates. Owing to in situ imaging in the presence and absence of a green fluorescent vancomycin derivative, we conclude that protuberances comprising vesicles arise at sites with enhanced levels of peptidoglycan subunits [pentapeptide of lipid II (C55)-linked disaccharides], and reduced levels of polymerized and cross-linked peptidoglycan within hyphae. These sites correlate with enhanced levels of anionic phospholipids and lipids. Vesicles provoke pronounced damages of Aspergillus proliferans, Verticillium dahliae and induced clumping and distortion of Escherichia coli. These harmful effects are likely attributable to the action of the identified vesicular compounds including different enzyme types, components of signal transduction cascades and undecylprodigiosin. Based on our pioneering findings, we highlight novel clues with environmental implications and application potential. PMID:25851532

  15. Extracellular Streptomyces lividans vesicles: composition, biogenesis and antimicrobial activity.

    PubMed

    Schrempf, Hildgund; Merling, Philipp

    2015-07-01

    We selected Streptomyces lividans to elucidate firstly the biogenesis and antimicrobial activities of extracellular vesicles that a filamentous and highly differentiated Gram-positive bacterium produces. Vesicle types range in diameter from 110 to 230 nm and 20 to 60 nm, respectively; they assemble to clusters, and contain lipids and phospholipids allowing their in situ imaging by specific fluorescent dyes. The presence of the identified secondary metabolite undecylprodigiosin provokes red fluorescence of a portion of the heterogeneous vesicle populations facilitating in vivo monitoring. Protuberances containing vesicles generate at tips, and alongside of substrate hyphae, and enumerate during late vegetative growth to droplet-like exudates. Owing to in situ imaging in the presence and absence of a green fluorescent vancomycin derivative, we conclude that protuberances comprising vesicles arise at sites with enhanced levels of peptidoglycan subunits [pentapeptide of lipid II (C55)-linked disaccharides], and reduced levels of polymerized and cross-linked peptidoglycan within hyphae. These sites correlate with enhanced levels of anionic phospholipids and lipids. Vesicles provoke pronounced damages of Aspergillus proliferans, Verticillium dahliae and induced clumping and distortion of Escherichia coli. These harmful effects are likely attributable to the action of the identified vesicular compounds including different enzyme types, components of signal transduction cascades and undecylprodigiosin. Based on our pioneering findings, we highlight novel clues with environmental implications and application potential. PMID:25851532

  16. Black cumin (Nigella sativa) and its constituent (thymoquinone): a review on antimicrobial effects

    PubMed Central

    Forouzanfar, Fatemeh; Bazzaz, Bibi Sedigheh Fazly; Hosseinzadeh, Hossein

    2014-01-01

    Nigella sativa seeds have wide therapeutic effects and have been reported to have significant effects against many ailments such as skin diseases, jaundice, gastrointestinal problems, anorexia, conjunctivitis, dyspepsia, rheumatism, diabetes, hypertension, intrinsic hemorrhage, paralysis, amenorrhea, anorexia, asthma, cough, bronchitis, headache, fever, influenza and eczema. Thymoquinone (TQ) is one of the most active constituent and has different beneficial properties. Focus on antimicrobial effects, different extracts of N. sativa as well as TQ, have a broad antimicrobial spectrum including Gram-negative, Gram-positive bacteria, viruses, parasites, schistosoma and fungi. The effectiveness of N. sativa seeds and TQ is variable and depends on species of target microorganisms. The present review paper tries to describe all antimicrobial activities that have been carried out by various researchers. PMID:25859296

  17. Black cumin (Nigella sativa) and its constituent (thymoquinone): a review on antimicrobial effects.

    PubMed

    Forouzanfar, Fatemeh; Bazzaz, Bibi Sedigheh Fazly; Hosseinzadeh, Hossein

    2014-12-01

    Nigella sativa seeds have wide therapeutic effects and have been reported to have significant effects against many ailments such as skin diseases, jaundice, gastrointestinal problems, anorexia, conjunctivitis, dyspepsia, rheumatism, diabetes, hypertension, intrinsic hemorrhage, paralysis, amenorrhea, anorexia, asthma, cough, bronchitis, headache, fever, influenza and eczema. Thymoquinone (TQ) is one of the most active constituent and has different beneficial properties. Focus on antimicrobial effects, different extracts of N. sativa as well as TQ, have a broad antimicrobial spectrum including Gram-negative, Gram-positive bacteria, viruses, parasites, schistosoma and fungi. The effectiveness of N. sativa seeds and TQ is variable and depends on species of target microorganisms. The present review paper tries to describe all antimicrobial activities that have been carried out by various researchers. PMID:25859296

  18. 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

  19. 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=(1.8200.034) mg/mL] when compared to the essential oil [IC50=(110.148.44) 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.

  20. Antimicrobial properties of membrane-active dodecapeptides derived from MSI-78.

    PubMed

    Monteiro, Claudia; Fernandes, Mariana; Pinheiro, Marina; Maia, Sílvia; Seabra, Catarina L; Ferreira-da-Silva, Frederico; Costa, Fabíola; Reis, Salette; Gomes, Paula; Martins, M Cristina L

    2015-05-01

    Antimicrobial peptides (AMPs) are a class of broad-spectrum antibiotics known by their ability to disrupt bacterial membranes and their low tendency to induce bacterial resistance, arising as excellent candidates to fight bacterial infections. In this study we aimed at designing short 12-mer AMPs, derived from a highly effective and broad spectrum synthetic AMP, MSI-78 (22 residues), by truncating this peptide at the N- and/or C-termini while spanning its entire sequence with 1 amino acid (aa) shifts. These designed peptides were evaluated regarding antimicrobial activity against selected gram-positive Staphylococcus strains and the gram-negative Pseudomonas aeruginosa (P. aeruginosa). The short 12-mer peptide CEM1 (GIGKFLKKAKKF) was identified as an excellent candidate to fight P. aeruginosa infections as it displays antimicrobial activity against this strain and selectivity, with negligible toxicity to mammalian cells even at high concentrations. However, in general most of the short 12-mer peptides tested showed a reduction in antimicrobial activity, an effect that was more pronounced for gram-positive Staphylococcus strains. Interestingly, CEM1 and a highly similar peptide differing by only one aa-shift (CEM2: IGKFLKKAKKFG), showed a remarkably contrasting AMP activity. These two peptides were chosen for a more detailed study regarding their mechanism of action, using several biophysical assays and simple membrane models that mimic the mammalian and bacterial lipid composition. We confirmed the correlation between peptide helicity and antimicrobial activity and propose a mechanism of action based on the disruption of the bacterial membrane permeability barrier. PMID:25680229

  1. 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

  2. Antimicrobial activity of silver nanoparticles impregnated wound dressing

    NASA Astrophysics Data System (ADS)

    Shinde, V. V.; Jadhav, P. R.; Patil, P. S.

    2013-06-01

    In this work, silver nanoparticles were synthesized by simple wet chemical reduction method. The silver nitrate was reduced by Sodium borohydride used as reducing agent and Poly (vinyl pyrrolidone) (PVP) as stabilizing agent. The formation of silver nanoparticles was evaluated by UV-visible spectroscope and transmission electron microscope (TEM). Absorption spectrum consist two plasmon peaks at 410 and 668 nm revels the formation of anisotropic nanoparticles confirmed by TEM. The formation of silver nanoparticles was also evidenced by dynamic light scattering (DLS) study. DLS showed polydisperse silver nanoparticles with hydrodynamic size 32 nm. Protecting mechanism of PVP was manifested by FT-Raman study. Silver nanoparticles were impregnated into wound dressing by sonochemical method. The Kirby-Bauer disc diffusion methods were used for antimicrobial susceptibility testing. The antimicrobial activity of the samples has been tested against gram-negative bacterium Escherichia coli and gram-positive bacterium Staphylococcus aureus.

  3. Multilayer hydrogel coatings to combine hemocompatibility and antimicrobial activity.

    PubMed

    Fischer, Marion; Vahdatzadeh, Maryam; Konradi, Rupert; Friedrichs, Jens; Maitz, Manfred F; Freudenberg, Uwe; Werner, Carsten

    2015-07-01

    While silver-loaded catheters are widely used to prevent early-onset catheter-related infections [1], long term antimicrobial protection of indwelling catheters remains to be achieved [2] and antiseptic functionalization of coatings often impairs their hemocompatibility characteristics. Therefore, this work aimed to capitalize on the antimicrobial properties of silver nanoparticles, incorporated in anticoagulant poly(ethylene glycol) (PEG)-heparin hydrogel coatings [3] on thermoplastic polyurethane materials. For prolonged antimicrobial activity, the silver-containing starPEG-heparin hydrogel layers were shielded with silver-free hydrogel layers of otherwise similar composition. The resulting multi-layered gel coatings showed long term antiseptic efficacy against Escherichia coli and Staphylococcus epidermidis strains in vitro, and similarly performed well when incubated with freshly drawn human whole blood with respect to hemolysis, platelet activation and plasmatic coagulation. The introduced hydrogel multilayer system thus offers a promising combination of hemocompatibility and long-term antiseptic capacity to meet an important clinical need. PMID:25934292

  4. Analysis of the antimicrobial activities of a chemokine-derived peptide (CDAP-4) on Pseudomonas aeruginosa

    SciTech Connect

    Martinez-Becerra, Francisco; Dominguez-Ramirez, Lenin; Mendoza-Hernandez, Guillermo; Lopez-Vidal, Yolanda; Soldevila, Gloria . E-mail: garciaze@servidor.unam.mx

    2007-04-06

    Chemokines are key molecules involved in the control of leukocyte trafficking. Recently, a novel function as antimicrobial proteins has been described. CCL13 is the only member of the MCP chemokine subfamily displaying antimicrobial activity. To determine Key residues involved in its antimicrobial activity, CCL13 derived peptides were synthesized and tested against several bacterial strains, including Pseudomonas aeruginosa. One of these peptides, corresponding to the C-terminal region of CCL13 (CDAP-4) displayed good antimicrobial activity. Electron microscopy studies revealed remarkable morphological changes after CDAP-4 treatment. By computer modeling, CDAP-4 in {alpha} helical configuration generated a positive electrostatic potential that extended beyond the surface of the molecule. This feature is similar to other antimicrobial peptides. Altogether, these findings indicate that the antimicrobial activity was displayed by CCL13 resides to some extent at the C-terminal region. Furthermore, CDAP-4 could be considered a good antimicrobial candidate with a potential use against pathogens including P. aeruginosa.

  5. Natural products from cyanobacteria with antimicrobial and antitumor activity.

    PubMed

    Silva-Stenico, Maria Estela; Kaneno, Ramon; Zambuzi, Fabiana Albani; Vaz, Marcelo G M V; Alvarenga, Danillo O; Fiore, Marli Fátima

    2013-01-01

    Cyanobacteria are an important source of structurally bioactive metabolites, with cytotoxic, antiviral, anticancer, antimitotic, antimicrobial, specific enzyme inhibition and immunosuppressive activities. This study focused on the antitumor and antimicrobial activities of intra and extracellular cyanobacterial extracts. A total of 411 cyanobacterial strains were screened for antimicrobial activity using a subset of pathogenic bacteria as target. The in vitro antitumor assays were performed with extracts of 24 strains tested against two murine cancer cell lines (colon carcinoma CT-26 and lung cancer 3LL). Intracellular extracts inhibited 49 and 35% of Gram-negative and Gram-positive pathogenic bacterial growth, respectively. Furthermore, the methanolic intracellular extract of Cylindrospermopsis raciborskii CYP011K and Nostoc sp. CENA69 showed inhibitory activity against the cancer cell lines. The extracellular extract from Fischerella sp. CENA213 and M. aeruginosa NPJB-1 exhibited inhibitory activity against 3LL lung cancer cells at 0.8 µg ml⁻¹ and Oxynema sp. CENA135, Cyanobium sp. CENA154, M. aeruginosa NPJB-1 and M. aeruginosa NPLJ-4 presented inhibitory activity against CT26 colon cancer cells at 0.8 µg ml⁻¹. Other extracts were able to inhibit 3LL cell-growth at higher concentrations (20 µg ml⁻¹) such as Nostoc sp. CENA67, Cyanobium sp. CENA154 and M. aeruginosa NPLJ-4, while CT26 cells were inhibited at the same concentration by Nostoc sp. CENA67 and Fischerella sp. CENA213. These extracts presented very low inhibitory activity on human peripheral blood lymphocytes. The results showed that some cyanobacterial strains are a rich source of natural products with potential for pharmacological and biotechnological applications. PMID:24372264

  6. Antimicrobial activities of the rhizome extract of Zingiber zerumbet Linn

    PubMed Central

    Kader, Golam; Nikkon, Farjana; Rashid, Mohammad Abdur; Yeasmin, Tanzima

    2011-01-01

    Objective To investigate antimicrobial effects of ethanolic extract of Zingiber zerumbet (Z. zerumbet) (L.) Smith and its chloroform and petroleum ether soluble fractions against pathogenic bacteria and fungi. Methods The fresh rhizomes of Zingiber zerumbet were extracted in cold with ethanol (4.0 L) after concentration. The crude ethanol extract was fractionated by petroleum ether and chloroform to form a suspension of ethanol extract (15.0 g), petroleum ether fraction (6.6 g) and chloroform soluble fraction (5.0 g). The crude ethanol extract and its petroleum ether and chloroform fractions were evaluated for antibacterial and antifungal activity against thirteen pathogenic bacteria and three fungi by the disc diffusion method. Commercially available kanamycin (30 µg/disc) was used as standard disc and blank discs impregnated with the respective solvents were used as negative control. Results At a concentration of 400 µg/disc, all the samples showed mild to moderate antibacterial and antifungal activity and produced the zone of inhibition ranging from 6 mm to 10 mm. Among the tested samples, the crude ethanol extract showed the highest activity against Vibrio parahemolyticus (V. parahemolyticus). The minimum inhibitory concentration (MIC) of the crude ethanol extract and its fractions were within the value of 128-256 µg/mL against two Gram positive and four Gram negative bacteria and all the samples showed the lowest MIC value against V. parahemolyticus (128 µg/mL). Conclusions It can be concluded that, potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z. zerumbet (L). PMID:23569803

  7. Anti-inflammatory, Antioxidant and Antimicrobial Effects of Artemisinin Extracts from Artemisia annua L.

    PubMed Central

    Kim, Wan-Su; Choi, Woo Jin; Lee, Sunwoo; Kim, Woo Joong; Lee, Dong Chae; Sohn, Uy Dong; Shin, Hyoung-Shik

    2015-01-01

    The anti-inflammatory, antioxidant, and antimicrobial properties of artemisinin derived from water, methanol, ethanol, or acetone extracts of Artemisia annua L. were evaluated. All 4 artemisinin-containing extracts had anti-inflammatory effects. Of these, the acetone extract had the greatest inhibitory effect on lipopolysaccharide-induced nitric oxide (NO), prostaglandin E2 (PGE2), and proinflammatory cytokine (IL-1β , IL-6, and IL-10) production. Antioxidant activity evaluations revealed that the ethanol extract had the highest free radical scavenging activity, (91.0±3.2%), similar to α-tocopherol (99.9%). The extracts had antimicrobial activity against the periodontopathic microorganisms Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum subsp. animalis, Fusobacterium nucleatum subsp. polymorphum, and Prevotella intermedia. This study shows that Artemisia annua L. extracts contain anti-inflammatory, antioxidant, and antimicrobial substances and should be considered for use in pharmaceutical products for the treatment of dental diseases. PMID:25605993

  8. In Vitro Antimicrobial Activity of Essential Oil of Thymus schimperi, Matricaria chamomilla, Eucalyptus globulus, and Rosmarinus officinalis.

    PubMed

    Mekonnen, Awol; Yitayew, Berhanu; Tesema, Alemnesh; Taddese, Solomon

    2016-01-01

    In this study, the in vitro antimicrobial activities of four plant essential oils (T. schimperi, E. globulus, R. officinalis, and M. Chamomilla) were evaluated against bacteria and fungi. The studies were carried out using agar diffusion method for screening the most effective essential oils and agar dilution to determine minimum inhibitory concentration of the essential oils. Results of this study revealed that essential oils of T. schimperi, E. globulus, and R. officinalis were active against bacteria and some fungi. The antimicrobial effect of M. chamomilla was found to be weaker and did not show any antimicrobial activity. The minimum inhibitory concentration values of T. schimperi were <15.75 mg/mL for most of the bacteria and fungi used in this study. The minimum inhibitory concentration values of the other essential oils were in the range of 15.75-36.33 mg/mL against tested bacteria. This study highlighted the antimicrobial activity of the essential oil of E. globulus, M. chamomilla, T. Schimperi, and R. officinalis. The results indicated that T. schimperi have shown strong antimicrobial activity which could be potential candidates for preparation of antimicrobial drug preparation. PMID:26880928

  9. In Vitro Antimicrobial Activity of Essential Oil of Thymus schimperi, Matricaria chamomilla, Eucalyptus globulus, and Rosmarinus officinalis

    PubMed Central

    Mekonnen, Awol; Yitayew, Berhanu; Tesema, Alemnesh; Taddese, Solomon

    2016-01-01

    In this study, the in vitro antimicrobial activities of four plant essential oils (T. schimperi, E. globulus, R. officinalis, and M. Chamomilla) were evaluated against bacteria and fungi. The studies were carried out using agar diffusion method for screening the most effective essential oils and agar dilution to determine minimum inhibitory concentration of the essential oils. Results of this study revealed that essential oils of T. schimperi, E. globulus, and R. officinalis were active against bacteria and some fungi. The antimicrobial effect of M. chamomilla was found to be weaker and did not show any antimicrobial activity. The minimum inhibitory concentration values of T. schimperi were <15.75 mg/mL for most of the bacteria and fungi used in this study. The minimum inhibitory concentration values of the other essential oils were in the range of 15.75–36.33 mg/mL against tested bacteria. This study highlighted the antimicrobial activity of the essential oil of E. globulus, M. chamomilla, T. Schimperi, and R. officinalis. The results indicated that T. schimperi have shown strong antimicrobial activity which could be potential candidates for preparation of antimicrobial drug preparation. PMID:26880928

  10. High Antimicrobial Activity and Low Human Cell Cytotoxicity of Core-Shell Magnetic Nanoparticles Functionalized with an Antimicrobial Peptide.

    PubMed

    Maleki, Hajar; Rai, Akhilesh; Pinto, Sandra; Evangelista, Marta; Cardoso, Renato M S; Paulo, Cristiana; Carvalheiro, Tiago; Paiva, Artur; Imani, Mohammad; Simchi, Abdolreza; Durães, Luísa; Portugal, António; Ferreira, Lino

    2016-05-11

    Superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with antimicrobial agents are promising infection-targeted therapeutic platforms when coupled with external magnetic stimuli. These antimicrobial nanoparticles (NPs) may offer advantages in fighting intracellular pathogens as well as biomaterial-associated infections. This requires the development of NPs with high antimicrobial activity without interfering with the biology of mammalian cells. Here, we report the preparation of biocompatible antimicrobial SPION@gold core-shell NPs based on covalent immobilization of the antimicrobial peptide (AMP) cecropin melittin (CM) (the conjugate is named AMP-NP). The minimal inhibitory concentration (MIC) of the AMP-NP for Escherichia coli was 0.4 μg/mL, 10-times lower than the MIC of soluble CM. The antimicrobial activity of CM depends on the length of the spacer between the CM and the NP. AMP-NPs are taken up by endothelial (between 60 and 170 pg of NPs per cell) and macrophage (between 18 and 36 pg of NPs per cell) cells and accumulate preferentially in endolysosomes. These NPs have no significant cytotoxic and pro-inflammatory activities for concentrations up to 200 μg/mL (at least 100 times higher than the MIC of soluble CM). Our results in membrane models suggest that the selectivity of AMP-NPs for bacteria and not eukaryotic membranes is due to their membrane compositions. The AMP-NPs developed here open new opportunities for infection-site targeting. PMID:27074633

  11. Effect of substituting arginine and lysine with alanine on antimicrobial activity and the mechanism of action of a cationic dodecapeptide (CL(14-25)), a partial sequence of cyanate lyase from rice.

    PubMed

    Taniguchi, Masayuki; Takahashi, Nobuteru; Takayanagi, Tomohiro; Ikeda, Atsuo; Ishiyama, Yohei; Saitoh, Eiichi; Kato, Tetsuo; Ochiai, Akihito; Tanaka, Takaaki

    2014-01-01

    The antimicrobial activity of analogs obtained by substituting arginine and lysine in CL(14-25), a cationic α-helical dodecapeptide, with alanine against Porphyromonas gingivalis, a periodontal pathogen, varied significantly depending on the number and position of cationic amino acids. The alanine-substituted analogs had no hemolytic activity, even at a concentration of 1 mM. The antimicrobial activities of CL(K20A) and CL(K20A, K25A) were 3.8-fold and 9.1-fold higher, respectively, than that of CL(14-25). The antimicrobial activity of CL(R15A) was slightly lower than that of CL(14-25), suggesting that arginine at position 15 is not essential but is important for the antimicrobial activity. The experiments in which the alanine-substituted analogs bearing the replacement of arginine at position 24 and/or lysine at position 25 were used showed that arginine at position 24 was crucial for the antimicrobial activity whenever lysine at position 25 was substituted with alanine. Helical wheel projections of the alanine-substituted analogs indicate that the hydrophobicity in the vicinity of leucine at position 16 and alanines at positions 18 and/or 21 increased by substituting lysine at positions 20 and 25 with alanine, respectively. The degrees of diSC3 -5 release from P. gingivalis cells and disruption of GUVs induced by the alanine-substituted analogs with different positive charges were not closely related to their antimicrobial activities. The enhanced antimicrobial activities of the alanine-substituted analogs appear to be mainly attributable to the changes in properties such as hydrophobicity and amphipathic propensity due to alanine substitution and not to their extents of positive charge (cationicity). PMID:23982951

  12. Antimicrobial activity and identification of potential antimicrobial compounds from aquatic pteridophyte, Azolla microphylla Kaulf.

    PubMed

    Abraham, G; Yadav, R K; Kaushik, G K

    2015-04-01

    Azolla microphylla Kaulf. is an aquatic nitrogen fixing pteridophyte commonly found in aquatic habitats including paddy fields. Methanolic extract of the fronds of A. microphylla was subjected to partial purification by solvent partitioning with diethyl ether and ethyl acetate followed by hydrolysis, and further partitioning with ethyl acetate. The two fractions, thus obtained were tested for antibacterial activity. It was observed that the ethyl acetate fraction inhibited the growth of the pathogenic bacterium Xanthomonas oryzae. The GC-MS analysis of the ethyl acetate fraction showed several prominent peaks with retention time ranging from 8.83 to 45.54 min. A comparison of these peaks with the GC-MS libraries revealed that it could be eicosenes and heptadecanes with potential of antimicrobial activity. PMID:26011985

  13. Antimicrobial Activity of Chitosan Derivatives Containing N-Quaternized Moieties in Its Backbone: A Review

    PubMed Central

    Martins, Alessandro F.; Facchi, Suelen P.; Follmann, Heveline D. M.; Pereira, Antonio G. B.; Rubira, Adley F.; Muniz, Edvani C.

    2014-01-01

    Chitosan, which is derived from a deacetylation reaction of chitin, has attractive antimicrobial activity. However, chitosan applications as a biocide are only effective in acidic medium due to its low solubility in neutral and basic conditions. Also, the positive charges carried by the protonated amine groups of chitosan (in acidic conditions) that are the driving force for its solubilization are also associated with its antimicrobial activity. Therefore, chemical modifications of chitosan are required to enhance its solubility and broaden the spectrum of its applications, including as biocide. Quaternization on the nitrogen atom of chitosan is the most used route to render water-soluble chitosan-derivatives, especially at physiological pH conditions. Recent reports in the literature demonstrate that such chitosan-derivatives present excellent antimicrobial activity due to permanent positive charge on nitrogen atoms side-bonded to the polymer backbone. This review presents some relevant work regarding the use of quaternized chitosan-derivatives obtained by different synthetic paths in applications as antimicrobial agents. PMID:25402643

  14. 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. PMID:24180553

  15. Antimicrobial activity of lactoferrin against foodborne pathogenic bacteria incorporated into edible chitosan film.

    PubMed

    Brown, Cynthia A; Wang, Baowu; Oh, Jun-Hyun

    2008-02-01

    The objectives of this research were to develop and characterize edible chitosan film containing lactoferrin as a natural antimicrobial agent, and to investigate the combination effects of lactoferrin with lysozyme in chitosan film against the growth of Escherichia coli O157:H7 and Listeria monocytogenes. Chitosan films containing lactoferrin, lysozyme, or nisin were fabricated, and the antimicrobial concentrations were 0.5, 1, or 2 mg in a circular disc of chitosan film. Three concentrations of lactoferrin or EDTA (0.28, 0.56, or 1.12 mg per disc) were also incorporated into the chitosan film containing lysozyme to investigate the combination effects of lactoferrin. The water barrier properties of the chitosan films containing lactoferrin were characterized. The antimicrobial activities against E. coli O157:H7 and L. monocytogenes were determined using the agar diffusion assay and cell count assay. The chitosan films containing lactoferrin less than 1 mg per disc did not alter the water vapor permeability of the chitosan film. Although the film containing lysozyme exhibited significant antimicrobial activity, the incorporation of lactoferrin alone into chitosan film did not exhibit significant antimicrobial activity against both E. coli O157:H7 and L. monocytogenes. However, the combination of lactoferrin with lysozyme-containing chitosan film significantly decreased the growth of E. coli O157:H7, exhibiting a comparable effect to that of the combination of EDTA with lysozyme (P < 0.05). Furthermore, the combination of lactoferrin with lysozyme in chitosan film exhibited greater reduction in the growth of L. monocytogenes than did the combination EDTA with lysozyme, resulting in an approximate 3-log reduction. PMID:18326181

  16. [New methyl-quinoxaline derivatives with antimicrobial activity].

    PubMed

    Ungureanu, Margareta; Poiată, Antonia; Tuchiluş, Cristina

    2004-01-01

    This paper presents the synthesis of six new quinoxaline derivatives cycloadditions products of N-monoxide and N,N'-dioxide of 6-methyl-quinoxaline. The chemical structure of new azabicyclic products was confirmed by C, H, N elemental analysis and spectral analysis (IR and RMN). We have tested the antimicrobial activity of the new synthesized azabicyclic derivatives by the diffusimetric method. The assay was made on the seven microorganisms, gram-positive and gram-negative bacteria. The results show that the new compounds are more active against the gram-positive bacteria and Candida albicans. PMID:15688781

  17. In vitro antimicrobial activity of ethanolic fractions of Cryptolepis sanguinolenta

    PubMed Central

    2012-01-01

    Background Following claims that some plants have antimicrobial activities against infectious microbes, the in vitro antimicrobial activities of different solvent fractions of ethanolic extract of Cryptolepis sanguinolenta were evaluated against eight standard bacteria and clinical isolates. Methods The solvent partitioning protocol involving ethanol, petroleum ether, chloroform, ethyl acetate and water, was used to extract various fractions of dried pulverized Cryptolepis sanguinolenta roots. Qualitative phyto-constituents screening was performed on the ethanol extract, chloroform fraction and the water fraction. The Kirby Bauer disk diffusion method was employed to ascertain the antibiogram of the test organisms while the agar diffusion method was used to investigate the antimicrobial properties of the crude plant extracts. The microplate dilution method aided in finding the MICs while the MBCs were obtained by the method of Nester and friends. The SPSS 16.0 version was used to analyze the percentages of inhibitions and bactericidal activities. Results The phytochemical screening revealed the presence of alkaloids, reducing sugars, polyuronides, anthocyanosides and triterpenes. The ethanol extract inhibited 5 out of 8 (62.5%) of the standard organisms and 6 out of 8 (75%) clinical isolates. The petroleum ether fraction inhibited 4 out of 8 (50%) of the standard microbes and 1 out of 8 (12.5%) clinical isolates. It was also observed that the chloroform fraction inhibited the growth of all the organisms (100%). Average inhibition zones of 14.0 ± 1.0 mm to 24.67 ± 0.58 mm was seen in the ethyl acetate fraction which halted the growth of 3 (37.5%) of the standard organisms. Inhibition of 7 (87.5%) of standard strains and 6 (75%) of clinical isolates were observed in the water fraction. The chloroform fraction exhibited bactericidal activity against all the test organisms while the remaining fractions showed varying degrees of bacteriostatic activity. Conclusion The study confirmed that fractions of Cryptolepis sanguinolenta have antimicrobial activity. The chloroform fraction had the highest activity, followed by water, ethanol, petroleum ether and ethyl acetate respectively. Only the chloroform fraction exhibited bactericidal activity and further investigations are needed to ascertain its safety and prospects of drug development. PMID:22709723

  18. Snake Cathelicidin NA-CATH and Smaller Helical Antimicrobial Peptides Are Effective against Burkholderia thailandensis.

    PubMed

    Blower, Ryan J; Barksdale, Stephanie M; van Hoek, Monique L

    2015-07-01

    Burkholderia thailandensis is a Gram-negative soil bacterium used as a model organism for B. pseudomallei, the causative agent of melioidosis and an organism classified category B priority pathogen and a Tier 1 select agent for its potential use as a biological weapon. Burkholderia species are reportedly "highly resistant" to antimicrobial agents, including cyclic peptide antibiotics, due to multiple resistance systems, a hypothesis we decided to test using antimicrobial (host defense) peptides. In this study, a number of cationic antimicrobial peptides (CAMPs) were tested in vitro against B. thailandensis for both antimicrobial activity and inhibition of biofilm formation. Here, we report that the Chinese cobra (Naja atra) cathelicidin NA-CATH was significantly antimicrobial against B. thailandensis. Additional cathelicidins, including the human cathelicidin LL-37, a sheep cathelicidin SMAP-29, and some smaller ATRA peptide derivatives of NA-CATH were also effective. The D-enantiomer of one small peptide (ATRA-1A) was found to be antimicrobial as well, with EC50 in the range of the L-enantiomer. Our results also demonstrate that human alpha-defensins (HNP-1 & -2) and a short beta-defensin-derived peptide (Peptide 4 of hBD-3) were not bactericidal against B. thailandensis. We also found that the cathelicidin peptides, including LL-37, NA-CATH, and SMAP-29, possessed significant ability to prevent biofilm formation of B. thailandensis. Additionally, we show that LL-37 and its D-enantiomer D-LL-37 can disperse pre-formed biofilms. These results demonstrate that although B. thailandensis is highly resistant to many antibiotics, cyclic peptide antibiotics such as polymyxin B, and defensing peptides, some antimicrobial peptides including the elapid snake cathelicidin NA-CATH exert significant antimicrobial and antibiofilm activity towards B. thailandensis. PMID:26196513

  19. Snake Cathelicidin NA-CATH and Smaller Helical Antimicrobial Peptides Are Effective against Burkholderia thailandensis

    PubMed Central

    Blower, Ryan J.; Barksdale, Stephanie M.; van Hoek, Monique L.

    2015-01-01

    Burkholderia thailandensis is a Gram-negative soil bacterium used as a model organism for B. pseudomallei, the causative agent of melioidosis and an organism classified category B priority pathogen and a Tier 1 select agent for its potential use as a biological weapon. Burkholderia species are reportedly “highly resistant” to antimicrobial agents, including cyclic peptide antibiotics, due to multiple resistance systems, a hypothesis we decided to test using antimicrobial (host defense) peptides. In this study, a number of cationic antimicrobial peptides (CAMPs) were tested in vitro against B. thailandensis for both antimicrobial activity and inhibition of biofilm formation. Here, we report that the Chinese cobra (Naja atra) cathelicidin NA-CATH was significantly antimicrobial against B. thailandensis. Additional cathelicidins, including the human cathelicidin LL-37, a sheep cathelicidin SMAP-29, and some smaller ATRA peptide derivatives of NA-CATH were also effective. The D-enantiomer of one small peptide (ATRA-1A) was found to be antimicrobial as well, with EC50 in the range of the L-enantiomer. Our results also demonstrate that human alpha-defensins (HNP-1 & -2) and a short beta-defensin-derived peptide (Peptide 4 of hBD-3) were not bactericidal against B. thailandensis. We also found that the cathelicidin peptides, including LL-37, NA-CATH, and SMAP-29, possessed significant ability to prevent biofilm formation of B. thailandensis. Additionally, we show that LL-37 and its D-enantiomer D-LL-37 can disperse pre-formed biofilms. These results demonstrate that although B. thailandensis is highly resistant to many antibiotics, cyclic peptide antibiotics such as polymyxin B, and defensing peptides, some antimicrobial peptides including the elapid snake cathelicidin NA-CATH exert significant antimicrobial and antibiofilm activity towards B. thailandensis. PMID:26196513

  20. Interleukin-15 Activates Proinflammatory and Antimicrobial Functions in Polymorphonuclear Cells

    PubMed Central

    Musso, Tiziana; Calosso, Liliana; Zucca, Mario; Millesimo, Maura; Puliti, Manuela; Bulfone-Paus, Silvia; Merlino, Chiara; Savoia, Dianella; Cavallo, Rossana; Ponzi, Alessandro Negro; Badolato, Raffaele

    1998-01-01

    Interleukin-15 (IL-15) is a recently discovered cytokine produced by a wide range of different cell types including fibroblasts, keratinocytes, endothelial cells, and macrophages in response to lipopolysaccharide or microbial infection. This suggests that IL-15 may play a crucial role in the activation of phagocytic cells against pathogens. We studied polymorphonuclear leukocyte (PMN) activation by IL-15, evaluated as enhancement of PMN anti-Candida activity as well as IL-8 production, following stimulation with the cytokine. The PMN response to IL-15 depends on binding to the IL-15 receptor. Our experiments show that binding of a biotinylated human IL-15–immunoglobulin G2b IgG2b fusion protein was competed by the addition of human recombinant IL-15 (rIL-15) or of human rIL-2, suggesting that IL-15 binding to PMN might involve the IL-2Rβ and IL-2Rγ chains, which have been shown to be constitutively expressed by PMN. In addition, we show by reverse transcription-PCR and by flow cytometry with a specific anti-IL-15Rα chain monoclonal antibody that PMN express the IL-15Rα chain at the mRNA and protein levels. Incubation with IL-15 activated PMN to secrete the chemotactic factor IL-8, and the amount secreted was increased by costimulation with heat-inactivated Candida albicans. In addition, IL-15 primed the metabolic burst of PMN in response to formyl-methionyl-leucyl-phenylalanine but was not sufficient to trigger the respiratory burst or to increase the production of superoxide in PMN exposed to C. albicans. IL-15 also increased the ability of PMN to phagocytose heat-killed C. albicans organisms in a dose-dependent manner, without opsonization by antibodies or complement-derived products. In the same concentration range, IL-15 was as effective as gamma interferon (IFN-γ) and IL-2 in increasing the C. albicans growth-inhibitory activity of PMN. Taken together, these results suggest that IL-15 is a potent stimulant of both proinflammatory and antifungal activities of PMN, activating several antimicrobial functions of PMN involved in the cellular response against C. albicans. PMID:9596728

  1. Activities of antimicrobial agents against clinical isolates of Mycobacterium haemophilum.

    PubMed Central

    Bernard, E M; Edwards, F F; Kiehn, T E; Brown, S T; Armstrong, D

    1993-01-01

    Mycobacterium haemophilum, first described in 1978, can cause severe infections of skin, respiratory tract, bone, and other organs of immunocompromised patients. There is no standardized antimicrobial susceptibility test, and for the 27 reported cases, a variety of test methods have been used. This paper reports the in vitro test results for 17 isolates of M. haemophilum recovered from 12 patients in the New York City area. MICs of 16 antimicrobial agents were determined in microtiter trays containing Middlebrook 7H9 broth plus 60 microM hemin, inoculated with 10(6) CFU of the organism per ml and incubated at 30 degrees C for 10 days. Ethambutol, ethionamide, tetracycline, cefoxitin, and trimethoprim-sulfamethoxazole were inactive against initial isolates from the 12 patients. Isoniazid was weakly active with a MIC for 50% of strains tested (MIC50) of 8 micrograms/ml and a MIC90 of > 32 micrograms/ml. Three quinolones, ciprofloxacin, ofloxacin, and sparfloxacin, were moderately active with MIC50s of 2 to 4 micrograms/ml and MIC90s of 4 to 8 micrograms/ml. Amikacin and clofazamine were active with MIC90s of 4 and 2 micrograms/ml, respectively. Clarithromycin was the most active macrolide with a MIC90 of < or = 0.25 microgram/ml. The MIC90 of azithromycin was 8 micrograms/ml, and the MIC90 of erythromycin was 4 micrograms/ml. The rifamycins were active with a MIC90 of 1 microgram/ml for rifampin and one of < or = 0.03 micrograms/ml for rifabutin. For a second isolate from the skin of one patient and a isolate from an autopsy culture of the spleen of a second patient, MICs of rifampin and rifabutin were > 16 microgram/ml, whereas initial isolates were inactivated by low concentrations of the rifamycins. Both patients had been treated for several months with several antimicrobial agents, including a rifamycin. PMID:8285613

  2. Antimicrobial and antioxidant activities of alcoholic extracts of Rumex dentatus L.

    PubMed

    Humeera, Nisa; Kamili, Azra N; Bandh, Suhaib A; Amin, Shajr-ul-; Lone, Bashir A; Gousia, Nisa

    2013-04-01

    In-vitro antimicrobial and antioxidant activities of various concentrations ranging from 150 to 500 μg/ml of alcoholic (methanol and ethanol) extracts of Rumex dentatus were analyzed on different clinical bacterial strains (Shigella flexneri, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus) and fungal strains (Aspergillus versicolor, Aspergillus flavus, Acremonium spp., Penicillium dimorphosporum, Candida albicans, Candida kruesie, Candida parapsilosis) using agar disk diffusion method and broth dilution method (MIC and MBC determination) for antimicrobial activity and DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, Riboflavin photo-oxidation assay, deoxyribose assay, lipid peroxidation assay for antioxidant activity. The extracts showed maximum inhibitory effect against K. pneumonia and P. aeruginosa with no activity against S. typhimurium from among the bacterial strains while as in case of the fungal strains the maximum effect was observed against C. albicans by both the extracts. MIC and MBC values determined for active fractions of the extracts against some bacterial strains (S. flexneri, K. pneumonia and E. coli) revealed that the test organisms were inhibited by all the extracts with methanol showing lower values of both MIC and MBC indicating it as a better antimicrobial agent. The antioxidant activity showed that the extracts exhibited scavenging effect in concentration-dependent manner on superoxide anion radicals and hydroxyl radicals leading to the conclusion that the plant has got a broad spectrum antimicrobial and antioxidant activity and could be a potential alternative for treating various diseases. PMID:23415966

  3. Antimicrobial activity of phenolics and glucosinolate hydrolysis products and their synergy with streptomycin against pathogenic bacteria.

    PubMed

    Saavedra, Maria J; Borges, Anabela; Dias, Carla; Aires, Alfredo; Bennett, Richard N; Rosa, Eduardo S; Simões, Manuel

    2010-05-01

    The purpose of the present study was to evaluate the in vitro antibacterial effects of different classes of important and common dietary phytochemicals (5 simple phenolics - tyrosol, gallic acid, caffeic acid, ferulic acid, and chlorogenic acid; chalcone - phloridzin; flavan-3-ol - (-) epicatechin; seco-iridoid - oleuropein glucoside; 3 glucosinolate hydrolysis products - allylisothiocyanate, benzylisothiocyanate and 2-phenylethylisothiocyanate) against Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus. Another objective of this study was to evaluate the effects of dual combinations of streptomycin with the different phytochemicals on antibacterial activity. A disc diffusion assay was used to evaluate the antibacterial activity of the phytochemicals and 3 standard antibiotics (ciprofloxacin, gentamicin and streptomycin) against the four bacteria. The antimicrobial activity of single compounds and dual combinations (streptomycin-phytochemicals) were quantitatively assessed by measuring the inhibitory halos. The results showed that all of the isothiocyanates had significant antimicrobial activities, while the phenolics were much less efficient. No antimicrobial activity was observed with phloridzin. In general P. aeruginosa was the most sensitive microorganism and L. monocytogenes the most resistant. The application of dual combinations demonstrated synergy between streptomycin and gallic acid, ferulic acid, chlorogenic acid, allylisothiocyanate and 2-phenylethylisothiocyanate against the Gram-negative bacteria. In conclusion, phytochemical products and more specifically the isothiocyanates were effective inhibitors of the in vitro growth of the Gram-negative and Gram-positive pathogenic bacteria. Moreover, they can act synergistically with less efficient antibiotics to control bacterial growth. PMID:20632977

  4. Exploitation of the antioxidant potential of Geranium macrorrhizum (Geraniaceae): hepatoprotective and antimicrobial activities.

    PubMed

    Radulovi?, Niko S; Stojkovi?, Milan B; Miti?, Snezana S; Randjelovi?, Pavle J; Ili?, Ivan R; Stojanovi?, Nikola M; Stojanovi?-Radi?, Zorica Z

    2012-12-01

    In this study we evaluated in vitro (radical scavenging) and in vivo (hepatoprotective effect) antioxidant activities and antimicrobial properties of the extracts of the above- and underground parts of Geranium macrorrhizum L. (Geraniaceae), an ethnopharmacologically renowned plant species. The antioxidant activity and total phenol and flavonoid contents of four different solvent extracts were evaluated by seven different methods. The methanol extracts, administered i.p. to rats (120-480 mg/kg), were evaluated for hepatoprotective activity in a CCl4-induced hepatotoxicity model. The same extracts were tested for antimicrobial activity against seven bacterial and two fungal species. The administered methanol extracts with the highest antioxidant potential showed a significant dose-dependent hepatoprotective action against CCl4-induced liver damage in both decreasing the levels of liver transaminases and bilirubin and in reducing the extent of morphological malformations of the liver. The leaf methanol extract displayed a very strong antibacterial activity, especially against Staphylococcus aureus, with low minimal inhibitory and bactericidal concentrations. These results justify the frequent use of this plant species in folk medicine. Besides the known astringent effect, one can expect that the observed antimicrobial activity against several human pathogens contributes to the wound healing properties of this plant. PMID:23413565

  5. Durable contact active antimicrobial materials formed by a one-step covalent modification of polyvinyl alcohol, cellulose and glass surfaces.

    PubMed

    Poverenov, Elena; Shemesh, Moshe; Gulino, Antonino; Cristaldi, Domenico A; Zakin, Varda; Yefremov, Tatiana; Granit, Rina

    2013-12-01

    In this work we have applied a direct covalent linkage of quaternary ammonium salts (QAS) to prepare a series of contact active antimicrobial surfaces based on widely utilized materials. Formation of antimicrobial polyvinyl alcohol (PVA-QAS), cellulose (cellulose-QAS) and glass (glass-QAS) surfaces was achieved by one step synthesis with no auxiliary linkers. The X-ray photoelectron spectroscopy (XPS) revealed tridentate binding mode of the antimicrobial agent. The antimicrobial activity of the prepared materials was tested on Bacillus cereus, Alicyclobacillus acidoterrestris, Escherichia coli and Pseudomonas aeruginosa. Active site density of the modified materials was examined and found to correlate with their antimicrobial activity. Stability studies at different pH values and temperatures confirmed that the linkage of the bioactive moiety to the surface is robust and resistant to a range of pH and temperatures. Prolonged long-term effectiveness of the contact active materials was demonstrated by their repeated usage, without loss of the antimicrobial efficacy. PMID:24012705

  6. Synthesis, antimicrobial, and antiproliferative activities of substituted phenylfuranylnicotinamidines

    PubMed Central

    Youssef, Magdy M; Arafa, Reem K; Ismail, Mohamed A

    2016-01-01

    This research work deals with the design and synthesis of a series of substituted phenylfuranylnicotinamidines 4a–i. Facile preparation of the target compounds was achieved by Suzuki coupling-based synthesis of the nitrile precursors 3a–i, followed by their conversion to the corresponding nicotinamidines 4a–i utilizing LiN(TMS)2. The antimicrobial activities of the newly synthesized nicotinamidine derivatives were evaluated against the Gram-negative bacterial strains Escherichia coli and Pseudomonas aeruginosa as well as the Gram-positive bacterial strains Staphylococcus aureus and Bacillus megaterium. The minimum inhibitory concentration values of nicotinamidines against all tested microorganisms were in the range of 10–20 μM. In specific, compounds 4a and 4b showed excellent minimum inhibitory concentration values of 10 μM against Staphylococcus aureus bacterial strain and were similar to ampicillin as an antibacterial reference. On the other hand, selected nicotinamidine derivatives were biologically screened for their cytotoxic activities against a panel of 60 cell lines representing nine types of human cancer at a single high dose at National Cancer Institute, Bethesda, MD, USA. Nicotinamidines showing promising activities were further assessed in a five-dose screening assay to determine their compound concentration causing 50% growth inhibition of tested cell (GI50), compound concentration causing 100% growth inhibition of tested cell (TGI), and compound concentration causing 50% lethality of tested cell (LC50) values. Structure-activity relationship studies demonstrated that the activity of members of this series can be modulated from cytostatic to cytotoxic based on the substitution pattern/nature on the terminal phenyl ring. The most active compound was found to be 4e displaying a submicromolar GI50 value of 0.83 μM, with TGI and LC50 values of 2.51 and 100 μM, respectively. Finally, the possible underlying mechanism of action of this series of compounds was investigated by determining their nuclease-like DNA degradation ability in addition to their antioxidant power and all monocations proved to be effective in all assays. PMID:27042005

  7. Synthesis, antimicrobial, and antiproliferative activities of substituted phenylfuranylnicotinamidines.

    PubMed

    Youssef, Magdy M; Arafa, Reem K; Ismail, Mohamed A

    2016-01-01

    This research work deals with the design and synthesis of a series of substituted phenylfuranylnicotinamidines 4a-i. Facile preparation of the target compounds was achieved by Suzuki coupling-based synthesis of the nitrile precursors 3a-i, followed by their conversion to the corresponding nicotinamidines 4a-i utilizing LiN(TMS)2. The antimicrobial activities of the newly synthesized nicotinamidine derivatives were evaluated against the Gram-negative bacterial strains Escherichia coli and Pseudomonas aeruginosa as well as the Gram-positive bacterial strains Staphylococcus aureus and Bacillus megaterium. The minimum inhibitory concentration values of nicotinamidines against all tested microorganisms were in the range of 10-20 μM. In specific, compounds 4a and 4b showed excellent minimum inhibitory concentration values of 10 μM against Staphylococcus aureus bacterial strain and were similar to ampicillin as an antibacterial reference. On the other hand, selected nicotinamidine derivatives were biologically screened for their cytotoxic activities against a panel of 60 cell lines representing nine types of human cancer at a single high dose at National Cancer Institute, Bethesda, MD, USA. Nicotinamidines showing promising activities were further assessed in a five-dose screening assay to determine their compound concentration causing 50% growth inhibition of tested cell (GI50), compound concentration causing 100% growth inhibition of tested cell (TGI), and compound concentration causing 50% lethality of tested cell (LC50) values. Structure-activity relationship studies demonstrated that the activity of members of this series can be modulated from cytostatic to cytotoxic based on the substitution pattern/nature on the terminal phenyl ring. The most active compound was found to be 4e displaying a submicromolar GI50 value of 0.83 μM, with TGI and LC50 values of 2.51 and 100 μM, respectively. Finally, the possible underlying mechanism of action of this series of compounds was investigated by determining their nuclease-like DNA degradation ability in addition to their antioxidant power and all monocations proved to be effective in all assays. PMID:27042005

  8. Isolation, identification and antimicrobial activity of ombuoside from Stevia triflora.

    PubMed

    Amaro-Luis, J M; Adrián, M; Díaz, C

    1997-01-01

    From aerial parts of Stevia triflora DC the flavonol glycoside ombuoside (7,4'-di-O-methylquercetin-3-O-beta-rutinoside) has been isolated and identified on the basis of spectral data. Ombuoside and the synthetic derivatives octa-acetylombuoside, ombuine and retusine were tested for antimicrobial activity against several strains of Gram-positive and Gram-negative bacteria and the yeast Candida albicans, using the agar diffusion method. The flavonol glycoside ombuoside and the respective aglycone ombuine, both exhibited moderated activity against Corynebacterium diphtheria, Staphylococcus aureus, Escherichia coli and Candida albicans. To a lesser degree, octaacetylombuoside and retusine showed activity against the Gram-positive bacteria C. diphtheria and S. aureus, but proved to be inactive against Gram-negative bacteria and Candida albicans. These results indicate that the presence of free hydroxyl groups, either alcoholic or phenolic, is an important chemical feature for the expression of flavonol antimicrobial activity. It is worth noting that this is the first study reported on the antibacterial and antifungal activity of these substances. PMID:9453171

  9. Cytotoxic and antimicrobial activities of Emex spinosa (L.) Campd. extract.

    PubMed

    Donia, Abd-El-Raheim Mohammed; Soliman, Gamal Abd-El-Hakim; El-Sakhawy, Mohamed Abd-El-Monem; Yusufoglu, Hasan; Zaghloul, Ahmed Mohamed

    2014-03-01

    The current research was designed to evaluate the phytochemical contents, cytotoxic and antimicrobial activity of Emex spinosa extracts. The different plant extracts and Aloe-emodin glucoside were screened using the colorimetric MTT method (3-(4,5-dimethylthiazo-2-yl)-2,5-diphenyl- tetrazolium bromide) assay to test their in vitro cytotoxic activity against HepG2, MCF-7, Caco-2 and HCT. The clinically used anticancer drug doxorubicin was used as standard for comparative purposes. Anthraquinones (Aloe-emodin-O-glucoside, Emodin and nataloin (1, 2, 8-trihydroxy, 6-methyl, 10-anthrone-C-glucoside) together with β-sistosterol and β-sitisterol-O-β-D-glucoside were isolated from Emex spinosa. Aloe-emodin glucoside together with four fractions from this plant were evaluated for their anticancer and antimicrobial activities. Aloe-emodin glucoside showed anticancer activity against HCT, HepG-2, MCF-7 and Caco-2 cell lines. The total ethanol extract of E. spinosa and diethyl ether, chloroform, ethyl acetate and butanol fractions shown antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes and Bacillus subtilis. PMID:24577925

  10. Enhancing antibiofilm efficacy in antimicrobial photodynamic therapy: effect of microbubbles

    NASA Astrophysics Data System (ADS)

    Kishen, Anil; George, Saji

    2013-02-01

    In this study, we tested the hypothesis that a microbubble containing photosensitizer when activated with light would enable comprehensive disinfection of bacterial biofilms in infected root dentin by antimicrobial photodynamic therapy (APDT). Experiments were conducted in two stages. In the stage-1, microbubble containing photosensitizing formulation was tested for its photochemical properties. In the stage-2, the efficacy of microbubble containing photosensitizing formulation was tested on in vitro infected root canal model, developed with monospecies biofilm models of Enterococcus faecalis on root dentin substrate. The findings from this study showed that the microbubble containing photosensitizing formulation was overall the most effective formulation for photooxidation, generation of singlet oxygen, and in disinfecting the biofilm bacteria in the infected root canal model. This modified photosensitizing formulation will have potential advantages in eliminating bacterial biofilms from infected root dentin.

  11. Antimicrobial activity of Willowherb (Epilobium angustifolium L.) leaves and flowers.

    PubMed

    Kosalec, Ivan; Kopjar, Nevenka; Kremer, Dario

    2013-08-01

    Since the aetiology of benign prostatic hyperplasia (BHP) is still unknown, the use of medicinal herb extracts and products prepared thereof are recommended due to their antimicrobial activity, especially during early stages of BHP. A comparison was performed of the in vitro antimicrobial activity (using broth microdilution assay) of flowers and leaves of willowherb (Epilobium angustifolium L., Onagraceae) from Mt. Velebit (Croatia). The strains (standard ATCC and clinical isolates) of Staphylococcus aureus (including MRSA), Bacillus subtilis, Escherichia coli (including p-fimbriae positive strain), Pseudomonas aeruginosa, Proteus mirabilis, Candida albicans, C. tropicalis, C. dubliniensis and Saccharomyces cerevisiae were susceptible with MIC values between 4.6±0.2 and 18.2±0.8 mg/mL. The results of in vitro studies showed that no differences were found in the antimicrobial activity between the ethanol extracts of leaves and flowers of E. angustifolium. Using the quantitative fluorescent assay with ethidium bromide and acridine orange, the viability of C. albicans ATCC 10231 was assessed after in vitro exposure to E. angustifolium leaf and flower ethanol extracts. Apoptosis of C. albicans blastospores dominated over necrosis in all treated samples after short-term exposure with 6 to 12 mg/mL of extracts. In addition to the valuable biological activity of E. angustifolium extracts, the data obtained from the in vitro diffusion, the dilution assay and antifungal viability fluorescent assay suggest that leaf and flower ethanol extracts of E. angustifolium L. are a promising complementary herbal therapy of conditions such as BHP. PMID:23796429

  12. Mucin Binding Reduces Colistin Antimicrobial Activity

    PubMed Central

    Huang, Johnny X.; Blaskovich, Mark A. T.; Pelingon, Ruby; Ramu, Soumya; Kavanagh, Angela; Elliott, Alysha G.; Butler, Mark S.

    2015-01-01

    Colistin has found increasing use in treating drug-resistant bacterial lung infections, but potential interactions with pulmonary biomolecules have not been investigated. We postulated that colistin, like aminoglycoside antibiotics, may bind to secretory mucin in sputum or epithelial mucin that lines airways, reducing free drug levels. To test this hypothesis, we measured binding of colistin and other antibiotics to porcine mucin, a family of densely glycosylated proteins used as a surrogate for human sputum and airway mucin. Antibiotics were incubated in dialysis tubing with or without mucin, and concentrations of unbound antibiotics able to penetrate the dialysis tubing were measured over time using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The percentage of antibiotic measured in the dialysate after 4 h in the presence of mucin, relative to the amount without mucin, was 15% for colistin, 16% for polymyxin B, 19% for tobramycin, 52% for ciprofloxacin, and 78% for daptomycin. Antibiotics with the strongest mucin binding had an overall polybasic positive charge, whereas those with comparatively little binding were less basic. When comparing MICs measured with or without added mucin, colistin and polymyxin B showed >100-fold increases in MICs for multiple Gram-negative bacteria. Preclinical evaluation of mucin binding should become a standard procedure when considering the potential pulmonary use of new or existing antibiotics, particularly those with a polybasic overall charge. In the airways, mucin binding may reduce the antibacterial efficacy of inhaled or intravenously administered colistin, and the presence of sub-MIC effective antibiotic concentrations could result in the development of antibiotic resistance. PMID:26169405

  13. Evaluation of three medicinal plants for anti-microbial activity.

    PubMed

    Pratap, Gowd M J S; Manoj, Kumar M G; Sai, Shankar A J; Sujatha, B; Sreedevi, E

    2012-07-01

    Herbal remedies have a long history of use for gum and tooth problems such as dental caries. The present microbiological study was carried out to evaluate the antimicrobial efficacy of three medicinal plants (Terminalia chebula Retz., Clitoria ternatea Linn., and Wedelia chinensis (Osbeck.) Merr.) on three pathogenic microorganisms in the oral cavity (Streptococcus mutans, Lactobacillus casei, and Staphylococcus aureus). Aqueous extract concentrations (5%, 10%, 25%, and 50%) were prepared from the fruits of Terminalia chebula, flowers of Clitoria ternatea, and leaves of Wedelia chinensis. The antimicrobial efficacy of the aqueous extract concentrations of each plant was tested using agar well diffusion method and the size of the inhibition zone was measured in millimeters. The results obtained showed that the diameter of zone of inhibition increased with increase in concentration of extract and the antimicrobial efficacy of the aqueous extracts of the three plants was observed in the increasing order - Wedelia chinensis < Clitoria ternatea < Terminalia chebula. It can be concluded that the tested extracts of all the three plants were effective against dental caries causing bacteria. PMID:23723653

  14. Evaluation of three medicinal plants for anti-microbial activity

    PubMed Central

    Pratap, Gowd M. J. S; Manoj, Kumar M. G.; Sai, Shankar A. J.; Sujatha, B.; Sreedevi, E.

    2012-01-01

    Herbal remedies have a long history of use for gum and tooth problems such as dental caries. The present microbiological study was carried out to evaluate the antimicrobial efficacy of three medicinal plants (Terminalia chebula Retz., Clitoria ternatea Linn., and Wedelia chinensis (Osbeck.) Merr.) on three pathogenic microorganisms in the oral cavity (Streptococcus mutans, Lactobacillus casei, and Staphylococcus aureus). Aqueous extract concentrations (5%, 10%, 25%, and 50%) were prepared from the fruits of Terminalia chebula, flowers of Clitoria ternatea, and leaves of Wedelia chinensis. The antimicrobial efficacy of the aqueous extract concentrations of each plant was tested using agar well diffusion method and the size of the inhibition zone was measured in millimeters. The results obtained showed that the diameter of zone of inhibition increased with increase in concentration of extract and the antimicrobial efficacy of the aqueous extracts of the three plants was observed in the increasing order – Wedelia chinensis < Clitoria ternatea < Terminalia chebula. It can be concluded that the tested extracts of all the three plants were effective against dental caries causing bacteria. PMID:23723653

  15. Preparation, characterization and in vitro antimicrobial activity of liposomal ceftazidime and cefepime against Pseudomonas aeruginosa strains

    PubMed Central

    Torres, Ieda Maria Sapateiro; Bento, Etiene Barbosa; Almeida, Larissa da Cunha; de Sá, Luisa Zaiden Carvalho Martins; Lima, Eliana Martins

    2012-01-01

    Pseudomonas aeruginosa is an opportunistic microorganism with the ability to respond to a wide variety of environmental changes, exhibiting a high intrinsic resistance to a number of antimicrobial agents. This low susceptibility to antimicrobial substances is primarily due to the low permeability of its outer membrane, efflux mechanisms and the synthesis of enzymes that promote the degradation of these drugs. Cephalosporins, particularty ceftazidime and cefepime are effective against P. aeruginosa, however, its increasing resistance has limited the usage of these antibiotics. Encapsulating antimicrobial drugs into unilamellar liposomes is an approach that has been investigated in order to overcome microorganism resistance. In this study, antimicrobial activity of liposomal ceftazidime and cefepime against P. aeruginosa ATCC 27853 and P. aeruginosa SPM-1 was compared to that of the free drugs. Liposomal characterization included diameter, encapsulation efficiency and stability. Minimum Inhibitory Concentration (MIC) was determined for free and liposomal forms of both drugs. Minimum Bactericidal Concentration (MBC) was determined at concentrations 1, 2 and 4 times MIC. Average diameter of liposomes was 131.88 nm and encapsulation efficiency for cefepime and ceftazidime were 2.29% end 5.77%, respectively. Improved stability was obtained when liposome formulations were prepared with a 50% molar ratio for cholesterol in relation to the phospholipid. MIC for liposomal antibiotics for both drugs were 50% lower than that of the free drug, demonstrating that liposomal drug delivery systems may contribute to increase the antibacterial activity of these drugs. PMID:24031917

  16. Influence of Surface Morphology on the Antimicrobial Effect of Transition Metal Oxides in Polymer Surface.

    PubMed

    Oh, Yoo Jin; Hubauer-Brenner, Michael; Hinterdorfer, Peter

    2015-10-01

    In this study, the physical properties of transition metal oxide surfaces were examined using scanning probe microscopic (SPM) techniques for elucidating the antimicrobial activity of molybdenum trioxide (MoO3), tungsten trioxide (WO3), and zinc oxide (ZnO) embedded into the polymers thermoplastic polyurethane (TPU) and polypropylene (PP). We utilized atomic force microscopy (AFM) in the contact imaging mode and its derivative single-pass Kelvin probe force microscopy for investigating samples that were presumably identical in their compositions, but showed different antimicrobial activity in bacterial adhesion tests. Our results revealed that surfaces with larger roughness and higher surface potential variation showed stronger antimicrobial activities compared to smoother and homogeneously charge-distributed surfaces. In addition, capacitance gradient (dC/dZ) measurements were performed to elucidate the antimicrobial activity arising from the different dielectric behavior of the transition metal oxides in this heterogeneous polymer surface. We found that the nano-scale exposure of transition metal oxides on polymer surfaces provided strong antimicrobial effects. Applications arising from our studies will be useful for public and healthcare environments. PMID:26726428

  17. Antimicrobial Activity of Xanthohumol and Its Selected Structural Analogues.

    PubMed

    Stompor, Monika; Żarowska, Barbara

    2016-01-01

    The objective of this study was to evaluate the antimicrobial activity of structural analogues of xanthohumol 1, a flavonoid compound found in hops (Humulus lupulus). The agar-diffusion method using filter paper disks was applied. Biological tests performed for selected strains of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, fungi (Alternaria sp.), and yeasts (Rhodotorula rubra, Candida albicans) revealed that compounds with at least one hydroxyl group-all of them have it at the C-4 position-demonstrated good activity. Our research showed that the strain S. aureus was more sensitive to chalcones than to the isomers in which the heterocyclic ring C is closed (flavanones). The strain R. rubra was moderately sensitive to only one compound: 4-hydroxy-4'-methoxychalcone 8. Loss of the hydroxyl group in the B-ring of 4'-methoxychalcones or its replacement by a halogen atom (-Cl, -Br), nitro group (-NO₂), ethoxy group (-OCH₂CH₃), or aliphatic substituent (-CH₃, -CH₂CH₃) resulted in the loss of antimicrobial activity towards both R. rubra yeast and S. aureus bacteria. Xanthohumol 1, naringenin 5, and chalconaringenin 7 inhibited growth of S. aureus, whereas 4-hydroxy-4'-methoxychalcone 8 was active towards two strains: S. aureus and R. rubra. PMID:27187329

  18. Benzofuranyl Esters: Synthesis, Crystal Structure Determination, Antimicrobial and Antioxidant Activities.

    PubMed

    Kumar, C S Chidan; Then, Li Yee; Chia, Tze Shyang; Chandraju, Siddegowda; Win, Yip-Foo; Sulaiman, Shaida Fariza; Hashim, Nurul Shafiqah; Ooi, Kheng Leong; Quah, Ching Kheng; Fun, Hoong-Kun

    2015-01-01

    A series of five new 2-(1-benzofuran-2-yl)-2-oxoethyl 4-(un/substituted)benzoates 4(a-e), with the general formula of C?H?O(C=O)CH?O(C=O)C?H?X, X = H, Cl, CH?, OCH? or NO?, was synthesized in high purity and good yield under mild conditions. The synthesized products 4(a-e) were characterized by FTIR, H-, (13)C- and H-(13)C HMQC NMR spectroscopic analysis and their 3D structures were confirmed by single-crystal X-ray diffraction studies. These compounds were screened for their antimicrobial and antioxidant activities. The tested compounds showed antimicrobial ability in the order of 4b < 4a < 4c < 4d < 4e and the highest potency with minimum inhibition concentration (MIC) value of 125 g/mL was observed for 4e. The results of antioxidant activities revealed the highest activity for compound 4e (32.62% 1.34%) in diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 4d (31.01% 4.35%) in ferric reducing antioxidant power (FRAP) assay and 4a (27.11% 1.06%) in metal chelating (MC) activity. PMID:26378514

  19. 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

  20. 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. PMID:25561928

  1. Characteristics and antimicrobial activity of copper-based materials

    NASA Astrophysics Data System (ADS)

    Li, Bowen

    In this study, copper vermiculite was synthesized, and the characteristics, antimicrobial effects, and chemical stability of copper vermiculite were investigated. Two types of copper vermiculite materials, micron-sized copper vermiculite (MCV) and exfoliated copper vermiculite (MECV), are selected for this research. Since most of the functional fillers used in industry products, such as plastics, paints, rubbers, papers, and textiles prefer micron-scaled particles, micron-sized copper vermiculite was prepared by jet-milling vermiculite. Meanwhile, since the exfoliated vermiculite has very unique properties, such as high porosity, specific surface area, high aspect ratio of laminates, and low density, and has been extensively utilized as a functional additives, exfoliated copper vermiculite also was synthesized and investigated. The antibacterial efficiency of copper vermiculite was qualitatively evaluated by the diffusion methods (both liquid diffusion and solid diffusion) against the most common pathogenic species: Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Klebsiella pneumoniae (K. pneumoniae). The result showed that the release velocity of copper from copper vermiculite is very slow. However, copper vermiculite clearly has excellent antibacterial efficiency to S. aureus, K. pneumoniae and E. coli. The strongest antibacterial ability of copper vermiculite is its action on S. aureus. The antibacterial efficiency of copper vermiculite was also quantitatively evaluated by determining the reduction rate (death rate) of E. coli versus various levels of copper vermiculite. 10 ppm of copper vermiculite in solution is sufficient to reduce the cell population of E. coli, while the untreated vermiculite had no antibacterial activity. The slow release of copper revealed that the antimicrobial effect of copper vermiculite was due to the strong interactions between copper ions and bacteria cells. Exfoliated copper vermiculite has even stronger antibacterial activity than copper vermiculite against E. coli. With 200 ppm exfoliated copper vermiculite in bacteria suspension (4.68 ppm of metal copper), the reduction of viable bacteria are 99.8% at 1 hour, and >99.9% at 2 hours. With 10 ppm exfoliated copper vermiculite in bacteria dilution (0.234 ppm of copper atoms), the reduction of viable E. coli reached 98.7% at 1 hour, and >95.6% at 2 hours. Molds have the potential to cause health problems, such as allergic reactions, irritations, and mycotoxins, and damage to buildings, historic relics, properties, etc. Since copper has better antifungal property, an initial antifungal activity of copper vermiculite was evaluated in this study. Fat-free milk was used to develop molds in the test samples by saturated samples. Incubated at 36°C for 48 hours, all of the surfaces of untreated control samples, including micron-sized vermiculite, exfoliated vermiculite, bentonite, and kaolin, have been covered by thick mold layers. However, there were no mold showed on copper vermiculite and exfoliated copper vermiculite. Even after the incubation was lasted for 10 days, copper vermiculite and exfoliated copper vermiculite did not show any mold on the surface. These results exhibited copper vermiculite has excellent antifungal activities against mold. Stability of copper ions in copper vermiculite was measured by aqueous leaching process. Copper vermiculite and exfoliated copper vermiculite were put into distilled water in a ratio of 2.0g/100ml, and then implemented leaching processes by continuously shaking (leaching) and statically storing (soaking) for desired periods of time, respectively. According to the analytic result by inductively coupled plasma spectroscopy (ICP), the major metals released were copper, magnesium, iron, silicon, and aluminum. The release rate of copper depends on the environmental conditions. Under the dynamic leaching condition, all the major elements had shown linear leaching rates, and slowly increases along with the leaching time. Copper concentration in 1 hour leached solutions had sufficient concentration to inhibit E. coli in aqueous solution. Lasting for 1 month, 1 gram of copper vermiculite only released 185mug of copper. At this velocity, 11.5 years are required to completely exhaust the copper atoms from copper vermiculite. A soaking process provided a lower release rate than leaching process. Comparably, exfoliated copper vermiculite had lower copper concentration, stronger antimicrobial effect, but faster release rate than copper vermiculite, due to their different structure characteristics. (Abstract shortened by UMI.)

  2. Design of antimicrobially active small amphiphilic peptide dendrimers.

    PubMed

    Polcyn, Piotr; Jurczak, Margarita; Rajnisz, Aleksandra; Solecka, Jolanta; Urbanczyk-Lipkowska, Zofia

    2009-01-01

    Novel polyfunctional small amphiphilic peptide dendrimers characterized by incorporation of a new core compounds - tris-amino acids or tetrakis-amino alcohols that originated from a series of basic amino acids - were efficiently synthesized. These new core elements yielded molecules with multiple branching and (+5)/(+6) charge at the 1-st dendrimer generation. Dendrimers exhibited significant antimicrobial potency against Gram(+) and Gram(-) strains involving also multiresistant reference strains (S. aureus ATCC 43300 and E. coli ATCC BAA-198). In addition, high activity against fungi from the Candida genus was detected. More charged and more hydrophobic peptide dendrimers expressed hemolytic properties. PMID:19924036

  3. Comparative in vitro bactericidal activity of 24 antimicrobial drugs against Clostridium perfringens.

    PubMed

    Traub, W H

    1990-01-01

    Twenty-four antimicrobial drugs were examined for rapidity of onset and magnitude of bactericidal activity against selected strains of Clostridium perfringens. Ceftriaxone, imipenem, metronidazole, mezlocillin, penicillin G, piperacillin, and teicoplanin reduced colony counts by at least 3 log10 units within 2-4 h after exposure. Clindamycin, fluoroquinolones, josamycin, and tetracycline caused delayed kill (greater than or equal to 99.9% reduction of viable counts at 4-22 h after exposure). Chloramphenicol and rifampin lacked bactericidal activity against 2 of 4 strains, whereas erythromycin, fusidic acid, and fosfomycin (with added glucose-6-phosphate) were merely inhibitory for all 4 strains. Imipenem and penicillin G were combined with 9 and 12 antimicrobial drugs, respectively. Essentially all drug combinations yielded indifferent effects; only penicillin G plus doxycycline resulted in an antagonistic effect against C. perfringens. PMID:2311441

  4. Mode of action of lactoperoxidase as related to its antimicrobial activity: a review.

    PubMed

    Bafort, F; Parisi, O; Perraudin, J-P; Jijakli, M H

    2014-01-01

    Lactoperoxidase is a member of the family of the mammalian heme peroxidases which have a broad spectrum of activity. Their best known effect is their antimicrobial activity that arouses much interest in in vivo and in vitro applications. In this context, the proper use of lactoperoxidase needs a good understanding of its mode of action, of the factors that favor or limit its activity, and of the features and properties of the active molecules. The first part of this review describes briefly the classification of mammalian peroxidases and their role in the human immune system and in host cell damage. The second part summarizes present knowledge on the mode of action of lactoperoxidase, with special focus on the characteristics to be taken into account for in vitro or in vivo antimicrobial use. The last part looks upon the characteristics of the active molecule produced by lactoperoxidase in the presence of thiocyanate and/or iodide with implication(s) on its antimicrobial activity. PMID:25309750

  5. Synthesis of Cu/CNTs nanocomposites for antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Singhal, Sunil Kumar; Lal, Maneet; Lata; Ranjan Kabi, Soumya; Behari Mathur, Rakesh

    2012-12-01

    We report a facile method for the synthesis of Cu/multi-walled carbon nanotubes (CNTs) composite powder employing a chemical reduction method followed by high-energy ball milling involving the use of sodium borohydride as a reducing agent and copper sulphate as the precursor material. Control of oxidation of Cu nanoparticles (CuNPs) is a key factor in the synthesis of Cu/CNTs nanocomposites via chemical reduction methods and other methods. To overcome this problem we have applied a new facile rapid synthesis method using a combination of molecular-level mixing followed by high-energy ball milling to produce mostly CuNPs. X-ray diffraction results indicated the presence of mostly CuNPs in composite powder. Scanning electron microscopy and high resolution transmission electron microscopy (HRTEM) was used to ascertain the dispersion of CNTs in Cu matrix. Most of the CuNPs synthesized in the present work had a particle size ranging from 20–50 nm as revealed by HRTEM characterization. Moreover, the CNTs were also found to be homogeneously dispersed in Cu matrix. The Cu/CNTs nanocomposite has a wide range of applications from fuel cells to electronic chip components. In the present work we have investigated the antimicrobial activity of Cu powder and varying concentrations of Cu/CNTs nanocomposite against gram negative Providencia sp. bacteria, and gram positive Bacillus sp. bacteria. These findings suggest that Cu/CNTs nanocomposite can be used in antibacterial controlling systems and as an effective growth inhibitor in the case of various microorganisms.

  6. Antimicrobial activity of leaf extract of Basilicum polystachyon (L) Moench.

    PubMed

    Chakraborty, D; Mandal, S M; Chakraborty, J; Bhattacharyaa, P K; Bandyopadhyay, A; Mitra, A; Gupta, K

    2007-08-01

    Phenolic extract of leaves of Basilicum polystachyon (L) Moench was tested for in vitro antimicrobial activity against five bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Micrococcus leuteus) and three fungi (Fusarium oxysporum, Aspergillus niger, Helminthosporium oryzae). Efficacy of organic solvents, methanol and ethanol, as agents for extraction was compared with acidic water (2M; HCl). High-pressure liquid chromatographic (HPLC) data showed that acidic extraction (2M; HCl) resulted in higher yield of caffeic acid (0.437 mg g(-1)) and rosmarinic acid (0.919 mg g(-1)). Acidic extract showed high activity against Gram (+) ve bacteria, but was less active against Gram (-) ve bacteria. Amongst the tested fungi, maximum activity was exhibited against Aspergillus niger. This is the first report on the phenolic constituents and bioactivity of B. polystachyon. PMID:17877153

  7. Antioxidant and antimicrobial activities of cinnamic acid derivatives.

    PubMed

    Sova, M

    2012-07-01

    Cinnamic acid is an organic acid occurring naturally in plants that has low toxicity and a broad spectrum of biological activities. In the search for novel pharmacologically active compounds, cinnamic acid derivatives are important and promising compounds with high potential for development into drugs. Many cinnamic acid derivatives, especially those with the phenolic hydroxyl group, are well-known antioxidants and are supposed to have several health benefits due to their strong free radical scavenging properties. It is also well known that cinnamic acid has antimicrobial activity. Cinnamic acid derivatives, both isolated from plant material and synthesized, have been reported to have antibacterial, antiviral and antifungal properties. Acids, esters, amides, hydrazides and related derivatives of cinnamic acid with such activities are here reviewed. PMID:22512578

  8. Distinct antimicrobial activities in aphid galls on Pistacia atlantica

    PubMed Central

    Yoram, Gerchman; Inbar, Moseh

    2011-01-01

    Gall-formers are parasitic organisms that manipulate plant traits for their own benefit. Galls have been shown to protect their inhabitants from natural enemies such as predators and parasitoids by various chemical and mechanical means. Much less attention, however, has been given to the possibility of defense against microbial pathogens in the humid and nutrient-rich gall environment. We found that the large, cauliflower-shaped, galls induced by the aphid Slavum wertheimae on buds of Pistacia atlantica trees express antibacterial and antifungal activities distinct from those found in leaves. Antibacterial activity was especially profound against Bacillus spp (a genus of many known insect pathogen) and against Pseudomonas aeruginosa (a known plant pathogen). Antifungal activity was also demonstrated against multiple filamentous fungi. Our results provide evidence for the protective antimicrobial role of galls. This remarkable antibacterial and antifungal activity in the galls of S. wertheimae may be of agricultural and pharmaceutical value. PMID:22105034

  9. Biosynthesis and Antimicrobial Activity of Semiconductor Nanoparticles against Oral Pathogens

    PubMed Central

    Malarkodi, C.; Rajeshkumar, S.; Paulkumar, K.; Vanaja, M.; Gnanajobitha, G.; Annadurai, G.

    2014-01-01

    Dental care is an essential phenomenon in human health. Oral pathogens can cause severe break which may show the way to serious issues in human disease like blood circulation and coronary disease. In the current study, we demonstrated the synthesis and antimicrobial activity of cadmium sulphide and zinc sulphide nanoparticles against oral pathogens. The process for the synthesis of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles is fast, novel, and ecofriendly. Formation of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles was confirmed by surface plasmon spectra using UV-Vis spectrophotometer. The morphology of crystalline phase of nanoparticles was determined from transmission electron microscopy (TEM) and X-ray diffraction (XRD) spectra. The average size of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles was in the range of 10 nm to 25 nm and 65 nm, respectively, and the observed morphology was spherical. The results indicated that the proteins, which contain amine groups, played a reducing and controlling responsibility during the formation of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles in the colloidal solution. The antimicrobial activity was assessed against oral pathogens such as Streptococcus sp. Staphylococcus sp. Lactobacillus sp., and Candida albicans and these results confirmed that the sulphide nanoparticles are exhibiting good bactericidal activity. PMID:24860280

  10. Antimicrobial activity of selected South African medicinal plants

    PubMed Central

    2012-01-01

    Background Nearly 3,000 plant species are used as medicines in South Africa, with approximately 350 species forming the most commonly traded and used medicinal plants. In the present study, twelve South African medicinal plants were selected and tested for their antimicrobial activities against eight microbial species belonging to fungi, Mycobacteria, Gram-positive and Gram-negative bacteria. Methods The radiometric respiratory technique using the BACTEC 460 system was used for susceptibility testing against Mycobacterium tuberculosis, and the liquid micro-broth dilution was used for other antimicrobial assays. Results The results of the minimal inhibitory concentration (MIC) determinations indicated that the methanol extracts from Acacia karoo, Erythrophleum lasianthum and Salvia africana were able to prevent the growth of all the tested microorganisms. All other samples showed selective activities. MIC values below 100 μg/ml were recorded with A. karoo, C. dentate, E. lasianthum, P. obligun and S. africana on at least one of the nine tested microorganisms. The best activity (MIC value of 39.06 μg/ml) was noted with S. africana against E. coli, S. aureus and M. audouinii, and Knowltonia vesitoria against M. tuberculosis. Conclusion The overall results of the present work provide baseline information for the possible use of the studied South African plant extracts in the treatment of microbial infections. PMID:22704594

  11. In vitro antimicrobial activity of Persian shallot (Allium hirtifolium).

    PubMed

    Soroush, Setareh; Taherikalani, Morovat; Asadollahi, Parisa; Asadollahi, Khairollah; Taran, Mojtaba; Emaneini, Mohammad; Alizadeh, Sajjad

    2012-01-01

    Allium hirtifolium is a Persian native plant grown in cool mountain slopes of Iran. It has been used as a spice in Iran for many years. According to the literature review, there are no considerable reports on the antimicrobial properties of this plant. In this study, the antimicrobial activity of Persian shallot hydroalcoholic extract and F1 fraction of the plant (containing amino acid derivatives and/or other cationic compounds) was investigated on some Gram positive cocci and bacilli, Gram negative bacilli, two protozoa, a yeast and a fungus. Excellent activity against Candida albicans (MIC = 64 microg/ml, MBC = 128 microg/ml), Leishmania infantum (MIC = 0.2 mg/ml on the first day of study) and Trichomonas vaginalis (MIC = 5 microg/ml in PSDE form) and a moderate activity against Bacillus spp and Pseudomonas aeroginosa (MIC = 128 microg/ml) was observed. The results showed that this plant contains some anti-trichomonas and anti-leishmania components. PMID:23210319

  12. Determination of antimicrobial activity and resistance to oxidation of moringa peregrina seed oil.

    PubMed

    Lalas, Stavros; Gortzi, Olga; Athanasiadis, Vasilios; Tsaknis, John; Chinou, Ioanna

    2012-01-01

    The antimicrobial activity of the oil extracted with n-hexane from the seeds of Moringa peregrina was tested against Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Candida albicans, C. tropicalis and C. glabrata. The oil proved effective against all of the tested microorganisms. Standard antibiotics (netilmycin, 5-flucytocine, intraconazole and 7-amino-4-methylcoumarin-3-acetic acid) were used for comparison. The resistance to oxidation of the extracted seed oil was also determined. PMID:22367027

  13. Non-anti-infective effects of antimicrobials and their clinical applications: a review.

    PubMed

    Sadarangani, Sapna P; Estes, Lynn L; Steckelberg, James M

    2015-01-01

    Antimicrobial agents are undoubtedly one of the key advances in the history of modern medicine and infectious diseases, improving the clinical outcomes of infection owing to their inhibitory effects on microbial growth. However, many antimicrobial agents also have biological activities stemming from their interactions with host receptors and effects on host inflammatory responses and other human or bacterial cellular biological pathways. These result in clinical uses of antimicrobial drugs that are distinct from their direct bacteriostatic or bactericidal properties. We reviewed the published literature regarding non-anti-infective therapeutic properties and proposed clinical applications of selected antimicrobials, specifically, macrolides, tetracyclines, sulfonamides, and ketoconazole. The clinical applications reviewed were varied, and we focused on uses that were clinically relevant (in terms of importance and burden of disease) and where published evidence exists. Such uses include chronic inflammatory pulmonary and skin disorders, chronic periodontitis, gastrointestinal dysmotility, rheumatoid arthritis, and cancer. Most of these potential therapeutic uses are not Food and Drug Administration approved. Clinicians need to weigh the use of antimicrobial agents for their non-anti-infective benefits, considering potential adverse effects and long-term effect on microbial resistance. PMID:25440726

  14. 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. PMID:22385168

  15. 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. PMID:23444311

  16. Pharmacological Assessment of the Medicinal Potential of Acacia mearnsii De Wild.: Antimicrobial and Toxicity Activities

    PubMed Central

    Olajuyigbe, Olufunmiso O.; Afolayan, Anthony J.

    2012-01-01

    Acacia mearnsii De Wild. (Fabaceae) is a medicinal plant used in the treatment of microbial infections in South Africa without scientific validation of its bioactivity and toxicity. The antimicrobial activity of the crude acetone extract was evaluated by both agar diffusion and macrobroth dilution methods while its cytotoxicity effect was assessed with brine shrimp lethality assay. The study showed that both bacterial and fungal isolates were highly inhibited by the crude extract. The MIC values for the gram-positive bacteria (78.1–312.5) μg/mL, gram-negative bacteria (39.1–625) μg/mL and fungal isolates (625–5000) μg/mL differ significantly. The bacteria were more susceptible than the fungal strains tested. The antibiosis determination showed that the extract was more (75%) bactericidal than bacteriostatic (25%) and more fungicidal (66.67%) than fungistatic (33.33%). The cytotoxic activity of the extract was observed between 31.25 μg/mL and 500 μg/mL and the LC50 value (112.36 μg/mL) indicates that the extract was nontoxic in the brine shrimp lethality assay (LC50 > 100 μg/mL). These results support the use of A. mearnsii in traditional medicine for treatment of microbial infections. The extract exhibiting significant broad spectrum antimicrobial activity and nontoxic effects has potential to yield active antimicrobial compounds. PMID:22605976

  17. Inhibitory Effects of Antimicrobial Peptides on Lipopolysaccharide-Induced Inflammation

    PubMed Central

    Sun, Yue; Shang, Dejing

    2015-01-01

    Antimicrobial peptides (AMPs) are usually small molecule peptides, which display broad-spectrum antimicrobial activity, high efficiency, and stability. For the multiple-antibiotic-resistant strains, AMPs play a significant role in the development of novel antibiotics because of their broad-spectrum antimicrobial activities and specific antimicrobial mechanism. Besides broad-spectrum antibacterial activity, AMPs also have anti-inflammatory activity. The neutralization of lipopolysaccharides (LPS) plays a key role in anti-inflammatory action of AMPs. On the one hand, AMPs can readily penetrate the cell wall barrier by neutralizing LPS to remove Gram-negative bacteria that can lead to infection. On the contrary, AMPs can also inhibit the production of biological inflammatory cytokines to reduce the inflammatory response through neutralizing circulating LPS. In addition, AMPs also modulate the host immune system by chemotaxis of leukocytes, to promote immune cell proliferation, epithelialization, and angiogenesis and thus play a protective role. This review summarizes some recent researches about anti-inflammatory AMPs, with a focus on the interaction of AMPs and LPS on the past decade. PMID:26612970

  18. Neomycin Sulfate Improves the Antimicrobial Activity of Mupirocin-Based Antibacterial Ointments.

    PubMed

    Blanchard, Catlyn; Brooks, Lauren; Beckley, Andrew; Colquhoun, Jennifer; Dewhurst, Stephen; Dunman, Paul M

    2015-01-01

    In the midst of the current antimicrobial pipeline void, alternative approaches are needed to reduce the incidence of infection and decrease reliance on last-resort antibiotics for the therapeutic intervention of bacterial pathogens. In that regard, mupirocin ointment-based decolonization and wound maintenance practices have proven effective in reducing Staphylococcus aureus transmission and mitigating invasive disease. However, the emergence of mupirocin-resistant strains has compromised the agent's efficacy, necessitating new strategies for the prevention of staphylococcal infections. Herein, we set out to improve the performance of mupirocin-based ointments. A screen of a Food and Drug Administration (FDA)-approved drug library revealed that the antibiotic neomycin sulfate potentiates the antimicrobial activity of mupirocin, whereas other library antibiotics did not. Preliminary mechanism of action studies indicate that neomycin's potentiating activity may be mediated by inhibition of the organism's RNase P function, an enzyme that is believed to participate in the tRNA processing pathway immediately upstream of the primary target of mupirocin. The improved antimicrobial activity of neomycin and mupirocin was maintained in ointment formulations and reduced S. aureus bacterial burden in murine models of nasal colonization and wound site infections. Combination therapy improved upon the effects of either agent alone and was effective in the treatment of contemporary methicillin-susceptible, methicillin-resistant, and high-level mupirocin-resistant S. aureus strains. From these perspectives, combination mupirocin-and-neomycin ointments appear to be superior to that of mupirocin alone and warrant further development. PMID:26596945

  19. Assessment of the in vitro antimicrobial activity of Lactobacillus species for identifying new potential antibiotics.

    PubMed

    Dubourg, Grégory; Elsawi, Ziena; Raoult, Didier

    2015-11-01

    The bacteriocin-mediated antimicrobial properties of Lactobacillus spp. have been widely studied, leading to the use of these micro-organisms in the food industry as preservative agents against foodborne pathogens. In an era in which antibiotic resistance is becoming a public health issue, the antimicrobial activity of Lactobacillus spp. could be used for the discovery of new potential antibiotics. Thus, it is essential to have an accurate method of screening the production of antimicrobial agents by prokaryotes. Many in vitro assays have been published to date, largely concerning but not limited to Lactobacillus spp. However, these methods mainly use the spot-on-the-lawn method, which is prone to contamination during the overlay stage, with protocols using methanol vapours or the reverse side agar technique being applied to avoid such contamination. In this study, a method combining the spot-on-the-lawn and well diffusion methods was tested, permitting clear identification of inhibition zones from eight Lactobacillus spp. towards clinical isolates of 12 species (11 bacteria and 1 yeast) commonly found in human pathology. Lactobacillus plantarum CIP 106786 and Lactobacillus rhamnosus CSUR P567 exhibited the widest antimicrobial activity, whereas Lactobacillus acidophilus strain DSM 20079 was relatively inactive. In addition, the putative MIC(50) of L. rhamnosus against Proteus mirabilis was estimated at 1.1×10(9)CFU/mL using culture broth dilution. In conclusion, considering the increasing cultivable bacterial human repertoire, these findings open the way of an effective method to screen in vitro for the production of potential antimicrobial compounds. PMID:26163158

  20. Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Janaki, A. Chinnammal; Sailatha, E.; Gunasekaran, S.

    2015-06-01

    The utilization of various plant resources for the bio synthesis of metallic nano particles is called green technology and it does not utilize any harmful protocols. Present study focuses on the green synthesis of ZnO nano particles by Zinc Carbonate and utilizing the bio-components of powder extract of dry ginger rhizome (Zingiber officinale). The ZnO nano crystallites of average size range of 23-26 nm have been synthesized by rapid, simple and eco friendly method. Zinc oxide nano particles were characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed the adsorption of surfactant molecules at the surface of ZnO nanoparticles and the presence of ZnO bonding. Antimicrobial activity of ZnO nano particles was done by well diffusion method against pathogenic organisms like Klebsiella pneumonia, Staphylococcus aureus and Candida albicans and Penicillium notatum. It is observed that the ZnO synthesized in the process has the efficient antimicrobial activity.

  1. Vibrational spectra and antimicrobial activity of selected bivalent cation benzoates

    NASA Astrophysics Data System (ADS)

    Borawska, M. H.; Koczoń, P.; Piekut, J.; Świsłocka, R.; Lewandowski, W.

    2009-02-01

    Selected bands of FT-IR spectra of Mg(II), Ca(II), Cu(II) and Zn(II) benzoates of both solid state and water solution, were assigned to appropriate molecular vibrations. Next evaluation of electronic charge distribution in both carboxylic anion and aromatic ring of studied compounds was performed. Classical plate tests and turbidimetry measurements, monitoring growth of bacteria Escherichia coli, Bacillus subtilis and yeasts Pichia anomala and Saccharomyces cerevisiae during 24 h of incubation, in optimal growth conditions (control) and in medium with addition of studied benzoate (concentration of 0.01% expressed as the concentration of benzoic acid), proved antimicrobial activity of studied compounds against investigated micro-organisms. PLS (partially least square) and PCR (principal component regression) techniques were applied to build a model, correlating spectral data reflecting molecular structure of studied compounds, with degree of influence of those compounds on growth of studied micro-organisms. Statistically significant correlation within cross validation diagnostic of PLS-1 calibration was found, when log 1/T of selected spectral regions of water solution samples were used as input data. The correlation coefficients between predicted with PLS calibration based on created 1, 2 or 3 factor models, and actual values of antimicrobial activity were: 0.70; 0.76, 0.81 for P. anomala, B. subtilis, and E. coli, respectively. Log(PRESS) values of appropriate models were 2.10, 2,39 and 3.23 for P. anomala, B. subtilis, and E. coli, respectively.

  2. Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles.

    PubMed

    Janaki, A Chinnammal; Sailatha, E; Gunasekaran, S

    2015-06-01

    The utilization of various plant resources for the bio synthesis of metallic nano particles is called green technology and it does not utilize any harmful protocols. Present study focuses on the green synthesis of ZnO nano particles by Zinc Carbonate and utilizing the bio-components of powder extract of dry ginger rhizome (Zingiber officinale). The ZnO nano crystallites of average size range of 23-26 nm have been synthesized by rapid, simple and eco friendly method. Zinc oxide nano particles were characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed the adsorption of surfactant molecules at the surface of ZnO nanoparticles and the presence of ZnO bonding. Antimicrobial activity of ZnO nano particles was done by well diffusion method against pathogenic organisms like Klebsiella pneumonia, Staphylococcus aureus and Candida albicans and Penicillium notatum. It is observed that the ZnO synthesized in the process has the efficient antimicrobial activity. PMID:25748589

  3. In Vitro Antimicrobial Activity of MSI-78, a Magainin Analog

    PubMed Central

    Fuchs, Peter C.; Barry, Arthur L.; Brown, Steven D.

    1998-01-01

    MSI-78 is a cationic peptide with broad-spectrum antimicrobial activity and is being developed as a topical agent. We compared the in vitro activity of MSI-78 with those of ofloxacin and other antibiotics against fresh clinical isolates. Based on MIC distribution statistics, strains for which the MSI-78 MIC was ≤64 μg/ml were assumed to be susceptible for purposes of this report. Of 411 aerobic isolates tested, 91% were susceptible to MSI-78, compared to 91% for ofloxacin and 92% for ciprofloxacin. Only enterococci consistently required ≥64 μg of MSI-78/ml for inhibition. MSI-78 demonstrated bactericidal activity equivalent to that of ofloxacin. Of 61 anaerobes, 97% were susceptible to MSI-78. Of 10 isolates of Candida albicans, 3 were inhibited by MSI-78 at 24 h. Further studies of this compound appear to be warranted. PMID:9593152

  4. Antimicrobial activity of a quaternized BODIPY against Staphylococcus strains.

    PubMed

    Aydın Tekdaş, Duygu; Viswanathan, Geetha; Zehra Topal, Sevinc; Looi, Chung Yeng; Wong, Won Fen; Min Yi Tan, Grace; Zorlu, Yunus; Gürek, Ayşe Gül; Lee, Hong Boon; Dumoulin, Fabienne

    2016-02-24

    A novel BODIPY derivative was designed for biomedical applications. Its mono-quaternized structure ensured its water-solubility and suitable amphiphilicity. Showing no singlet oxygen generation to avoid damage to healthy cells, this new derivative proved to be an extremely promising antimicrobial agent, with activity equal or superior to ampicillin against MRS Staphylococcus strains with no short-term resistance issue. Its activity against MSS Staphylococcus strains was largely superior to those of ampicillin and reached the activity of vancomycin against MSS S. epidermidis. This latter result is in particular extremely promising for the treatment of hospital-acquired infections. Also the fluorescence properties of BODIPY allowed imaging of the uptake. PMID:26831779

  5. Anthelmintic and antimicrobial activity of methanolic and aqueous extracts of Euphorbia helioscopia L.

    PubMed

    Lone, Bashir A; Bandh, Suhaib A; Chishti, Mohammad Zahoor; Bhat, Fayaz Ahmad; Tak, Hidayatullah; Nisa, Humeera

    2013-03-01

    The aim of this study was to evaluate the anthelmintic and antimicrobial efficacy of Euphorbia helioscopia crude extracts. A worm motility inhibition assay and egg hatch assay were used for in vitro study, and a faecal egg count reduction assay was used for in vivo study. The in vitro study revealed anthelmintic effects of crude methanolic extracts of E. helioscopia on live Haemonchus contortus worms as evident from their paralysis and/or death at 8 h after exposure. Different concentrations (12.5 mg ml(-1), 25 mg ml(-1) and 50 mg ml(-1)) of aqueous and methanolic extracts were used against H. contortus which exhibited dose-dependent anthelmintic effects on H. contortus. Different extracts of E. helioscopia on percent inhibitory egg hatching was very low as compared to levamisole. The antimicrobial activity of extracts ranging from 100 to 500 mg ml(-1) screened by disc diffusion method against four selected bacterial (Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas multocida and Escherichia coli) and two fungal strains (Aspergillus flavus and Candida albicans) was also dose dependent with the extract showing more inhibitory effects against S. aureus and E. coli and a minimum inhibitory effect against A. flavus. It is concluded that the entire plant of E. helioscopia possesses significant anthelmintic and antimicrobial activity and could be a potential alternative for treating cases of helminth infections in ruminants. PMID:23065392

  6. Comparative Antimicrobial Activities of Aerosolized Sodium Hypochlorite, Chlorine Dioxide, and Electrochemically Activated Solutions Evaluated Using a Novel Standardized Assay

    PubMed Central

    Thorn, R. M. S.; Robinson, G. M.

    2013-01-01

    The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard microbiological challenges were developed by surface-associating typed Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis spores, or a clinical methicillin-resistant S. aureus (MRSA) strain on stainless steel, polypropylene, or fabric. All test coupons were subjected to 20-min biocidal aerosols of chlorine-matched (100 ppm) sodium hypochlorite, chlorine dioxide, or ECAS within a standard aerosolization chamber using a commercial humidifier under defined conditions. Biocidal treatment type and material surface had a significant effect on the number of microorganisms recovered from various material surfaces following treatment exposure. Under the conditions of the assay, the order of antimicrobial efficacy of biocidal aerosol treatment was as follows: ECAS > chlorine dioxide > sodium hypochlorite. For all biocides, greater antimicrobial reductions were seen when treating stainless steel and fabric than when treating plastic-associated microorganisms. The experimental fogging system and assay protocol designed within this study were shown capable of differentiating the comparative efficacies of multiple chlorine-matched biocidal aerosols against a spectrum of target organisms on a range of test surface materials and would be appropriate for testing other biocidal aerosol treatments or material surfaces. PMID:23459480

  7. Antimicrobial activity of selected synbiotics targeted for the elderly against pathogenic Escherichia coli strains.

    PubMed

    Likotrafiti, E; Tuohy, K M; Gibson, G R; Rastall, R A

    2016-03-01

    The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited. PMID:26754553

  8. Evaluation of the Antimicrobial Effect of Chitosan/Polyvinyl Alcohol Electrospun Nanofibers Containing Mafenide Acetate

    PubMed Central

    Abbaspour, Mohammadreza; Sharif Makhmalzadeh, Behzad; Rezaee, Behjat; Shoja, Saeed; Ahangari, Zohreh

    2015-01-01

    Background: Chitosan, an important biodegradable and biocompatible polymer, has demonstrated wound-healing and antimicrobial properties. Objectives: This study aimed to evaluate the antimicrobial properties of mafenide acetate-loaded nanofibrous films, prepared by the electrospinning technique, using chitosan and polyvinyl alcohol (PVA). Materials and Methods: A 32 full factorial design was used for formulating electrospinning solutions. The chitosan percentage in chitosan/PVA solutions (0%, 10%, and 30%) and the drug content (0%, 20%, and 40%) were chosen as independent variables. The release rate of mafenide acetate from nanofibrous films and their microbial penetration were evaluated. The antimicrobial activity of different nanofibrous film formulations against Staphylococcus aureus and Pseudomonas aeruginosa was studied. Results: The results indicated that all nanofibrous films, with and without drug, can prevent bacterial penetration. Incorporation of mafenide acetate into chitosan/PVA nanofibers enhanced their antimicrobial activity against P. aeruginosa and S. aureus. Conclusions: Overall, the results showed that chitosan/polyvinyl alcohol (PVA) nanofibrous films are applicable for use as a wound dressing with protective, healing, and antimicrobial effects. PMID:26587214

  9. In vitro antimicrobial activity of natural toxins and animal venoms tested against Burkholderia pseudomallei

    PubMed Central

    Perumal Samy, R; Pachiappan, A; Gopalakrishnakone, P; Thwin, Maung M; Hian, Yap E; Chow, Vincent TK; Bow, Ho; Weng, Joseph T

    2006-01-01

    Background Burkholderia pseudomallei are the causative agent of melioidosis. Increasing resistance of the disease to antibiotics is a severe problem in treatment regime and has led to intensification of the search for new drugs. Antimicrobial peptides are the most ubiquitous in nature as part of the innate immune system and host defense mechanism. Methods Here, we investigated a group of venoms (snakes, scorpions and honey bee venoms) for antimicrobial properties against two strains of Gram-negative bacteria Burkholderia pseudomallei by using disc-diffusion assay for in vitro susceptibility testing. The antibacterial activities of the venoms were compared with that of the isolated L-amino acid oxidase (LAAO) and phospholipase A2 (PLA2s) enzymes. MICs were determined using broth dilution method. Bacterial growth was assessed by measurement of optical density at the lowest dilutions (MIC 0.25 mg/ml). The cell viability was measured using tetrazolium salts (XTT) based cytotoxic assay. Results The studied venoms showed high antimicrobial activity. The venoms of C. adamanteus, Daboia russelli russelli, A. halys, P. australis, B. candidus and P. guttata were equally as effective as Chloramphenicol and Ceftazidime (30 μg/disc). Among those tested, phospholipase A2 enzymes (crotoxin B and daboiatoxin) showed the most potent antibacterial activity against Gram-negative (TES) bacteria. Naturally occurring venom peptides and phospholipase A2 proved to possess highly potent antimicrobial activity against Burkholderia pseudomallei. The XTT-assay results showed that the cell survival decreased with increasing concentrations (0.05–10 mg/mL) of Crotalus adamanteus venom, with no effect on the cell viability evident at 0.5 mg/mL. Conclusion This antibacterial profile of snake venoms reported herein will be useful in the search for potential antibacterial agents against drug resistant microorganisms like B. pseudomallei. PMID:16784542

  10. Chemical Compositions and Antimicrobial Activities of Ocimum sanctum L. Essential Oils at Different Harvest Stages

    PubMed Central

    Saharkhiz, Mohammad Jamal; Kamyab, Amir Alam; Kazerani, Narges Khatoon; Zomorodian, Kamiar; Pakshir, Keyvan; Rahimi, Mohammad Javad

    2014-01-01

    Background: Essential Oils (EOs) possess antibacterial properties and represent a natural source to treat infections and prevent food spoilage. Their chemical composition might be affected by the environmental condition and the developmental growth stages of the plant. Objectives: The current study aimed to determine the variations in chemical compositions and antimicrobial activities of the EOs of Ocimum sanctum L. at different stages of harvesting. Materials and Methods: The oils constituents were analyzed by gas chromatography/mass spectrometry (GC/MS). The effects of three different harvest stages of O. sanctum EOs against most common causes of food-borne were evaluated by broth micro-dilution method as recommended by the Clinical and Laboratory Standards Institute (CLSI). Results: The analysis of the EOs indicated that eugenol was the major compound of the EOs at all developmental stages which reached its maximum level at the second stage. The results showed that the tested EOs exhibited antimicrobial activities against all of the examined pathogens at concentrations of 0.125-32 µL/mL, except Pseudomonas aeruginosa which was only inhibited by high concentrations of the floral budding and full flowering EOs. EO distilled from the second developmental growth stage (floral budding) of O. sanctum exhibited the strongest antibacterial activities against the food borne bacteria. Conclusions: Considering the wide range of antimicrobial activities of the examined EOs, they might have the potential to be used to manage infectious diseases or extend the shelf life of food products. PMID:25763132

  11. In vivo antimicrobial activity of marbofloxacin against Pasteurella multocida in a tissue cage model in calves

    PubMed Central

    Cao, Changfu; Qu, Ying; Sun, Meizhen; Qiu, Zhenzhen; Huang, Xianhui; Huai, Binbin; Lu, Yan; Zeng, Zhenling

    2015-01-01

    Marbofloxacin is a fluoroquinolone specially developed for use in veterinary medicine with broad-spectrum antibacterial activity. The objective of our study was to re-evaluate in vivo antimicrobial activity of marbofloxacin against Pasteurella multocida using subcutaneously implanted tissue cages in calves. Calves were infected by direct injection into tissue cages with P. multocida(type B, serotype 2), then intramuscularly received a range of marbofloxacin doses 24 h after inoculation. The ratio of 24 h area under the concentration-time curve divided by the minimum inhibitory concentration or the mutant prevention concentration (AUC24 h/MIC or AUC24 h/MPC) was the pharmacokinetic-pharmacodynamic (PK/PD) index that best described the effectiveness of marbofloxacin against P. multocida (R2 = 0.8514) by non-linear regression analysis. Marbofloxacin exhibited a good antimicrobial activity in vivo. The levels of AUC24 h/MIC and AUC24 h/MPC that produced 50% (1.5log10 CFU/mL reduction) and 90% (3log10 CFU/mL reduction) of maximum response were 18.60 and 50.65 h, 4.67 and 12.89 h by using sigmoid Emax model WINNONLIN software, respectively. The in vivo PK/PD integrated methods by tissue cage model display the advantage of the evaluation of antimicrobial activity and the optimization of the dosage regimen for antibiotics in the presence of the host defenses, especially in target animal of veterinary interest. PMID:26257726

  12. Essential oils and isolated compounds from Lippia alba leaves and flowers: antimicrobial activity and osteoclast apoptosis.

    PubMed

    Juiz, Paulo José Lima; Lucchese, Angelica Maria; Gambari, Roberto; Piva, Roberta; Penolazzi, Letizia; Di Ciano, Martina; Uetanabaro, Ana Paula Trovatti; Silva, Franceli; Avila-Campos, Mario Julio

    2015-01-01

    In the present study, essential oils extracted from the leaves and flowers of Lippia alba (Mill.) N.E.Br. (L. alba) were analyzed for their antimicrobial activity and their effects on osteoclasts. The periodontal pathogens, Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans; ATCC 43717), Fusobacterium nucleatum (F. nucleatum; ATCC 25586) and Porphyromonas gingivalis (P. gingivalis); ATCC 33277) were used in antimicrobial activity assays for determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC), whereas Bacteroides fragilis (B. fragilis; ATCC 25285) was used as the control microorganism. Osteoclast (OC) apoptosis was assessed by TUNEL assay and Fas receptor expression was detected by immunocytochemistry. The analysis of antimicrobial activity revealed that P. gingivalis had the lowest MIC values, whereas A. actinomycetemcomitans had the highest. L. alba essential oils were found to be toxic to human cells, although the compounds, carvone, limonene and citral, were non-toxic and induced apoptosis in the OCs. This study demonstrates that L. alba has potential biotechnological application in dentistry. In fact periodontal disease has a multifactorial etiology, and the immune response to microbial challenge leads to osteoclast activation and the resorption of the alveolar bone, resulting in tooth loss. PMID:25384405

  13. Phenolic compounds from the leaf extract of artichoke (Cynara scolymus L.) and their antimicrobial activities.

    PubMed

    Zhu, Xianfeng; Zhang, Hongxun; Lo, Raymond

    2004-12-01

    A preliminary antimicrobial disk assay of chloroform, ethyl acetate, and n-butanol extracts of artichoke (Cynara scolymus L.) leaf extracts showed that the n-butanol fraction exhibited the most significant antimicrobial activities against seven bacteria species, four yeasts, and four molds. Eight phenolic compounds were isolated from the n-butanol soluble fraction of artichoke leaf extracts. On the basis of high-performance liquid chromatography/electrospray ionization mass spectrometry, tandem mass spectrometry, and nuclear magnetic resonance techniques, the structures of the isolated compounds were determined as the four caffeoylquinic acid derivatives, chlorogenic acid (1), cynarin (2), 3,5-di-O-caffeoylquinic acid (3), and 4,5-di-O-caffeoylquinic acid (4), and the four flavonoids, luteolin-7-rutinoside (5), cynaroside (6), apigenin-7-rutinoside (7), and apigenin-7-O-beta-D-glucopyranoside (8), respectively. The isolated compounds were examined for their antimicrobial activities on the above microorganisms, indicating that all eight phenolic compounds showed activity against most of the tested organisms. Among them, chlorogenic acid, cynarin, luteolin-7-rutinoside, and cynaroside exhibited a relatively higher activity than other compounds; in addition, they were more effective against fungi than bacteria. The minimum inhibitory concentrations of these compounds were between 50 and 200 microg/mL. PMID:15563206

  14. Grafted α-hydroxyphosphonic acids onto polymeric supports: preparation, characterization, and antimicrobial effect.

    PubMed

    Nichita, Ileana; Popa, Adriana; Dragan, Ecaterina Stela; Iliescu, Smaranda; Ilia, Gheorghe

    2015-01-01

    The paper deals with the preparation and characterization of compounds with antimicrobial activity: α-hydroxyphosphonic acids grafted onto styrene-12%-(15%)-divinylbenzene copolymer. These products proved to have antimicrobial effect against two species of gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and two species of gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and a species of yeast (Candida albicans). Tests showed the reduction of bacterial load at different time intervals during the 18 h of contact. PMID:25789417

  15. Green Synthesis and Characterization of Silver Nanoparticles for Antimicrobial Activity Against Burn Wounds Contaminating Bacteria

    NASA Astrophysics Data System (ADS)

    Rout, Anandini; Jena, Padan K.; Sahoo, Debasish; Parida, Umesh K.; Bindhani, Birendra K.

    2014-04-01

    Silver nanoparticles (AgNPs) were prepared from the plant extract of N. arbor-tristis under atmospheric conditions through green synthesis and characterized by various physicochemical techniques like UV-Visible spectroscopy, IR Spectra, energy dispersive X-ray spectrometry (EDS), X-ray diffraction and transmission electron microscopy (TEM) and the results confirmed the synthesis of homogeneous and stable AgNPs by the plant extracts. The antimicrobial activity of AgNPs was investigated against most common bacteria found in burn wound Staphylococcus epidermidis and Pseudomonas aeruginosa. In these tests, Mueller Hinton agar plates were used with AgNPs of various concentrations, supplemented in liquid systems. P. aeruginosa was inhibited at the low concentration of AgNPs, whereas the growth-inhibitory effect on S. epidermidis was mild. These results suggest that AgNPs can be used as effective growth inhibitors of various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.

  16. Antimicrobial activity of different filling pastes for deciduous tooth treatment.

    PubMed

    Antoniazzi, Bruna Feltrin; Pires, Carine Weber; Bresolin, Carmela Rampazzo; Weiss, Rita Niederauer; Praetzel, Juliana Rodrigues

    2015-01-01

    Guedes-Pinto paste is the filling material most employed in Brazil for endodontic treatment of deciduous teeth; however, the Rifocort® ointment has been removed. Thus, the aim of this study was to investigate the antimicrobial potential of filling pastes, by proposing three new pharmacological associations to replace Rifocort® ointment with drugs of already established antimicrobial power: Nebacetin® ointment, 2% Chlorhexidine Gluconate gel, and Maxitrol® ointment. A paste composed of Iodoform, Rifocort® ointment and Camphorated Paramonochlorophenol (CPC) was employed as the gold standard (G1). The other associations were: Iodoform, Nebacetin® ointment and CPC (G2); Iodoform, 2% Chlorhexidine Digluconate gel and CPC (G3); Iodoform, Maxitrol® ointment and CPC (G4). The associations were tested for Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), Enterococcus faecalis (E. faecalis), Escherichia coli (E. coli), and Bacillus subtilis (B. subtilis), using the methods of dilution on solid medium - orifice agar - and broth dilution. The results were tested using statistical analysis ANOVA and Kruskal-Wallis. They showed that all the pastes had a bacteriostatic effect on all the microorganisms, without any statistically significant difference, compared with G1. S. aureus was statistically significant (multiple comparison test of Tukey), insofar as G2 and G3 presented the worst and the best performance, respectively. All associations were bactericidal for E. coli, S. aureus, S. mutans and S. oralis. Only G3 and G4 were bactericidal for E. faecalis, whereas no product was bactericidal for B. subtilis. Thus, the tested pastes have antimicrobial potential and have proved acceptable for endodontic treatment of primary teeth. PMID:25466327

  17. Effect of dietary antimicrobials on immune status in broiler chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present experiment was conducted to evaluate the effect of dietary antimicrobials (anticoccidials plus antibiotic growth promoters) on the development of post-hatch immune systems in commercial broiler chickens. One hundred and five day-old broiler chicks were raised on the used litter and provi...

  18. Antimicrobial activity of extracts from Tamarindus indica L. leaves

    PubMed Central

    Escalona-Arranz, Julio César; Péres-Roses, Renato; Urdaneta-Laffita, Imilci; Camacho-Pozo, Miladis Isabel; Rodríguez-Amado, Jesús; Licea-Jiménez, Irina

    2010-01-01

    Tamarindus indica L. leaves are reported worldwide as antibacterial and antifungal agents; however, this observation is not completely accurate in the case of Cuba. In this article, decoctions from fresh and sun dried leaves, as well as fluid extracts prepared with 30 and 70% ethanol-water and the pure essential oil from tamarind leaves were microbiologically tested against Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Pseudomona aeruginosa and Candida albicans. Aqueous and fluid extracts were previously characterized by spectrophotometric determination of their total phenols and flavonoids, while the essential oil was chemically evaluated by gas chromatography/mass spectroscopy (GC/MS). Experimental data suggest phenols as active compounds against B. subtilis cultures, but not against other microorganisms. On the other hand, the essential oil exhibited a good antimicrobial spectrum when pure, but its relative low concentrations in common folk preparations do not allow for any good activity in these extracts. PMID:20931087

  19. In vitro antimicrobial activity of peroxide-based bleaching agents.

    PubMed

    Napimoga, Marcelo Henrique; de Oliveira, Rogério; Reis, André Figueiredo; Gonçalves, Reginaldo Bruno; Giannini, Marcelo

    2007-06-01

    Antibacterial activity of 4 commercial bleaching agents (Day White, Colgate Platinum, Whiteness 10% and 16%) on 6 oral pathogens (Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis, Candida albicans, Lactobacillus casei, and Lactobacillus acidophilus) and Staphylococcus aureus were evaluated. A chlorhexidine solution was used as a positive control, while distilled water was the negative control. Bleaching agents and control materials were inserted in sterilized stainless-steel cylinders that were positioned under inoculated agar plate (n = 4). After incubation according to the appropriate period of time for each microorganism, the inhibition zones were measured. Data were analyzed by 2-way analysis of variance and Tukey test (a = 0.05). All bleaching agents and the chlorhexidine solution produced antibacterial inhibition zones. Antimicrobial activity was dependent on peroxide-based bleaching agents. For most microorganisms evaluated, bleaching agents produced inhibition zones similar to or larger than that observed for chlorhexidine. C albicans, L casei, and L acidophilus were the most resistant microorganisms. PMID:17625621

  20. Chemical analysis and antimicrobial activity of Greek propolis.

    PubMed

    Melliou, Eleni; Chinou, Ioanna

    2004-06-01

    One new 2,3-dihydroflavone derivative, 7- O-prenylstrobopinin, and 25 known diterpenes and phenolic compounds were identified from the n-butanol extract of Greek propolis. This is the first time that diterpenes have been isolated from propolis of European origin, while six of the known compounds are reported as propolis constituents for the first time. The structures of the isolated compounds were determined by spectroscopic methods, mainly by the concerted application of 1D, 2D NMR techniques (HMQC, HMBC, NOESY) and mass spectrometry. The studied sample and the isolated compounds were tested for their antimicrobial activity against Gram (+/-) bacteria and fungi and five of them exhibited strong activities. PMID:15229802

  1. Antioxidant, Antimicrobial Activity and Medicinal Properties of Grewia asiatica L.

    PubMed

    Shukla, Ritu; Sharma, Dinesh C; Baig, Mohammad H; Bano, Shabana; Roy, Sudeep; Provazník, Ivo; Kamal, Mohammad A

    2016-01-01

    Since ancient time, India is a well known subcontinent for medicinal plants where diversity of plants is known for the treatment of many human disorders. Grewia asiatica is a dicot shrub belonging to the Grewioideae family and well known for its medicinally important fruit commonly called Falsa. G. asiatica, a seasonal summer plant is distributed in the forest of central India, south India, also available in northern plains and western Himalaya up to the height of 3000 ft. Fruits of G. asiatica are traditionally used as a cooling agent, refreshing drink, anti-inflammatory agent and for the treatment of some urological disorders. Recent advancement of Falsa researches concluded its antimicrobial and anti-diabetic activity. Since ancient time medicinal plants are traditionally used for the treatment of different diseases G. asiatica fruit is the edible and tasty part of the plant, now considered as a valuable source of unique natural product for the development of medicines which are used in different disease conditions like anti-diabetic, anti-inflammatory, anti-cancerous and antimicrobial. Now a days, G. asiatica is being used in different Ayurvedic formulation for the cure of different types of diseases. Different pharmacological investigations reveal the presence of phenols, saponnins, flavonoids and tannins compound in the fruits. Present review highlights the phytopharmacological and different traditional use of G. asiatica which is mentioned in ancient Ayurvedic texts. This review stimulates the researchers and scientists for further research on G. asiatica. PMID:26516779

  2. IL-27 Suppresses Antimicrobial Activity in Human Leprosy.

    PubMed

    Teles, Rosane M B; Kelly-Scumpia, Kindra M; Sarno, Euzenir N; Rea, Thomas H; Ochoa, Maria T; Cheng, Genhong; Modlin, Robert L

    2015-10-01

    The mechanisms by which intracellular pathogens trigger immunosuppressive pathways are critical for understanding the pathogenesis of microbial infection. One pathway that inhibits host defense responses involves the induction of type I interferons and subsequently IL-10, yet the mechanism by which type I IFN induces IL-10 remains unclear. Our studies of gene expression profiles derived from leprosy skin lesions suggested a link between IL-27 and the IFN-β induced IL-10 pathway. Here, we demonstrate that the IL-27p28 subunit is upregulated following treatment of monocytes with IFN-β and Mycobacterium leprae, the intracellular bacterium that causes leprosy. The ability of IFN-β and M. leprae to induce IL-10 was diminished by IL-27 knockdown. Additionally, treatment of monocytes with recombinant IL-27 was sufficient to induce the production of IL-10. Functionally, IL-27 inhibited the ability of IFN-γ to trigger antimicrobial activity against M. leprae in infected monocytes. At the site of disease, IL-27 was more strongly expressed in skin lesions of patients with progressive lepromatous leprosy, correlating and colocalizing with IFN-β and IL-10 in macrophages. Together, these data provide evidence that in the human cutaneous immune responses to microbial infection, IL-27 contributes to the suppression of host antimicrobial responses. PMID:26030183

  3. Antimicrobial Activity of Terminalia catappa, Manilkara zapota and Piper betel Leaf Extract

    PubMed Central

    Nair, R.; Chanda, Sumitra

    2008-01-01

    Aqueous and methanol extract of the leaves of Terminalia catappa L., Manilkara zapota L. and Piper betel L. were evaluated for antibacterial activity against 10 Gram positive, 12 Gram negative bacteria and one fungal strain, Candida tropicalis. Piperacillin and gentamicin were used as standards for antibacterial assay, while fluconazole was used as standard for antifungal assay. The three plants showed different degree of activity against the microorganisms investigated. The methanolic extract was considerably more effective than aqueous extract in inhibiting the investigated microbial strains. The most active antimicrobial plant was Piper betel. PMID:20046756

  4. Antimicrobial Activity of Terminalia catappa, Manilkara zapota and Piper betel Leaf Extract.

    PubMed

    Nair, R; Chanda, Sumitra

    2008-01-01

    Aqueous and methanol extract of the leaves of Terminalia catappa L., Manilkara zapota L. and Piper betel L. were evaluated for antibacterial activity against 10 Gram positive, 12 Gram negative bacteria and one fungal strain, Candida tropicalis. Piperacillin and gentamicin were used as standards for antibacterial assay, while fluconazole was used as standard for antifungal assay. The three plants showed different degree of activity against the microorganisms investigated. The methanolic extract was considerably more effective than aqueous extract in inhibiting the investigated microbial strains. The most active antimicrobial plant was Piper betel. PMID:20046756

  5. Comparison of antibacterial effects between antimicrobial peptide and bacteriocins isolated from Lactobacillus plantarum on three common pathogenic bacteria

    PubMed Central

    Ming, Liu; Zhang, Qian; Yang, Le; Huang, Jian-An

    2015-01-01

    New strategies for the prevention or treatment of infections are required. The purpose of this study is to evaluate the effects of antimicrobial peptides and bacteriocins isolated from Lactobacillus plantarum on growth and biofilm formation of three common pathogenic microbes. The antibacterial properties of the antimicrobial peptide Tet213 and bacteriocins were tested by the disc diffusion method. Tet213 and bacteriocins showed inhibitory effects on biofilm formation for the three organisms, as observed by fluorescence microscopy. Furthermore, Tet213 and the bacteriocins all showed antimicrobial activity against the three bacterial species, with Tet213 having a greater inhibitory effect on S. aureus than the bacteriocins (P < 0.05), while the bacteriocins showed stronger antimicrobial activity against S. sanguis (P < 0.05). PMID:26131169

  6. Antimicrobial and antioxidant activities of Cortex Magnoliae Officinalis and some other medicinal plants commonly used in South-East Asia

    PubMed Central

    Chan, Lai Wah; Cheah, Emily LC; Saw, Constance LL; Weng, Wanyu; Heng, Paul WS

    2008-01-01

    Background Eight medicinal plants were tested for their antimicrobial and antioxidant activities. Different extraction methods were also tested for their effects on the bioactivities of the medicinal plants. Methods Eight plants, namely Herba Polygonis Hydropiperis (Laliaocao), Folium Murraya Koenigii (Jialiye), Rhizoma Arachis Hypogea (Huashenggen), Herba Houttuyniae (Yuxingcao), Epipremnum pinnatum (Pashulong), Rhizoma Typhonium Flagelliforme (Laoshuyu), Cortex Magnoliae Officinalis (Houpo) and Rhizoma Imperatae (Baimaogen) were investigated for their potential antimicrobial and antioxidant properties. Results Extracts of Cortex Magnoliae Officinalis had the strongest activities against M. Smegmatis, C. albicans, B. subtilis and S. aureus. Boiled extracts of Cortex Magnoliae Officinalis, Folium Murraya Koenigii, Herba Polygonis Hydropiperis and Herba Houttuyniae demonstrated greater antioxidant activities than other tested medicinal plants. Conclusion Among the eight tested medicinal plants, Cortex Magnoliae Officinalis showed the highest antimicrobial and antioxidant activities. Different methods of extraction yield different spectra of bioactivities. PMID:19038060

  7. Phytochemical screening and antimicrobial activities of the constituents isolated from Koelreuteria paniculata leaves.

    PubMed

    Ghahari, Somayeh; Alinezhad, Heshmatollah; Nematzadeh, Ghorban Ali; Ghahari, Sajjad

    2015-01-01

    Methanolic extract of Golden rain leaves was fractionated by column chromatography on silica gel and 18 fractions were obtained. Antimicrobial activities of fractions were investigated against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa as quality control bacteria and fungus Pyricularia grisea which causes Blast disease in rice. Fractions showed more antibacterial activity at 0.04 g/mL concentration only on B. subtilis and S. aureus as gram positive bacteria. Also, three fractions indicated excellent antifungal effect on fungus P. grisea. Moreover, in the present study, fractions that showed very good effect on microorganisms were used for gas chromatography-mass spectrometry analysis to identify different phytochemicals. PMID:25813082

  8. Antimicrobial activity and cellular toxicity of nanoparticle-polymyxin B conjugates

    NASA Astrophysics Data System (ADS)

    Park, Soonhyang; Chibli, Hicham; Wong, Jody; Nadeau, Jay L.

    2011-05-01

    We investigate the antimicrobial activity and cytotoxicity to mammalian cells of conjugates of the peptide antibiotic polymyxin B (PMB) to Au nanoparticles and CdTe quantum dots. Au nanoparticles fully covered with PMB are identical in antimicrobial activity to the free drug alone, whereas partially-conjugated Au particles show decreased effectiveness in proportion to the concentration of Au. CdTe-PMB conjugates are more toxic to Escherichia coli than PMB alone, resulting in a flattening of the steep PMB dose-response curve. The effect is most pronounced at low concentrations of PMB, with a greater effect on the concentration required to reduce growth by half (IC50) than on the concentration needed to inhibit all growth (minimum inhibitory concentration, MIC). The Gram positive organism Staphylococcus aureus is resistant to both PMB and CdTe, showing minimal increased sensitivity when the two are conjugated. Measurement of reactive oxygen species (ROS) generation shows a significant reduction in photo-generated hydroxyl and superoxide radicals with CdTe-PMB as compared with bare CdTe. There is a corresponding reduction in toxicity of QD-PMB versus bare CdTe to mammalian cells, with nearly 100% survival in fibroblasts exposed to bactericidal concentrations of QD-PMB. The situation in bacteria is more complex: photoexcitation of the CdTe particles plays a small role in IC50 but has a significant effect on the MIC, suggesting that at least two different mechanisms are responsible for the antimicrobial action seen. These results show that it is possible to create antimicrobial agents using concentrations of CdTe quantum dots that do not harm mammalian cells.

  9. Curvularia haloperoxidase: antimicrobial activity and potential application as a surface disinfectant.

    PubMed

    Hansen, Eva H; Albertsen, Line; Schäfer, Thomas; Johansen, Charlotte; Frisvad, Jens C; Molin, Søren; Gram, Lone

    2003-08-01

    A presumed antimicrobial enzyme system, the Curvularia haloperoxidase system, was examined with the aim of evaluating its potential as a sanitizing agent. In the presence of hydrogen peroxide, Curvularia haloperoxidase facilitates the oxidation of halides, such as chloride, bromide, and iodide, to antimicrobial compounds. The Curvularia haloperoxidase system caused several-log-unit reductions in counts of bacteria (Pseudomonas spp., Escherichia coli, Serratia marcescens, Aeromonas salmonicida, Shewanella putrefaciens, Staphylococcus epidermidis, and Listeria monocytogenes), yeasts (Candida sp. and Rhodotorula sp.), and filamentous fungi (Aspergillus niger, Aspergillus tubigensis, Aspergillus versicolor, Fusarium oxysporum, Penicillium chrysogenum, and Penicillium paxilli) cultured in suspension. Also, bacteria adhering to the surfaces of contact lenses were killed. The numbers of S. marcescens and S. epidermidis cells adhering to contact lenses were reduced from 4.0 and 4.9 log CFU to 1.2 and 2.7 log CFU, respectively, after treatment with the Curvularia haloperoxidase system. The killing effect of the Curvularia haloperoxidase system was rapid, and 10(6) CFU of E. coli cells/ml were eliminated within 10 min of treatment. Furthermore, the antimicrobial effect was short lived, causing no antibacterial effect against E. coli 10 min after the system was mixed. Bovine serum albumin (1%) and alginate (1%) inhibited the antimicrobial activity of the Curvularia haloperoxidase system, whereas glucose and Tween 20 did not affect its activity. In conclusion, the Curvularia haloperoxidase system is an effective sanitizing system and has the potential for a vast range of applications, for instance, for disinfection of contact lenses or medical devices. PMID:12902249

  10. Curvularia Haloperoxidase: Antimicrobial Activity and Potential Application as a Surface Disinfectant

    PubMed Central

    Hansen, Eva H.; Albertsen, Line; Schäfer, Thomas; Johansen, Charlotte; Frisvad, Jens C.; Molin, Søren; Gram, Lone

    2003-01-01

    A presumed antimicrobial enzyme system, the Curvularia haloperoxidase system, was examined with the aim of evaluating its potential as a sanitizing agent. In the presence of hydrogen peroxide, Curvularia haloperoxidase facilitates the oxidation of halides, such as chloride, bromide, and iodide, to antimicrobial compounds. The Curvularia haloperoxidase system caused several-log-unit reductions in counts of bacteria (Pseudomonas spp., Escherichia coli, Serratia marcescens, Aeromonas salmonicida, Shewanella putrefaciens, Staphylococcus epidermidis, and Listeria monocytogenes), yeasts (Candida sp. and Rhodotorula sp.), and filamentous fungi (Aspergillus niger, Aspergillus tubigensis, Aspergillus versicolor, Fusarium oxysporum, Penicillium chrysogenum, and Penicillium paxilli) cultured in suspension. Also, bacteria adhering to the surfaces of contact lenses were killed. The numbers of S. marcescens and S. epidermidis cells adhering to contact lenses were reduced from 4.0 and 4.9 log CFU to 1.2 and 2.7 log CFU, respectively, after treatment with the Curvularia haloperoxidase system. The killing effect of the Curvularia haloperoxidase system was rapid, and 106 CFU of E. coli cells/ml were eliminated within 10 min of treatment. Furthermore, the antimicrobial effect was short lived, causing no antibacterial effect against E. coli 10 min after the system was mixed. Bovine serum albumin (1%) and alginate (1%) inhibited the antimicrobial activity of the Curvularia haloperoxidase system, whereas glucose and Tween 20 did not affect its activity. In conclusion, the Curvularia haloperoxidase system is an effective sanitizing system and has the potential for a vast range of applications, for instance, for disinfection of contact lenses or medical devices. PMID:12902249

  11. Effect of tea tree (Melaleuca alternifolia) oil as a natural antimicrobial agent in lipophilic formulations.

    PubMed

    Mantil, Elisabeth; Daly, Grace; Avis, Tyler J

    2015-01-01

    There has been increased interest surrounding the use of tea tree oil (TTO) as a natural antimicrobial. In this study, the antimicrobial activity of TTO and its components were investigated in vitro and in a predominantly lipid-based personal care formulation. In vitro, TTO showed minimal inhibitory concentrations of 0.2% (for Saccharomyces cerevisiae and Pythium sulcatum), 0.4% (for Escherichia coli, Bacillus subtilis, and Rhizopus stolonifer), and 0.8% (for Botrytis cinerea). TTO at 0.08%-0.8% was often as efficient as parabens. Comparison of the antimicrobial activities of TTO components showed that terpinen-4-ol and γ-terpinene were generally most effective in inhibiting microbial growth. TTO activity in a personal care product was evaluated through air and water exposure, artificial inoculation, and shelf life studies. While TTO did not increase shelf life of unopened products, it decreased microbial load in products exposed to water and air. Results from this study support that antimicrobial activity of TTO can be attributed to varying levels of its components and that low levels of TTO were effective in reducing microbial growth during the use of the product. This study showed that TTO can act as a suitable preservative system within an oil-based formulation. PMID:25515896

  12. Protocols to test the activity of antimicrobial peptides against the honey bee pathogen Paenibacillus larvae.

    PubMed

    Khilnani, Jasmin C; Wing, Helen J

    2015-10-01

    Paenibacillus larvae is the causal agent of the honey bee disease American Foulbrood. Two enhanced protocols that allow the activity of antimicrobial peptides to be tested against P. larvae are presented. Proof of principle experiments demonstrate that the honey bee antimicrobial peptide defensin 1 is active in both assays. PMID:26210039

  13. Antimicrobial susceptibilities of multidrug-resistant Campylobacter jejuni and C. coli strains: in vitro activities of 20 antimicrobial agents.

    PubMed

    Lehtopolku, Mirva; Nakari, Ulla-Maija; Kotilainen, Pirkko; Huovinen, Pentti; Siitonen, Anja; Hakanen, Antti J

    2010-03-01

    There is a paucity of information regarding antimicrobial agents that are suitable to treat severe infections caused by multidrug-resistant Campylobacter spp. Our aim was to identify agents that are potentially effective against multiresistant Campylobacter strains. The in vitro activities of 20 antimicrobial agents against 238 Campylobacter strains were analyzed by determining MICs by the agar plate dilution method or the Etest. These strains were selected from 1,808 Campylobacter isolates collected from Finnish patients between 2003 and 2005 and screened for macrolide susceptibility by using the disk diffusion test. The 238 strains consisted of 183 strains with erythromycin inhibition zone diameters of < or =23 mm and 55 strains with inhibition zone diameters of >23 mm. Of the 238 Campylobacter strains, 19 were resistant to erythromycin by MIC determinations (MIC > or = 16 microg/ml). Given that the resistant strains were identified among the collection of 1,808 isolates, the frequency of erythromycin resistance was 1.1%. All erythromycin-resistant strains were multidrug resistant, with 18 (94.7%) of them being resistant to ciprofloxacin (MIC > or = 4 microg/ml). The percentages of resistance to tetracycline and amoxicillin-clavulanic acid (co-amoxiclav) were 73.7% and 31.6%, respectively. All macrolide-resistant strains were susceptible to imipenem, meropenem, and tigecycline. Ten (52.6%) multiresistant strains were identified as being Campylobacter jejuni strains, and 9 (47.4%) were identified as being C. coli strains. These data demonstrate that the incidence of macrolide resistance was low but that the macrolide-resistant Campylobacter strains were uniformly multidrug resistant. In addition to the carbapenems, tigecycline was also highly effective against these multidrug-resistant Campylobacter strains in vitro. Its efficacy for the treatment of human campylobacteriosis should be evaluated in clinical trials. PMID:20038624

  14. Broad Spectrum Antimicrobial Activity of Forest-Derived Soil Actinomycete, Nocardia sp. PB-52

    PubMed Central

    Sharma, Priyanka; Kalita, Mohan C.; Thakur, Debajit

    2016-01-01

    A mesophilic actinomycete strain designated as PB-52 was isolated from soil samples of Pobitora Wildlife Sanctuary of Assam, India. Based on phenotypic and molecular characteristics, the strain was identified as Nocardia sp. which shares 99.7% sequence similarity with Nocardia niigatensis IFM 0330 (NR_112195). The strain is a Gram-positive filamentous bacterium with rugose spore surface which exhibited a wide range of antimicrobial activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative bacteria, and yeasts. Optimization for the growth and antimicrobial activity of the strain PB-52 was carried out in batch culture under shaking condition. The optimum growth and antimicrobial potential of the strain were recorded in GLM medium at 28°C, initial pH 7.4 of the medium and incubation period of 8 days. Based on polyketide synthases (PKS) and non-ribosomal peptide synthetases (NRPS) gene-targeted PCR amplification, the occurrence of both of these biosynthetic pathways was detected which might be involved in the production of antimicrobial compounds in PB-52. Extract of the fermented broth culture of PB-52 was prepared with organic solvent extraction method using ethyl acetate. The ethyl acetate extract of PB-52 (EA-PB-52) showed lowest minimum inhibitory concentration (MIC) against S. aureus MTCC 96 (0.975 μg/mL) whereas highest was recorded against Klebsiella pneumoniae ATCC 13883 (62.5 μg/mL). Scanning electron microscopy (SEM) revealed that treatment of the test microorganisms with EA-PB-52 destroyed the targeted cells with prominent loss of cell shape and integrity. In order to determine the constituents responsible for its antimicrobial activity, EA-PB-52 was subjected to chemical analysis using gas chromatography-mass spectrometry (GC-MS). GC-MS analysis showed the presence of twelve different chemical constituents in the extract, some of which are reported to possess diverse biological activity. These results confirmed that the presence of bioactive constituents in EA-PB-52 could be a promising source for the development of potent antimicrobial agents effective against wide range of microbial pathogens including MRSA. PMID:27047463

  15. Broad Spectrum Antimicrobial Activity of Forest-Derived Soil Actinomycete, Nocardia sp. PB-52.

    PubMed

    Sharma, Priyanka; Kalita, Mohan C; Thakur, Debajit

    2016-01-01

    A mesophilic actinomycete strain designated as PB-52 was isolated from soil samples of Pobitora Wildlife Sanctuary of Assam, India. Based on phenotypic and molecular characteristics, the strain was identified as Nocardia sp. which shares 99.7% sequence similarity with Nocardia niigatensis IFM 0330 (NR_112195). The strain is a Gram-positive filamentous bacterium with rugose spore surface which exhibited a wide range of antimicrobial activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative bacteria, and yeasts. Optimization for the growth and antimicrobial activity of the strain PB-52 was carried out in batch culture under shaking condition. The optimum growth and antimicrobial potential of the strain were recorded in GLM medium at 28°C, initial pH 7.4 of the medium and incubation period of 8 days. Based on polyketide synthases (PKS) and non-ribosomal peptide synthetases (NRPS) gene-targeted PCR amplification, the occurrence of both of these biosynthetic pathways was detected which might be involved in the production of antimicrobial compounds in PB-52. Extract of the fermented broth culture of PB-52 was prepared with organic solvent extraction method using ethyl acetate. The ethyl acetate extract of PB-52 (EA-PB-52) showed lowest minimum inhibitory concentration (MIC) against S. aureus MTCC 96 (0.975 μg/mL) whereas highest was recorded against Klebsiella pneumoniae ATCC 13883 (62.5 μg/mL). Scanning electron microscopy (SEM) revealed that treatment of the test microorganisms with EA-PB-52 destroyed the targeted cells with prominent loss of cell shape and integrity. In order to determine the constituents responsible for its antimicrobial activity, EA-PB-52 was subjected to chemical analysis using gas chromatography-mass spectrometry (GC-MS). GC-MS analysis showed the presence of twelve different chemical constituents in the extract, some of which are reported to possess diverse biological activity. These results confirmed that the presence of bioactive constituents in EA-PB-52 could be a promising source for the development of potent antimicrobial agents effective against wide range of microbial pathogens including MRSA. PMID:27047463

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  17. General principles of antimicrobial therapy.

    PubMed

    Leekha, Surbhi; Terrell, Christine L; Edson, Randall S

    2011-02-01

    Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community. PMID:21282489

  18. The antimicrobial effects of propolis collected in different regions in the Basque Country (Northern Spain).

    PubMed

    Bonvehí, Josep Serra; Gutiérrez, Arrate Lacalle

    2012-04-01

    The antimicrobial activity of 19 propolis extracts prepared in different solvents (ethanol and propylene glycol) (EEP/PEP), was evaluated against some bacterial and fungal isolates using the agar-well diffusion method. It was verified that all the samples tested showed antimicrobial activity, although results varied considerably between samples. Results revealed that both types of propolis extracts showed highly sensitive antimicrobial action against Gram-positive bacteria and fungi at a concentration of 20% (Staphylococcus aureus, Streptococcus mutans, Candida albicans and Saccharomyces cerevisae) with a minimal inhibitory concentration (MIC) ranging from 0.5 to 1.5 mg/ml, with a moderate effect against Streptococcus pyogenes (MIC from 17 to 26 mg/ml). To our knowledge, this is the first study showing elevated antimicrobial activity against Gram-negative bacteria [Salmonella enterica (MIC from 0.6 to 1.4 mg/ml)] and lesser activity against Helicobacter pylori (MIC from 6 to 14 mg/ml), while Escherichia coli was resistant. This concluded that the Basque propolis had a strong and dose-dependent activity against most of the microbial strains tested, while database comparison revealed that phenolic substances were responsible for this inhibition, regardless of their geographical origin and the solvent employed for extraction. Statistical analysis showed no significant differences (P ≤ 0.05) between EEP and PEP extracts. PMID:22805915

  19. Antimicrobial activity of clove and cinnamon essential oils against Listeria monocytogenes in pasteurized milk.

    PubMed

    Cava, R; Nowak, E; Taboada, A; Marin-Iniesta, F

    2007-12-01

    The antimicrobial activity of essential oils (EOs) of cinnamon bark, cinnamon leaf, and clove against Listeria monocytogenes Scott A were studied in semiskimmed milk incubated at 7 degrees C for 14 days and at 35 degrees C for 24 h. The MIC was 500 ppm for cinnamon bark EO and 3,000 ppm for the cinnamon leaf and clove EOs. These effective concentrations increased to 1,000 ppm for cinnamon bark EO, 3,500 ppm for clove EO, and 4,000 ppm for cinnamon leaf EO when the semiskimmed milk was incubated at 35 degrees C for 24 h. Partial inhibitory concentrations and partial bactericidal concentrations were obtained for all the assayed EOs. The MBC was 3,000 ppm for the cinnamon bark EO, 10,500 ppm for clove EO, and 11,000 ppm for cinnamon leaf EO. The incubation temperature did not affect the MBC of the EOs but slightly increased the MIC at 35 degrees C. The increased activity at the lower temperature could be attributed to the increased membrane fluidity and to the membrane-perturbing action of EOs. The influence of the fat content of milk on the antimicrobial activity of EOs was tested in whole and skimmed milk. In milk samples with higher fat content, the antimicrobial activity of the EOs was reduced. These results indicate the possibility of using these three EOs in milk beverages as natural antimicrobials, especially because milk beverages flavored with cinnamon and clove are consumed worldwide and have been increasing in popularity in recent years. PMID:18095427

  20. Chemical compositions and antimicrobial activities of four different Anatolian propolis samples.

    PubMed

    Uzel, Ataç; Sorkun, Kadriye; Onçağ, Ozant; Cogŭlu, Dilşah; Gençay, Omür; Salih, Bekir

    2005-01-01

    Propolis means a gum that is gathered by bees from various plants. It is known for its biological properties, having antibacterial, antifungal and healing properties. The aims of this study were to evaluate the antimicrobial activity of four different Anatolian propolis samples on different groups of microorganisms including some oral pathogens and comparison between their chemical compositions. Ethanol extracts of propolis (EEP) were prepared from four different Anatolian propolis samples and examined whether EEP inhibit the growth of the test microorganisms or not. For the antimicrobial activity assays, minimum inhibitory concentrations (MIC) were determined by using macrodilution method. The MIC values of the most effective propolis (TB) were 2 microg/ml for Streptococcus sobrinus and Enterococcus faecalis, 4 microg/ml for Micrococcus luteus, Candida albicans and C. krusei, 8 microg/ml for Streptococcus mutans, Staphylococcus aureus, Staphylococcus epidermidis and Enterobacter aerogenes, 16 microg/ml for Escherichia coli and C. tropicalis and 32 microg/ml for Salmonella typhimurium and Pseudomonas aeruginosa. The chemical compositions of EEP's were determined by high-temperature high-resolution gas chromatography coupled to mass spectrometry. The main compounds of four Anatolian propolis samples were flavonoids such as pinocembrin, pinostropin, isalpinin, pinobanksin, quercetin, naringenin, galangine and chrysin. Although propolis samples were collected from different regions of Anatolia all showed significant antimicrobial activity against the Gram positive bacteria and yeasts. Propolis can prevent dental caries since it demonstrated significant antimicrobial activity against the microorganisms such as Streptococcus mutans, Streptococcus sobrinus and C. albicans, which involves in oral diseases. PMID:15881836

  1. In vitro antimicrobial activity of phytotherapic Uncaria tomentosa against endodontic pathogens.

    PubMed

    Herrera, Daniel R; Tay, Lidia Y; Rezende, Eluise C; Kozlowski, Vitoldo A; Santos, Elizabete B dos

    2010-09-01

    The aim of this study was to evaluate the antimicrobial activity of Uncaria tomentosa (Willd.) DC (cat's claw) against Enterococcus faecalis, Staphylococcus aureus, and Candida albicans. Suspensions with 10(8) cells/ml of each microorganism were plated in triplicate on Mueller-Hinton agar. Wells in the agar were made and filled with 2% chlorhexidine (CHX) gel, 2% cat's claw (CC) gel, 2% CHX+CC, and 1% hydroxyethylcellulose (NAT) gel. Inhibition halos were measured after 24 h at 37°C and differences were analyzed using one-way ANOVA. The mean diameter of the microbial growth inhibition zones of 2% CHX+CC against the tested microbial strains ranged from 21.7 to 33.5 mm. This was the most effective substance against E. faecalis and C. albicans, followed by CHX and CC. Against S. aureus, CHX+CC, CHX, and CC showed similar antimicrobial activity (P > 0.05). The results indicate that all the investigated compounds had antimicrobial activity against microorganisms frequently found in infected root-filled teeth. PMID:20881342

  2. Antimicrobial activity of endodontic sealers based on calcium hydroxide and MTA.

    PubMed

    Tanomaru, Juliane M G; Tanomaru-Filho, Mário; Hotta, Juliana; Watanabe, Evandro; Ito, Izabel Y

    2008-01-01

    The aim of this study was to evaluate the antimicrobial activity of a new root canal sealer containing calcium hydroxide (Acroseal) and the root canal sealer based on MTA (Endo CPM Sealer), in comparison with traditional sealers (Sealapex, Sealer 26 and Intrafill) and white MTA-Angelus, against five different microorganism strains. The materials and their components were evaluated after manipulation, employing the agar diffusion method. A base layer was made using Müller-Hinton agar (MH) and wells were made by removing agar. The materials were placed into the wells immediately after manipulation. The microorganisms used were: Micrococcus luteus (ATCC9341), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (ATCC27853), Candida albicans (ATCC 10231), and Enterococcus faecalis (ATCC 10541). The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37 degrees C for 24 h. The results showed that Sealapex and its base paste, Sealer 26 and its powder, Endo CPM Sealer and its powder, white MTA and its powder all presented antimicrobial activity against all strains. Intrafill and its liquid presented antimicrobial activity against all strains except P. aeruginosa and Acroseal was effective only against M. luteus and S. aureus. PMID:19177851

  3. Composition, antimicrobial activity and in vitro cytotoxicity of essential oil from Cinnamomum zeylanicum Blume (Lauraceae).

    PubMed

    Unlu, Mehmet; Ergene, Emel; Unlu, Gulhan Vardar; Zeytinoglu, Hulya Sivas; Vural, Nilufer

    2010-11-01

    The essential oil from the bark of Cinnamomum zeylanicum Blume was analyzed by GC-MS and bioassays were carried out. Nine constituents representing 99.24% of the oil were identified by GC-MS. The major compounds in the oil were (E)-cinnamaldehyde (68.95%), benzaldehyde (9.94%) and (E)-cinnamyl acetate (7.44%). The antimicrobial activity of the oil was investigated in order to evaluate its efficacy against 21 bacteria and 4 Candida species, using disc diffusion and minimum inhibitory concentration methods. The essential oil showed strong antimicrobial activity against all microorganisms tested. The cytotoxic and apoptotic effects of the essential oil on ras active (5RP7) and normal (F2408) fibroblasts were examined by MTT assay and acridine orange/ethidium bromide staining, respectively. The cytotoxicity of the oil was quite strong with IC(50) values less than 20 μg/mL for both cell lines. 5RP7 cells were affected stronger than normal cells. Morphological observation of apoptotic cells indicated the induction of apoptosis at the high level of the oil, especially in 5RP7 cells. The present study showed the potential antimicrobial and anticarcinogenic properties of the essential oil of cinnamon bark, indicating the possibilities of its potential use in the formula of natural remedies for the topical treatment of infections and neoplasms. PMID:20828600

  4. Morphology-dependent antimicrobial activity of Cu/CuxO nanoparticles.

    PubMed

    Xiong, Lu; Tong, Zhong-Hua; Chen, Jie-Jie; Li, Ling-Li; Yu, Han-Qing

    2015-12-01

    Cu/CuxO nanoparticles (NPs) with different morphologies have been synthesized with glucose as a reducing agent. The X-ray diffraction and Scanning electron microscopy imaging show that the Cu/CuxO NPs have fine crystalline peaks with homogeneous polyhedral, flower-like, and thumbtack-like morphologies. Their antimicrobial activities were evaluated on inactivation of Escherichia coli using a fluorescence-based live/dead staining method. Dissolution of copper ions from these NPs was determined. Results demonstrated a significant growth inhibition for these NPs with different morphologies, and the flower-like Cu/CuxO NPs were the most effective form, where more copper ions were dissolved into the culture media. Surface free energy calculations based on first-principle density functional theory show that different crystal facets of the copper NPs have diverse surface energy, indicating the highest reactivity of the flower-like NPs, which is consistent with the results from the dissolution study and antimicrobial activity test. Together, these results suggest that the difference between the surface free energy may be a cause for their morphology-dependent antimicrobial activity. PMID:26407711

  5. In vitro antimicrobial activity of propolis samples from different geographical origins against certain oral pathogens.

    PubMed

    Koru, Ozgur; Toksoy, Fulya; Acikel, Cengiz Han; Tunca, Yasar Meric; Baysallar, Mehmet; Uskudar Guclu, Aylin; Akca, Eralp; Ozkok Tuylu, Asli; Sorkun, Kadriye; Tanyuksel, Mehmet; Salih, Bekir

    2007-01-01

    Propolis is an agent having antimicrobial properties, however, its composition can vary depending on the area where it is collected. In the present study, the antimicrobial activity of five propolis samples, collected from four different regions in Turkey and from Brazil, against nine anaerobic strains was evaluated. Ethanol extracts of propolis (EEP) were prepared from propolis samples and we determined minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of EEP on the growth of test microorganisms by using agar dilution method. All strains were susceptible and MIC values ranged from 4 to 512 microg/ml for propolis activity. Propolis from Kazan-Ankara showed most effective MIC values to the studied microorganisms. MBC values of Kazan-Ankara EEP samples were ranged from 8 to 512 microg/ml. Death was observed within 4 h of incubation for Peptostreptococcus anaerobius and micros and Lactobacillus acidophilus and Actinomyces naeslundii, while 8 h for Prevotella oralis and Prevotella melaninogenica and Porphyromonas gingivalis, 12 h for Fusobacterium nucleatum, 16 h for Veillonella parvula. It was shown that propolis samples were more effective against Gram positive anaerobic bacteria than Gram negative ones. The organic chemical compositions of EEPs were determined by high-resolution gas chromatography coupled to mass spectrometry (GC-MS). The main compounds of EEPs were flavonoids such as pinobanksin, quercetin, naringenin, galangine, chrysin and aromatic acids such as cafeic acid. Because of increased antimicrobial resistance, propolis may be kept in mind in the treatment of oral cavity diseases. PMID:17475517

  6. Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

    PubMed Central

    PRADO, Maíra; da SILVA, Emmanuel João Nogueira Leal; DUQUE, Thais Mageste; ZAIA, Alexandre Augusto; FERRAZ, Caio Cezar Randi; de ALMEIDA, José Flávio Affonso; GOMES, Brenda Paula Figueiredo de Almeida

    2015-01-01

    Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer. Objectives : The purpose of this study was to compare the antimicrobial and cytotoxic effects of a 37% phosphoric acid solution to other irrigants commonly used in endodontics. Material and Methods : The substances 37% phosphoric acid, 17% EDTA, 10% citric acid, 2% chlorhexidine (solution and gel), and 5.25% NaOCl were evaluated. The antimicrobial activity was tested against Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Actinomyces meyeri, Parvimonas micra, Porphyromonas gingivalis, and Prevotella nigrescens according to the agar diffusion method. The cytotoxicity of the irrigants was determined by using the MTT assay. Results : Phosphoric acid presented higher antimicrobial activity compared to the other tested irrigants. With regard to the cell viability, this solution showed results similar to those with 5.25% NaOCl and 2% chlorhexidine (gel and solution), whereas 17% EDTA and 10% citric acid showed higher cell viability compared to other irrigants. Conclusion : Phosphoric acid demonstrated higher antimicrobial activity and cytotoxicity similar to that of 5.25% NaOCl and 2% chlorhexidine (gel and solution). PMID:26018307

  7. Olive Mill Waste Extracts: Polyphenols Content, Antioxidant, and Antimicrobial Activities

    PubMed Central

    Leouifoudi, Inass; Harnafi, Hicham; Zyad, Abdelmajid

    2015-01-01

    Natural polyphenols extracts have been usually associated with great bioactive properties. In this work, we investigated in vitro antioxidant and antimicrobial potential of the phenolic olive mill wastewater extracts (OWWE) and the olive cake extracts (OCE). Using the Folin Ciocalteux method, OWWE contained higher total phenol content compared to OCE (8.90 ± 0.728 g/L versus 0.95 ± 0.017 mg/g). The phenolic compounds identification was carried out with a performance liquid chromatograph coupled to tandem mass spectrometry equipment (HPLC-ESI-MS). With this method, a list of polyphenols from OWWE and OCE was obtained. The antioxidant activity was measured in aqueous (DPPH) and emulsion (BCBT) systems. Using the DPPH assay, the results show that OWWE was more active than OCE and interestingly the extracts originating from mountainous areas were more active than those produced from plain areas (EC50 = 12.1 ± 5.6 μg/mL; EC50 = 157.7 ± 34.9 μg/mL, resp.). However, when the antioxidant activity was reversed in the BCBT, OCE produced from plain area was more potent than mountainous OCE. Testing by the gel diffusion assay, all the tested extracts have showed significant spectrum antibacterial activity against Staphylococcus aureus, whereas the biophenols extracts showed more limited activity against Escherichia coli and Streptococcus faecalis. PMID:26693221

  8. Antimicrobial and inhibitory enzyme activity of N-(benzyl) and quaternary N-(benzyl) chitosan derivatives on plant pathogens.

    PubMed

    Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M

    2014-10-13

    Chemical modification of a biopolymer chitosan by introducing quaternary ammonium moieties into the polymer backbone enhances its antimicrobial activity. In the present study, a series of quaternary N-(benzyl) chitosan derivatives were synthesized and characterized by (1)H-NMR, FT-IR and UV spectroscopic techniques. The antimicrobial activity against crop-threatening bacteria Agrobacterium tumefaciens and Erwinia carotovora and fungi Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum and Phytophthora infestans were evaluated. The results proved that the grafting of benzyl moiety or quaternization of the derivatives onto chitosan molecule was successful in inhibiting the microbial growth. Moreover, increase water-solubility of the compounds by quaternization significantly increased the activity against bacteria and fungi. Exocellular enzymes including polygalacturonase (PGase), pectin-lyase (PLase), polyphenol oxidase (PPOase) and cellulase were also affected at 1000 mg/L. These compounds especially quaternary-based chitosan derivatives that have good inhibitory effect should be potentially used as antimicrobial agents in crop protection. PMID:25037402

  9. Antimicrobial activity of thin solid films of silver doped hydroxyapatite prepared by sol-gel method.

    PubMed

    Iconaru, Simona Liliana; Chapon, Patrick; Le Coustumer, Philippe; Predoi, Daniela

    2014-01-01

    In this work, the preparation and characterization of silver doped hydroxyapatite thin films were reported and their antimicrobial activity was characterized. Silver doped hydroxyapatite (Ag:HAp) thin films coatings substrate was prepared on commercially pure Si disks by sol-gel method. The silver doped hydroxyapatite thin films were characterized by various techniques such as Scanning electron microscopy (SEM) with energy Dispersive X-ray attachment (X-EDS), Fourier transform infrared spectroscopy (FT-IR), and glow discharge optical emission spectroscopy (GDOES). These techniques have permitted the structural and chemical characterisation of the silver doped hydroxyapatite thin films. The antimicrobial effect of the Ag:HAp thin films on Escherichia coli and Staphylococcus aureus bacteria was then investigated. This is the first study on the antimicrobial effect of Ag:HAp thin films obtained by sol-gel method. The results of this study have shown that the Ag:HAp thin films with x(Ag) = 0.5 are effective against E. coli and S. aureus after 24 h. PMID:24523630

  10. Antimicrobial Activity of Thin Solid Films of Silver Doped Hydroxyapatite Prepared by Sol-Gel Method

    PubMed Central

    Iconaru, Simona Liliana; Chapon, Patrick; Le Coustumer, Philippe; Predoi, Daniela

    2014-01-01

    In this work, the preparation and characterization of silver doped hydroxyapatite thin films were reported and their antimicrobial activity was characterized. Silver doped hydroxyapatite (Ag:HAp) thin films coatings substrate was prepared on commercially pure Si disks by sol-gel method. The silver doped hydroxyapatite thin films were characterized by various techniques such as Scanning electron microscopy (SEM) with energy Dispersive X-ray attachment (X-EDS), Fourier transform infrared spectroscopy (FT-IR), and glow discharge optical emission spectroscopy (GDOES). These techniques have permitted the structural and chemical characterisation of the silver doped hydroxyapatite thin films. The antimicrobial effect of the Ag:HAp thin films on Escherichia coli and Staphylococcus aureus bacteria was then investigated. This is the first study on the antimicrobial effect of Ag:HAp thin films obtained by sol-gel method. The results of this study have shown that the Ag:HAp thin films with xAg = 0.5 are effective against E. coli and S. aureus after 24 h. PMID:24523630

  11. Antimicrobial Organometallic Dendrimers with Tunable Activity against Multidrug-Resistant Bacteria.

    PubMed

    Abd-El-Aziz, Alaa S; Agatemor, Christian; Etkin, Nola; Overy, David P; Lanteigne, Martin; McQuillan, Katherine; Kerr, Russell G

    2015-11-01

    Multidrug-resistant pathogens are an increasing threat to public health. In an effort to curb the virulence of these pathogens, new antimicrobial agents are sought. Here we report a new class of antimicrobial organometallic dendrimers with tunable activity against multidrug-resistant Gram-positive bacteria that included methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Mechanistically, these redox-active, cationic organometallic dendrimers induced oxidative stress on bacteria and also disrupted the microbial cell membrane. The minimum inhibitory concentrations, which provide a quantitative measure of the antimicrobial activity of these dendrimers, were in the low micromolar range. AlamarBlue cell viability assay also confirms the antimicrobial activity of these dendrimers. Interestingly, these dendrimers were noncytotoxic to epidermal cell lines and to mammalian red blood cells, making them potential antimicrobial platforms for topical applications. PMID:26452022

  12. Preclinical screening of phyllanthus amarus ethanolic extract for its analgesic and antimicrobial activity

    PubMed Central

    Bhat, S. Sham; Hegde, K. Sundeep; Chandrashekhar, Sharath; Rao, S. N.; Manikkoth, Shyamjith

    2015-01-01

    Background: To discover a new agent which possesses dual property of analgesic and antimicrobial activity, thereby reducing the burden of polypharmacy. Phyllanthus amarus was screened for its analgesic and antimicrobial activities. Objectives: The objective was to evaluate the analgesic and antimicrobial activity, of P. amarus ethanolic extract (PAEE). Materials and Methods: The ethanolic extract of P. amarus was prepared using Soxhlet apparatus. An in vivo study using Swiss albino mice was done to screen the central and peripheral analgesic activity of P. amarus extract. The extract was administered at a dose of 100 mg/kg body weight orally. The peripheral analgesic activity was assessed using acetic acid induced writhing test. The central analgesic activity was assessed using Eddy's hot plate apparatus. An in vitro study was carried out to study the antimicrobial activity of the above extract using selected species of Streptococcus mutans, and S. salivarius. The antimicrobial activities were determined using the agar well method. Results: The ethanolic extract of P. amarus showed significant (P < 0.05) peripheral and central analgesic activity. In vitro antimicrobial screening indicated that the ethanolic extract had shown a zone of inhibition against S. mutans and S. salivarius in the agar wells. Conclusion: This study showed that PAEE exhibited significant analgesic and antimicrobial activities. PMID:26692753

  13. In vitro antimicrobial activity of linezolid tested against vancomycin-resistant enterococci isolated in Brazilian hospitals.

    PubMed

    Reis, A O; Cordeiro, J C; Machado, A M; Sader, H S

    2001-10-01

    The emergence of vancomycin-resistant enterococci (VRE) has been described recently in Brazil. This is in contrast to the USA and Europe, where the VRE appeared in the late 1980s. The progressive increase in VRE isolation poses important problems in the antimicrobial therapy of nosocomial infections. Treatment options and effective antimicrobial agents for VRE are often limited and the possibility of transfer of vancomycin genes to other Gram-positive microorganisms continues. In the search for antimicrobial agents for multiresistant Gram-positive cocci, compounds such as linezolid and quinupristin/dalfopristin have been evaluated. The present study was conducted to evaluate the in vitro activity of the oxazolidinone linezolid and 10 other antimicrobial agents, including quinupristin-dalfopristin, against multiresistant enterococci isolated in Brazilian hospitals. Thirty-three vancomycin resistant isolates (17 Enterococcus faecium and 16 E. faecalis), were analyzed. Strains were isolated from patients at São Paulo Hospital, Oswaldo Cruz Hospital, Hospital do Servidor Público Estadual, Santa Marcelina Hospital, Santa Casa de Misericórdia de São Paulo, and Hospital de Clínicas do Paraná. The samples were tested by a broth microdilution method following the National Committee for Clinical Laboratory Standards (NCCLS) recommendations. All isolates were molecular typed using pulsed-field gel electrophoresis (PFGE). Linezolid was the most active compound against these multiresistant enterococci, showing 100% inhibition at the susceptible breakpoints. Quinupristin/dalfopristin and teicoplanin showed poor activity against both species. The molecular typing results suggest that there has been interhospital spread of vancomycin resistant E. faecium and E. faecalis among Brazilian hospitals. The results of this study indicate that linezolid is an appropriate therapeutic option for the treatment of vancomycin-resistant enterococci infections in Brazil. PMID:11779450

  14. Biological activities of commercial bee pollens: antimicrobial, antimutagenic, antioxidant and anti-inflammatory.

    PubMed

    Pascoal, Ananias; Rodrigues, Sandra; Teixeira, Alfredo; Fes, Xesus; Estevinho, Leticia M

    2014-01-01

    Bee pollen is considered, since memorable times, a good source of nourishing substances and energy. The present study aimed to evaluate the biological activities of eight commercial bee pollens purchased from the market. The origin of sample A was not specified in the labeling; samples B, C, D and G were from Portugal and the remaining were from Spain. The sample E presented the highest value of phenolics (32.152.12 mg/g) and the H the lowest (18.55095 mg/g). Sample C had the highest value of flavonoids (10.141.57 mg/g) and sample H the lowest (3.920.68 mg/g). All the samples exhibited antimicrobial activity, being Staphylococcus aureus the most sensitive and Candida glabrata the most resistant of the microorganisms studied. All the samples exhibited antimutagenic activity, even though some samples were more effective in decreasing the number of gene conversion colonies and mutant colonies. Regarding the antioxidant activity, assessed using two methods, the more effective was sample B. The anti-inflammatory activity, assessed using the hyaluronidase enzyme, was highest in samples B and D. Pearson's correlation coefficients between polyphenols, flavonoids, antioxidant activity and antimicrobial activity were computed. It was also performed a discriminant analysis. PMID:24262487

  15. Gram-positive bacterial cell envelopes: The impact on the activity of antimicrobial peptides.

    PubMed

    Malanovic, Nermina; Lohner, Karl

    2016-05-01

    A number of cationic antimicrobial peptides, effectors of innate immunity, are supposed to act at the cytoplasmic membrane leading to permeabilization and eventually membrane disruption. Thereby, interaction of antimicrobial peptides with anionic membrane phospholipids is considered to be a key factor in killing of bacteria. Recently, evidence was provided that killing takes place only when bacterial cell membranes are completely saturated with peptides. This adds to an ongoing debate, which role cell wall components such as peptidoglycan, lipoteichoic acid and lipopolysaccharide may play in the killing event, i.e. if they rather entrap or facilitate antimicrobial peptides access to the cytoplasmic membrane. Therefore, in this review we focused on the impact of Gram-positive cell wall components for the mode of action and activity of antimicrobial peptides as well as in innate immunity. This led us to conclude that interaction of antimicrobial peptides with peptidoglycan may not contribute to a reduction of their antimicrobial activity, whereas interaction with anionic lipoteichoic acids may reduce the local concentration of antimicrobial peptides on the cytoplasmic membrane necessary for sufficient destabilization of the membranes and bacterial killing. Further affinity studies of antimicrobial peptides toward the different cell wall as well as membrane components will be needed to address this problem on a quantitative level. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26577273

  16. Antimicrobial polymers - The antibacterial effect of photoactivated nano titanium dioxide polymer composites

    SciTech Connect

    Huppmann, T. Leonhardt, S. E-mail: erhard.krampe@tum.de; Krampe, E. E-mail: erhard.krampe@tum.de; Wintermantel, E.; Yatsenko, S. Radovanovic, I. E-mail: m.bastian@skz.de; Bastian, M. E-mail: m.bastian@skz.de

    2014-05-15

    To obtain a polymer with antimicrobial properties for medical and sanitary applications nanoscale titanium dioxide (TiO{sub 2}) particles have been incorporated into a medical grade polypropylene (PP) matrix with various filler contents (0 wt %, 2 wt %, 10 wt % and 15 wt %). The standard application of TiO{sub 2} for antimicrobial efficacy is to deposit a thin TiO{sub 2} coating on the surface. In contrast to the common way of applying a coating, TiO{sub 2} particles were applied into the bulk polymer. With this design we want to ensure antimicrobial properties even after application of impact effects that could lead to surface defects. The filler material (Aeroxide® TiO{sub 2} P25, Evonik) was applied via melt compounding and the compounding parameters were optimized with respect to nanoscale titanium dioxide. In a next step the effect of UV-irradiation on the compounds concerning their photocatalytic activity, which is related to the titanium dioxide amount, was investigated. The photocatalytic effect of TiO{sub 2}-PP-composites was analyzed by contact angle measurement, by methylene blue testing and by evaluation of inactivation potential for Escherichia coli (E.coli) bacteria. The dependence of antimicrobial activity on the filler content was evaluated, and on the basis of different titanium dioxide fractions adequate amounts of additives within the compounds were discussed. Specimens displayed a higher photocatalytic and also antimicrobial activity and lower contact angles with increasing titania content. The results suggest that the presence of titania embedded in the PP matrix leads to a surface change and a photocatalytic effect with bacteria killing result.

  17. Antimicrobial polymers - The antibacterial effect of photoactivated nano titanium dioxide polymer composites

    NASA Astrophysics Data System (ADS)

    Huppmann, T.; Yatsenko, S.; Leonhardt, S.; Krampe, E.; Radovanovic, I.; Bastian, M.; Wintermantel, E.

    2014-05-01

    To obtain a polymer with antimicrobial properties for medical and sanitary applications nanoscale titanium dioxide (TiO2) particles have been incorporated into a medical grade polypropylene (PP) matrix with various filler contents (0 wt %, 2 wt %, 10 wt % and 15 wt %). The standard application of TiO2 for antimicrobial efficacy is to deposit a thin TiO2 coating on the surface. In contrast to the common way of applying a coating, TiO2 particles were applied into the bulk polymer. With this design we want to ensure antimicrobial properties even after application of impact effects that could lead to surface defects. The filler material (Aeroxide TiO2 P25, Evonik) was applied via melt compounding and the compounding parameters were optimized with respect to nanoscale titanium dioxide. In a next step the effect of UV-irradiation on the compounds concerning their photocatalytic activity, which is related to the titanium dioxide amount, was investigated. The photocatalytic effect of TiO2-PP-composites was analyzed by contact angle measurement, by methylene blue testing and by evaluation of inactivation potential for Escherichia coli (E.coli) bacteria. The dependence of antimicrobial activity on the filler content was evaluated, and on the basis of different titanium dioxide fractions adequate amounts of additives within the compounds were discussed. Specimens displayed a higher photocatalytic and also antimicrobial activity and lower contact angles with increasing titania content. The results suggest that the presence of titania embedded in the PP matrix leads to a surface change and a photocatalytic effect with bacteria killing result.

  18. Antimicrobial activity of extractable conifer heartwood compounds toward Phytophthora ramorum.

    PubMed

    Manter, Daniel K; Kelsey, Rick G; Karchesy, Joseph J

    2007-11-01

    Ethyl acetate extracts from heartwood of seven western conifer trees and individual volatile compounds in the extracts were tested for antimicrobial activity against Phytophthora ramorum. Extracts from incense and western redcedar exhibited the strongest activity, followed by yellow-cedar, western juniper, and Port-Orford-cedar with moderate activity, and no activity for Douglas-fir and redwood extracts. Chemical composition of the extracts varied both qualitatively and quantitatively among the species with a total of 37 compounds identified by mass spectrometry. Of the 13 individual heartwood compounds bioassayed, three showed strong activity with a Log(10) EC(50) less than or equal to 1.0 ppm (hinokitiol, thymoquinone, and nootkatin), three expressed moderate activity ranging from 1.0-2.0 ppm (nootkatol, carvacrol, and valencene-11,12-diol), four compounds had weak activity at 2.0-3.0 ppm [alpha-terpineol, valencene-13-ol, (+)-beta-cedrene, (-)-thujopsene], and three had no activity [(+)-cedrol, delta-cadinene, and methyl carvacrol]. All of the most active compounds contained a free hydroxyl group, except thymoquinone. The importance of a free hydroxyl was demonstrated by the tremendous difference in activity between carvacrol (Log(10) EC(50) 1.81 +/- 0.08 ppm) and methyl carvacrol (Log(10) EC(50) >3.0 ppm). A field trial in California, showed that heartwood chips from redcedar placed on the forest floor for 4 months under Umbellularia californica (California bay laurel) with symptoms of P. ramorum leaf blight significantly limited the accumulation of P. ramorum DNA in the litter layer, compared with heartwood chips from redwood. PMID:17929093

  19. Antimicrobial, antioxidant and anti-inflammatory phenolic activities in extra virgin olive oil.

    PubMed

    Cicerale, S; Lucas, L J; Keast, R S J

    2012-04-01

    The Mediterranean diet is associated with a lower incidence of chronic degenerative diseases and higher life expectancy. These health benefits have been partially attributed to the dietary consumption of extra virgin olive oil (EVOO) by Mediterranean populations, and more specifically the phenolic compounds naturally present in EVOO. Studies involving humans and animals (in vivo and in vitro) have demonstrated that olive oil phenolic compounds have potentially beneficial biological effects resulting from their antimicrobial, antioxidant and anti-inflammatory activities. This paper summarizes current knowledge on the biological activities of specific olive oil phenolic compounds together with information on their concentration in EVOO, bioavailability and stability over time. PMID:22000808

  20. Preliminary Screening of Endophytic Fungi from Medicinal Plants in Malaysia for Antimicrobial and Antitumor Activity

    PubMed Central

    Radu, Son; Kqueen, Cheah Yoke

    2002-01-01

    The screening of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeast and fungi was carried out on isopropanol extracts prepared from 121 isolates of endophytic fungi isolated from medicinal plants in Malaysia. Sensitivity was found to vary among the microorganisms. Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were susceptible to extracts from three, two and two isolates of endophytic fungi, respectively. None were found effective against Salmonella typhimurium. Sixteen endophytic fungal isolates tested were also found to exhibit antitumor activity in the yeast cell-based assay. PMID:22844221

  1. Antimicrobial Activity of Artemisinin and Precursor Derived from In Vitro Plantlets of Artemisia annua L.

    PubMed Central

    Appalasamy, Suganthi; Lo, Kiah Yann; Ch'ng, Song Jin; Nornadia, Ku; Othman, Ahmad Sofiman; Chan, Lai-Keng

    2014-01-01

    Artemisia annua L., a medicinal herb, produces secondary metabolites with antimicrobial property. In Malaysia due to the tropical hot climate, A. annua could not be planted for production of artemisinin, the main bioactive compound. In this study, the leaves of three in vitro A. annua L. clones were, extracted and two bioactive compounds, artemisinin and a precursor, were isolated by thin layer chromatography. These compounds were found to be effective in inhibiting the growth of Gram-positive and Gram-negative bacteria but not Candida albicans. Their antimicrobial activity was similar to that of antibactericidal antibiotic streptomycin. They were found to inhibit the growth of the tested microbes at the minimum inhibition concentration of 0.09 mg/mL, and toxicity test using brine shrimp showed that even the low concentration of 0.09 mg/mL was very lethal towards the brine shrimps with 100% mortality rate. This study hence indicated that in vitro cultured plantlets of A. annua can be used as the alternative method for production of artemisinin and its precursor with antimicrobial activities. PMID:24575401

  2. Alarin but not its alternative-splicing form, GALP (Galanin-like peptide) has antimicrobial activity

    SciTech Connect

    Wada, Akihiro; Wong, Pooi-Fong; Hojo, Hironobu; Hasegawa, Makoto; Ichinose, Akitoyo; Llanes, Rafael; Kubo, Yoshinao; Senba, Masachika; Ichinose, Yoshio

    2013-05-03

    Highlights: • Alarin inhibits the growth of E. coli but not S. aureus. • Alarin’s potency is comparable to LL-37 in inhibiting the growth of E. coli. • Alarin can cause bacterial membrane blebbing. • Alalin does not induce hemolysis on erythrocytes. -- Abstract: Alarin is an alternative-splicing form of GALP (galanin-like peptide). It shares only 5 conserved amino acids at the N-terminal region with GALP which is involved in a diverse range of normal brain functions. This study seeks to investigate whether alarin has additional functions due to its differences from GALP. Here, we have shown using a radial diffusion assay that alarin but not GALP inhibited the growth of Escherichia coli (strain ML-35). The conserved N-terminal region, however, remained essential for the antimicrobial activity of alarin as truncated peptides showed reduced killing effect. Moreover, alarin inhibited the growth of E. coli in a similar potency as human cathelicidin LL-37, a well-studied antimicrobial peptide. Electron microscopy further showed that alarin induced bacterial membrane blebbing but unlike LL-37, it did not cause hemolysis of erythrocytes. In addition, alarin is only active against the gram-negative bacteria, E. coli but not the gram-positive bacteria, Staphylococcus aureus. Thus, these data suggest that alarin has potentials as an antimicrobial and should be considered for the development in human therapeutics.

  3. Colonic MUC2 mucin regulates the expression and antimicrobial activity of β-defensin 2.

    PubMed

    Cobo, E R; Kissoon-Singh, V; Moreau, F; Chadee, K

    2015-11-01

    In this study we identified mechanisms at the colonic mucosa by which MUC2 mucin regulated the production of β-defensin in a proinflammatory milieu but functionally protected susceptible bacteria from its antimicrobial effects. The regulator role of MUC2 on production of β-defensin 2 in combination with the proinflammatory cytokine interleukin-1β (IL-1β) was confirmed using purified human colonic MUC2 mucin and colonic goblet cells short hairpin RNA (shRNA) silenced for MUC2. In vivo, Muc2(-/-) mice showed impaired β-defensin mRNA expression and peptide localization in the colon as compared with Muc2(+/-) and Muc2(+/+) littermates. Importantly, purified MUC2 mucin abrogated the antimicrobial activity of β-defensin 2 against nonpathogenic and enteropathogenic Escherichia coli. Sodium metaperiodate oxidation of MUC2 removed the capacity of MUC2 to stimulate β-defensin production and MUC2's inhibition of defensin antimicrobial activity. This study highlights that a defective MUC2 mucin barrier, typical in inflammatory bowel diseases, may lead to deficient stimulation of β-defensin 2 and an unbalanced microbiota that favor the growth of β-defensin-resistant microbes such as Clostridium difficile. PMID:25921338

  4. Colonic MUC2 mucin regulates the expression and antimicrobial activity of β-defensin 2

    PubMed Central

    Cobo, E R; Kissoon-Singh, V; Moreau, F; Chadee, K

    2015-01-01

    In this study we identified mechanisms at the colonic mucosa by which MUC2 mucin regulated the production of β-defensin in a proinflammatory milieu but functionally protected susceptible bacteria from its antimicrobial effects. The regulator role of MUC2 on production of β-defensin 2 in combination with the proinflammatory cytokine interleukin-1β (IL-1β) was confirmed using purified human colonic MUC2 mucin and colonic goblet cells short hairpin RNA (shRNA) silenced for MUC2. In vivo, Muc2−/− mice showed impaired β-defensin mRNA expression and peptide localization in the colon as compared with Muc2+/− and Muc2+/+ littermates. Importantly, purified MUC2 mucin abrogated the antimicrobial activity of β-defensin 2 against nonpathogenic and enteropathogenic Escherichia coli. Sodium metaperiodate oxidation of MUC2 removed the capacity of MUC2 to stimulate β-defensin production and MUC2's inhibition of defensin antimicrobial activity. This study highlights that a defective MUC2 mucin barrier, typical in inflammatory bowel diseases, may lead to deficient stimulation of β-defensin 2 and an unbalanced microbiota that favor the growth of β-defensin-resistant microbes such as Clostridium difficile. PMID:25921338

  5. Antimicrobial activity of Nerolidol and its derivatives against airborne microbes and further biological activities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nerolidol and its derivatives, namely cis-nerolidol, O-methyl-nerolidol, O-ethyl-nerolidol, (-)-alpha-bisabolol, trans,trans-farnesol and its main natural source Cabreuva essential oil, were tested for their antimicrobial activity against airborne microbes and antifungal properties against plant pat...

  6. Antimicrobial activity of lemongrass oil against Salmonella enterica on organic leafy greens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to discover new and natural antimicrobial treatments against Salmonella Newport on organic produce, we evaluated the antimicrobial effect of lemongrass essential oil on four different types of organic leafy greens inoculated with S. Newport. The effects of lemongrass treatment exposure...

  7. Antioxidant capacity, radical scavenger activity, lipid oxidation protection analysis and antimicrobial activity of red grape extracts from different varieties cultivated in Portugal.

    PubMed

    Correia, Ana C; Jordão, António M

    2015-01-01

    The aim of this study was to investigate the antioxidant capacity, radical scavenger activity, lipid oxidation protection and antimicrobial activity of grape extracts from 12 different red grape varieties cultivated in Portugal. The mean values of total phenolic content quantified in grape extracts varied from 833.7 to 2005.6 mg/L gallic acid. Antioxidant capacity results showed different values for each grape variety ranging from 3.96 to 32.96 mm/L Fe(II). The scavenger activity values ranged from 15.99% to 54.82% for the superoxide radical and from 11.79% to 29.67% for the hydroxyl radical. The grape extracts with the highest antioxidant capacity had a positive effect on the lipid oxidation protection and induced low peroxide values in butter samples. Finally, concerning antimicrobial activity, grape extracts from Touriga Nacional and Tinta Roriz grape varieties had significant antimicrobial activity, especially notable for total mesophilic aerobics. PMID:25110146

  8. Antimicrobial activity and phytochemical analysis of crude extracts and essential oils from medicinal plants.

    PubMed

    Silva, N C C; Barbosa, L; Seito, L N; Fernandes, A

    2012-01-01

    We aimed to establish a phytochemical analysis of the crude extracts and performed GC-MS of the essential oils (EOs) of Eugenia uniflora L. (Myrtaceae) and Asteraceae species Baccharis dracunculifolia DC, Matricaria chamomilla L. and Vernonia polyanthes Less, as well as determining their antimicrobial activity. Establishment of the minimal inhibitory concentrations of the crude extracts and EOs against 16 Staphylococcus aureus and 16 Escherichia coli strains from human specimens was carried out using the dilution method in Mueller-Hinton agar. Some phenolic compounds with antimicrobial properties were established, and all EOs had a higher antimicrobial activity than the extracts. Matricaria chamomilla extract and E. uniflora EO were efficient against S. aureus strains, while E. uniflora and V. polyanthes extracts and V. polyanthes EO showed the best antimicrobial activity against E. coli strains. Staphylococcus aureus strains were more susceptible to the tested plant products than E. coli, but all natural products promoted antimicrobial growth inhibition. PMID:22007687

  9. Scolopendin 2, a cationic antimicrobial peptide from centipede, and its membrane-active mechanism.

    PubMed

    Lee, Heejeong; Hwang, Jae-Sam; Lee, Jaeho; Kim, Jae Il; Lee, Dong Gun

    2015-02-01

    Scolopendin 2 is a 16-mer peptide (AGLQFPVGRIGRLLRK) derived from the centipede Scolopendra subspinipes mutilans. We observed that this peptide exhibited antimicrobial activity in a salt-dependent manner against various fungal and bacterial pathogens and showed no hemolytic effect in the range of 1.6 μM to 100 μM. Circular dichroism analysis showed that the peptide has an α-helical properties. Furthermore, we determined the mechanism(s) of action using flow cytometry and by investigating the release of intracellular potassium. The results showed that the peptide permeabilized the membranes of Escherichia coli O157 and Candida albicans, resulting in loss of intracellular potassium ions. Additionally, bis-(1,3-dibutylbarbituric acid) trimethine oxonol and 3,3'-dipropylthiacarbocyanine iodide assays showed that the peptide caused membrane depolarization. Using giant unilamellar vesicles encapsulating calcein and large unilamellar vesicles containing fluorescein isothiocyanate-dextran, which were similar in composition to typical E. coli O157 and C. albicans membranes, we demonstrated that scolopendin 2 disrupts membranes, resulting in a pore size between 4.8 nm and 5.0 nm. Thus, we have demonstrated that a cationic antimicrobial peptide, scolopendin 2, exerts its broad-spectrum antimicrobial effects by forming pores in the cell membrane. PMID:25462167

  10. Lack of Antimicrobial Bactericidal Activity in Mycobacterium abscessus

    PubMed Central

    Maurer, Florian P.; Bruderer, Vera L.; Ritter, Claudia; Castelberg, Claudio; Bloemberg, Guido V.

    2014-01-01

    Antibiotic therapy of infections caused by the emerging pathogen Mycobacterium abscessus is challenging due to the organism's natural resistance toward most clinically available antimicrobials. We investigated the bactericidal activity of antibiotics commonly administered in M. abscessus infections in order to better understand the poor therapeutic outcome. Time-kill curves were generated for clinical M. abscessus isolates, Mycobacterium smegmatis, and Escherichia coli by using antibiotics commonly categorized as bactericidal (amikacin and moxifloxacin) or bacteriostatic (tigecycline and linezolid). In addition, the impact of aminoglycoside-modifying enzymes on the mode of action of substrate and nonsubstrate aminoglycosides was studied by using M. smegmatis as a model organism. While amikacin and moxifloxacin were bactericidal against E. coli, none of the tested compounds showed bactericidal activity against M. abscessus. Further mechanistic investigations of the mode of action of aminoglycosides in M. smegmatis revealed that the bactericidal activity of tobramycin and gentamicin was restored by disruption of the chromosomal aac(2′) gene in the mycobacterial genome. The lack of bactericidal antibiotics in currently recommended treatment regimens provides a reasonable explanation for the poor therapeutic outcome in M. abscessus infection. Our findings suggest that chromosomally encoded drug-modifying enzymes play an important role in the lack of aminoglycoside bactericidal activity against rapidly growing mycobacteria. PMID:24752273

  11. In vitro antimicrobial effect of the tissue conditioner containing silver nanoparticles

    PubMed Central

    2011-01-01

    PURPOSE The aim of this study was to identify in vitro antimicrobial activity of the tissue conditioner containing silver nanoparticles on microbial strains, Staphylococcus aureus, Streptococcus mutans and Candida albicans. MATERIALS AND METHODS Experimental disc samples (20.0×3.0 mm) of tissue conditioner (GC Soft-Liner, GC cooperation, Tokyo, Japan) containing 0.1 - 3.0% silver nanoparticles (0%: control) were fabricated. Samples were placed on separate culture plate dish and microbial suspensions (100 µL) of tested strains were inoculated then incubated at 37℃. Microbial growth was verified at 24 hrs and 72 hrs and the antimicrobial effects of samples were evaluated as a percentage of viable cells in withdrawn suspension (100 µL). Data were recorded as the mean of three colony forming unit (CFU) numerations and the borderline of the antimicrobial effect was determined at 0.1% viable cells. RESULTS A 0.1% silver nanoparticles combined to tissue conditioner displayed minimal bactericidal effect against Staphylococcus aureus and Streptococcus mutans strains, a 0.5% for fungal strain. Control group did not show any microbial inhibitory effect and there were no statistical difference between 24 hrs and extended 72 hrs incubation time (P > .05). CONCLUSION Within the limitation of this in vitro study, the results suggest that the tissue conditioner containing silver nanoparticles could be an antimicrobial dental material in denture plaque control. Further mechanical stability and toxicity studies are still required. PMID:21503189

  12. In vitro activity of 79 antimicrobial agents against Corynebacterium group D2.

    PubMed Central

    García-Rodriguez, J A; García Sánchez, J E; Muñoz Bellido, J L; Nebreda Mayoral, T; García Sánchez, E; García García, I

    1991-01-01

    Corynebacterium group D2 (CGD2) is involved in urinary tract infections in patients with underlying predisposing factors. This microorganism is highly resistant to a number of antimicrobial agents. We tested the activities of 79 antimicrobial agents against CGD2. beta-Lactams, aminoglycosides, and macrolides were ineffective. Fluorinated quinolones showed irregular activities, ofloxacin being the most active one. Doxycycline, rifampin, and mainly glycopeptides (vancomycin and teicoplanin) were the most active antibiotics against CGD2. PMID:1759839

  13. Native thrombocidin-1 and unfolded thrombocidin-1 exert antimicrobial activity via distinct structural elements.

    PubMed

    Kwakman, Paulus H S; Krijgsveld, Jeroen; de Boer, Leonie; Nguyen, Leonard T; Boszhard, Laura; Vreede, Jocelyne; Dekker, Henk L; Speijer, Dave; Drijfhout, Jan W; te Velde, Anje A; Crielaard, Wim; Vogel, Hans J; Vandenbroucke-Grauls, Christina M J E; Zaat, Sebastian A J

    2011-12-16

    Chemokines (chemotactic cytokines) can have direct antimicrobial activity, which is apparently related to the presence of a distinct positively charged patch on the surface. However, chemokines can retain antimicrobial activity upon linearization despite the loss of their positive patch, thus questioning the importance of this patch for activity. Thrombocidin-1 (TC-1) is a microbicidal protein isolated from human blood platelets. TC-1 only differs from the chemokine NAP-2/CXCL7 by a two-amino acid C-terminal deletion, but this truncation is crucial for antimicrobial activity. We assessed the structure-activity relationship for antimicrobial activity of TC-1. Reduction of the charge of the TC-1-positive patch by replacing lysine 17 with alanine reduced the activity against bacteria and almost abolished activity against the yeast Candida albicans. Conversely, augmentation of the positive patch by increasing charge density or size resulted in a 2-3-fold increased activity against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis but did not substantially affect activity against C. albicans. Reduction of TC-1 resulted in loss of the folded conformation, but this disruption of the positive patch did not affect antimicrobial activity. Using overlapping 15-mer synthetic peptides, we demonstrate peptides corresponding to the N-terminal part of TC-1 to have similar antimicrobial activity as intact TC-1. Although we demonstrate that the positive patch is essential for activity of folded TC-1, unfolded TC-1 retained antimicrobial activity despite the absence of a positive patch. This activity is probably exerted by a linear peptide stretch in the N-terminal part of the molecule. We conclude that intact TC-1 and unfolded TC-1 exert antimicrobial activity via distinct structural elements. PMID:22025617

  14. Native Thrombocidin-1 and Unfolded Thrombocidin-1 Exert Antimicrobial Activity via Distinct Structural Elements

    PubMed Central

    Kwakman, Paulus H. S.; Krijgsveld, Jeroen; de Boer, Leonie; Nguyen, Leonard T.; Boszhard, Laura; Vreede, Jocelyne; Dekker, Henk L.; Speijer, Dave; Drijfhout, Jan W.; te Velde, Anje A.; Crielaard, Wim; Vogel, Hans J.; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2011-01-01

    Chemokines (chemotactic cytokines) can have direct antimicrobial activity, which is apparently related to the presence of a distinct positively charged patch on the surface. However, chemokines can retain antimicrobial activity upon linearization despite the loss of their positive patch, thus questioning the importance of this patch for activity. Thrombocidin-1 (TC-1) is a microbicidal protein isolated from human blood platelets. TC-1 only differs from the chemokine NAP-2/CXCL7 by a two-amino acid C-terminal deletion, but this truncation is crucial for antimicrobial activity. We assessed the structure-activity relationship for antimicrobial activity of TC-1. Reduction of the charge of the TC-1-positive patch by replacing lysine 17 with alanine reduced the activity against bacteria and almost abolished activity against the yeast Candida albicans. Conversely, augmentation of the positive patch by increasing charge density or size resulted in a 2–3-fold increased activity against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis but did not substantially affect activity against C. albicans. Reduction of TC-1 resulted in loss of the folded conformation, but this disruption of the positive patch did not affect antimicrobial activity. Using overlapping 15-mer synthetic peptides, we demonstrate peptides corresponding to the N-terminal part of TC-1 to have similar antimicrobial activity as intact TC-1. Although we demonstrate that the positive patch is essential for activity of folded TC-1, unfolded TC-1 retained antimicrobial activity despite the absence of a positive patch. This activity is probably exerted by a linear peptide stretch in the N-terminal part of the molecule. We conclude that intact TC-1 and unfolded TC-1 exert antimicrobial activity via distinct structural elements. PMID:22025617

  15. Analysis of the antimicrobial activity of local anaesthetics used for dental analgesia.

    PubMed

    Pelz, Klaus; Wiedmann-Al-Ahmad, Margit; Bogdan, Christian; Otten, Jörg-Elard

    2008-01-01

    Seven local anaesthetics and their active anaesthetic components [Ultracaine D-S (articaine hydrochloride), Carbostesin (bupivacaine hydrochloride), Scandicaine (mepivacaine hydrochloride), Xylonest (prilocaine hydrochloride), Xylocaine (lidocaine hydrochloride), Hostacaine (butanilicaine phosphate) and Novocaine (procaine hydrochloride)] were tested for their antimicrobial activity against 311 bacterial strains from 52 different species and 14 Candida albicans strains. The tested pathogens were members of the oral flora, and partly members of the skin and intestinal flora. Additionally, the antimicrobial activity of methyl-4-hydroxybenzoate, sodium disulfite, adrenaline hydrogen tartrate and adrenaline (the preservative and vasoconstrictive components of the anaesthetics) was tested. For determination of MIC and minimal bactericidal concentration (MBC), the agar dilution method using Wilkins-Chalgren agar was applied. The trade preparation Ultracaine D-S showed the most prominent antimicrobial activity with regard to both MIC and MBC. Ultracaine D-S and its active substance, articaine hydrochloride, showed similar MIC values, suggesting that the antimicrobial activity is mainly caused by the anaesthetic component. Novocaine showed the lowest antimicrobial activity and did not inhibit 35 of the species tested. The MIC values of all local anaesthetics were between 0.25 and 16 mg ml(-1). The routinely applied concentration of Ultracaine D-S was roughly four times higher, and of Hostacaine was two times higher, than the MBC values for the tested bacteria, whereas for the other anaesthetics, the MBC values were not reached or exceeded with the concentrations used. The MIC range of the preservatives was 0.5-1.0 mg ml(-1) for methyl-4-hydroxybenzoate and 0.2-0.5 mg ml(-1) for sodium disulfite. The articaine MIC values were two to three serial dilution steps lower, and the butanilicaine MIC values one to two serial dilution steps lower, than the MIC of the preservatives. The mepivacaine mean MIC values were slightly lower for Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis and Staphylococcus aureus, but higher for Streptococcus intermedius, compared with the preservative methyl-4-hydroxybenzoate. The same result was found with Streptococcus intermedius and lidocaine. Screening of 20 MIC values of 4 pure anaesthetic substances and the corresponding preservative found 2/20 instances where the MICs of the preservatives against 5 representative species (67 strains) were lower, indicating that the antimicrobial effect was mainly due to the preservative, but 18/20 results where the pure anaesthetic component showed greater antimicrobial effects compared with the preservative. The in vitro results for Carbostesin, Scandicaine and especially for Novocaine indicate that a local disinfection should be done prior to injection of the anaesthetics. Due to the results obtained with nosocomial strains (Escherichia coli, S. aureus and Pseudomonas), disinfection of the mucous membranes should be performed routinely in immunocompromised patients, regardless of the anaesthetic used. PMID:18065672

  16. 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. PMID:26680221

  17. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the effects of storage and handling conditions on the antimicrobial activity of biodegradable composite films (polylactic acid and sugar beet pulp) coated with allyl isothiocyanate (AIT). Polylactic acid (PLA) and chitosan were incorporated with AIT and coated on one side of the film. T...

  18. Effects of the antimicrobial sulfamethoxazole on groundwater bacterial enrichment

    USGS Publications Warehouse

    Underwood, J.C.; Harvey, R.W.; Metge, D.W.; Repert, D.A.; Baumgartner, L.K.; Smith, R.L.; Roane, T.M.; Barber, L.B.

    2011-01-01

    The effects of "trace" (environmentally relevant) concentrations of the antimicrobial agent sulfamethoxazole (SMX) on the growth, nitrate reduction activity, and bacterial composition of an enrichment culture prepared with groundwater from a pristine zone of a sandy drinking-water aquifer on Cape Cod, MA, were assessed by laboratory incubations. When the enrichments were grown under heterotrophic denitrifying conditions and exposed to SMX, noticeable differences from the control (no SMX) were observed. Exposure to SMX in concentrations as low as 0.005 ??M delayed the initiation of cell growth by up to 1 day and decreased nitrate reduction potential (total amount of nitrate reduced after 19 days) by 47% (p = 0.02). Exposure to 1 ??M SMX, a concentration below those prescribed for clinical applications but higher than concentrations typically detected in aqueous environments, resulted in additional inhibitions: reduced growth rates (p = 5 ?? 10-6), lower nitrate reduction rate potentials (p = 0.01), and decreased overall representation of 16S rRNA gene sequences belonging to the genus Pseudomonas. The reduced abundance of Pseudomonas sequences in the libraries was replaced by sequences representing the genus Variovorax. Results of these growth and nitrate reduction experiments collectively suggest that subtherapeutic concentrations of SMX altered the composition of the enriched nitrate-reducing microcosms and inhibited nitrate reduction capabilities. ?? 2011 American Chemical Society.

  19. Clofazimine Contributes Sustained Antimicrobial Activity after Treatment Cessation in a Mouse Model of Tuberculosis Chemotherapy.

    PubMed

    Swanson, Rosemary V; Ammerman, Nicole C; Ngcobo, Bongani; Adamson, John; Moodley, Chivonne; Dorasamy, Afton; Moodley, Sashen; Mgaga, Zinhle; Bester, Linda A; Singh, Sanil D; Almeida, Deepak V; Grosset, Jacques H

    2016-05-01

    Experimental and clinical studies have indicated that the antileprosy drug clofazimine may contribute treatment-shortening activity when included in tuberculosis treatment regimens. Clofazimine accumulates to high levels in tissues, has a long half-life, and remains in the body for months after administration is stopped. We hypothesized that in tuberculosis treatment, accumulated clofazimine may contribute sustained antimicrobial activity after treatment cessation, and we used the BALB/c mouse model of chronic tuberculosis chemotherapy to address this hypothesis. Mycobacterium tuberculosis-infected mice were treated for 4 weeks or 8 weeks with either isoniazid alone, clofazimine alone, the first-line regimen rifampin-isoniazid-pyrazinamide-ethambutol, or a first-line regimen where clofazimine was administered in place of ethambutol. To evaluate posttreatment antimicrobial activity, bacterial regrowth in the lungs and spleens was assessed at the day of treatment cessation and 2, 4, 6, and 8 weeks after treatment was stopped. Bacterial regrowth was delayed in all mice receiving clofazimine, either alone or in combination, compared to the mice that did not receive clofazimine. This effect was especially evident in mice receiving multidrug therapy. In mice not receiving clofazimine, bacterial regrowth began almost immediately after treatment was stopped, while in mice receiving clofazimine, bacterial regrowth was delayed for up to 6 weeks, with the duration of sustained antimicrobial activity being positively associated with the time that serum clofazimine levels remained at or above the 0.25-μg/ml MIC for M. tuberculosis Thus, sustained activity of clofazimine may be important in the treatment-shortening effect associated with this drug. PMID:26926638

  20. Underlying Mechanism of Antimicrobial Activity of Chitosan Microparticles and Implications for the Treatment of Infectious Diseases

    PubMed Central

    Jeon, Soo Jin; Oh, Manhwan; Yeo, Won-Sik; Galvão, Klibs N.; Jeong, Kwang Cheol

    2014-01-01

    The emergence of antibiotic resistant microorganisms is a great public health concern and has triggered an urgent need to develop alternative antibiotics. Chitosan microparticles (CM), derived from chitosan, have been shown to reduce E. coli O157:H7 shedding in a cattle model, indicating potential use as an alternative antimicrobial agent. However, the underlying mechanism of CM on reducing the shedding of this pathogen remains unclear. To understand the mode of action, we studied molecular mechanisms of antimicrobial activity of CM using in vitro and in vivo methods. We report that CM are an effective bactericidal agent with capability to disrupt cell membranes. Binding assays and genetic studies with an ompA mutant strain demonstrated that outer membrane protein OmpA of E. coli O157:H7 is critical for CM binding, and this binding activity is coupled with a bactericidal effect of CM. This activity was also demonstrated in an animal model using cows with uterine diseases. CM treatment effectively reduced shedding of intrauterine pathogenic E. coli (IUPEC) in the uterus compared to antibiotic treatment. Since Shiga-toxins encoded in the genome of bacteriophage is often overexpressed during antibiotic treatment, antibiotic therapy is generally not recommended because of high risk of hemolytic uremic syndrome. However, CM treatment did not induce bacteriophage or Shiga-toxins in E. coli O157:H7; suggesting that CM can be a potential candidate to treat infections caused by this pathogen. This work establishes an underlying mechanism whereby CM exert antimicrobial activity in vitro and in vivo, providing significant insight for the treatment of diseases caused by a broad spectrum of pathogens including antibiotic resistant microorganisms. PMID:24658463

  1. Antimicrobial activity of pentacyclic triterpenes isolated from Acacia mellifera.

    PubMed

    Mutai, C; Bii, C; Rukunga, G; Ondicho, J; Mwitari, P; Abatis, D; Vagias, C; Roussis, V; Kirui, J

    2008-01-01

    Acacia mellifera has been used widely in traditional African medicines against various diseases. Among the Kipsigis community of Kenya, water extracts from the plant is used for the treatment of skin diseases, coughs and gastrointestinal ailments. The aim of the study was to provide scientific rationale for the use of the plant in traditional medicine through bioassay-guided fractionation of A. mellifera stem bark. Bioactivity testing was done against selected microbes using disc diffusion technique as outlined in Clinical Laboratory Standard Institute (CLSI). Structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR analyses, including HMQC, HMBC, and NOESY correlations. Fractionation yielded three triterpenoids; (20S)-oxolupane-30-al, (20R)-oxolupane-30-al, and betulinic acid. The three compounds were active against Staphylococcus aureus ATCC 25923 and only (20S)-oxolupane-30-al against clinical isolate of Microsporum gypseum. The three compounds had no activity against Escherichia coli ATCC 25922, Enterococcus feacalis, Candida albicans ATCC 90028, Cryptococcus neoformans, Trichophyton mentagrophyte, Candida krusei, Microsporum gypseum, and Sacharomyces cerevisiae. These results explain and support the use of A. mellifera stem barks for the treatment of infectious diseases in traditional Kenya medicine. It also shows that the antimicrobial activity is concentrated in the triterpenoid fractions. PMID:20162040

  2. Effect of naturally occurring antimicrobials and chemical preservatives on the growth of Aspergillus Parasiticus.

    PubMed

    Pillai, Prathesha; Ramaswamy, K

    2012-04-01

    Effect of water activity (aw, 0.99), pH (4.5) and their interaction on the growth inhibition of Aspergillus parasiticus was studied on potato dextrose agar (PDA) using various antimicrobial agents (citral, carvacrol, eugenol, cineole, thymol guaiacol, vanillin, anethol, potassium sorbate and sorbic acid). The results demonstrate that colony diameter (mm) exhibited a constant increase with time (zero order kinetics) for all antimicrobials evaluated. Eugenol and sorbic acid inhibited the test fungi at 300 and 600 ppm, respectively. Radial growth rate (RGR) of A. parasiticus was significantly (p < 0.05) different among different antimicrobials as well as the concentrations tested. However, this difference was not observed with higher concentration of citral, eugenol, vanillin and sorbic acid. Among the antimicrobials evaluated potassium sorbate, cineole, anethol and guaiacol were least effective. Thymol, eugenol and carvacrol were more effective in inhibiting A. parasiticus even with low concentration (150 ppm) as their mean RGR was zero even after 20 days of incubation (pH 4.5). PMID:23572846

  3. Evaluation of antioxidant and antimicrobial activities and phenolic profile for Hyssopus officinalis, Ocimum basilicum and Teucrium chamaedrys.

    PubMed

    Vlase, Laurian; Benedec, Daniela; Hanganu, Daniela; Damian, Grigore; Csillag, Ioan; Sevastre, Bogdan; Mot, Augustin C; Silaghi-Dumitrescu, Radu; Tilea, Ioan

    2014-01-01

    This study was designed to examine the in vitro antioxidant and antimicrobial activities and to characterize the polyphenolic composition of the ethanolic extracts of Hyssopus officinalis, Ocimum basilicum and Teucrium chamaedrys. Qualitative and quantitative analysis of the major phenolic compounds were conducted using high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). The total polyphenols, caffeic acid derivatives and flavonoids content was spectrophotometrically determined. The phenolic profile showed the presence of phenolic acid derivatives (caftaric, gentisic, caffeic, p-coumaric, chlorogenic and ferulic acids), flavonoid glycosides (rutin, isoquercitrin and quercitrin) and free flavonoid aglycons (luteolin, quercetin), in different concentrations. DPPH radical scavenging assay, Trolox equivalent antioxidant capacity (TEAC) method, hemoglobin ascorbate peroxidase activity inhibition (HAPX) assay, and electron paramagnetic resonance (EPR) radicals detection were employed, revealing several aspects of the antioxidant activities of these species. The antimicrobial tests were performed using the disk diffusion assay. These extracts contained a large amount of the polyphenolic compounds (77.72, 175.57, and 243.65 mg/g, respectively), and they showed a good antioxidant activity, as witnessed by a number of methods. T. chamaedrys had a high antimicrobial activity. Besides their antioxidant activity, the antimicrobial effect of these extracts confirms the biological activities of these herbal medicinal products. PMID:24786688

  4. Antimicrobial activity of aridicins, novel glycopeptide antibiotics with high and prolonged levels in blood.

    PubMed Central

    Grappel, S F; Giovenella, A J; Phillips, L; Pitkin, D H; Nisbet, L J

    1985-01-01

    Three new glycopeptide antibiotics, aridicins A, B, and C, produced by Kibdelosporangium aridum have a spectrum of antimicrobial activity in vitro which is similar to that of vancomycin. The antimicrobial activities of these glycopeptides against clinical bacterial isolates were compared with those of vancomycin and other related glycopeptide antibiotics in vitro by agar dilution and microtiter broth dilution tests and in vivo in mouse protection studies. In vitro they were somewhat less effective than vancomycin against strains of Staphylococcus aureus and less active against coagulase-negative Staphylococcus spp. However, they were more active than vancomycin against strains of Streptococcus faecalis and markedly superior to vancomycin and other glycopeptide antibiotics against strains of Clostridium difficile. In experimental infections, aridicin A was effective against strains of S. aureus, S. epidermidis, Streptococcus faecalis, and Streptococcus pyogenes, although its 50% effective doses were higher than those of vancomycin when administered after infection. After subcutaneous administration, aridicin A had a higher peak level in serum and a longer half-life than vancomycin or teicoplanin. The aridicins were markedly superior to vancomycin when administered prior to infection in mouse protection tests, indicating long-acting potential. PMID:3937489

  5. Draft Genome Sequence of Paenibacillus sp. Strain MSt1 with Broad Antimicrobial Activity, Isolated from Malaysian Tropical Peat Swamp Soil

    PubMed Central

    Ong, Kuan Shion; Yule, Catherine M.; Gan, Han Ming; Lee, Sui Mae

    2014-01-01

    We report the draft genome sequence of Paenibacillus sp. strain MSt1, which has broad-range antimicrobial activity, isolated from tropical peat swamp soil. Genes involved in antimicrobial biosynthesis are found to be present in this genome. PMID:25301658

  6. Draft Genome Sequence of Paenibacillus sp. Strain MSt1 with Broad Antimicrobial Activity, Isolated from Malaysian Tropical Peat Swamp Soil.

    PubMed

    Aw, Yoong Kit; Ong, Kuan Shion; Yule, Catherine M; Gan, Han Ming; Lee, Sui Mae

    2014-01-01

    We report the draft genome sequence of Paenibacillus sp. strain MSt1, which has broad-range antimicrobial activity, isolated from tropical peat swamp soil. Genes involved in antimicrobial biosynthesis are found to be present in this genome. PMID:25301658

  7. Antimicrobial activity of plant extracts against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes on fresh lettuce.

    PubMed

    Kim, Sung-Youn; Kang, Dong-Hyun; Kim, Jin-Ki; Ha, Yong-Geun; Hwang, Ju Young; Kim, Taewan; Lee, Seon-Ho

    2011-01-01

    Plant extracts have been found to be effective in reducing microorganisms. This study evaluated antimicrobial activity of 12 plant extracts against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes by using a disk diffusion assay, and Syzygium aromaticum (clove) showed the highest inhibitory effect. To investigate the efficacy of clove extract that inactivates pathogens on lettuce, inoculated lettuce with S. Typhimurium, E. coli O157:H7, and L. monocytogenes was treated with diluted clove extracts or distilled water for 0, 1, 3, 5, and 10 min. Clove extract treatment significantly reduced populations of the 3 tested pathogens from the surface of lettuce. Practical Application: This result indicated that clove extract is a useful antimicrobial agent to reduce the microbial level of foodborne pathogens on fresh lettuce. It also might be a natural antimicrobial for reducing or replacing chemical sanitizers in food preservation. PMID:21535692

  8. Silver Oxynitrate, an Unexplored Silver Compound with Antimicrobial and Antibiofilm Activity

    PubMed Central

    Lemire, Joe A.; Kalan, Lindsay; Bradu, Alexandru

    2015-01-01

    Historically it has been accepted, and recent research has established, that silver (Ag) is an efficacious antimicrobial agent. A dwindling pipeline of new antibiotics, combined with an increase in the number of antibiotic-resistant infections, is bringing Ag to the fore as a therapeutic compound to treat infectious diseases. Currently, many formulations of Ag are being deployed for commercial and medical purposes, with various degrees of effectiveness at killing microbial cells. Here, we evaluated the antimicrobial and antibiofilm capacity of our lead compound, silver oxynitrate [Ag(Ag3O4)2NO3 or Ag7NO11], against other metal compounds with documented antimicrobial activity, including Ag2SO4, AgNO3, silver sulfadiazine (AgSD), AgO, Ag2O, and CuSO4. Our findings reveal that Ag7NO11 eradicates biofilm and planktonic populations of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, uropathogenic Escherichia coli (UPEC), fluoroquinolone-resistant Pseudomonas aeruginosa (FQRP), and methicillin-resistant Staphylococcus aureus (MRSA) at lower concentrations than those of the other tested metal salts. Altogether, our results demonstrate that Ag7NO11 has an enhanced efficacy for the treatment of biofilm-forming pathogens. PMID:25918137

  9. Antimicrobial activity of a quaternary ammonium methacryloxy silicate-containing acrylic resin: a randomised clinical trial

    PubMed Central

    Liu, Si-ying; Tonggu, Lige; Niu, Li-na; Gong, Shi-qiang; Fan, Bing; Wang, Liguo; Zhao, Ji-hong; Huang, Cui; Pashley, David H.; Tay, Franklin R.

    2016-01-01

    Quaternary ammonium methacryloxy silicate (QAMS)-containing acrylic resin demonstrated contact-killing antimicrobial ability in vitro after three months of water storage. The objective of the present double-blind randomised clinical trial was to determine the in vivo antimicrobial efficacy of QAMS-containing orthodontic acrylic by using custom-made removable retainers that were worn intraorally by 32 human subjects to create 48-hour multi-species plaque biofilms, using a split-mouth study design. Two control QAMS-free acrylic disks were inserted into the wells on one side of an orthodontic retainer, and two experimental QAMS-containing acrylic disks were inserted into the wells on the other side of the same retainer. After 48 hours, the disks were retrieved and examined for microbial vitality using confocal laser scanning microscopy. No harm to the oral mucosa or systemic health occurred. In the absence of carry-across effect and allocation bias (disks inserted in the left or right side of retainer), significant difference was identified between the percentage kill in the biovolume of QAMS-free control disks (3.73 ± 2.11%) and QAMS-containing experimental disks (33.94 ± 23.88%) retrieved from the subjects (P ≤ 0.001). The results validated that the QAMS-containing acrylic exhibits favourable antimicrobial activity against plaque biofilms in vivo. The QAMS-containing acrylic may also be used for fabricating removable acrylic dentures. PMID:26903314

  10. Antimicrobial activity of a quaternary ammonium methacryloxy silicate-containing acrylic resin: a randomised clinical trial.

    PubMed

    Liu, Si-Ying; Tonggu, Lige; Niu, Li-Na; Gong, Shi-Qiang; Fan, Bing; Wang, Liguo; Zhao, Ji-Hong; Huang, Cui; Pashley, David H; Tay, Franklin R

    2016-01-01

    Quaternary ammonium methacryloxy silicate (QAMS)-containing acrylic resin demonstrated contact-killing antimicrobial ability in vitro after three months of water storage. The objective of the present double-blind randomised clinical trial was to determine the in vivo antimicrobial efficacy of QAMS-containing orthodontic acrylic by using custom-made removable retainers that were worn intraorally by 32 human subjects to create 48-hour multi-species plaque biofilms, using a split-mouth study design. Two control QAMS-free acrylic disks were inserted into the wells on one side of an orthodontic retainer, and two experimental QAMS-containing acrylic disks were inserted into the wells on the other side of the same retainer. After 48 hours, the disks were retrieved and examined for microbial vitality using confocal laser scanning microscopy. No harm to the oral mucosa or systemic health occurred. In the absence of carry-across effect and allocation bias (disks inserted in the left or right side of retainer), significant difference was identified between the percentage kill in the biovolume of QAMS-free control disks (3.73 ± 2.11%) and QAMS-containing experimental disks (33.94 ± 23.88%) retrieved from the subjects (P ≤ 0.001). The results validated that the QAMS-containing acrylic exhibits favourable antimicrobial activity against plaque biofilms in vivo. The QAMS-containing acrylic may also be used for fabricating removable acrylic dentures. PMID:26903314

  11. Production and antimicrobial activity of 3-hydroxypropionaldehyde from Bacillus subtilis strain CU12.

    PubMed

    Wise, C; Novitsky, L; Tsopmo, A; Avis, T J

    2012-12-01

    Bacillus subtilis strains are known to produce a vast array of antimicrobial compounds. However, some compounds remain to be identified. Disk assays performed in vitro with Bacillus subtilis CU12 showed a significant reduction in mycelial growth of Alternaria solani, Botrytis cinerea, Fusarium sambucinum, and Pythium sulcatum. Crude B. subtilis culture filtrates were subsequently extracted with ethyl acetate and butanol. A bioassay guided purification procedure revealed the presence of one major antifungal compound in the butanol extract. Purification of the compound was performed using a reverse-phase C18 solid phase extraction (SPE) cartridge and flash column chromatography. NMR data showed that the main antimicrobial compound was a cyclic dimer of 3-hydroxypropionaldehyde (HPA). This study demonstrated the antimicrobial activity of B. subtilis strain CU12 against phytopathogenic microorganisms is mediated at least in part by the production of HPA. It also suggests that this B. subtilis strain could be effective at controlling pathogens through protection of its ecological niche by antibiosis. PMID:23179100

  12. Silver oxynitrate, an unexplored silver compound with antimicrobial and antibiofilm activity.

    PubMed

    Lemire, Joe A; Kalan, Lindsay; Bradu, Alexandru; Turner, Raymond J

    2015-07-01

    Historically it has been accepted, and recent research has established, that silver (Ag) is an efficacious antimicrobial agent. A dwindling pipeline of new antibiotics, combined with an increase in the number of antibiotic-resistant infections, is bringing Ag to the fore as a therapeutic compound to treat infectious diseases. Currently, many formulations of Ag are being deployed for commercial and medical purposes, with various degrees of effectiveness at killing microbial cells. Here, we evaluated the antimicrobial and antibiofilm capacity of our lead compound, silver oxynitrate [Ag(Ag3O4)2NO3 or Ag7NO11], against other metal compounds with documented antimicrobial activity, including Ag2SO4, AgNO3, silver sulfadiazine (AgSD), AgO, Ag2O, and CuSO4. Our findings reveal that Ag7NO11 eradicates biofilm and planktonic populations of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, uropathogenic Escherichia coli (UPEC), fluoroquinolone-resistant Pseudomonas aeruginosa (FQRP), and methicillin-resistant Staphylococcus aureus (MRSA) at lower concentrations than those of the other tested metal salts. Altogether, our results demonstrate that Ag7NO11 has an enhanced efficacy for the treatment of biofilm-forming pathogens. PMID:25918137

  13. Structure-Activity Relationship Study of Novel Peptoids That Mimic the Structure of Antimicrobial Peptides

    PubMed Central

    Mojsoska, Biljana; Zuckermann, Ronald N.

    2015-01-01

    The constant emergence of new bacterial strains that resist the effectiveness of marketed antimicrobials has led to an urgent demand for and intensive research on new classes of compounds to combat bacterial infections. Antimicrobial peptoids comprise one group of potential candidates for antimicrobial drug development. The present study highlights a library of 22 cationic amphipathic peptoids designed to target bacteria. All the peptoids share an overall net charge of +4 and are 8 to 9 residues long; however, the hydrophobicity and charge distribution along the abiotic backbone varied, thus allowing an examination of the structure-activity relationship within the library. In addition, the toxicity profiles of all peptoids were assessed in human red blood cells (hRBCs) and HeLa cells, revealing the low toxicity exerted by the majority of the peptoids. The structural optimization also identified two peptoid candidates, 3 and 4, with high selectivity ratios of 4 to 32 and 8 to 64, respectively, and a concentration-dependent bactericidal mode of action against Gram-negative Escherichia coli. PMID:25941221

  14. Surface-engineered core-shell nano-size ferrites and their antimicrobial activity

    SciTech Connect

    Baraliya, Jagdish D. Joshi, Hiren H.

    2014-04-24

    We report the results of biological study on core-shell structured MFe{sub 2}O{sub 4} (where M = Co, Mn, Ni) nanoparticles and influence of silica- DEG dual coating on their antimicrobial activity. Spherical MFe{sub 2}O{sub 4} nanoparticles were prepared via a Co-precipitation method. The microstructures and morphologies of these nanoparticles were studied by x-ray diffraction and FTIR. The antimicrobial activity study carried out in nutrient agar medium with addition of antimicrobial synthesis compound which is tested for its activity against different types of bacteria.

  15. Phytochemical Characterization, Antimicrobial Activity, and Antioxidant Potential of Equisetum hyemale L. (Equisetaceae) Extracts.

    PubMed

    de Queiroz, Geisiany M; Politi, Flávio A S; Rodrigues, Edvânio R; Souza-Moreira, Tatiana M; Moreira, Raquel R D; Cardoso, Cássia R P; Santos, Lourdes C; Pietro, Rosemeire C L R

    2015-07-01

    Equisetum hyemale species is considered a medicinal plant used in the form of infusions to combat infectious or inflammation diseases and also diuretic effects, presenting several compounds related to these actions. In previous studies different species of Equisetum showed several phenolic compounds. The objective of this study was, for the first time, based on phytochemistry analysis to evaluate the antioxidant and antimicrobial activity. The 70% ethanolic and methanolic extracts of E. hyemale were characterized by spectrophotometric and high-performance liquid chromatography with pulsed amperometric detector analyses, as well as its antioxidant potential based on the scavenger activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). In addition was verified the antimicrobial activity by broth microdilution technique against bacteria and fungi. The extracts showed phytochemical similarity, which demonstrated the presence of phenolic compounds, the scavenging activity for free radicals was about 30% and was observed better antifungal activity against dermatophyte fungi, with minimum inhibitory concentration and minimum fungicidal concentration of 0.62 mg/mL to Trichophyton rubrum and Microsporum canis. The extracts exhibits great potential to therapeutic applications or product development, since both possess antifungal activity and antioxidant action associated with little difference in their phytochemical composition. PMID:25587637

  16. A novel microbial synthesis of catalytically active Ag-alginate biohydrogel and its antimicrobial activity.

    PubMed

    Otari, S V; Patil, R M; Waghmare, S R; Ghosh, S J; Paw