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1

Antimicrobial activity of spices  

Microsoft Academic Search

Spices have been shown to possess medicinal value, in particular, antimicrobial activity. This study compares the sensitivity of some human pathogenic bacteria and yeasts to various spice extracts and commonly employed chemotherapeutic substances. Of the different spices tested only garlic and clove were found to possess antimicrobial activity. The bactericidal effect of garlic extract was apparent within 1 h of

Daljit S Arora; Jasleen Kaur

1999-01-01

2

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

PubMed

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 10(13), 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. PMID:22777687

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

2012-08-21

3

Super-SERS-active and highly effective antimicrobial Ag nanodendrites  

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

4

Antimicrobial activity and cytotoxic effects of Magnolia dealbata and its active compounds.  

PubMed

Multi-drug resistance is of great concern for public health worldwide and necessitates the search for new antimicrobials from sources such as plants. Several Magnolia (Magnoliaceae) species have been reported to exert antimicrobial effects on sensitive and multidrug-resistant microorganisms. However, the antimicrobial properties of Magnolia dealbata have not been experimentally evaluated. The antimicrobial effects of an ethanol extract of Magnolia dealbata seeds (MDE) and its active compounds honokiol (HK) and magnolol (MG) were tested against the phytopathogen Clavibacter michiganensis subsp. michiganensis and several human multi-drug resistant pathogens using the disk-diffusion assay. The effects of MDE and its active compounds on the viability of human peripheral blood mononuclear cells (PBMC) were evaluated using MTT assay. MDE and its active compounds had antimicrobial activity (inhibition zone > 10 mm) against C. michiganensis, Pseudomonas aeruginosa, Acinetobacter baumannii, Acinetobacter lwoffii, Candida albicans, Candida tropicalis and Trichosporon belgeii. The results suggest that M. dealbata and its active compounds have selective antimicrobial effects against drug-resistant fungal and Gram (-) bacteria and exert minimal toxic effects on human PMBC. PMID:21922914

Jacobo-Salcedo, Maria del Rosario; Gonzalez-Espindola, Luis Angel; Alonso-Castro, Angel Josabad; Gonzalez-Martinez, Marisela del Rocio; Domínguez, Fabiola; Garcia-Carranca, Alejandro

2011-08-01

5

Antimicrobial activity of isopteropodine.  

PubMed

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

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

2005-01-01

6

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

PubMed

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

Al-Habsi, Nasser A; Niranjan, Keshavan

2012-12-01

7

Antimicrobial effect of zinc pyrithione  

Microsoft Academic Search

Synopsis The antimicrobial effect of zinc pyrithione has been studied with healthy scalps in relation to its ANTIDANDRUFF effect. Use of zinc pyrithione-containing shampoo sharply reduced the CORNEOCYTE COUNTS, while the similarly active antimicrobial agent, Irgasan DP-300 © had no effect on the corneocyte counts. Quantitative estimation of scalp microorganisms revealed that corresponding to the decrease in dandruff, Pityrospbrum ovale

GENJI IMOKAWA; HARUO SHIMIZU

8

Essential oils--their antimicrobial activity against Escherichia coli and effect on intestinal cell viability.  

PubMed

Essential oils are known to possess antimicrobial activity against a wide spectrum of bacteria. The main objective of this study was to evaluate possible harmful effects of four commonly used essential oils and their major components on intestinal cells. Antimicrobial activity of selected plant extracts against enteroinvasive Escherichia coli was dose dependent. However, doses of essential oils with the ability to completely inhibit bacterial growth (0.05%) showed also relatively high cytotoxicity to intestinal-like cells cultured in vitro. Lower doses of essential oils (0.01%) had only partial antimicrobial activity and their damaging effect on Caco-2 cells was only modest. Cell death assessment based on morphological and viability staining followed by fluorescence microscopy showed that essential oils of cinnamon and clove and their major component eugenol had almost no cytotoxic effect at lower doses. Although essential oil of oregano and its component carvacrol slightly increased the incidence of apoptotic cell death, they showed extensive antimicrobial activity even at lower concentrations. Relatively high cytotoxicity was demonstrated by thyme oil, which increased both apoptotic and necrotic cell death incidence. In contrast, its component thymol showed no cytotoxic effect as well as greatly-reduced ability to inhibit visible growth of the chosen pathogen in the doses used. On the other hand, the addition of all essential oils and their components at lower doses, with the exception of thyme oil, to bacterial suspension significantly reduced the cytotoxic effect of E. coli on Caco-2 cells after 1h culture. In conclusion, it is possible to find appropriate doses of essential oils showing both antimicrobial activity and very low detrimental effect on intestinal cells. PMID:16919909

Fabian, Dusan; Dusan, Fabian; Sabol, Marián; Marián, Sabol; Domaracká, Katarína; Katarína, Domaracká; Bujnáková, Dobroslava; Dobroslava, Bujnáková

2006-12-01

9

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

PubMed Central

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

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

2012-01-01

10

Heat treatment effects on the antimicrobial activity of macrolide and lincosamide antibiotics in milk.  

PubMed

Antibiotic residues in milk can cause serious problems for consumers and the dairy industry. Heat treatment of milk may diminish the antimicrobial activity of these antibiotic residues. This study analyzed the effect of milk processing (60 °C for 30 min, 120 °C for 20 min, and 140 °C for 10 s) on the antimicrobial activity of milk samples fortified with three concentrations of three macrolides (erythromycin: 20, 40 and 80 ?g/liter; spiramycin: 100, 200, and 400 ?g/liter; and tylosin: 500, 1,000, and 2,000 ?g/liter) and one lincosamide (lincomycin: 1,000, 2,000, and 4,000 ?g/liter). To measure the loss of antimicrobial activity, a bioassay based on the growth inhibition of Micrococcus luteus was done. The data were analyzed using a multiple linear regression model. The results indicate that treatment at 120 °C for 20 min produces inactivation percentages of 93% (erythromycin), 64% (spiramycin), 51% (tylosin), and 5% (lincomycin), while treatment at 140 °C for 10 s results in generally lower percentages (30% erythromycin, 35% spiramycin, 12% tylosin, and 5% lincomycin). The lowest loss or lowest reduction of antimicrobial activity (21% erythromycin and 13% spiramycin) was obtained by treatment at 60 °C for 30 min. PMID:21333154

Zorraquino, M A; Althaus, R L; Roca, M; Molina, M P

2011-02-01

11

Effects of cyclodextrins on the antimicrobial activity of plant-derived essential oil compounds.  

PubMed

Essential oils (EOs) from plants are considered to be a safer alternative when compared to synthetic antimicrobial food additives. However, a major drawback of many EOs is their hydrophobic nature, which makes them insoluble in water based media and matrices. Although cyclodextrins (CDs) can increase the solubility of EO compounds, the effects of CDs on the antimicrobial activity of EOs have not been reported. In this paper, four different EO compounds (carvacrol, eugenol, linalool and 2-pentanoylfuran) were chosen to study the influence of CDs on the solubility and antimicrobial activity on bacteria and yeast. The greatest enhancement with regards to solubility of the four test compounds was achieved by hydroxypropyl-?-CD. In most instances, not only were the minimal antimicrobial concentrations of EO compounds decreased, but the interactivity of two combined EO compounds could be strengthened by the co-addition of CDs. Furthermore, the combination of carvacrol with hydroxypropyl-?-CD caused a marked change in the major membrane lipid composition of all microorganisms investigated; while scanning electron microscopy revealed that cellular integrity was significantly affected by 2× MIC, ultimately resulting in cell lysis. PMID:22953819

Liang, Hao; Yuan, Qipeng; Vriesekoop, Frank; Lv, Fei

2012-12-01

12

Antimicrobial activity of resveratrol analogues.  

PubMed

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

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

2014-01-01

13

Antimicrobial activity of trout hepcidin.  

PubMed

Hepcidin is an antimicrobial peptide and a hormone produced mostly the liver. It is a cysteine-rich peptide with a highly conserved ?-sheet structure. Recently, we described the hepcidin expression in liver of rainbow trout and its inducibility by iron overloading and lipopolysaccharide (LPS). Thus, in this work, we focused in analyzing the importance of the peptide conformation associated to its oxidative state in the antimicrobial activity. This peptide showed a ?-helix conformation in reduced state and the characteristic ?-sheet conformation in the oxidized state. Antimicrobial activity assays showed that the oxidized peptide is more effective than the reduced peptide against Escherichia coli and the important salmon fish pathogen Piscirickettsia salmonis. In addition, confocal analysis of P. salmonis culture exposed to trout hepcidin coupled with rhodamine revealed the intracellular location of this peptide and Sytox permeation assay showed that membrane disruption is not the mechanism of its antimicrobial action. Moreover, a conserved ATCUN motif was detected in the N-terminus of this peptide. This sequence has been described as a small metal-binding site that has been implicated in DNA cleavage. In this work we proved that this peptide is able to induce DNA hydrolysis in the presence of ascorbate and CuCl2. When the same experiments were carried out using a variant with truncated N-terminus no DNA hydrolysis was observed. Our results suggest that correct folding of hepcidin is required for its antimicrobial activity and most likely the metal-binding site (ATCUN motif) present in its N-terminus is involved in the oxidative damage to macromolecules. PMID:24794583

Alvarez, Claudio A; Guzmán, Fanny; Cárdenas, Constanza; Marshall, Sergio H; Mercado, Luis

2014-11-01

14

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

PubMed Central

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

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

15

Effect of electrical current on the activities of antimicrobial agents against Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis biofilms.  

PubMed

Bacterial biofilms are resistant to conventional antimicrobial agents. Prior in vitro studies have shown that electrical current (EC) enhances the activities of aminoglycosides, quinolones, and oxytetracycline against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus epidermidis, Escherichia coli, and Streptococcus gordonii. This phenomenon, known as the bioelectric effect, has been only partially defined. The purpose of this work was to study the in vitro bioelectric effect on the activities of 11 antimicrobial agents representing a variety of different classes against P. aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and S. epidermidis. An eight-channel current generator/controller and eight chambers delivering a continuous flow of fresh medium with or without antimicrobial agents and/or EC to biofilm-coated coupons were used. No significant decreases in the numbers of log(10) CFU/cm(2) were seen after exposure to antimicrobial agents alone, with the exception of a 4.57-log-unit reduction for S. epidermidis and trimethoprim-sulfamethoxazole. We detected a statistically significant bioelectric effect when vancomycin plus 2,000 microamperes EC were used against MRSA biofilms (P = 0.04) and when daptomycin and erythromycin were used in combination with 200 or 2,000 microamperes EC against S. epidermidis biofilms (P = 0.02 and 0.0004, respectively). The results of these experiments indicate that the enhancement of the activity of antimicrobial agents against biofilm organisms by EC is not a generalizable phenomenon across microorganisms and antimicrobial agents. PMID:18725436

del Pozo, Jose L; Rouse, Mark S; Mandrekar, Jayawant N; Sampedro, Marta Fernandez; Steckelberg, James M; Patel, Robin

2009-01-01

16

Effect of nitrogen source on the antimicrobial activity of the bacilli air flora  

Microsoft Academic Search

The antimicrobial activity of strainsBacillus megaterium NB-3,Bacillus cereus NB-4,Bacillus cereus NB-5,Bacillus subtilis NB-6 andBacillus circulans NB-7, previously isolated from the air flora, now in the Jerash Culture Collection (Jordan), was investigated in media containing\\u000a different nitrogen sources. Maximum antimicrobial activity of strains NB-4, NB-5 and NB-6 was observed using Ca(NO3)2 as nitrogen source, (NH4)2SO4 and KNO2 strongly enhanced the antimicrobial

Nasser M. El-Banna; Samar S. Quddoumi

2007-01-01

17

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

PubMed

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

Do?an, Hasan Hüseyin; Ayd?n, Sema

2013-01-01

18

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

PubMed Central

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 ?-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

Bali, Elif Burcu; Aç?k, Leyla; Akca, Gülçin; Sarper, Meral; Elçi, Mualla P?nar; Avcu, Ferit; Vural, Mecit

2014-01-01

19

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

PubMed

This study focuses on the effect of extrusion processing on tannin reduction, phenolic content, flavonoid content, antioxidant and anitimicrobial activity. Extrusion temperature (120 and 140 °C) and feed moisture (25% and 28%) were used on the tannin content, antioxidant and antimicrobial activities. Extrusion cooking reduced tannin content up to 78%, and improved antioxidant activity from 12.89% to 21.17% in a concentration dependant manner without affecting its antimicrobial activity that varied from 250 to 500 mg. The time-kill assay confirmed the ability of extruded chestnut to reduce Pseudomonas aeruginosa count below detectable limit that reduced the original inoculum by 3log10 CFU/mL. Overall, the results showed that extrusion cooking might serve as a tool for tannin reduction and could improve the antioxidant and antimicrobial properties of chestnut, which might be helpful for chestnut related products in the food industry. PMID:23993601

Obiang-Obounou, Brice Wilfried; Ryu, Gi Hyung

2013-12-15

20

Study on antimicrobial activity of chitosan with different molecular weights  

Microsoft Academic Search

E. coli and Staphylococcus aureus are used to study the antimicrobial activity of chitosan of different molecular weights (MW). The effect of the concentration and MW of chitosan were investigated, respectively, and the antimicrobial mechanism was discussed. For chitosan with MW below 300 kDa, the antimicrobial effect on S. aureus was strengthened as the MW increased. In contrast, the effect

Lian-Ying Zheng; Jiang-Feng Zhu

2003-01-01

21

Synergistic effects of guanidine-grafted CMC on enhancing antimicrobial activity and dry strength of paper.  

PubMed

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

Liu, Kai; Xu, Yaoguang; Lin, Xinxing; Chen, Lihui; Huang, Liulian; Cao, Shilin; Li, Jian

2014-09-22

22

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

PubMed Central

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

Hoefer, Dirk; Hammer, Timo R.

2011-01-01

23

Myrtus communis L. infusions: the effect of infusion time on phytochemical composition, antioxidant, and antimicrobial activities.  

PubMed

In traditional medicine, myrtle (Myrtus communis L.) is frequently consumed as an infusion and decoction. In this study, we investigate the phenolic and volatile compositions and antioxidant and antibacterial activities of leaf infusions prepared during 3 different times. The total phenolics contents (146.74 to 179.55 mg GAE/g DM) varied significantly between infusions. Eleven phenolic compounds were identified by reversed-phase high-performance liquid chromatography. Phenolic acids (7.64 to 14.28 ?mol/g DM) and flavonol glycosides (7.05 to 12.11 ?mol/g DM) were the major phenolic fractions of infusions. Significant quantitative variation in 6 phenolic components was observed between infusions. Sixteen volatile components were identified by gas chromatography (GC) and GC mass spectrometry analyses. The main constituents were 1,8-cineole (42.58% to 51.39%), ?-terpineol (9.45% to 9.72%), methyl eugenol (6.69% to 7.11%), and linalool (5.91% to 6.06%). Quantitative variations of the volatile components of the analyzed oils in relation to the infusion time were observed. The antioxidant properties of infusions, assayed through DPPH (2,2- diphenyl-1-picrylhydrazyl) method, ?-carotene bleaching test, chelating effect on ferrous ions, and ferric reducing power method, were considerable and varied according to the infusion time. Myrtle infusions exhibited a substantial antimicrobial activity against 6 tested bacteria. PMID:22888790

Messaoud, Chokri; Laabidi, Abdelmonoem; Boussaid, Mohamed

2012-09-01

24

Antimicrobial activity of Securidaca longipedunculata.  

PubMed

The folk herbal uses of Securidaca longipedunculata in the treatment of diarrhea, boils, gonorrhea, and cough prompted phytochemical analyses and antimicrobial activity screening of extracts of the root. Some flavonoids isolated showed activity against many micro-organisms. These flavonoids were isolated using chromatographic methods. PMID:15636189

Ajali, U; Chukwurah, B K C

2004-11-01

25

Antimicrobial activity of Potentilla species  

Microsoft Academic Search

The antibacterial and antifungal activities of aqueous extracts obtained from aerial parts of Potentilla species: P. anserina, P. argentea, P. erecta, P. fruticosa, P. grandiflora, P. nepalensis var.‘MissWillmott’, P. recta, P. rupestris and P. thuringiaca were investigated. The extracts showed the strongest antimicrobial activity against H. pylori (MIC=0.1÷0.5 mg\\/ml).

Micha? Tomczyk; Katarzyna Leszczy?ska; Piotr Jakoniuk

2008-01-01

26

Antimicrobial activity of Potentilla species.  

PubMed

The antibacterial and antifungal activities of aqueous extracts obtained from aerial parts of Potentilla species: P. anserina, P. argentea, P. erecta, P. fruticosa, P. grandiflora, P. nepalensis var.'Miss Willmott', P. recta, P. rupestris and P. thuringiaca were investigated. The extracts showed the strongest antimicrobial activity against H. pylori (MIC=0.1/0.5 mg/ml). PMID:18664379

Tomczyk, Micha?; Leszczy?ska, Katarzyna; Jakoniuk, Piotr

2008-12-01

27

Antimicrobial activity of Bryum argenteum  

Microsoft Academic Search

The antimicrobial activity of Bryum argenteum ethanol extracts was evaluated by microdilution method against four bacterial (Escherichia coli, Bacillus subtilis, Micrococcus luteus and Staphilococcus aureus) and four fungal species (Aspergillus niger, Penicillium ochrochloron, Candida albicans and Trichophyton mentagrophyes). All the investigated ethanol extracts have been proved to be active against all bacteria and fungi tested.

Aneta Sabovljevic; Marina Sokovic; Marko Sabovljevic; Dragoljub Grubisic

2006-01-01

28

Antimicrobial activity of Bryum argenteum.  

PubMed

The antimicrobial activity of Bryum argenteum ethanol extracts was evaluated by microdilution method against four bacterial (Escherichia coli, Bacillus subtilis, Micrococcus luteus and Staphilococcus aureus) and four fungal species (Aspergillus niger, Penicillium ochrochloron, Candida albicans and Trichophyton mentagrophyes). All the investigated ethanol extracts have been proved to be active against all bacteria and fungi tested. PMID:16388916

Sabovljevic, Aneta; Sokovic, Marina; Sabovljevic, Marko; Grubisic, Dragoljub

2006-02-01

29

Effects of cathode design parameters on in vitro antimicrobial efficacy of electrically-activated silver-based iontophoretic system.  

PubMed

Post-operative infection is a major risk associated with implantable devices. Prior studies have demonstrated the effectiveness of ionic silver as an alternative to antibiotic-based infection prophylaxis and treatment. The focus of this study is on an electrically activated implant system engineered for active release of antimicrobial silver ions. The objective was to evaluate the effects of the cathode design, especially the cathode material, on the in vitro antimicrobial efficacy of the system. A modified Kirby-Bauer diffusion technique was used for the antimicrobial efficacy evaluations (24 h testing interval). In phase-1 of the study, a three-way ANOVA (n = 6, ? = 0.05) was performed to determine the effects of cathode material (silver, titanium, and stainless steel), cathode surface area and electrode separation distance on the efficacy of the system against Staphylococcus aureus. The results show that within the design space tested, none of these parameters had a statistically significant effect on the antimicrobiality of the system (P > 0.15). Subsequently, one-way ANOVA (n = 6, ? = 0.05) was conducted in phase-2 to validate the inference regarding the non-significance of the cathode material to the system efficacy using a broader spectrum of pathogens (methicillin-resistant S. aureus, Escherichia coli, Streptococcus agalactiae and Aspergillus flavus) responsible for osteomyelitis. The results confirmed the lack of statistical difference between efficacies of the three cathode material configurations against all pathogens tested (P > 0.58). Overall, the results demonstrate the ability to alter the cathode material and related design parameters in order to minimize the silver usage in the system without adversely affecting its antimicrobial efficacy. PMID:25589207

Tan, Zhuo; Ganapathy, Anirudh; Orndorff, Paul E; Shirwaiker, Rohan A

2015-01-01

30

Antimicrobial activity of blended essential oil preparation.  

PubMed

Antimicrobial activities of two blended essential oil preparations comprising lavender oil, petigrain oil, clary sage oil, ylang ylang oil and jasmine oil were evaluated against various pathogenic microorganisms. Both preparations showed antimicrobial activity in the agar disc diffusion assay against the Gram-positive bacteria, Staphylococcus aureus ATCC6538 and S. epidermidis isolated strain, the fungus, Candida albicans ATCC10231, and the Gram-negative bacterium, Escherichia coli ATCC25922, but showed no activity against Pseudomonas aeruginosa ATCC9027. The minimum inhibitory concentration (MIC) of these preparations was evaluated. By the broth microdilution assay, preparation 1, comprising lavender oil, clary sage oil, and ylang ylang oil (volume ratio 3:4:3), exhibited stronger antimicrobial activity than preparation 2, which was composed of petigrain oil, clary sage oil, and jasmine oil (volume ratio 3:4:3). Moreover, the sum of the fractional inhibitory concentrations (Sigma fic) of preparation 1 expressed a synergistic antimicrobial effect against the tested microorganisms (Sigma ficantimicrobial effect of either blended oil preparations or single/pure essential oils may be influenced by the amount of linalool and linalyl acetate, and the number of active components in either the blended preparations or single/pure essential oils. In addition, blended oil preparations expressed synergistic antimicrobial effect by the accumulation of active components such as linalool and linalyl acetate and combining active constituents of more than one oil. PMID:23157022

Tadtong, Sarin; Suppawat, Supatcha; Tintawee, Anchalee; Saramas, Phanida; Jareonvong, Suchada; Hongratanaworakit, Tapanee

2012-10-01

31

High Antimicrobial Effectiveness with Low Hemolytic and Cytotoxic Activity for PEG/Quaternary Copolyoxetanes  

PubMed Central

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 1H 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 ?g/mL, E. coli; 2 ?g/mL, S. aureus; and 24 ?g/mL, P. aeruginosa. At 5 × MIC, C8–50 effected >99% kill in 1 h against S. aureus, E. coli, and P. aeruginosa challenges of 108 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) ?g/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

2015-01-01

32

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

PubMed

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 ?g/mL, E. coli ; 2 ?g/mL, S. aureus ; and 24 ?g/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) ?g/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

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

2014-02-10

33

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

PubMed Central

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

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

2014-01-01

34

Characterization of hLF1-11 immobilization onto chitosan ultrathin films, and its effects on antimicrobial activity.  

PubMed

hLF1-11 (GRRRRSVQWCA) is an antimicrobial peptide (AMP) with high activity against methicillin-resistant Staphylococcus aureus (MRSA), the most prevalent species in implant-associated infection. In this work, the effect of the surface immobilization on hLF1-11 antimicrobial activity was studied. Immobilization was performed onto chitosan thin films as a model for an implant coating due to its reported osteogenic and antibacterial properties. Chitosan thin films were produced by spin-coating on gold surfaces. hLF1-11 was immobilized onto these films by its C-terminal cysteine in an orientation that exposes the antimicrobial activity-related arginine-rich portion of the peptide. Two levels of exposure (with and without a polyethylene glycol (PEG) spacer) were analyzed. Covalent immobilization was further compared with the AMP physical adsorption onto chitosan films. Surfaces were characterized using ellipsometry, contact angle measurements, atomic force microscopy, infrared and X-ray photoelectron spectroscopies and using a fluorimetric assay for hLF1-11 quantification. Surface antimicrobial activity was assessed through surface adhesion and viability assays using an MRSA (S. aureus ATCC 33591). The incorporation of hLF1-11 increased significantly bacterial adhesion to chitosan films. However, the presence of hLF1-11, namely when immobilized through a PEG spacer, decreased the viability of adherent bacteria with regard to the control surface. These results demonstrated that hLF1-11 after covalent immobilization by its cysteine can maintain activity, particularly if a spacer is applied. However, further studies, exploring the opposite orientation or the same C-terminal orientation, but non-cysteine related, can help to clarify the potential of the hLF1-11 immobilization strategy. PMID:24631659

Costa, Fabíola; Maia, Sílvia; Gomes, Joana; Gomes, Paula; Martins, M Cristina L

2014-08-01

35

Antimicrobial Activity of Commercial Nanoparticles  

NASA Astrophysics Data System (ADS)

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.

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

2009-07-01

36

In vitro antimicrobial activity of olive leaves.  

PubMed

We investigated the antimicrobial effect of olive leaves against bacteria and fungi. The microorganisms tested were inoculated in various concentrations of olive leaf water extract. Olive leaf 0.6% (w/v) water extract killed almost all bacteria tested, within 3 h. Dermatophytes were inhibited by 1.25% (w/v) plant extract following a 3-day exposure whereas Candida albicans was killed following a 24 h incubation in the presence of 15% (w/v) plant extract. Olive leaf extract fractions, obtained by dialysis, that showed antimicrobial activity consisted of particles smaller than 1000 molecular rate cutoffs. Scanning electron microscopic observations of C. albicans, exposed to 40% (w/v) olive leaf extract, showed invaginated and amorphous cells. Escherichia coli cells, subjected to a similar treatment but exposed to only 0.6% (w/v) olive leaf extract showed complete destruction. These findings suggest an antimicrobial potential for olive leaves. PMID:12870202

Markin, D; Duek, L; Berdicevsky, I

2003-04-01

37

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

PubMed Central

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

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

38

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

PubMed

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 3month water-aging period. Bromophenol blue assay showed minimal leaching of quaternary ammonium species when an appropriate amount of QAMS (<4wt.%) 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

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

2013-06-01

39

Leaves Antimicrobial Activity of Glycyrrhiza glabra L.  

PubMed

Licorice (Glycyrrhiza glabra L.) is an important medicinal plant. In this study, the antimicrobial activities of ethanolic and aqueous extracts from licorice leaves were studied compared to root extracts activities. Bacillus subtilis, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli, and Candida albicans were used as test organisms. Antimicrobial activity was tested by paper disc agar diffusion and serial dilution methods in order to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The root and leave extracts showed activity against Candida albicans, and tested gram-positive bacteria in a dose dependent manner. The ethanolic extract of the leaves was the most active extract against gram-positive bacteria. Its effectiveness against strains provides hope that it can serve as an alternative therapeutic agent. PMID:24381608

Irani, Mahboubeh; Sarmadi, Marziyeh; Bernard, Françoise; Ebrahimi Pour, Gholam Hossein; Shaker Bazarnov, Hossein

2010-01-01

40

Antimicrobial Activities of Fidaxomicin  

PubMed Central

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 ?g/mL, with a maximum MIC for inhibition of 90% of organisms (MIC90) of 0.5 ?g/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 ?g/mL and an MIC90 of 8 ?g/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

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

2012-01-01

41

?-Boomerang Antimicrobial and Antiendotoxic Peptides: Lipidation and Disulfide Bond Effects on Activity and Structure  

PubMed Central

Drug-resistant Gram-negative bacterial pathogens and endotoxin- or lipopolysaccharide (LPS)-mediated inflammations are among some of the most prominent health issues globally. Antimicrobial peptides (AMPs) are eminent molecules that can kill drug-resistant strains and neutralize LPS toxicity. LPS, the outer layer of the outer membrane of Gram-negative bacteria safeguards cell integrity against hydrophobic compounds, including antibiotics and AMPs. Apart from maintaining structural integrity, LPS, when released into the blood stream, also induces inflammatory pathways leading to septic shock. In previous works, we have reported the de novo design of a set of 12-amino acid long cationic/hydrophobic peptides for LPS binding and activity. These peptides adopt ?-boomerang like conformations in complex with LPS. Structure-activity studies demonstrated some critical features of the ?-boomerang scaffold that may be utilized for the further development of potent analogs. In this work, ?-boomerang lipopeptides were designed and structure-activity correlation studies were carried out. These lipopeptides were homo-dimerized through a disulfide bridge to stabilize conformations and for improved activity. The designed peptides exhibited potent antibacterial activity and efficiently neutralized LPS toxicity under in vitro assays. NMR structure of C4YI13C in aqueous solution demonstrated the conserved folding of the lipopeptide with a boomerang aromatic lock stabilized with disulfide bond at the C-terminus and acylation at the N-terminus. These lipo-peptides displaying bacterial sterilization and low hemolytic activity may be useful for future applications as antimicrobial and antiendotoxin molecules. PMID:24756162

Mohanram, Harini; Bhattacharjya, Surajit

2014-01-01

42

Plant essential oils as active antimicrobial agents.  

PubMed

Essential oils derived from plants have been recognized for decades to exhibit biological activities, including antioxidant, anticancer, and antimicrobial attributes. Antimicrobial activities of these natural plant materials have been intensively explored in recent years, mainly in response to the overwhelming concern of consumers over the safety of synthetic food additives. Gram-negative organisms are believed to be slightly less sensitive to essential oils than Gram-positive bacteria. Generally, a higher concentration is required to obtain the same efficacy in foods than in synthetic media. The combinations of different types of essential oils or with other food additives have been found to potentially exhibit synergistic if not additive effects. This suggests a cost-efficient and wholesome alternative to both food industry and consumers, at the same time adhering to the hurdle technology in inhibiting proliferation of foodborne pathogens. This review aims to examine the conventional methods commonly used for assessment of antimicrobial activities of essential oils and phytochemicals, the use of these substances as antimicrobials in food products, factors that affect their efficacy, synergism between components or with available food preservatives as well as the challenges and future directions of using essential oils and phytochemicals as natural food preservatives. PMID:24261536

Seow, Yi Xin; Yeo, Chia Rou; Chung, Hui Ling; Yuk, Hyun-Gyun

2014-01-01

43

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

PubMed

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

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

44

Antimicrobial activity of bovine seminal plasma  

Microsoft Academic Search

Bovine seminal plasma (BSP) had marked antimicrobial activity against a wide variety of Gram-positive and Gram-negative bacteria. Several mycoplasma species were also sensitive to bpvine genital secretions. The activity spectrum differs significantly from that of other antimicrobial factors found in normal tissues such as egg white lysozyme, polylysine, salmine sulphate, spermidine phosphate, and human seminal plasma. Inhibitory activity of BSP

L. M. Schollum; B. D. W. Jarvis; D. F. Bacon

1977-01-01

45

Antimicrobial activity of preparation Bioaron C.  

PubMed

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

Gawron-Gzella, Anne; Michalak, Anna; K?dzia, Anna

2014-01-01

46

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

NASA Astrophysics Data System (ADS)

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

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

2008-02-01

47

Flexibility is a mechanical determinant of antimicrobial activity for amphipathic cationic ?-helical antimicrobial peptides.  

PubMed

Antimicrobial peptides (AMPs) are recognized as the potential substitutions for common antibiotics. Flexibility has been demonstrated to be a dominant on antimicrobial activity of an AMP, similar to the structural parameters such as hydrophobicity and hydrophobic moment as well as positive charge. To better understand the effect of flexibility on antimicrobial activity, we herein examined seventy-eight peptides derived from nine different species. Defined as a weighted average of amino acid flexibility indices over whole residue chain of AMP, flexibility index was used to scale the peptide flexibility and indicated to be a reflection of mechanical properties such as tensile and flexural rigidities. The results demonstrated that flexibility index is relevant to but different from other structural properties, may enhance activity against Escherichia coli for stiff clustered peptides or reduce activity against E. coli for flexible clustered peptides, and its optimum occurs at about -0.5. This effect of flexibility on antimicrobial activity may be involved to the antimicrobial actions, such as stable peptide-bound leaflet formation and sequent stress concentration in target cell membrane, mechanically. The present results provide a new insight in understanding antimicrobial actions and may be useful in seeking for a new structure-activity relationship for cationic and amphipathic ?-helical peptides. PMID:23806649

Liu, Li; Fang, Ying; Wu, Jianhua

2013-11-01

48

Effect of aminoisobutyric acid (Aib) substitutions on the antimicrobial and cytolytic activities of the frog skin peptide, temporin-1DRa.  

PubMed

Temporin-1DRa (HFLGTLVNLAKKIL.NH(2)), first isolated from the skin of the California red-legged frog Rana draytonii, shows broad-spectrum antimicrobial activity but its therapeutic potential is limited by its toxicity against mammalian cells. The cytolytic properties of cationic alpha-helical peptides are determined by a complex interaction between cationicity, hydrophobicity, conformation, and amphipathicity. This study has investigated the cytolytic properties of conformationally constrained analogs of temporin-1DRa containing alpha-aminoisobutyric acid (Aib) substitutions. Cytolytic activity was determined against the bacteria Escherichia coli and Staphylococcus aureus, the opportunistic yeast pathogen, Candida albicans, human erythrocytes, HepG2 hepatoma-derived cells, and L929 fibroblasts. Aib substitutions at Gly(4), Asn(8), and Ala(10) increased both % helicity, determined in methanol solution, and hydrophobicity resulting in increases in both antimicrobial potencies and toxicities against the mammalian cells. Substitution at Leu(6) resulted in an appreciable decrease in cytolytic activity against all cells whereas the substitutions at His(1), Phe(2), Leu(3), Thr(5), and Val(7) had only minor effects on activity. Substitutions at Leu(9), Ile(13), Leu(14) produced analogs with decreased helicity and hydrophobicity that retained activity against microorganisms but showed appreciably lower cytolytic activities against mammalian cells. In particular, the fourfold increase in therapeutic index [ratio of LC(50) against erythrocytes to minimum inhibitory concentration (MIC) against microorganisms] of [Aib(13)]temporin-1DRa identifies it as a compound with potential for development as a therapeutically valuable anti-infective agent. PMID:17767978

Conlon, J Michael; Al-Kharrge, Rokaya; Ahmed, Eman; Raza, Haider; Galadari, Sehamuddin; Condamine, Eric

2007-10-01

49

A Novel Beta-Defensin Antimicrobial Peptide in Atlantic Cod with Stimulatory Effect on Phagocytic Activity  

PubMed Central

A novel defensin antimicrobial peptide gene was identified in Atlantic cod, Gadus morhua. This three exon/two intron defensin gene codes for a peptide precursor consisting of two domains: a signal peptide of 26 amino acids and a mature peptide of 40 residues. The mature cod defensin has six conserved cysteine residues that form 1–5, 2–4 and 3–6 disulphide bridges. This pattern is typical of beta-defensins and this gene was therefore named cod beta-defensin (defb). The tertiary structure of Defb exhibits an ?/? fold with one ? helix and ?1?2?3 sheets. RT-PCR analysis indicated that defb transcripts were present mainly in the swim bladder and peritoneum wall but could also be detected at moderate to low levels in skin, head- and excretory kidneys. In situ hybridisation revealed that defb was specifically expressed by cells located in the swim bladder submucosa and the oocytes. During embryonic development, defb gene transcripts were detectable from the golden eye stage onwards and their expression was restricted to the swim bladder and retina. Defb was differentially expressed in several tissues following antigenic challenge with Vibrio anguillarum, being up-regulated up to 25-fold in head kidney. Recombinant Defb displayed antibacterial activity, with a minimal inhibitory concentration of 0.4–0.8 µM and 25–50 µM against the Gram-(+) bacteria Planococcus citreus and Micrococcus luteus, respectively. In addition, Defb stimulated phagocytic activity of cod head kidney leucocytes in vitro. These findings imply that beta-defensins may play an important role in the innate immune response of Atlantic cod. PMID:23638029

Ruangsri, Jareeporn; Kitani, Yoichiro; Kiron, Viswanath; Lokesh, Jep; Brinchmann, Monica F.; Karlsen, Bård Ove; Fernandes, Jorge M. O.

2013-01-01

50

Biotransformation of monoterpenoids and their antimicrobial activities.  

PubMed

Biotransformation is an economically and ecologically viable technology which has been used extensively to modify the structures of many classes of biologically active products. The discovery of novel antimicrobial metabolites from biotransformation is an important alternative to overcome the increasing levels of drug resistance by plant and human pathogens. Monoterpenes, the main constituents of essential oils, are known for their antimicrobial activities. In 2004, Farooq, Atta-Ur-Rahman and Choudhary published a review on fungal transformation of monoterpenes which covers papers published up to 2002. The present review not only updates the previous one but also discusses the antimicrobial activities (antibacterial, antifungal and antiviral) of biotransformed compounds. PMID:25442268

Bhatti, Haq Nawaz; Khan, Saleha Suleman; Khan, Ajmal; Rani, Mubeen; Ahmad, Viqar Uddin; Choudhary, Muhammad Iqbal

2014-10-15

51

Characterization of antimicrobial peptide activity by electrochemical impedance spectroscopy  

E-print Network

Characterization of antimicrobial peptide activity by electrochemical impedance spectroscopy Accepted 21 June 2008 Available online 1 July 2008 Keywords: Antimicrobial peptides Cationic peptides exposure to antimicrobial peptides (AMPs). We show that two model cationic peptides, very similar

Wimley, William C.

52

Effects of net charge and the number of positively charged residues on the biological activity of amphipathic alpha-helical cationic antimicrobial peptides.  

PubMed

In our previous study, we utilized a 26-residue amphipathic alpha-helical antimicrobial peptide L-V13K (Chen et al., Antimicrob Agents Chemother 2007, 51, 1398-1406) as the framework to study the effects of peptide hydrophobicity on the mechanism of its antimicrobial action. In this study, we explored the effects of net charge and the number of positively charged residues on the hydrophilic/polar face of L-V13K on its biological activity (antimicrobial and hemolytic) and biophysical properties (hydrophobicity, amphipathicity, helicity, and peptide self-association). The net charge of V13K analogs at pH 7 varied between -5 and +10 and the number of positively charged residues varied from 1 to 10. The minimal inhibitory concentrations (MIC) against six strains of Pseudomonas aeruginosa as well as other gram-negative and gram-positive bacteria were determined along with the maximal peptide concentration that produces no hemolysis of human red blood cells (MHC). Our results show that the number of positively charged residues on the polar face and net charge are both important for both antimicrobial activity and hemolytic activity. The most dramatic observation is the sharp transition of hemolytic activity on increasing one positive charge on the polar face of V13K i.e., the change from +8 to +9 resulted in greater than 32-fold increase in hemolytic activity (250 microg/ml to <7.8 microg/ml, respectively). PMID:18098173

Jiang, Ziqing; Vasil, Adriana I; Hale, John D; Hancock, Robert E W; Vasil, Michael L; Hodges, Robert S

2008-01-01

53

Antimicrobial activity of Epilobium spp. extracts.  

PubMed

The antimicrobial activity of the Epilobium angustifolium, E. hirsutum, E. palustre, E. tetragonum and E. rosmarinifolium ethanolic extracts was studied in vitro on Gram-positive and Gram-negative bacteria, yeasts and fungi. The cytotoxicity of the extracts was also evaluated using the Artemia salina test. All the extracts showed antimicrobial activity in a range of concentrations between 10 and 650 microgml of dry extract. E. angustifolium and E. rosmarinifolium had the most broad spectrum of action inhibiting bacteria, yeasts and fungi. The extracts were devoid of toxicity on Artemia salina within the range of antimicrobial concentrations, suggesting that the action is selective on microorganisms. PMID:11482755

Battinelli, L; Tita, B; Evandri, M G; Mazzanti, G

2001-01-01

54

Antimicrobial activity of Epilobium spp. extracts  

Microsoft Academic Search

The antimicrobial activity of the Epilobium angustifolium, E. hirsutum, E. palustre, E. tetragonum and E. rosmarinifolium ethanolic extracts was studied in vitro on Gram-positive and Gram-negative bacteria, yeasts and fungi. The cytotoxicity of the extracts was also evaluated using the Artemia salina test. All the extracts showed antimicrobial activity in a range of concentrations between 10 and 650 ?g\\/ml of

Lucia Battinelli; Beatrice Tita; Maria Grazia Evandri; Gabriela Mazzanti

2001-01-01

55

Development of elastin-like recombinamer films with antimicrobial activity.  

PubMed

In the present work we explored the ABP-CM4 peptide properties from Bombyx mori for the creation of biopolymers with broad antimicrobial activity. An antimicrobial recombinant protein-based polymer (rPBP) was designed by cloning the DNA sequence coding for ABP-CM4 in frame with the N-terminus of the elastin-like recombinamer consisting of 200 repetitions of the pentamer VPAVG, here named A200. The new rPBP, named CM4-A200, was purified via a simplified nonchromatographic method, making use of the thermoresponsive behavior of the A200 polymer. ABP-CM4 peptide was also purified through the incorporation of a formic acid cleavage site between the peptide and the A200 sequence. In soluble state the antimicrobial activity of both CM4-A200 polymer and ABP-CM4 peptide was poorly effective. However, when the CM4-A200 polymer was processed into free-standing films high antimicrobial activity against Gram-positive and Gram-negative bacteria, yeasts and filamentous fungi was observed. The antimicrobial activity of CM4-A200 was dependent on the physical contact of cells with the film surface. Furthermore, CM4-A200 films did not reveal a cytotoxic effect against both normal human skin fibroblasts and human keratinocytes. Finally, we have developed an optimized ex vivo assay with pig skin demonstrating the antimicrobial properties of the CM4-A200 cast films for skin applications. PMID:25580615

da Costa, André; Machado, Raul; Ribeiro, Artur; Collins, Tony; Thiagarajan, Viruthachalam; Neves-Petersen, Maria Teresa; Rodríguez-Cabello, José Carlos; Gomes, Andreia C; Casal, Margarida

2015-02-01

56

Investigating the effects of L-to D-amino acid substitution and deamidation on the activity and membrane interactions of antimicrobial peptide anoplin  

E-print Network

and membrane interactions of antimicrobial peptide anoplin Amy Won a , Mourin Khan a , Sorin Gustin a , Akuvi October 2010 Accepted 8 November 2010 Available online 12 November 2010 Keywords: Antimicrobial peptide - helical antimicrobial peptide found naturally with broad spectrum activity against both Gram

Hitchcock, Adam P.

57

Original article Antimicrobial activity of fatty acids  

E-print Network

Original article Antimicrobial activity of fatty acids against Bacillus larvae, the causative agent and unsaturated free fatty acids were tested for their antibiotic activ- ity against Bacillus larvae by the addition of one or more double bonds. The antibiotic activity of fatty acids may make them suitable for use

Paris-Sud XI, Université de

58

Antimicrobial activity of different Finnish monofloral honeys against human pathogenic bacteria  

PubMed Central

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?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

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

2013-01-01

59

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

PubMed

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

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

2013-09-01

60

Antimicrobial activity of UMFix tissue fixative  

PubMed Central

Aims: The aim of this study was to determine the antimicrobial effects of UMFix, an alcohol based tissue fixative, on various microorganisms. The UMFix solution was compared with 10% neutral buffered formalin. Methods: Standard methods to determine microorganism colony counts were performed after exposure of the microorganisms to UMFix and 10% neutral buffered formalin. Results: After a short exposure, UMFix rapidly killed vegetative bacteria, yeasts, moulds, and viruses. Bacterial spores were resistant to killing by UMFix. All organisms were killed by the 10% neutral buffered formalin preparation. Conclusions: UMFix was microbicidal for vegetative bacteria, yeasts, and aspergillus species after a short exposure, although it was not active against spore forming bacillus species. The methanol content of the fixative was responsible for the killing effect of this fixative. No killing was seen when polyethylene glycol was used alone. PMID:15623477

Cleary, T J; Morales, A R; Nadji, M; Nassiri, M; Vincek, V

2005-01-01

61

Antimicrobial activity of microencapsulated lemongrass essential oil and the effect of experimental parameters on microcapsules size and morphology  

Microsoft Academic Search

Lemongrass (Cymbopogom citratus) essential oil, known due to its broad-spectrum antimicrobial activity, was microencapsulated by simple coacervation. Poly(vinyl alcohol) (PVA, 78,000 Da and 88 mol% degree of hydrolysis) crosslinked with glutaraldehyde was used as wall-forming polymer. The influence of stirring rate and oil volume fraction on the microcapsule size distribution were evaluated. Sodium dodecil sulphate (SDS) and Poly(vinyl pirrolidone) were tested in

Fernanda V. Leimann; Odinei H. Gonçalves; Ricardo A. F. Machado; Ariovaldo Bolzan

2009-01-01

62

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

PubMed Central

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

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

63

Synergistic effects of chitosan-guanidine complexes on enhancing antimicrobial activity and wet-strength of paper.  

PubMed

Chitosan-guanidine complexes were prepared by reacting chitosan and polyhexamethylene guanidine hydrochloride or crosslinked polyhexamethylene guanidine hydrochloride in the presence of sodium tripolyphosphate as a crosslinking agent. The complexes, used as functional additives for paper, synergistically improved wet-strength and antimicrobial activities. In comparison with the control sample, the wet/dry strength ratio of hand-sheets treated with the complexes was increased from 2.65% up to 23.3%. The MIC values of the chitosan-PHGH and chitosan-PHGHE complexes against Escherichia coli were 15.6 and 31.2 microg mL(-1), respectively, thus demonstrating excellent antimicrobial activity. Hand-sheets treated with the complexes exhibited antibacterial activity against E. coli and Staphylococcus aureus. The release of the guanidine polymers included in the complexes was dynamically monitored using UV and the results showed the amount released exceeded 80%. Atomic force microscopy images indicated that the antimicrobial mechanism of the complexes was likely due to membrane damage. PMID:20202835

Sun, Shengling; An, Qiaozhi; Li, Xu; Qian, Liying; He, Beihai; Xiao, Huining

2010-07-01

64

Cell viability effects and antioxidant and antimicrobial activities of Tunisian date syrup (Rub El Tamer) polyphenolic extracts.  

PubMed

The aqueous-acetone polyphenolic extract of the traditionally derived date syrup, known as "Rub El Tamer", was analyzed using RP-HPLC-DAD and ESI-MS. The phenolic content of the extract was 394.53 ± 1.13 mg per 100 g of syrup with caffeoylsinapylquinic acid as the most abundant compound (72.23%). The extract exhibited strong antioxidant activities as evaluated using the ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) methods. The extract antimicrobial potential against a range of microorganism strains showed that Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus cereus were the most sensitive bacteria with MBC in the range of 0.5-0.05 mg/mL. Furthermore, in the presence of the syrup extract (8.18-131 ?g/mL), the Human SH-SY5Y neuroblastoma and the 3T3 fibroblast cell lines showed dissimilar reduction of viability suggesting a higher cytotoxic effect against tumorigenic cells. Our results provide new insights into date syrup characterization which should stimulate further studies of this hot desert resource. PMID:21155604

Dhaouadi, Karima; Raboudi, Faten; Estevan, Carmen; Barrajón, Enrique; Vilanova, Eugenio; Hamdaoui, Mohamed; Fattouch, Sami

2011-01-12

65

Antimicrobial activities of four Tunisian Chrysanthemum species  

Microsoft Academic Search

Methods: Different parts (flowers, leaves, stems, roots, leaves and flowers and leaves and stems) of four Tunisian Chrysanthemum species, were extracted with solvents of increasing polarity to obtain aqueous and organic extracts. These extracts were tested in vitro for their antimicrobial activity against 14 bacteria and four yeasts, using agar diffusion and microdilution methods. Activity was evaluated by measuring the

Ahlem Ben Sassi; Fethia Harzallah-Skhiri; Nathalie Bourgougnon; Mahjoub Aouni

2008-01-01

66

Antimicrobial activity of chicken egg white cystatin  

Microsoft Academic Search

The cysteine protease inhibitor cystatin was purified from chicken egg white and its antimicrobial activity determined for a series of pathogenic bacteria. The results indicate that Acinetobacter lwoffii, Escherichia coli, Oligella sp. and Pseudomonas aeruginosa are highly sensitive to low concentrations of cystatin, which possesses bactericidal activity. No inhibition was observed with a Citrobacter freundii strain. Fifty percent growth inhibition

Ewelina Wesierska; Yousif Saleh; Tadeusz Trziszka; Wieslaw Kopec; Maciej Siewinski; Kamila Korzekwa

2005-01-01

67

Bacillus clausii probiotic strains: antimicrobial and immunomodulatory activities.  

PubMed

The clinical benefits observed with probiotic use are mainly attributed to the antimicrobial substances produced by probiotic strains and to their immunomodulatory effects. Currently, the best-documented probiotic bacteria used in human therapy are lactic acid bacteria. In contrast, studies aiming to characterize the mechanisms responsible for the probiotic beneficial effects of Bacillus are rare. The current work seeks to contribute to such characterization by evaluating the antimicrobial and immunomodulatory activities of probiotic B. clausii strains. B. clausii strains release antimicrobial substances in the medium. Moreover, the release of these antimicrobial substances was observed during stationary growth phase and coincided with sporulation. These substances were active against Gram-positive bacteria, in particular against Staphylococcus aureus, Enterococcus faecium, and Clostridium difficile. The antimicrobial activity was resistant to subtilisin, proteinase K, and chymotrypsin treatment, whereas it was sensitive to pronase treatment. The evaluation of the immunomodulatory properties of probiotic B. clausii strains was performed in vitro on Swiss and C57 Bl/6j murine cells. The authors demonstrate that these strains, in their vegetative forms, are able to induce NOS II synthetase activity, IFN-gamma production, and CD4 T-cell proliferation. PMID:15220667

Urdaci, Maria C; Bressollier, Philippe; Pinchuk, Irina

2004-07-01

68

Antimicrobial Activity of Root Bark of Salacia reticulata  

PubMed Central

Antimicrobial activity of chloroform and methanolic extracts of Salacia reticulata were tested against gram positive, gram negative and fungus strains using zone of inhibition and minimum inhibitory concentrations. It was observed that both extracts have inhibitory effect towards all microorganisms used in the test. Chloroform extract was more effective than methanolic extract. PMID:22557181

Choudhary, G. P.; Vijay Kanth, M. S.

2005-01-01

69

Antimicrobial effect of various combinations of plant extracts  

Microsoft Academic Search

The combined extracts of corni fructus, cinnamon and Chinese chive were used to evaluate its antimicrobial activity on common foodborne micro-organisms, including bacteria, yeasts and moulds. The combined extract (8:1:1, v\\/v\\/v) showed an entire antimicrobial spectrum and outstanding inhibitory effect. The combined extract was very stable under heat treatment. The inhibitory effect of the combined extract was greater with more

Pao-Chuan Hsieh; Jeng-Leun Mau; Shu-Hui Huang

2001-01-01

70

Synthesis and antimicrobial activity of cysteine-free coprisin nonapeptides.  

PubMed

Coprisin is a 43-mer defensin-like peptide from the dung beetle, Copris tripartitus. CopA3 (LLCIALRKK-NH?), a 9-mer peptide containing a single free cysteine residue at position 3 of its sequence, was derived from the ?-helical region of coprisin and exhibits potent antibacterial and anti-inflammatory activities. The single cysteine implies a tendency for dimerization; however, it remains unknown whether this cysteine residue is indispensible for CopA3's antimicrobial activity. To address this issue, in the present study we synthesized eight cysteine-substituted monomeric CopA3 analogs and two dimeric analogs, CopA3 (Dimer) and CopIK (Dimer), and evaluated their antimicrobial effects against bacteria and fungi, as well as their hemolytic activity toward human erythrocytes. Under physiological conditions, CopA3 (Mono) exhibits a 6/4 (monomer/dimer) molar ratio in HPLC area percent, indicating that its effects on bacterial strains likely reflect a CopA3 (Mono)/CopA3 (Dimer) mixture. We also report the identification of CopW, a new cysteine-free nonapeptide derived from CopA3 that has potent antimicrobial activity with virtually no hemolytic activity. Apparently, the cysteine residue in CopA3 is not essential for its antimicrobial function. Notably, CopW also exhibited significant synergistic activity with ampicillin and showed more potent antifungal activity than either wild-type coprisin or melittin. PMID:24321546

Lee, Jaeho; Lee, Daeun; Choi, Hyemin; Kim, Ha Hyung; Kim, Ho; Hwang, Jae Sam; Lee, Dong Gun; Kim, Jae Il

2014-01-10

71

Antimicrobial Activity and Stability of Electron Beam Irradiated Dental Irrigants  

PubMed Central

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

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

2014-01-01

72

Antimicrobial activity of two essential oils.  

PubMed

The aim of the study was to evaluate the antimicrobial activity of essential oils in vitro for possible application to reduce the content of microorganisms in the air of animal houses. The essential oils of Cymbopogon citrarus L. and Malaleuca alternifolia L. were screened against bacteria Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis and yeast Candida albicans. The minimal inhibitory concentration of the active essential oils was tested using broth dilution assay. The essential oils concentrations ranged from 0.1-50.0%. The combined effects of essential oils were tested for Malaleuca alternifolia L. and Cymbopogon citrarus L. concentrations ranged from 0.005-50.0%. The oils showed a wide spectrum of antibacterial activity. Concentrations of 0.1-0.5% of Cymbopogon citrarus L. and Malaleuca alternifolia L. reduced total microorganisms count of Proteus mirabilis and Candida albicans. High antibacterial activity was also revealed for Cymbopogon citrarus L. with bactericidal concentrations of 0.8% for Escherichia coli, 5.0% for Enterococcus faecium, 5.0% for Pseudomonas aeruginosa and 8.0% for Staphylococcus aureus. Bactericidal concentrations of Malaleuca alternifolia L. were 5.0% for Pseudomonas aeruginosa and Enterococcus faecium, and 8.0% for Staphylococcus aureus. The essential oils of Cymbopogon citrarus and Malaleuca alternifolia may be a promising alternative of air disinfection in animal houses. PMID:21739934

Mickien?, R?ta; Bakutis, Bronius; Baliukonien?, Violeta

2011-06-01

73

Antimicrobial activity of UMFix tissue fixative  

Microsoft Academic Search

Aims: The aim of this study was to determine the antimicrobial effects of UMFix, an alcohol based tissue fixative, on various microorganisms. The UMFix solution was compared with 10% neutral buffered formalin.Methods: Standard methods to determine microorganism colony counts were performed after exposure of the microorganisms to UMFix and 10% neutral buffered formalin.Results: After a short exposure, UMFix rapidly killed

T J Cleary; A R Morales; M Nadji; M Nassiri; V Vincek

2005-01-01

74

Antimicrobial and Immunomodulatory Activities of PR-39 Derived Peptides  

PubMed Central

The porcine cathelicidin PR-39 is a host defence peptide that plays a pivotal role in the innate immune defence of the pig against infections. Besides direct antimicrobial activity, it is involved in immunomodulation, wound healing and several other biological processes. In this study, the antimicrobial- and immunomodulatory activity of PR-39, and N- and C-terminal derivatives of PR-39 were tested. PR-39 exhibited an unexpected broad antimicrobial spectrum including several Gram positive strains such as Bacillus globigii and Enterococcus faecalis. Of organisms tested, only Staphylococcus aureus was insensitive to PR-39. Truncation of PR-39 down to 15 (N-terminal) amino acids did not lead to major loss of activity, while peptides corresponding to the C-terminal part of PR-39 were hampered in their antimicrobial activity. However, shorter peptides were all much more sensitive to inhibition by salt. Active peptides induced ATP leakage and loss of membrane potential in Bacillus globigii and Escherichia coli, indicating a lytic mechanism of action for these peptides. Finally, only the mature peptide was able to induce IL-8 production in porcine macrophages, but some shorter peptides also had an effect on TNF-? production showing differential regulation of cytokine induction by PR-39 derived peptides. None of the active peptides showed high cytotoxicity highlighting the potential of these peptides for use as an alternative to antibiotics. PMID:24755622

Veldhuizen, Edwin J. A.; Schneider, Viktoria A. F.; Agustiandari, Herfita; van Dijk, Albert; Tjeerdsma-van Bokhoven, Johanna L. M.; Bikker, Floris J.; Haagsman, Henk P.

2014-01-01

75

Antimicrobial silver: An unprecedented anion effect  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

76

Antimicrobial silver: An unprecedented anion effect  

PubMed Central

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

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

2014-01-01

77

Effect of the association of reduced glutathione and ciprofloxacin on the antimicrobial activity in Staphylococcus aureus.  

PubMed

We report the effect of glutathione and the role of reactive oxygen species (ROS), assayed by a nitro blue tetrazolium reaction, on the antibacterial action of ciprofloxacin, gentamicin and chloramphenicol in Staphylococcus aureus 22 resistant to ciprofloxacin and gentamicin, and in S. aureus ATCC 29213 sensitive to the above three antibiotics. The association of glutathione with ciprofloxacin or gentamicin significantly reduced the value of the minimum inhibitory concentration (MIC) in resistant S. aureus 22, measured using the macrodilution method, with a concomitant increase of intracellular ROS and a decrease of extracellular ROS. However, glutathione did not induce modifications in MIC or ROS generated by chloramphenicol. Furthermore, in the sensitive S. aureus ATCC 29213, the association of glutathione with ciprofloxacin, gentamicin or chloramphenicol did not induce any significant variations of MIC or ROS. There was a correlation between the stimulus of intracellular ROS and the decrease of MIC caused by exogenous glutathione. According to the results obtained, it is possible to modify the sensitivity of resistant strains of S. aureus by the addition of exogenous glutathione. PMID:20030722

Páez, Paulina Laura; Becerra, María Cecilia; Albesa, Inés

2010-02-01

78

Antimicrobial and Antifungal Activity of Pelargonium roseum Essential Oils  

PubMed Central

Purpose: The antiseptic qualities of aromatic and medicinal plants and their extracts have been recognized since antiquity, while attempts to characterize these properties in the laboratory date back the beginning of the XXth century. In the current study essential oils obtained from Pelargonium roseum (Geraniacea) were analyzed for their antibacterial and antifungal activities. Methods: The antimicrobial activity of the Pelargonium essential oil was tested against Gram-negative bacteria (Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli), Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis) and fungi (Candida albicans). Disc diffusion method was used to study antimicrobial activity. Results: Inhibition zones showed that the studied essential oils were active against all of the studied bacteria. In the case of Candida albicans, the complete inhibition of the fungus’s development was observed. In the cases of Pseudomonas aeruginosa and Staphylococcus aureus we observed an inhibition comparable to that obtained by the use of an appropriate antimicrobial substance. Conclusion: The volatile oils exhibited considerable inhibitory effects against all the organisms under test, in some cases comparable with those of the reference antibiotics. There were no considerable differences between the antimicrobial activities of the oil obtained by distillation and commercially available Pelargonium oils. PMID:25671182

Carmen, Gâlea; Hancu, Gabriel

2014-01-01

79

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

PubMed

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

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

2014-01-01

80

Antimicrobial and antitumor activities of mycosporulone.  

PubMed

The conditions for optimal production of mycosporulone (1) are given. Its cytotoxic, antimicrobial, and antitumor activities are described. The biological activities of 1 were compared with those of known antibacterial, antifungal, and antitumor agents. The compound was particularly active against Pseudomonas aeruginosa and Staphylococcus aureus (resistant to penicillin). Compound 1 was not toxic to normal human cells (MRC(5)), although it exhibited cytotoxic activity against the human tumor cell lines MDA-MB 231 and PC(3) and the murine L-1210 leukemia cell line. PMID:10514301

Guiraud, P; Steiman, R; Seigle-Murandi, F; Buarque De Gusmao, N

1999-09-01

81

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

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 ?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

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

2014-01-01

82

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

PubMed

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, ?-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

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

2011-03-01

83

Antimicrobial activity of aroma chemicals and essential oils  

Microsoft Academic Search

Determination of the minimum inhibitory concen-trations (MIC) of 212 common soap fragrance raw materials demonstrated that\\u000a the paper disc-petri plate technique does not reflect the relative anti-microbial activity of these materials. Commonly used\\u000a soap bacteriostats were shown to be 100 to 1000 times more effective than the most active fragrance materials. Of 521 fragrance\\u000a materials initially screened by the petri

J. A. Morris; A. Khettry; E. W. Seitz

1979-01-01

84

Evaluation of antimicrobial activity of Rasaka Bhasma.  

PubMed

Rasaka, one among the Maharasas, has been indicated in various diseases like Netrarogas, Prameha, etc. Lately, the use of Rasaka bhasma has been declined as an identification of Rasaka. The present study aims to prepare Rasaka bhasma from two different samples of Rasaka and undertake comparative antimicrobial activity study against Gram-positive and Gram-negative organisms by agar disk diffusion method. PMID:22131722

Shubha, H S; Hiremath, R S

2010-04-01

85

Evaluation of antimicrobial activity of Rasaka Bhasma  

PubMed Central

Rasaka, one among the Maharasas, has been indicated in various diseases like Netrarogas, Prameha, etc. Lately, the use of Rasaka bhasma has been declined as an identification of Rasaka. The present study aims to prepare Rasaka bhasma from two different samples of Rasaka and undertake comparative antimicrobial activity study against Gram-positive and Gram-negative organisms by agar disk diffusion method. PMID:22131722

Shubha, H. S.; Hiremath, R. S.

2010-01-01

86

Antimicrobial activities of naphthazarins from Arnebia euchroma.  

PubMed

Bioassay-directed fractionation of extract of Arnebia euchroma led to the isolation of alkannin (1), shikonin (2), and their derivatives (3-8) as the active principles against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). The stereochemistry of alpha-methylbutyryl alkannin (8) is revealed for the first time, and the antimicrobial activity of 8 was compared with its corresponding diastereomer (9). The derivatives 3-9 showed stronger anti-MRSA activity [minimum inhibitory concentrations (MICs) ranged from 1.56 to 3.13 microg/mL] than alkannin or shikonin (MIC = 6.25 microg/mL). Anti-MRSA activity of derivatives was bactericidal with minimum bactericidal concentration (MBC)/MIC < or = 2. In a time-kill assay, the bactericidal activity against MRSA was achieved as rapidly as 2 h. The derivatives 3-9 were also active against vancomycin-resistant Enterococcus faecium (F935) and vancomycin-resistant Enterococcus faecalis (CKU-17) with MICs similar to those with MRSA. Aromatic ester derivatives were also synthesized for antimicrobial activity comparison. None of these compounds were active against Gram-negative bacteria tested. Their cytotoxicity was also evaluated on selected cancer cell lines, and they expressed their activity in the range 0.6-5.4 microg/mL (CD(50)). Our results indicate that the ester derivatives of alkannin are potential candidates of anti-MRSA and anti-VRE agents with antitumor activity. PMID:12502328

Shen, Chien-Chang; Syu, Wan-Jr; Li, Shyh-Yuan; Lin, Chia-Hung; Lee, Gum-Hee; Sun, Chang-Ming

2002-12-01

87

Antimicrobial stewardship activities: a survey of Queensland hospitals.  

PubMed

Objective In 2011, the Australian Commission on Safety and Quality in Health Care (ACSQHC) recommended that all hospitals in Australia must have an Antimicrobial Stewardship (AMS) program by 2013. Nevertheless, little is known about current AMS activities. This study aimed to determine the AMS activities currently undertaken, and to identify gaps, barriers to implementation and opportunities for improvement in Queensland hospitals. Methods The AMS activities of 26 facilities from 15 hospital and health services in Queensland were surveyed during June 2012 to address strategies for effective AMS: implementing clinical guidelines, formulary restriction, reviewing antimicrobial prescribing, auditing antimicrobial use and selective reporting of susceptibility results. Results The response rate was 62%. Nineteen percent had an AMS team (a dedicated multidisciplinary team consisting of a medically trained staff member and a pharmacist). All facilities had access to an electronic version of Therapeutic Guidelines: Antibiotic, with a further 50% developing local guidelines for antimicrobials. One-third of facilities had additional restrictions. Eighty-eight percent had advice for restricted antimicrobials from in-house infectious disease physicians or clinical microbiologists. Antimicrobials were monitored with feedback given to prescribers at point of care by 76% of facilities. Deficiencies reported as barriers to establishing AMS programs included: pharmacy resources, financial support by hospital management, and training and education in antimicrobial use. Conclusions Several areas for improvement were identified: reviewing antimicrobial prescribing with feedback to the prescriber, auditing, and training and education in antimicrobial use. There also appears to be a lack of resources to support AMS programs in some facilities. What is known about the topic? The ACSQHC has recommended that all hospitals implement an AMS program by 2013 as a requirement of Standard 3 (Preventing and Controlling Healthcare-Associated Infections) of the National Safety and Quality Health Service Standards. The intent of AMS is to ensure appropriate prescribing of antimicrobials as part of the broader systems within a health service organisation to prevent and manage healthcare-associated infections, and improve patient safety and quality of care. This criterion also aligns closely with Standard 4: Medication Safety. Despite this recommendation, little is known about what AMS activities are undertaken in these facilities and what additional resources would be required in order to meet these national standards. What does the paper add? This is the first survey that has been conducted of public hospital and health services in Queensland, a large decentralised state in Australia. This paper describes what AMS activities are currently being undertaken, identifies practice gaps, barriers to implementation and opportunities for improvement in Queensland hospitals. What are the implications for practitioners? Several areas for improvement such as reviewing antimicrobial prescribing with feedback to the prescriber, auditing, and training and education in antimicrobial use have been identified. In addition, there appears to be a lack of resources to support AMS programs in some facilities. PMID:25376911

Avent, Minyon L; Hall, Lisa; Davis, Louise; Allen, Michelle; Roberts, Jason A; Unwin, Sean; McIntosh, Kylie A; Thursky, Karin; Buising, Kirsty; Paterson, David L

2014-11-01

88

Antimicrobial activity of the metals and metal oxide nanoparticles.  

PubMed

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

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

2014-11-01

89

Antimicrobial cyclic decapeptides with anticancer activity  

Microsoft Academic Search

Antimicrobial peptides have been considered as potential candidates for cancer therapy. We report here the cytotoxicity of a library of 66 antibacterial cyclodecapeptides on human carcinoma cell lines, and their effects on apoptosis [as assessed by cleavage of poly(ADP-ribose) polymerase (PARP)] and cell signaling proteins (p53 and ERK1\\/2) in cultured human cervical carcinoma cells. A design of experiments approach permitted

Lidia Feliu; Glòria Oliveras; Anna D. Cirac; Emili Besalú; Cristina Rosés; Ramon Colomer; Eduard Bardají; Marta Planas; Teresa Puig

2010-01-01

90

Antioxidant, antimicrobial, and anticancer activity of 3 Umbilicaria species.  

PubMed

The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activity of the acetone extracts of the lichens Umbilicaria crustulosa, U. cylindrica, and U. polyphylla. Antioxidant activity was evaluated by 5 separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds, and determination of total flavonoid content. Of the lichens tested, U. polyphylla?had largest free radical scavenging activity (72.79% inhibition at a concentration of 1 mg/mL), which was similar as standard antioxidants in the same concentration. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was extract of U. polyphylla?with minimum inhibitory concentration values ranging from 1.56 to 12.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All extracts were found to be strong anticancer activity toward both cell lines with IC?? values ranging from 28.45 to 97.82 ?g/mL. The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggests that lichens may be used as possible natural antioxidant, antimicrobial, and anticancer agents. PMID:22260138

Kosani?, Marijana; Rankovi?, Branislav; Stanojkovi?, Tatjana

2012-01-01

91

The Effect of Anti-Inflammatory and Antimicrobial Herbal Remedy PADMA 28 on Immunological Angiogenesis and Granulocytes Activity in Mice  

PubMed Central

PADMA 28 is a herbal multicompound remedy that originates from traditional Tibetan medicine and possesses anti-inflammatory, antioxidant, antimicrobial, angioprotecting, and wound healing properties. The aim of the present study was to evaluate the influence of this remedy on immunological angiogenesis and granulocytes metabolic activity in Balb/c mice. Mice were fed daily, for seven days, with 5.8?mg of PADMA (calculated from recommended human daily dose) or 0.085?mg (dose in the range of active doses of other herbal extracts studied by us previously). Results. Highly significant increase of newly formed blood vessels number in ex vivo cutaneous lymphocyte-induced angiogenesis test (LIA) after grafting of Balb/c splenocytes from both dosage groups to F1 hybrids (Balb/c × C3H); increase of blood lymphocytes and granulocytes number only in mice fed with lower dose of remedy; and significant suppression of metabolic activity (chemiluminescence test) of blood granulocytes in mice fed with higher dose of PADMA. Conclusion. PADMA 28 behaves as a good stimulator of physiological angiogenesis, but for this purpose it should be used in substantially lower doses than recommended by producers for avoiding the deterioration of granulocyte function. PMID:23864768

Radomska-Le?niewska, Dorota M.; Skopi?ski, Piotr; Zdanowski, Robert; Lewicki, S?awomir; Kocik, Janusz; Skopi?ska-Ró?ewska, Ewa; Stankiewicz, Wanda

2013-01-01

92

Antimicrobial activity of Micromeria nervosa from the Palestinian area  

Microsoft Academic Search

Organic and aqueous solvent extracts and fractions of Micromeria nervosa (Desf.) Benth. (Labiatae) were investigated for antimicrobial activities on several microorganisms including bacteria and yeast. The different extracts differed significantly in their antimicrobial activities with the ethanolic extract being most active, followed by ethyl acetate and petroleum ether extracts. The least active extract was the aqueous. No significant difference between

M. S. Ali-Shtayeh; M. A. Al-Nuri; Reem M.-R. Yaghmour; Y. R. Faidi

1997-01-01

93

Antimicrobial activity of Lactobacillus against microbial flora of cervicovaginal infections  

PubMed Central

Objective To assess the probiotic nature of Lactobacillus in preventing cervical pathogens by studying the effectiveness of antimicrobial activity against vaginal pathogens. Methods Lactobacilli were isolated from healthy vaginal swabs on selective media and different pathogenic bacteria were isolated by using different selective media. The Lactobacillus strains were tested for the production of hydrogen peroxide and antimicrobial compounds along with probiotic properties. Results Of the 10 isolated Lactobacillus strains, strain 1, 3 and 6 are high hydrogen peroxide producers and the rest were low producers. Results of pH and amines tests indicated that pH increased with fishy odour in the vaginal fluids of cervicovaginal infection patients when compared with vaginal fluids of healthy persons. The isolates were found to be facultative anaerobic, Gram-positive, non-spore-forming, non-capsule forming and catalase-negative bacilli. The results of antimicrobial activity of compounds indicated that 280 and 140 µg/mL was the minimum concentration to inhibit the growth of both pathogens and test organisms respectively. Conclusions The results demonstrated that Lactobacillus producing antimicrobial compounds inhibits the growth of cervical pathogens, revealing that the hypothesis of preventing vaginal infection by administering probiotic organisms has a great appeal to patients, which colonize the vagina to help, restore and maintain healthy vagina.

Dasari, Subramanyam; Shouri, Raju Naidu Devanaboyaina; Wudayagiri, Rajendra; Valluru, Lokanatha

2014-01-01

94

Antimicrobial resistance and the activities of the Codex Alimentarius Commission.  

PubMed

The Codex Alimentarius Commission has been working on the subject of antimicrobial resistance, mainly through the activities of the Committee on Residues of Veterinary Drugs in Foods and the ad hoc Intergovernmental Task Force on Antimicrobial Resistance. Principal texts developed by Codex include the 'Code of Practice to Minimize and Contain Antimicrobial Resistance (CAC/RCP 61-2005) and 'Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance' (CAC/GL 77-2011). The successful containment of antimicrobial resistance requires the collaboration of a wide range of stakeholders, working together to protect consumer health by ensuring the safety of food products of animal origin. PMID:22849286

Bruno, A V; Mackay, Carolissen

2012-04-01

95

Designed supramolecular filamentous peptides: balance of nanostructure, cytotoxicity and antimicrobial activity.  

PubMed

This work demonstrates a design strategy to optimize antimicrobial peptides with an ideal balance of minimal cytotoxicity, enhanced stability, potent cell penetration and effective antimicrobial activity, which hold great promise for the treatment of intracellular microbial infections and potentially systemic anti-infective therapy. PMID:25476705

Xu, Dawei; Jiang, Linhai; Singh, Anju; Dustin, Derek; Yang, Miao; Liu, Ling; Lund, Reidar; Sellati, Timothy J; Dong, He

2014-12-23

96

Antimicrobial activity of Sesbania grandiflora flower polyphenol extracts on some pathogenic bacteria and growth stimulatory effect on the probiotic organism Lactobacillus acidophilus.  

PubMed

Polyphenolic extracts (PE) of edible flower of Sesbania grandiflora were tested to evaluate its antimicrobial effect against some common pathogenic bacteria and growth promoting property against probiotic organism Lactobacillus acidophilus. The antimicrobial activity of S. grandiflora flower PE against selected pathogens was evaluated using both in vitro and in situ methods. In vitro studies suggested that PE has inhibitory effect against Staphylococcus aureus, Shigella flexneri 2a, Salmonella Typhi, Escherichia coli and Vibrio cholerae. The gram-positive organism S. aureus was the most sensitive organism to PE and minimum inhibitory concentration (MIC) was found to be 0.013 mg/mL where as the MIC of PE against V. cholerae was the highest (0.25 mg/mL). On the other hand PE showed growth promoting effect on the common probiotic bacterium L. acidophilus. The major finding was that S. grandiflora PE induced a significant biomass increase of L. acidophilus grown in liquid culture media. PE showed reduction of S. aureus growth in food (fish) during storage at 10°C. High performance liquid chromatography analysis showed that rutin, a major flavonoid of the PE diminished in the culture medium MRS broth with the growth of L. acidophilus. PMID:22583547

China, Ratna; Mukherjee, Sayani; Sen, Sauradip; Bose, Sreedipa; Datta, Sanjukta; Koley, Hemanta; Ghosh, Santinath; Dhar, Pubali

2012-09-01

97

Evaluation of antimicrobial activity of Cleome viscosa and Gmelina asiatica.  

PubMed

The ethanolic extracts of the leaves and flowers of Cleome viscosa and roots of Gmelina asiatica were tested for antimicrobial activity. The two plants exhibited a broad spectrum of antimicrobial activity, particularly significative against Escherichia coli , Proteus vulgaris and Pseudomonas aeruginosa. The leaf extract of C. viscosa showed moderate activity against pathogenic fungi. PMID:16325351

Sudhakar, M; Rao, Ch V; Rao, P M; Raju, D B

2006-01-01

98

Antimicrobial properties and membrane-active mechanism of a potential ?-helical antimicrobial derived from cathelicidin PMAP-36.  

PubMed

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

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

2014-01-01

99

Antimicrobial activity of endophytic fungi isolated from Swietenia macrophylla leaves.  

PubMed

The endophytic fungi isolated from leaves of Swietenia macrophylla of different ages were examined for antimicrobial activity. The agar plug diffusion assay was used for primary screening, followed by the disc diffusion method. A total of 461 filamentous endophytic fungi were isolated and cultured to examine their antimicrobial properties. In the primary screen, 315 isolates (68.3%) exhibited activity against at least one of the test pathogenic microorganisms. The percentage of isolates exhibiting antimicrobial activity increased with leaf age. Endophytic fungal assemblages, as well as those isolates exhibiting antimicrobial properties appeared to increase with leaf age. The main antimicrobial compounds were produced extracellularly by the endophytic fungi. The results suggest that healthy leaves at older stages of growth can be a potential source for the isolation of endophytic fungi with antimicrobial properties. PMID:24689302

Ibrahim, Darah; Lee, Chong Chai; Sheh-Hong, Lim

2014-02-01

100

Quaternized Chitosan as an Antimicrobial Agent: Antimicrobial Activity, Mechanism of Action and Biomedical Applications in Orthopedics  

PubMed Central

Chitosan (CS) is a linear polysaccharide with good biodegradability, biocompatibility and antimicrobial activity, which makes it potentially useful for biomedical applications, including an antimicrobial agent either alone or blended with other polymers. However, the poor solubility of CS in most solvents at neutral or high pH substantially limits its use. Quaternary ammonium CS, which was prepared by introducing a quaternary ammonium group on a dissociative hydroxyl group or amino group of the CS, exhibited improved water solubility and stronger antibacterial activity relative to CS over an entire range of pH values; thus, this quaternary modification increases the potential biomedical applications of CS in the field of anti-infection. This review discusses the current findings on the antimicrobial properties of quaternized CS synthesized using different methods and the mechanisms of its antimicrobial actions. The potential antimicrobial applications in the orthopedic field and perspectives regarding future studies in this field are also considered. PMID:23325051

Tan, Honglue; Ma, Rui; Lin, Chucheng; Liu, Ziwei; Tang, Tingting

2013-01-01

101

Effects of different substituents on the crystal structures and antimicrobial activities of six Ag(I) quinoline compounds.  

PubMed

The syntheses and single crystal X-ray structures of [Ag(5-nitroquinoline)2]NO3 (1), [Ag(8-nitroquinoline)2]NO3·H2O (2), [Ag(6-methoxy-8-nitroquinoline)(NO3)]n (3), [Ag(3-quinolinecarbonitrile)(NO3)]n (4), [Ag(3-quinolinecarbonitrile)2]NO3 (5), and [Ag(6-quinolinecarboxylic acid)2]NO3 (6) are described. As an alternative to solution chemistry, solid-state grinding could be used to prepare compounds 1 and 3, but the preparation of 4 and 5 in this way failed. The Ag(I) ions in the monomeric compounds 1, 2, 5, and 6 are coordinated to two ligands via the nitrogen atoms of the quinoline rings, thereby forming a distorted linear coordination geometry with Ag-N bond distances of 2.142(2)-2.336(2) Å and N-Ag-N bond angles of 163.62(13)°-172.25(13)°. The 1D coordination polymers 3 and 4 contain Ag(I) centers coordinating one ligand and two bridging nitrate groups, thereby forming a distorted trigonal planar coordination geometry with Ag-N bond distances of 2.2700(14) and 2.224(5) Å, Ag-O bond distances of 2.261(4)-2.536(5) Å, and N-Ag-O bond angles of 115.23(5)°-155.56(5)°. Hirshfeld surface analyses of compounds 1-6 are presented as d(norm) and curvedness maps. The d(norm) maps show different interaction sites around the Ag(I) ions, i.e., Ag···Ag interactions and possible O-H···O, C-H···O, C-H···N, and C-H···C hydrogen bonds. Curvedness maps are a good way of visualizing ?-? stacking interactions between molecules. The antimicrobial activities of compounds 1, 2, and 6 were screened against 15 different multidrug-resistant strains of bacteria isolated from diabetic foot ulcers and compared to the antimicrobial activities of the clinically used silver sulfadiazine (SS). Compound 2 showed activity similar to SS against this set of test organisms, being active against all strains and having slightly better average silver efficiency than SS (5 vs 6 ?g Ag/mL). Against the standard nonresistant bacterial strains of Staphylococcus aureus , Pseudomonas aeruginosa , Proteus mirabilis , and Streptococcus pyogenes , compound 1 performed better than silver nitrate, with an average MIC of 6 ?g Ag/mL versus 18 ?g Ag/mL for the reference AgNO3. Electrospray ionization mass spectrometry (ESI-MS) analyses of compounds 3 and 6 in DMSO/MeOH confirm the two-coordinated Ag(+) complexes in solution, and the results of the (1)H NMR titrations of DMSO solutions of 5-nitroquinoline and 8-nitroquinoline with AgNO3 in DMSO suggest that 5-nitroquinoline is more strongly coordinated to the silver ion. PMID:23458224

Massoud, Alshima'a A; Langer, Vratislav; Gohar, Yousry M; Abu-Youssef, Morsy A M; Jänis, Janne; Lindberg, Gabriella; Hansson, Karl; Öhrström, Lars

2013-04-01

102

Prediction of antimicrobial activity of synthetic peptides by a decision tree model.  

PubMed

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 ?g/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

Lira, Felipe; Perez, Pedro S; Baranauskas, José A; Nozawa, Sérgio R

2013-05-01

103

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

PubMed Central

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 ?g/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

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

2013-01-01

104

Antimicrobial activity of prodigiosin isolated from Serratia marcescens UFPEDA 398.  

PubMed

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 ?g/mL, respectively, while the minimum bactericidal concentrations ranged from 2, 4, 8 and 16 ?g/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

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

2015-02-01

105

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...

106

Effects of Cultivation Techniques and Processing on Antimicrobial and Antioxidant Activities of Hericium erinaceus (Bull.:Fr.) Pers. Extracts  

Microsoft Academic Search

Summary Hericium erinaceus, a temperate mushroom, is currently cultivated in Malaysia. As culti- vation and processing conditions may affect the medicinal properties, antimicrobial and an- tioxidant properties of locally grown H. erinaceus have been investigated. The fruitbodies that were fresh, oven-dried or freeze-dried were extracted with methanol. Their properties were compared to those exhibited by mycelium extract of the same

Kah Hui Wong; Vikineswary Sabaratnam; Noorlidah Abdullah; Umah Rani Kuppusamy; Murali Naidu

2009-01-01

107

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

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

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

2013-01-01

108

Antioxidant and antimicrobial activities of individual and combined phenolics in Olea europaea leaf extract.  

PubMed

Olive leaves, an agricultural waste, have great potential as a natural antioxidant. The current study was made to assess the antioxidant and antimicrobial activities of both the individual and combined phenolics in olive leaf extract. A combined phenolics mixture was prepared by amount ratios of the phenolic compounds in the olive leaf extract. The results showed that both the individual and combined phenolics exhibited good radical scavenging abilities, and also revealed superoxide dismutase (SOD)-like activity. In terms of antimicrobial activity, both oleuropein and caffeic acid showed inhibition effects against microorganisms. Furthermore, the antimicrobial effect of the combined phenolics was significantly higher than those of the individual phenolics. These results show that the combination of olive leaf extract phenolics possessed antioxidant and antimicrobial activities. This study indicates that olive leaf extract might be a valuable bioactive source, and would seem to be applicable in both the health and medical food. PMID:20106659

Lee, Ok-Hwan; Lee, Boo-Yong

2010-05-01

109

Antimicrobial and healing activity of kefir and kefiran extract  

Microsoft Academic Search

Kefir and its insoluble polysaccharide, kefiran, were both tested for antimicrobial and cicatrizing activities against several bacterial species and Candida albicans using an agar diffusion method. Comparator antimicrobials were also tested. Cicatrizing experiments were carried out on Wistar rats with induced skin lesions and Staphylococcus aureus inoculation, using a topical application of a 70% kefir gel. Both kefir and kefiran

Kamila Leite Rodrigues; Lucélia Rita Gaudino Caputo; Jose Carlos Tavares Carvalho; João Evangelista; Jose Maurício Schneedorf

2005-01-01

110

In vitro antimicrobial activity of Medilox® super-oxidized water  

PubMed Central

Aim Super-oxidized water is one of the broad spectrum disinfectants, which was introduced recently. There are many researches to find reliable chemicals which are effective, inexpensive, easy to obtain and use, and effective for disinfection of microorganisms leading hospital infections. Antimicrobial activity of super-oxidized water is promising. The aim of this study was to investigate the in-vitro antimicrobial activity of different concentrations of Medilox® super-oxidized water that is approved by the Food and Drug Administration (FDA) as high level disinfectant. Material and methods In this study, super-oxidized water obtained from Medilox® [Soosan E & C, Korea] device, which had been already installed in our hospital, was used. Antimicrobial activities of different concentrations of super-oxidized water (1/1, 1/2, 1/5, 1/10, 1/20, 1/50, 1/100) at different exposure times (1, 2, 5, 10, 30 min) against six ATCC strains, eight antibiotic resistant bacteria, yeasts and molds were evaluated using qualitative suspension test. Dey-Engley Neutralizing Broth [Sigma-Aldrich, USA] was used as neutralizing agent. Results Medilox® was found to be effective against all standard strains (Acinetobacter baumannii 19606, Escherichia coli 25922, Enterococcus faecalis 29212, Klebsiella pneumoniae 254988, Pseudomonas aeruginosa 27853, Staphylococcus aureus 29213), all clinical isolates (Acinetobacter baumannii, Escherichia coli, vancomycin-resistant Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Myroides spp.), and all yeastsat 1/1 dilution in ??1 minute. It was found to be effective on Aspergillus flavus at 1/1 dilution in ??2 minutes and on certain molds in ??5 minutes. Conclusion Medilox® super-oxidized water is a broad spectrum, on-site producible disinfectant, which is effective on bacteria and fungi and can be used for the control of nosocomial infection. PMID:25023905

2014-01-01

111

Insertion selectivity of antimicrobial peptide protegrin-1 into lipid monolayers: Effect of head group electrostatics and tail group packing  

E-print Network

Insertion selectivity of antimicrobial peptide protegrin-1 into lipid monolayers: Effect of head of the antimicrobial peptides (AMPs). This selectivity strongly depends on the chemical and structural properties plays in the activity of AMPs. © 2006 Elsevier B.V. All rights reserved. Keywords: Antimicrobial peptide

Lee, Ka Yee C.

112

Self-aggregation and antimicrobial activity of imidazolium and pyridinium based ionic liquids in aqueous solution.  

PubMed

Two series of long-chain imidazolium and pyridinium based ionic liquids (1-alkyl-3-methylimidazolium and 1-alkylpyridinium bromides) were synthesised and the effect of the alkyl chain length and the nature of the cationic head group on micellization and antimicrobial activity of the ionic liquids (ILs) were investigated. Tensiometry, conductometry, spectrofluorimetry and PGSE-NMR were applied to study the self-aggregation of the amphiphilic ILs in aqueous solution. The ILs investigated displayed surface activity and the characteristic chain length dependence of the micellization process of surfactants. The antimicrobial activity was evaluated against Gram-negative and Gram-positive bacteria and fungi. ILs containing more than eight carbon atoms in the alkyl chain showed antimicrobial activity. Their efficiency as antimicrobial agents increased with the hydrophobicity of the amphiphilic cation being the C(14) homologous the most active compounds. PMID:21186035

Cornellas, Anna; Perez, Lourdes; Comelles, Francesc; Ribosa, Isabel; Manresa, Angeles; Garcia, M Teresa

2011-03-01

113

Antimicrobial activity of fermented Theobroma cacao pod husk extract.  

PubMed

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

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

2014-01-01

114

Antimicrobial and cytotoxic effects of Mexican medicinal plants.  

PubMed

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

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

115

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

PubMed

Currently, novel antibiotics are urgently required to combat the emergence of drug-resistant bacteria. Antimicrobial peptides with membrane-lytic mechanism of action have attracted considerable interest. Anoplin, a natural ?-helical amphiphilic antimicrobial peptide, is an ideal research template because of its short sequence. In this study, we designed and synthesized a group of analogues of anoplin. Among these analogues, anoplin-4 composed of d-amino acids displayed the highest antimicrobial activity due to increased charge, hydrophobicity and amphiphilicity. Gratifyingly, anoplin-4 showed low toxicity to host cells, indicating high bacterial selectivity. Furthermore, the mortality rate of mice infected with Escherichia coli was significantly reduced by anoplin-4 treatment relative to anoplin. In conclusion, anoplin-4 is a novel anoplin analogue with high antimicrobial activity and enzymatic stability, which may represent a potent agent for the treatment of infection. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. PMID:25316570

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

2014-12-01

116

Antidiarrhoeal and antimicrobial activity of Calpurnia aurea leaf extract  

PubMed Central

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

2013-01-01

117

Antimicrobial activity of basic cholane derivatives, VIII.  

PubMed

Two series of new compounds derived from deoxycholic acid have been synthesized: 3,12-dioxo-5 beta-cholan-24-N-substituted amides and their 3 beta-amino and 3 beta-N-alkylamino derivatives. The first series of five compounds 1-5 carries at C-24 the residue of benzylamine, morpholine, diethanolamine, N,N-diethyl-ethylenediamine, and N-methylpiperazine. The second series of twenty compounds 1A-D - 5A-D was prepared by means of reductive amination starting from the compounds of the first series. This reaction proved to be regioselective and stereospecific: it attacks only C-3 of the steroid moiety and introduces the following axial beta-oriented substituents: amino, methylamino, ethylamino, and benzylamino. The compounds of the first series showed moderate scattered antimicrobial activity; while introduction of the 3 beta-amino and 3 beta-N-alkylamino residue greatly increased activity towards Gram (+) strains; even yeast and fungi appear to be sensitive towards this last series of compounds. The results have been discussed with respect to the nature of the substituents both at C-3 and C-24, the highest activity being associated to the hydrophobicity of these residues. PMID:2619517

Bellini, A M; Quaglio, M P; Mencini, E; Guarneri, M; Cavazzini, G; Fini, A

1989-12-01

118

INSECT-SYMBIONT INTERACTIONS Actinomycetes with Antimicrobial Activity Isolated from Paper Wasp  

E-print Network

antibiotic, natural products, actinobacteria, Polistes dominula Antimicrobial producing bacteria have beenINSECT-SYMBIONT INTERACTIONS Actinomycetes with Antimicrobial Activity Isolated from Paper Wasp ABSTRACT ActinomycetesÃ?a group of antimicrobial producing bacteriaÃ?have been successfully cultured

Starks, Philip

119

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

PubMed Central

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

2009-01-01

120

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

PubMed Central

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

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

2014-01-01

121

Size-Dependent Antimicrobial Effects of Novel Palladium Nanoparticles  

PubMed Central

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, 2.0±0.1 nm, 2.5±0.2 nm and 3.1±0.2 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 (2.5×10?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

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

2014-01-01

122

Endophytic Fungi Isolated from Coleus amboinicus Lour Exhibited Antimicrobial Activity  

PubMed Central

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

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

2014-01-01

123

Synergistic effects of antimicrobial peptides and antibiotics against Clostridium difficile.  

PubMed

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

Nuding, Sabine; Frasch, Tina; Schaller, Martin; Stange, Eduard F; Zabel, Lutz T

2014-10-01

124

Antimicrobial and antioxidative activity of extracts and essential oils of Myrtus communis L.  

PubMed

Since synthetic antimicrobial agents and food additives can cause a number of adverse effects, there is a growing interest from consumers in ingredients from natural sources. Medicinal plants, such as Myrtus communis L. are a source of new compounds which can be used in both the food industry and for medical purposes, primarily as antimicrobial agents. In this review, the characteristics of myrtle essential oils and extracts are summarized, with particular attention to their chemical composition, biological activities and potential applications. PMID:24291016

Aleksic, Verica; Knezevic, Petar

2014-04-01

125

Structural Dissection of a Highly Knotted Peptide Reveals Minimal Motif with Antimicrobial Activity*S  

E-print Network

Structural Dissection of a Highly Knotted Peptide Reveals Minimal Motif with Antimicrobial Activity. Antimicrobial peptides (1­4) are important constituents of the innate immune system (5) of most organisms to classical antibiotics (8­10) drives much of the current interest on antimicrobial peptides, in the hope

Pompeu Fabra, Universitat

126

Effect of Extraction Techniques on Phenolic Content, Antioxidant and Antimicrobial Activity of Bauhinia purpurea : HPTLC Determination of Antioxidants  

Microsoft Academic Search

Bauhinia purpurea leaf was extracted by Soxhlet, ultrasonication and maceration extraction methods using ethanol (99.5%, v\\/v) to obtain Soxhlet (SBE), ultrasonicated (UBE) and macerated (MBE) B. purpurea leaf extract. The effects of different extracting methods on the polyphenolic content and antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl\\u000a (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), ferric-reducing antioxidant power (FRAP)\\u000a and total antioxidant capacity (TAC)

H. V. Annegowda; M. N. Mordi; S. Ramanathan; M. R. Hamdan; S. M. Mansor

127

Antioxidant and Antimicrobial activity of Pedicularis sibthorpii Boiss. And Pedicularis wilhelmsiana Fisch ex.  

PubMed Central

Purpose: This research paper presents antioxidant and antimicrobial activities of Pedicularis sibthorpii and Pedicularis wilhelmsiana which grow in Azerbaijan/Iran with claimed a lot of therapeutic effects. Methods: DPPH assay and agar well diffusion method were carried out to determine antioxidant and antimicrobial activities respectively. Results: Methanolic extract showed better antioxidant activity compared to other crude extracts (n-hexane and dichloromethane). Methanolic extracts of both Pedicularis sibthorpii and Pedicularis wilhelmsiana were found to have antibacterial activity especially against gram positive strains of S. ureus, S.epidermidis. No antifungal activity was observed in the tested extracts. Conclusion: Existence of some phenolic compounds in methanolic extracts, such as phenylethanoids and flavonoids (found in other species of Pedicularis), which cause both antioxidant and antibacterial activities, is probable. Antimicrobial and antioxidant activity of the methanolic extracts supports further studies related to phytochemical investigation and bioassay of different fractions to isolate pure compounds of plants. PMID:24312775

khodaie, Laleh; Delazar, Abbas; Lotfipour, Farzaneh; Nazemiyeh, Hossein

2012-01-01

128

Effectiveness of antimicrobial food packaging materials.  

PubMed

Antimicrobial additives have been used successfully for many years as direct food additives. The literature provides evidence that some of these additives may be effective as indirect food additives incorporated into food packaging materials. Antimicrobial food packaging is directed toward the reduction of surface contamination of processed, prepared foods such as sliced meats and Frankfurter sausages (hot dogs). The use of such packaging materials is not meant to be a substitute for good sanitation practices, but it should enhance the safety of food as an additional hurdle for the growth of pathogenic and/or spoilage microorganisms. Studies have focused on establishing methods for coating low-density polyethylene film or barrier films with methyl cellulose as a carrier for nisin. These films have significantly reduced the presence of Listeria monocytogenes in solutions and in vacuum packaged hot dogs. Other research has focused on the use of chitosan to inhibit L. monocytogenes and chlorine dioxide sachets for the reduction of Salmonella on modified atmosphere-packaged fresh chicken breasts. Overall, antimicrobial packaging shows promise as an effective method for the inhibition of certain bacteria in foods, but barriers to their commercial implementation continue to exist. PMID:16227182

Cooksey, K

2005-10-01

129

Investigation of the antimicrobial activity and biocompatibility of magnesium alloy coated with HA and antimicrobial peptide.  

PubMed

Implant-associated infection is one of the biggest problems in orthopedic surgery. Antimicrobial peptides (AMPs) are well-known components of the innate immunity and less susceptible to the development of pathogen resistance compared to conventional antibiotics. Magnesium alloys as potential biodegradable bone implants have been received much attention in biomaterials field. This study investigated the deposition of calcium phosphate (CaP) coatings and loading of AMPs on the magnesium alloy surface by a biomimetic method. Scanning electron microscope (SEM) results presented that a microporous and plate-like CaP coating was processed on the magnesium alloy surface. X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis showed the main component of coating was hydroxyapatite (HA). Degradation assay in vitro showed that the HA coating deposited onto the magnesium alloy was corroded more slowly than the bare one. The amount of AMP loaded in the HA coating was 11.16 ± 1.99 ?g/cm(2). The AMP loaded onto HA coatings had slow release for 7 days. The AMP-loaded coating showed antimicrobial activity against Staphylococcus aureus. Its bacterial inhibition rate exceeded 50 % after 4 days and the antibacterial effect was sustained for 7 days. The coated magnesium alloys loaded with AMP could improve rat bone marrow mesenchymal stem cells (rBMMSCs) proliferation. Furthermore, it could also promote alkaline phosphatase (ALP) activity of rBMMSCs. Both radiographic evaluation and histopathology analysis demonstrated that implantation of the coated magnesium alloy into the rabbit femoral condyle had promoted bone repair and showed anti-inflammatory effect. The results showed that the AMP loaded onto HA coatings on the magnesium alloy surface could be considered an ideal orthopedic implant against S. aureus infection. PMID:25631264

Tian, Jinhuan; Shen, Si; Zhou, Changren; Dang, Xiangli; Jiao, Yanpeng; Li, Lihua; Ding, Shan; Li, Hong

2015-02-01

130

Phenolic antioxidant mobilization in cranberry pomace by solid-state bioprocessing using food grade fungus Lentinus edodes and effect on antimicrobial activity against select food borne pathogens  

Microsoft Academic Search

Cranberry pomace is a byproduct of the cranberry processing industry. Solid-state bioprocessing of cranberry pomace using food grade fungus Lentinus edodes improved phenolic profile and antioxidant activity. We investigated whether these phenolic phytochemicals mobilized during bio-processing of the pomace would improve the antimicrobial functionality. Listeria monocytogenes, Vibrio parahaemolyticus and Escherichia coli-O157: H7 are important food borne pathogens. Control of these

D. A Vattem; Y.-T Lin; R. G Labbe; K Shetty

2004-01-01

131

Nanoliposomes containing Eucalyptus citriodora as antibiotic with specific antimicrobial activity.  

PubMed

Bacterial infections are a serious issue for public health and represent one of the major challenges of modern medicine. In this work, a selective antimicrobial strategy based on triggering of pore-forming toxin, which is secreted by infective bacteria, was designed to fight Staphylococcus aureus. The antimicrobial activity is realized by employing Eucalyptus citriodora oil as antibiotic which in this study is encapsulated in nanoliposomes. PMID:25573466

Lin, Lin; Cui, Haiying; Zhou, Hui; Zhang, Xuejing; Bortolini, Christian; Chen, Menglin; Liu, Lei; Dong, Mingdong

2015-01-29

132

Antimicrobial Effect of Chitosan Nanoparticles on Streptococcus mutans Biofilms?  

PubMed Central

Nanoparticle complexes were prepared from chitosans of various molecular weights (MW) and degrees of deacetylation (DD). The antimicrobial effect was assessed by the Live/Dead BacLight technique in conjunction with confocal scanning laser microscopy (CSLM) and image analysis. Nanocomplexes prepared from chitosans with high MW showed a low antimicrobial effect (20 to 25% of cells damaged), whereas those prepared from low-MW chitosans showed high antimicrobial effect (>95% of cells damaged). PMID:21498764

Chávez de Paz, Luis E.; Resin, Anton; Howard, Kenneth A.; Sutherland, Duncan S.; Wejse, Peter L.

2011-01-01

133

Antimicrobial activity of Uncaria tomentosa against oral human pathogens.  

PubMed

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

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

2007-01-01

134

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

PubMed Central

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

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

2013-01-01

135

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

NASA Astrophysics Data System (ADS)

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)2?2H2O (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.

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

2014-01-01

136

Investigating the effects of L- to D-amino acid substitution and deamidation on the activity and membrane interactions of antimicrobial peptide anoplin.  

PubMed

Isolated from the venom sac of solitary spider wasp, Anoplius samariensis, anoplin is the smallest linear ?-helical antimicrobial peptide found naturally with broad spectrum activity against both Gram-positive and Gram-negative bacteria, and little hemolytic activity toward human erythrocytes. Deamidation was found to decrease the peptide's antibacterial properties. In the present work, interactions of amidated (Ano-NH2) and deamidated (Ano-OH) forms of anoplin as well as Ano-NH2 composed of all D-amino acids (D-Ano-NH2) with model cell membranes were investigated by means of Langmuir Blodgett (LB) technique, atomic force microscopy (AFM), X-ray photoemission electron microscopy (X-PEEM) and carboxyfluorescein leakage assay in order to gain a better understanding of the effect of these peptide modifications on membrane binding and lytic properties. According to LB, all three peptides form stable monolayers at the air/water interface with Ano-NH2 occupying a slightly greater area per molecule than Ano-OH. All three forms of the peptide interact preferentially with anionic 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DPPG), rather than zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayer. Peptides form nanoscale clusters in zwitterionic but not in anionic monolayers. Finally, membrane lytic activity of all derivatives was found to depend strongly on membrane composition and lipid/peptide ratio. The results suggest that amidated forms of peptides are likely to possess higher membrane binding affinity due to the increased charge. PMID:21078293

Won, Amy; Khan, Mourin; Gustin, Sorin; Akpawu, Akuvi; Seebun, Deeptee; Avis, Tyler J; Leung, Bonnie O; Hitchcock, Adam P; Ianoul, Anatoli

2011-06-01

137

Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity  

NASA Astrophysics Data System (ADS)

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.

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

2012-05-01

138

Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity  

PubMed Central

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

2012-01-01

139

Antimicrobial activity of Ammodaucus leucotrichus fruit oil from Algerian Sahara.  

PubMed

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

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

2014-05-01

140

Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity.  

PubMed

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

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

2012-01-01

141

Antioxidant and antimicrobial activity of some lichen species  

Microsoft Academic Search

The aim of the research is to explore the overall in vitro antioxidant activity, total phenol content, reduction power and\\u000a antimicrobial activity of the methanol extracts of the lichens Cetraria pinastri, Cladonia digitata, Cladonia fimbriata, Fulgensia fulgens, Ochrolechia parella and Parmelia crinita. The methanol extract of the Cetraria pinastri showed a strong antioxidant activity, whereas the extracts of the species

B. Rankovi?; D. Rankovic; D. Maric

2010-01-01

142

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

PubMed

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 ?L/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

Marina?, Ioana Cristina; Chifiriuc, Carmen; Oprea, Eliza; Laz?r, Veronica

2014-01-01

143

Radical scavenging, antioxidant and antimicrobial activities of halophytic species Laetitia Meot-Durosa*  

E-print Network

Radical scavenging, antioxidant and antimicrobial activities of halophytic species Laetitia Meot-11Jan2011 #12;scavenging activity (Ksouri et al., 2006), but no antimicrobial properties have been investigations on in vitro antibacterial, radical scavenging and antioxidant activities of the extracts

Paris-Sud XI, Université de

144

Antimicrobial activity of two bactenecins against spirochetes.  

PubMed Central

Bac5 and Bac7 are antimicrobial peptides of bovine neutrophils that act on enteric gram-negative bacteria. We report here that these two peptides immobilize and kill Leptospira interrogans and Leptospira biflexa with MBCs of 6 to 25 micrograms/ml. Conversely, although both peptides bind to Borrelia burgdorferi, the organism is resistant to their action. Images PMID:8514417

Scocchi, M; Romeo, D; Cinco, M

1993-01-01

145

Antimicrobial activity of rabbit CAP18-derived peptides.  

PubMed Central

A cationic antimicrobial protein of 18 kDa (CAP18) was originally isolated from rabbit granulocytes by using as an assay the agglutination of Re-lipopolysaccharide-coated erythrocytes. The C-terminal 37 amino acids of CAP18 (CAP18(106-142)) make up the lipopolysaccharide-binding domain. Synthetic CAP18(106-142) has broad antimicrobial activity against both gram-positive (50% inhibitory concentration, 130 to 200 nM) and gram-negative (50% inhibitory concentration, 20 to 100 nM) bacteria. Susceptible strains include Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium. Antimicrobial activity is highly dependent on peptide structure. Although a 32-amino-acid peptide resulting from the truncation of 5 amino acids from the C terminus of CAP18(106-142) is highly active, other fragments of CAP18(106-142), including CAP18(106-142) with a truncated N terminus, do not exhibit antimicrobial activity. Unlike previously characterized antimicrobial peptides derived from granulocyte proteins, CAP18(106-142) is active in serum. CAP18(106-142) or a derivative peptide may have therapeutic potential for bacterial sepsis. Images PMID:8109914

Larrick, J W; Hirata, M; Shimomoura, Y; Yoshida, M; Zheng, H; Zhong, J; Wright, S C

1993-01-01

146

Trachyspermum ammi (L.) sprague: chemical composition of essential oil and antimicrobial activities of respective fractions.  

PubMed

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 ?-terpinene (48.07%), ?-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

Moein, Mahmoodreza R; Zomorodian, Kamiar; Pakshir, Keyvan; Yavari, Farnoosh; Motamedi, Marjan; Zarshenas, Mohammad M

2015-01-01

147

Fractionation of Mastic Gum in Relation to Antimicrobial Activity  

PubMed Central

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.

Sharifi, Mohammad Sharif; Hazell, Stuart Loyd

2009-01-01

148

Mechanism of a prototypical synthetic membrane-active antimicrobial: Efficient hole-punching  

E-print Network

a prototypical class of synthetic antimicrobial compounds that mimic antimicrobial peptides pro- duced of antibiotic-resistant bacteria is a worldwide public health problem (1). Antimicrobial peptides (AMPs) fromMechanism of a prototypical synthetic membrane- active antimicrobial: Efficient hole-punching via

Tew, Gregory N.

149

Antimicrobial, antibiofilm and cytotoxic activities of Hakea sericea Schrader extracts  

PubMed Central

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

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

2014-01-01

150

A screening for antimicrobial activities of Caribbean herbal remedies  

PubMed Central

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 ?g/mL and MBC?=?1.0 mg/mL against P. vulgaris and T. ananassae that showed MIC?=?15 ?g/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

2013-01-01

151

Chemical composition and antimicrobial activity of Polish herbhoneys.  

PubMed

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

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

2015-03-15

152

Antimicrobial activity of Hedeoma drummondii against opportunistic pathogens.  

PubMed

Hedeoma drummondii is a medicinal plant with diverse properties; however, validations of its medicinal uses are scarce. To evaluate its antimicrobial properties H. drummondii, was tested against opportunistic pathogens of medical importance. Antimicrobial tests were performed by the microdilution method in order to determine the Minimal Inhibitory Concentration (MIC) for each extract. Extracts of this plant showed relevant antimicrobial activity, results revealed that the hexanic extract has stronger activity and broader spectrum compared to acetone and methanol extracts. The activity of hexanic extract may be attributed mainly to the presence of the monoterpenes pulegone and menthol. In conclusion, the hexanic extract possess relevant antibacterial properties which suggests that H. drummondii have bioactive principles; these new data provide scientific support for the use of this plant in traditional medicine, particularly for gastrointestinal diseases. PMID:21870634

Viveros-Valdez, E; Rivas-Morales, C; Oranday-Cardenas, A; Verde-Star, M J; Carranza-Rosales, P

2011-02-15

153

Antimicrobial Textiles - Evaluation of Their Effectiveness and Safety  

Microsoft Academic Search

The number of biofunctional textiles with an antimicrobial activity has increased considerably over the last few years. Whilst in the past it was predominantly technical textiles which had antimicrobial finishes, in particular to protect against fungi, nowadays textiles worn close to the body have been developed for a variety of different applications as far as medical and hygienic tasks. Together

2006-01-01

154

Antimicrobial activity of 20 plants used in folkloric medicine in the Palestinian area  

Microsoft Academic Search

Ethanolic and aqueous extracts of 20 Palestinian plant species used in folk medicine were investigated for their antimicrobial activities against five bacterial species (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa) and one yeast (Candida albicans). The plants showed 90% of antimicrobial activity, with significant difference in activity between the different plants. The most antimicrobially active plants were

M. S Ali-Shtayeh; Reem M.-R Yaghmour; Y. R Faidi; Khalid Salem; M. A Al-Nuri

1998-01-01

155

Screening antimicrobial activity of various extracts of Artemisia dracunculus L.  

PubMed

The antimicrobial activities of chloroform, acetone and two different concentrations of methanol extracts of Artemisia dracunculus L. were studied. These extracts were tested against nine bacteria and four yeasts strains by the disc diffusion method. The results indicated that the methanol extract of A. dracunculus is more effective against tested microorganisms than chloroform or acetone extracts. The chloroform and acetone extracts were inhibitory only towards Pseudomonas aeruginosa (ATCC 27853). While the methanol extract that was diluted with 10 ml distilled water showed inhibition zones against Shigella (RSHI), Listeria monocytogenes ATCC 7644, P. aeruginosa (ATCC 27853), the methanol extract that was diluted with 5 ml distilled water showed inhibition zones against two different strains of Escherichia coli (RSHI, ATCC 25922), Shigella (RSHI), L. monocytogenes (ATCC 7644), and P. aeruginosa ATCC 27853. The cells of microorganisms treated with plant extracts and normal microorganism cells were observed by scanning electron microscope. It was apparent that cells are damaged after treatment with A. dracunculus. PMID:16986171

Benli, Mehlika; Kaya, Ilhan; Yigit, Nazife

2007-01-01

156

The Synthesis and Antimicrobial Activity of Heterocyclic Derivatives of Totarol  

PubMed Central

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

2012-01-01

157

Comparison of antimicrobial activities of naphthoquinones from Impatiens balsamina.  

PubMed

Lawsone (1), lawsone methyl ether (2), and methylene-3,3'-bilawsone (3) are the main naphthoquinones in the leaf extracts of Impatiens balsamina L. (Balsaminaceae). Antimicrobial activities of these three naphthoquinones against dermatophyte fungi, yeast, aerobic bacteria and facultative anaerobic and anaerobic bacteria were evaluated by determination of minimal inhibitory concentrations (MICs) and minimal bactericidal or fungicidal concentrations (MBCs or MFCs) using a modified agar dilution method. Compound 2 showed the highest antimicrobial activity. It showed antifungal activity against dermatophyte fungi and Candida albicans with the MICs and MFCs in the ranges of 3.9-23.4 and 7.8-23.4?µg?mL(-1), respectively, and also had some antibacterial activity against aerobic, facultative anaerobic and anaerobic bacteria with MICs in the range of 23.4-93.8, 31.2-62.5 and 125?µg?mL(-1), respectively. Compound 1 showed only moderate antimicrobial activity against dermatophytes (MICs and MFCs in the ranges of 62.5-250 and 125-250?µg?mL(-1), respectively), but had low potency against aerobic bacteria, and was not active against C. albicans and facultative anaerobic bacteria. In contrast, 3 showed significant antimicrobial activity only against Staphylococus epidermidis and Bacillus subtilis (MIC and MBC of 46.9 and 93.8?µg?mL(-1), respectively). PMID:21895457

Sakunphueak, Athip; Panichayupakaranant, Pharkphoom

2012-01-01

158

Antimicrobial Activity of the Volatile Oil of Nigella sativa Linneaus Seeds  

PubMed Central

The antimicrobial activity of the volatile oil of Nigella sativa Linneaus seeds was studied. The antimicrobial principle has been isolated, identified as thymohydroquinone, and found to be active against gram-positive bacteria and yeasts. PMID:15828195

Toama, Mohamed A.; El-Alfy, Taha S.; El-Fatatry, Hamed M.

1974-01-01

159

Measuring antimicrobial peptide activity on epithelial surfaces in cell culture  

PubMed Central

To more accurately assess the activity and role of epithelial-cell derived antimicrobial peptides in their native settings, it is essential to perform assays at the surfaces under relevant conditions. In order to carry this out, we utilize 3-dimensional cultures of airway and gingival epithelium, which are grown at an air-liquid interface. Under these conditions, the cultures can be subjected to challenge with a variety of factors known to cause an increase in antimicrobial peptide gene expression. The functional relevance of this induction can then be assessed by quantifying antibacterial activity either directly on the surface of the cells or using the fluid secreted onto the apical surface of the cultures. The relative contribution of the peptides can also be measured by pre-incubation of the secreted fluid with specific inhibitory antibodies. Thus, a relatively inexpensive in vitro model can be used to evaluate the role of antimicrobial peptides in mucosal epithelium. PMID:20094876

Diamond, Gill; Yim, Sunghan; Rigo, Isaura; McMahon, Laura

2009-01-01

160

Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the antimicrobial activity.  

PubMed

Salmonella enterica is a predominant foodborne pathogen that causes diarrheal illness worldwide. A potential method of inhibiting pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. The objectives of this study were to investigate the influence of heat (70°C for 5 min) and subsequent cold storage (4°C up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella enterica serovar Typhimurium DT104 in ground pork and to evaluate the activity of the most effective antimicrobials (cinnamon oil and olive extract) at higher concentrations in heated ground pork. The surviving Salmonella populations in two groups (heated and unheated) of antimicrobial-treated pork were compared. Higher concentrations of the most effective compounds were then tested (cinnamon oil at 0.5 to 1.0% and olive extract at 3, 4, and 5%) against Salmonella Typhimurium in heated ground pork. Samples were stored at 4°C and taken on days 0, 3, 5, and 7 for enumeration of survivors. The heating process did not affect the activity of antimicrobials. Significant 1.3- and 3-log reductions were observed with 1.0% cinnamon oil and 5% olive extract, respectively, on day 7. The minimum concentration required to achieve . 1-log reduction in Salmonella population was 0.8% cinnamon oil or 4% olive extract. The results demonstrate the effectiveness of these antimicrobials against multidrug-resistant Salmonella Typhimurium in ground pork and their stability during heating and cold storage. The most active formulations have the potential to enhance the microbial safety of ground pork. PMID:23834804

Chen, Cynthia H; Ravishankar, Sadhana; Marchello, John; Friedman, Mendel

2013-07-01

161

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

PubMed

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

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

1998-05-01

162

Osmoprotective Polymer Additives Attenuate the Membrane Pore-Forming Activity of Antimicrobial Peptoids.  

PubMed

Antimicrobial peptides (AMPs) are critical components of the innate immune system and exhibit bactericidal activity against a broad spectrum of bacteria. We investigated the use of N-substituted glycine peptoid oligomers as AMP mimics with potent antimicrobial activity. The antimicrobial mechanism of action varies among different AMPs, but many of these peptides can penetrate bacterial cell membranes, causing cell lysis. We previously hypothesized that amphiphilic cyclic peptoids may act through a similar pore formation mechanism against methicillin-resistant Staphylococcus aureus (MRSA). Peptoid-induced membrane disruption is observed by scanning electron microscopy and results in a loss of membrane integrity. We demonstrate that the antimicrobial activity of the peptoids is attenuated with the addition of polyethylene glycol osmoprotectants, signifying protection from a loss of osmotic balance. This decrease in antimicrobial activity is more significant with larger osmoprotectants, indicating that peptoids form pores with initial diameters of ~2.0-3.8 nm. The initial membrane pores formed by cyclic peptoid hexamers are comparable in diameter to those formed by larger and structurally distinct AMPs. After 24 h, the membrane pores expand to >200 nm in diameter. Together, these results indicate that cyclic peptoids exhibit a mechanism of action that includes effects manifested at the cell membrane of MRSA. This article is protected by copyright. All rights reserved. PMID:25403751

Smith, Peter T; Huang, Mia L; Kirshenbaum, Kent

2014-11-18

163

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

PubMed Central

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.

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

2013-01-01

164

In vitro antimicrobial activity of novel azaphenothiazine derivatives.  

PubMed

Antimicrobial activity in vitro of a series of novel azaphenothiazine derivatives containing a quinoline moiety was investigated using Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) strains as well as in Candida albicans yeast. The examined compounds showed the highest activity against Enterococcus faecalis and Escherichia coli whereas activity against Pseudomonas aeruginosa was the lowest. Compound 1d demonstrates the highest activity against all tested bacterial strains. Compounds 1c, 1h and 1k with various substituents (CH3, OH, NH2) at C11 position of the quinobenzothiazine ring, did not exhibit activity against any tested bacterial strain. Only compounds 1m and 1n with long aliphatic chains at the quinoline nitrogen atom showed antifungal activity. Correlations between antimicrobial activity and chemical structure of the tested compounds were observed. PMID:23285676

Zieba, Andrzej; Czuba, Zenon Pawe?; Król, Wojciech

2012-01-01

165

Poly(ethyleneimines) in dermal applications: biocompatibility and antimicrobial effects.  

PubMed

Cationic polyamines, such as poly(ethyleneimines) (PEIs), may recommend themselves for antimicrobial applications as they can interact with microbial membranes resulting in their disruption. The purpose of the study was the assessment of biocompatibility and antibacterial activity of PEIs with different architectures (branched (b) and linear (l)) and molar masses (0.8-750 kDa). lPEI and bPEI exhibited a strong antibacterial activity against Staphylococcus aureus and Escherichia coli with a more pronounced effect on the Gram-positive bacteria. lPEIs further demonstrated a higher antibacterial efficacy compared to bPEIs but no significant differences between 5 and 25 kDa were observed. In accordance, antibacterial activity of bPEI did not specifically depend on molar mass. Only slightly lower minimal inhibitory concentrations (MIC) were observed at 5 kDa (S. aureus) and 25 kDa (E. coli) in the tests. As PEIs are compelling candidates for use in antimicrobial treatment, two basic aspects have to be investigated: treatment effectiveness and safety. PEIs clearly induced molecular weight dependent cytotoxic effects in vitro. PEIs with low molecular weight (0.8 and 5 kDa) exhibited higher biocompatibility. Nonetheless, the results confirmed a low genotoxic potential of lPEI and bPEIs. In conclusion, 2.5 kDa-lPEI and 0.8 kDa-bPEI can be recommended for use as antimicrobial polymers in dermal applications due to their high biocompatibility with concomitant antibacterial efficacy. PMID:23948135

Wiegand, Cornelia; Bauer, Marius; Hipler, Uta-Christina; Fischer, Dagmar

2013-11-01

166

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

PubMed Central

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

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

2014-01-01

167

Antimicrobial activity of the essential oils of Turkish plant spices  

Microsoft Academic Search

The antimicrobial activity of the essential oils of nine plant spices (savory, laurel, oregano, basil, cumin, seafennel, myrtle, pickling herb, and mint) were tested at three concentrations (1, 10, and 15%) and tested on various microorganisms (Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Yersinia enterocolitica, Saccharomyces cerevisiae, Candida rugosa, Rhizopus oryzae and Aspergillus niger). The results showed

M. Özcan; Osman Erkmen

2001-01-01

168

Antimicrobial Activity of Indigenous Medicinal Plants Against Enterococcus  

E-print Network

. However, both the plants themselves and the shamanic knowledge of the plants are fading fast dueAntimicrobial Activity of Indigenous Medicinal Plants Against Enterococcus faecalis By Daniel The knowledge of medicinal plant use by indigenous populations constitutes the most understudied medical

Firestone, Jeremy

169

Antimicrobial and antibiofilm activity of LL-37 and its truncated variants against Burkholderia pseudomallei.  

PubMed

The Gram-negative bacterium Burkholderia pseudomallei is the aetiological agent of melioidosis, which is an endemic disease in tropical areas of Southeast Asia and Northern Australia. Burkholderia pseudomallei has intrinsic resistance to a number of commonly used antibiotics and has also been reported to develop a biofilm. Resistance to killing by antimicrobial agents is one of the hallmarks of bacteria grown in biofilm. The aim of this study was to determine the antimicrobial activity and mechanisms of action of LL-37 and its truncated variants against B. pseudomallei both in planktonic and biofilm form, as LL-37 is an antimicrobial peptide that possessed strong killing activity against several pathogens. Antimicrobial assays revealed that LL-31, a truncated variant of LL-37 lacking the six C-terminus residues, exhibited the strongest killing effect. Time-kill experiments showed that 20 ?M LL-31 can reach the bactericidal endpoint within 2h. Freeze-fracture electron microscopy of bacterial cells demonstrated that these peptides disrupt the membrane and cause leakage of intracellular molecules leading to cell death. Moreover, LL-31 also possessed stronger bactericidal activity than ceftazidime against B. pseudomallei grown in biofilm. Thus, LL-31 should be considered as a potent antimicrobial agent against B. pseudomallei both in planktonic and biofilm form. PMID:22005071

Kanthawong, Sakawrat; Bolscher, Jan G M; Veerman, Enno C I; van Marle, Jan; de Soet, Hans J J; Nazmi, Kamran; Wongratanacheewin, Surasakdi; Taweechaisupapong, Suwimol

2012-01-01

170

?-Lapachone activity in synergy with conventional antimicrobials against methicillin resistant Staphylococcus aureus strains.  

PubMed

The aim of this study was to evaluate the antimicrobial activity of lapachol, ?-lapachone, ?-lapachone and six antimicrobials (ampicillin, amoxicillin/clavulanic acid, cefoxitin, gentamicin, ciprofloxacin and meropenem) against twelve strains of Staphylococcus aureus from which resistance phenotypes were previously determined by the disk diffusion method. Five S. aureus strains (LFBM 01, LFBM 26, LFBM 28, LFBM 31 and LFBM 33) showed resistance to all antimicrobial agents tested and were selected for the study of the interaction between ?-lapachone and antimicrobial agents, busing checkerboard method. The criteria used to evaluate the synergistic activity were defined by the Fractional Inhibitory Concentration Index (FICI). Among the naphthoquinones, ?-lapachone was the most effective against S. aureus strains. FICI values ranged from 0.07 to 0.5, suggesting a synergistic interaction against multidrug resistant S. aureus (MRSA) strains. An additive effect was observed with the combination ?-lapachone/ciprofloxacin against the LFBM 33 strain. The combination of ?-lapachone with cefoxitin showed no added benefit against LFBM 31 and LFBM 33 strains. This study demonstrated that, in general, ?-lapachone combined with beta lactams antimicrobials, fluoroquinolones and carbapenems acts synergistically inhibiting MRSA strains. PMID:24035227

Macedo, L; Fernandes, T; Silveira, L; Mesquita, A; Franchitti, A A; Ximenes, E A

2013-12-15

171

The antimicrobial activity of lactic acid bacteria from fermented maize (kenkey) and their interactions during fermentation.  

PubMed

A total of 241 lactic acid bacteria belonging to Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus fermentum/reuteri and Lactobacillus brevis from various processing stages of maize dough fermentation were investigated. Results indicated that each processing stage has its own microenvironment with strong antimicrobial activity. About half of the Lact. plantarum and practically all of the Lact. fermentum/reuteri investigated were shown to inhibit other Gram-positive and Gram-negative bacteria, explaining the elimination of these organisms during the initial processing stages. Further, widespread microbial interactions amounting to 85% to 18% of all combinations tested were demonstrated amongst lactic acid bacteria within the various processing stages, i.e. raw material, steeping, 0 h and 48 h of fermentation, explaining the microbial succession taking place amongst lactic acid bacteria during fermentation. The antimicrobial effect was explained by the combined effect of acids, compounds sensitive to proteolytic enzymes and other compounds with antimicrobial activity with the acid production being the most important factor. The pattern of antimicrobial factors was not species-specific and the safety and storage stability of fermented maize seem to depend on a mixed population of lactic acid bacteria with different types of antimicrobial characteristics. This means that introduction of pure cultures as starters may impose a risk to the product. PMID:8567490

Olsen, A; Halm, M; Jakobsen, M

1995-11-01

172

Antimicrobial activity of Amazonian oils against Paenibacillus species.  

PubMed

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

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

173

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

PubMed

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

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

2013-07-01

174

Structure-activity studies of 14-helical antimicrobial beta-peptides: probing the relationship between conformational stability and antimicrobial potency.  

PubMed

Antimicrobial alpha-helical alpha-peptides are part of the host-defense mechanism of multicellular organisms and could find therapeutic use against bacteria that are resistant to conventional antibiotics. Recent work from Hamuro et al. has shown that oligomers of beta-amino acids ("beta-peptides") that can adopt an amphiphilic helix defined by 14-membered ring hydrogen bonds ("14-helix") are active against Escherichia coli [Hamuro, Y.; Schneider, J. P.; DeGrado, W. F. J. Am. Chem. Soc. 1999, 121, 12200-12201]. We have created two series of cationic 9- and 10-residue amphiphilic beta-peptides to probe the effect of 14-helix stability on antimicrobial and hemolytic activity. 14-Helix stability within these series is modulated by varying the proportions of rigid trans-2-aminocyclohexanecarboxylic acid (ACHC) residues and flexible acyclic residues. We have previously shown that a high proportion of ACHC residues in short beta-peptides encourages 14-helical structure in aqueous solution [Appella, D. H.; Barchi, J. J.; Durell, S. R.; Gellman, S. H. J. Am. Chem. Soc. 1999, 121, 2309-2310]. Circular dichroism of the beta-peptides described here reveals a broad range of 14-helix population in aqueous buffer, but this variation in helical propensity does not lead to significant changes in antibiotic activity against a set of four bacteria. Several of the 9-mers display antibiotic activity comparable to that of a synthetic magainin derivative. Among these 9-mers, hemolytic activity increases slightly with increasing 14-helical propensity, but all of the 9-mers are less hemolytic than the magainin derivative. Previous studies with conventional peptides (alpha-amino acid residues) have provided conflicting evidence on the relationship between helical propensity and antimicrobial activity. This uncertainty has arisen because alpha-helix stability can be varied to only a limited extent among linear alpha-peptides without modifying parameters important for antimicrobial activity (e.g., net charge or hydrophobicity); a much greater range of helical stability is accessible with beta-peptides. For example, it is very rare for a linear alpha-peptide to display significant alpha-helix formation in aqueous solution and manifest antibacterial activity, while the linear beta-peptides described here range from fully unfolded to very highly folded in aqueous solution. This study shows that beta-peptides can be unique tools for analyzing relationships between conformational stability and biological activity. PMID:12392424

Raguse, Tami L; Porter, Emilie A; Weisblum, Bernard; Gellman, Samuel H

2002-10-30

175

Rational design of alpha-helical antimicrobial peptides with enhanced activities and specificity/therapeutic index.  

PubMed

In the present study, the 26-residue peptide sequence Ac-KWKSFLKTFKSAVKTVLHTALKAISS-amide (V681) was utilized as the framework to study the effects of peptide hydrophobicity/hydrophilicity, amphipathicity, and helicity (induced by single amino acid substitutions in the center of the polar and nonpolar faces of the amphipathic helix) on biological activities. The peptide analogs were also studied by temperature profiling in reversed-phase high performance liquid chromatography, from 5 to 80 degrees C, to evaluate the self-associating ability of the molecules in solution, another important parameter in understanding peptide antimicrobial and hemolytic activities. A higher ability to self-associate in solution was correlated with weaker antimicrobial activity and stronger hemolytic activity of the peptides. Biological studies showed that strong hemolytic activity of the peptides generally correlated with high hydrophobicity, high amphipathicity, and high helicity. In most cases, the D-amino acid substituted peptides possessed an enhanced average antimicrobial activity compared with L-diastereomers. The therapeutic index of V681 was improved 90- and 23-fold against Gram-negative and Gram-positive bacteria, respectively. By simply replacing the central hydrophobic or hydrophilic amino acid residue on the nonpolar or the polar face of these amphipathic derivatives of V681 with a series of selected D-/L-amino acids, we demonstrated that this method has excellent potential for the rational design of antimicrobial peptides with enhanced activities. PMID:15677462

Chen, Yuxin; Mant, Colin T; Farmer, Susan W; Hancock, Robert E W; Vasil, Michael L; Hodges, Robert S

2005-04-01

176

Antimicrobial activity and molecular analysis of azoderivatives of ?-diketones.  

PubMed

The emergence and increase in the number of multidrug resistant microorganisms have highly increased the need of therapeutic trials, necessitating a deep exploration on novel antimicrobial response tactics. This study is intended to screen and analyze the activity of a novel set of azoderivatives of ?-diketones and their known analogs for antimicrobial properties. The compounds were analyzed to determine their minimum inhibitory concentration. Hit compounds 5-(2-(2-hydroxyphenyl)hydrazono)pyrimidine-2,4,6(1H,3H,5H)-trione (C5), 5-chloro-3-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-2-hydroxybenzenesulfonic acid (C8), 2-(2-carboxyphenylhydrazo)malononitrile (C11) were then considered in evaluating their effect on transcription, translation and cellular oxidation impact. All three compounds were found to have in vitro inhibitory action on E.coli cell growth. The study also revealed that those compounds have a notable impact on cellular activities. It is determined that the newly synthesized azoderivative of barbituric acid (C8) have maximum growth inhibitory activity among the three compounds considered, characterized by a MIC50 of 0.42mg/ml. The MS2 reporter system was used to detect the transcriptional response of the bacteria to the treatment with the selected drugs. All three compounds are found to down regulate the transcriptional pathway. The novel compound, C5, showed maximum inhibition of transcription mechanism, followed by C8 and C11. The effect of the compounds on translation was analyzed using a Yellow Fluorescent protein reporter system. All the compounds displayed reductive impact on translation of which C8 was found to the best, exhibiting 8.5-fold repression followed by C5 and C11, respectively. Fluctuations of the Reactive Oxygen Species (ROS) concentrations were investigated upon incubation in hit compounds using ROS sensor protein. All the three compounds were found to contribute to oxidative pathway. C8 is found to have the best oxidative effect than C5 and C11. All experiments were repeated at least twice, the results being verified to be significant using statistical analysis. PMID:25312345

Viswanathan, Anisha; Sala, Adrien; Yli-Harja, Olli; Kandhavelu, Meenakshisundaram

2014-10-12

177

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

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

Harer, Sunil L.; Bhatia, Manish S.

2014-01-01

178

Composition and antimicrobial activity of Achillea clavennae L. essential oil.  

PubMed

The volatile constituents of Achillea clavennae L. (Asteraceae), rare plant of Europe, have been analysed using GC/MS. Twenty- five components making up 81.6% of the oil were characterized with camphor (29.5%), myrcene (5.5%), 1,8-cineole (5.3%), beta-caryophyllene (5.1%) and linalool (4.9%) being the major constituents. The essential oil was evaluated for antibacterial and antifungal activities. The screening of the antimicrobial activity of essential oil was conducted by a disc diffusion test against Gram-positive (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus faecalis), Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis) and fungal organisms (Aspergillus niger, Aspergillus fumigatus, Candida albicans). The activity was more pronounced against Gram-negative and fungal organisms than against Gram-positive bacteria. A. clavennae oil was found to possess antimicrobial activity against Klebsiella pneumoniae, Pseudomonas aeruginosa and all fungal organisms. PMID:14595583

Bezi?, Nada; Skocibusi?, Mirjana; Dunki?, Valerija; Radoni?, Ani

2003-11-01

179

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

PubMed Central

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 ?g/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

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

2011-01-01

180

Synthesis, antimycobacterial, antiviral, antimicrobial activity and QSAR studies of N(2)-acyl isonicotinic acid hydrazide derivatives.  

PubMed

A series of N(2)-acyl isonicotinic acid hydrazides (1-17) was synthesized and tested for its in vitro antimycobacterial activity against Mycobacterium tuberculosis and the results indicated that the compound, isonicotinic acid N'- tetradecanoyl-hydrazide (12) was more active than the reference compound isoniazid. The results of antimicrobial activity of the synthesized compounds against S. aureus, B. subtilis, E. coli, C. albicans and A. niger indicated that compounds with dichloro, hydroxyl, tri-iodo and N(2)-tetradecanoyl substituent were the most active ones. The antiviral activity studies depicted that none of the tested compounds were active against DNA or RNA viruses. The multi-target QSAR model was found to be effective in describing the antimicrobial activity of N(2)-acyl isonicotinic acid hydrazides. PMID:22762163

Judge, Vikramjeet; Narasimhan, Balasubramanian; Ahuja, Munish; Sriram, Dharmarajan; Yogeeswari, Perumal; De Clercq, Erik; Pannecouque, Christophe; Balzarini, Jan

2013-02-01

181

Antimicrobial activity of essential oil components against potential food spoilage microorganisms.  

PubMed

The antimicrobial activity of six essential oil components against the potential food spoilage bacteria Aeromonas (A.) hydrophila, Escherichia (E.) coli, Brochothrix (B.) thermosphacta, and Pseudomonas (P.) fragi at single use and in combination with each other was investigated. At single use, the most effective oil components were thymol (bacteriostatic effect starting from 40 ppm, bactericidal effect with 100 ppm) and carvacrol (50 ppm/100 ppm), followed by linalool (180 ppm/720 ppm), ?-pinene (400 ppm/no bactericidal effect), 1,8-cineol (1,400 ppm/2,800 ppm), and ?-terpineol (600 ppm/no bactericidal effect). Antimicrobial effects occurred only at high, sensorial not acceptable concentrations. The most susceptible bacterium was A. hydrophila, followed by B. thermosphacta and E. coli. Most of the essential oil component combinations tested showed a higher antimicrobial effect than tested at single use. Antagonistic antimicrobial effects were observed particularly against B. thermosphacta, rarely against A. hydrophila. The results show that the concentration of at least one of the components necessary for an antibacterial effect is higher than sensorial acceptable. So the use of herbs with a high content of thymol, carvacrol, linalool, 1,8-cineol, ?-pinene or ?-terpineol alone or in combination must be weighted against sensorial quality. PMID:23503789

Klein, G; Rüben, C; Upmann, M

2013-08-01

182

Antimicrobial, antimalarial and antileishmanial activities of mono- and bisquaternary pyridinium compounds  

PubMed Central

Pyridinium-based oxime compounds have been utilized worldwide as antidotes following exposure to anticholinesterase agents. In the event of combined chemical and biological incident, it is of vital importance to know the ability of antidotes to provide additional protection against biological threats. This paper reports results of in vitro antimicrobial and antiprotozoal activities of a series of quaternary pyridinium oximes against a number of lower pathogenicity BSL-1 and 2 agents. In general, our compound panel had little to no antimicrobial action except for thiophene- and benzothiophene-substituted monoquaternary pyridinium compounds 21 and 24 that showed moderate antibacterial activity against Staphylococus aureus and methicillin resistant S. aureus with IC50 values ranging from 12.2–17.7 µg/mL. Compounds 21 and 24 also exhibited antileishmanial activity against Leishmania donovani with IC50 values of 19 and 18 µg/mL, respectively. Another monoquaternary pyridinium compound with a bromobutyl side chain 17 showed antimalarial activity against both a chloroquine sensitive and resistant strains of Plasmodium falciparum with IC50 values of 3.7 and 4.0 µg/mL, respectively. None of the bisquaternary pyridinium compounds showed antimicrobial, or antiprotozoal activity. None of the compounds showed cytotoxic effects towards mammalian kidney fibroblasts. Results of this study indicate that the pyridinium compounds, some of which are already in use as antidotes, do not have significant antimicrobial and antiprotozoal activities and cannot be relied upon for additional protection in the event of combined chemical-biological incident. PMID:21040494

Bharate, Sandip B.; Thompson, Charles M.

2010-01-01

183

Study of the nanomaterials and their antimicrobial activities  

NASA Astrophysics Data System (ADS)

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.

Ramadi, Muntaha

184

Antimicrobial activity of poly(acrylic acid) block copolymers.  

PubMed

The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid-base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure. PMID:24656357

Gratzl, Günther; Paulik, Christian; Hild, Sabine; Guggenbichler, Josef P; Lackner, Maximilian

2014-05-01

185

A demonstration of the antimicrobial effectiveness of various copper surfaces  

PubMed Central

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

2013-01-01

186

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

PubMed

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

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

2010-05-28

187

Inducible factors with antimicrobial activity after immune challenge in the haemolymph of Red Palm Weevil (Insecta).  

PubMed

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

Mastore, Maristella; Binda Rossetti, Simona; Giovannardi, Stefano; Scarì, Giorgio; Brivio, Maurizio F

2014-08-10

188

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

Microsoft Academic Search

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

Juyoung Kim; Soonjo Kwon; Erik Ostler

2009-01-01

189

Isolation and Antimicrobial and Antioxidant Evaluation of Bio-Active Compounds from Eriobotrya Japonica Stems  

PubMed Central

Purpose: The present study was carried out to evaluate antimicrobial and antioxidant activities from Eriobotrya japonica stems as well investigation of its chemical composition. Methods: Methanol 80% extract of Eriobotrya japonica stems was tested for antimicrobial activity against bacterial and fungal strains and for antioxidant activity using oxygen radical absorbance capacity (ORAC) and the trolox equivalent antioxidant capacity (TEAC) assays and also total content of polyphenols with phytochemical analysis of the extract were determined. Results: The results showed that the extract has a significant antimicrobial activity, it inhibited significantly the growth of Candida albicans suggesting that it can be used in the treatment of fungal infections, and it showed no effect on the other bacterial and fungal strains, the extract has a good antioxidant activity, it has shown high values of oxygen radical absorbance capacity and trolox equivalent antioxidant capacity, while it showed a low value of polyphenol content. Phytochemical analysis of the extract showed the presence of carbohydrates, terpenes, tannins and flavonoids, further phytochemical analysis resulted in the isolation and identification of three triterpenic acids, oleanolic, ursolic and corosolic acids and four flavonoids, naringenin, quercetin, kaempferol 3-O-?-glucoside and quercetin 3-O-?-rhamnoside. Conclusion: These results may help to discover new chemical classes of natural antimicrobial antioxidant substances. PMID:24409413

Rashed, Khaled Nabih; Butnariu, Monica

2014-01-01

190

Synthesis, DNA cleavage and antimicrobial activity of 4-thiazolidinones-benzothiazole conjugates.  

PubMed

Antimicrobial screening of several novel 4-thiazolidinones with benzothiazole moiety has been performed. These compounds were evaluated for antimicrobial activity against a panel of bacterial and fungal strains. The strains were treated with these benzothiazole derivatives at varying concentrations, and MIC's were calculated. Structures of these compounds have been determined by spectroscopic studies viz., FT-IR, 1H NMR, 13C NMR and elemental analysis. Significant antimicrobial activity was observed for some members of the series, and compounds viz. 3-(4-(benzo[d]thiazol-2-yl) phenyl-2-(4-methoxyphenyl)thiazolidin-4-one and 3-(4-(benzo[d]thiazol-2-yl)phenyl)-2-(4-hydroxy phenyl)thiazolidin-4-one were found to be the most active against E.coli and C. albicans with MIC values in the range of 15.6-125 microg/ml. Preliminary study of the structure-activity relationship revealed that electron donating groups associated with thiazolidine bearing benzothiazole rings had a great effect on the antimicrobial activity of these compounds and contributes positively for the action. DNA cleavage experiments gave valuable hints with supporting evidence for describing the mechanism of action and hence showed a good correlation between their calculated MIC's and its lethality. PMID:25507699

Singh, Meenakshi; Gangwar, Mayank; Nath, Gopal; Singh, Sushil K

2014-11-01

191

Synthesis, DNA cleavage and antimicrobial activity of 4-thiazolidinones-benzothiazole conjugates.  

PubMed

Antimicrobial screening of several novel 4-thiazolidinones with benzothiazole moiety has been performed. These compounds were evaluated for antimicrobial activity against a panel of bacterial and fungal strains. The strains were treated with these benzothiazole derivatives at varying concentrations, and MIC's were calculated. Structures of these compounds have been determined by spectroscopic studies viz., FT-IR, 1H NMR, 13C NMR and elemental analysis. Significant antimicrobial activity was observed for some members of the series, and compounds viz. 3-(4-(benzo[d]thiazol-2-yl) phenyl-2-(4-methoxyphenyl)thiazolidin-4-one and 3-(4-(benzo[d]thiazol-2-yl)phenyl)-2-(4-hydroxy phenyl)thiazolidin-4-one were found to be the most active against E.coli and C. albicans with MIC values in the range of 15.6-125 microg/ml. Preliminary study of the structure-activity relationship revealed that electron donating groups associated with thiazolidine bearing benzothiazole rings had a great effect on the antimicrobial activity of these compounds and contributes positively for the action. DNA cleavage experiments gave valuable hints with supporting evidence for describing the mechanism of action and hence showed a good correlation between their calculated MIC's and its lethality. PMID:25434101

Singh, Meenakshi; Gangwar, Mayank; Nath, Gopal; Singh, Sushil K

2014-11-01

192

A theoretical approach to spot active regions in antimicrobial proteins  

Microsoft Academic Search

BACKGROUND: Much effort goes into identifying new antimicrobial compounds able to evade the increasing resistance of microorganisms to antibiotics. One strategy relies on antimicrobial peptides, either derived from fragments released by proteolytic cleavage of proteins or designed from known antimicrobial protein regions. RESULTS: To identify these antimicrobial determinants, we developed a theoretical approach that predicts antimicrobial proteins from their amino

Marc Torrent; Victòria M. Nogués; Ester Boix

2009-01-01

193

Antimicrobial Activities of Isothiocyanates Against Campylobacter jejuni Isolates  

PubMed Central

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??g?mL?1) compared to AITC (MIC of 50–200??g?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 (?-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

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

2012-01-01

194

Antioxidant and antimicrobial activities of Tamarix ramosissima  

Microsoft Academic Search

The ethylacetate and water–acetone extracts of Tamarixramosissima were screened for their antioxidant, antibacterial, antifungal and DNA damaging activities through in vitro experiments. All fractions as well as precipitates showed significant antioxidant activity. A known compound tamarixetin (1) was isolated which showed significant DNA damaging activity in mutant yeast bioassay. Results revealed that antioxidant and antibacterial activities were associated with the

N Sultanova; T Makhmoor; Z. A Abilov; Z Parween; V. B Omurkamzinova; Atta-ur-Rahman; M. Iqbal Choudhary

2001-01-01

195

Activating the antimicrobial activity of an anionic singlet-oxygen sensitizer through surfactant complexation.  

PubMed

Cationic oligo-p-phenylene ethynylenes have shown much promise as broad-spectrum light-activated antimicrobial compounds against both Gram-positive and Gram-negative bacteria. The anionic varieties, however, have weak biocidal activity. In this study, a complex is formed between a weakly biocidal anionic oligomer and a cationic surfactant, and the effects on their biocidal activity against Gram-negative E. coli and Gram-positive S. aureus are explored. The enhancement in biocidal activity that is observed when the complex is irradiated suggests that interfacial surfactant gives the complex a net-positive charge, allowing it to associate strongly with the bacterial membrane. The results of this study demonstrate a method for the enhancement of biocidal activity of singlet-oxygen sensitizers and corroborate the use of surfactants as trans-membrane drug-delivery agents. PMID:24786342

Hill, Eric H; Pappas, Harry C; Whitten, David G

2014-05-13

196

Antimicrobial activities of endophytic fungi isolated from Ophiopogon japonicus (Liliaceae)  

PubMed Central

Background Drug resistance in bacteria has become a global concern and the search for new antibacterial agents is urgent and ongoing. Endophytes provide an abundant reservoir of bioactive metabolites for medicinal exploitation, and an increasing number of novel compounds are being isolated from endophytic fungi. Ophiopogon japonicus, containing compounds with antibacterial activity, is a traditional Chinese medicinal plant used for eliminating phlegm, relieving coughs, latent heat in the lungs, and alleviating diabetes mellitus. We investigated the antimicrobial activities of 30 strains of O. japonicus. Methods Fungal endophytes were isolated from roots and stems of O. japonicus collected from Chongqing City, southwestern China. Mycelial extracts (MC) and fermentation broth (FB) were tested for antimicrobial activity using peptide deformylase (PDF) inhibition fluorescence assays and MTT cell proliferation assays. Results A total of 30 endophytic strains were isolated from O. japonicus; 22 from roots and eight from stems. 53.33% of the mycelial extracts (MC) and 33.33% of the fermentation broths (FB) displayed potent inhibition of PDF. 80% of MC and 33.33% of FB significantly inhibited Staphylococcus aureus. 70% of MC and 36.67% of FB showed strong activities against Cryptococcus neoformans. None showed influence on Escherichia coli. Conclusion The secondary metabolites of endophytic fungi from O. japonicus are potential antimicrobial agents. PMID:23190550

2012-01-01

197

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

PubMed

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

Kosalec, Ivan; Kopjar, Nevenka; Kremer, Dario

2013-08-01

198

Phytochemical and antimicrobial effects of Chrozophora senegalensis.  

PubMed

The in vitro antimicrobial activities of the whole plant extract (ethanolic-CEE) of Chrozophora senegalensis and its fractions (ethyl acetate-EAA, n-butanol-NBE, aqueous-AQE) were assayed using the agar plate diffusion and nutrient broth dilution methods. Test microorganisms were Bacillus subtilis (NCTC 8326 B76), Escherichia coli (ATCC 11775), Pseudomonas aeruginosa (ATCC 10145), Staphylococcus aureus (ATCC 021001). Aspergillus flavus, Aspergillus niger, Candida albicans and Salmonella typhi--laboratory isolates. CEE, EAA and NBE inhibited all the test bacterial organisms and a fungus--Aspergillus flavus. AQE inhibited only Salmonella typhi and Bacillus subtilis. None of the extracts had activity on other 3 fungal organisms tested. CEE and EAA showed minimum inhibition concentration (MIC) of 0.390 and 3.125 mg/ml against S. typhi and E. coli, while NBE and AQE had MIC of 3.125 and 1.563 mg/ml against S. typhi respectively. NBE had an MIC of 12.500 mg/ml against E. coli. The minimum bactericidal concentration (MBC) of CEE and EAA was found to be <0.098 against S. typhi. The MBC of AQE was 12.5 mg/ml against E. coli and S. aureus, and 6.25 mg/ml towards P. aeruginosa. CEE and EAA exhibited similar antibacterial activities, followed by AQE. The extracts revealed the presence of carbohydrates, tannins, saponins, sterols determined by utilizing standard methods of analysis. This study has justified the traditional use of the plant for treating diarrhea, boils and syphilis. PMID:20161917

Usman, H; Musa, Y M; Ahmadu, A A; Tijjani, M A

2007-01-01

199

Antimicrobial activity of a newly identified bacteriocin of Bacillus cereus.  

PubMed Central

A bacteriocin-producing Bacillus cereus strain was isolated. The bacteriocin, here called cerein, was shown to be active specifically against other B. cereus strains and inactive against all other bacterial species tested. Cerein was detected in the culture supernatants of stationary-phase cells, and its appearance was inhibited by induction of sporulation. The bacterial activity of cerein was insensitive to organic solvents and nonproteolytic enzymes, partially stable to heat, and active over a wide range of pH values. Direct detection of antimicrobial activity on sodium dodecyl sulfate-polyacrylamide gel suggested an apparent molecular mass of about 9 kDa. Images PMID:8285719

Naclerio, G; Ricca, E; Sacco, M; De Felice, M

1993-01-01

200

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

PubMed Central

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

Bellik, Yuva

2014-01-01

201

Molecular mechanisms behind the antimicrobial activity of hop iso-?-acids in Lactobacillus brevis.  

PubMed

The main bittering component in beer, hop iso-?-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-?-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-?-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-?-acids to enhance the basic understanding of the molecular mechanism of antimicrobial iso-?-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-?-acids. PMID:25475328

Schurr, Benjamin C; Hahne, Hannes; Kuster, Bernhard; Behr, Jürgen; Vogel, Rudi F

2015-04-01

202

Antimicrobial activity of an abiotic host defense peptide mimic Gregory N. Tew a,, Dylan Clements b  

E-print Network

Antimicrobial activity of an abiotic host defense peptide mimic Gregory N. Tew a,, Dylan Clements b of the most significant challenges to human health. Antimicrobial peptides (AMPs), which are produced by many infections [1­3]. Antimicrobial peptides (AMPs) operate via non-specific mechanisms, targeting the bacterial

Tew, Gregory N.

203

Antioxidant and antimicrobial activities of Tamarix ramosissima.  

PubMed

The ethylacetate and water-acetone extracts of Tamarix ramosissima were screened for their antioxidant, antibacterial, antifungal and DNA damaging activities through in vitro experiments. All fractions as well as precipitates showed significant antioxidant activity. A known compound tamarixetin (1) was isolated which showed significant DNA damaging activity in mutant yeast bioassay. Results revealed that antioxidant and antibacterial activities were associated with the presence of polyphenolic substances. PMID:11694365

Sultanova, N; Makhmoor, T; Abilov, Z A; Parween, Z; Omurkamzinova, V B; ur-Rahman, A; Choudhary, M I

2001-12-01

204

Antimicrobial Activity of Nanoemulsion in Combination with Cetylpyridinium Chloride in Multidrug-Resistant Acinetobacter baumannii  

PubMed Central

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

Hwang, Yoon Y.; Ramalingam, Karthikeyan; Bienek, Diane R.; Lee, Valerie; You, Tao

2013-01-01

205

Antimicrobial polymers: mechanism of action, factors of activity, and applications  

Microsoft Academic Search

Complex epidemiological situation, nosocomial infections, microbial contamination, and infection risks in hospital and dental\\u000a equipment have led to an ever-growing need for prevention of microbial infection in these various areas. Macromolecular systems,\\u000a due to their properties, allow one to efficiently use them in various fields, including the creation of polymers with the\\u000a antimicrobial activity. In the past decade, the intensive

Larisa Timofeeva; Natalia Kleshcheva

2011-01-01

206

Facile synthesis, antioxidant and antimicrobial activity of amino methylene bisphosphonates.  

PubMed

A green and efficient preparation method for the amino bisphosphonates is accomplished by simple mixing and stirring of diethylphosphite, triethylorthoformate and various amines in the presence of amberlyst-15 as catalyst at room temperature under solvent free conditions. The title compounds are characterized by IR, (1)H-, (13)C-, (31)P-NMR and mass spectra, also studied their antimicrobial and antioxidant activity. PMID:22223381

Kunda, Uma Maheswara Rao; Balam, Satheesh Krishna; Nemallapudi, Bakthavatchala Reddy; Chereddy, Syama Sundar; Nayak, Sandip Kumar; Cirandur, Suresh Reddy

2012-01-01

207

Distribution and Antimicrobial Activity of Ciprofloxacin in Human Soft Tissues  

Microsoft Academic Search

Interstitial ciprofloxacin concentrations in soft tissues were measured by microdialysis following intravenous administration of 200 mg to each of eight healthy volunteers. Interstitial ciprofloxacin concentrations were significantly lower than corresponding total serum drug concentrations; the interstitium-to-serum concentra- tion ratios ranged from 0.55 to 0.73. An in vitro simulation based on interstitial pharmacokinetics showed a substantially lower antimicrobial activity than did

MARTIN BRUNNER; URSULA HOLLENSTEIN; SIMON DELACHER; DOROTHEA JAGER; RAINER SCHMID; EDITH LACKNER; APOSTOULOS GEORGOPOULOS; HANS GEORG EICHLER; MARKUS MULLER

1999-01-01

208

Antimicrobial activity of berberine—a constituent of Mahonia aquifolium  

Microsoft Academic Search

The antimicrobial activity of the protoberberine, alkaloid, berberine, isolated fromMahonia aquifolium, was evaluated against 17 microorganisms including two Gram-negative bacteria—Pseudomonas aeruginosa andEscherichia coli (both resistant and sensitive), two Gram-positive bacteria—Bacillus subtilis andStaphylococcus aureus, Zoogloea ramigera, six filamentous fungi—Penicilium chrysogenum, Aspergillus niger, Aureobasidium pullulans (black and white strain),Trichoderma viride (original green strain and brown mutant),Fusarium nivale, Mycrosporum gypseum, and two yeasts—Candida,

M. ?er?áková; D. Koš?álová

2002-01-01

209

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

PubMed Central

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-1? , 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 ?-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

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

2015-01-01

210

Screening antimicrobial activity of various extracts of Urtica dioica.  

PubMed

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

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

2012-12-01

211

Antimicrobial activity of beta-lactams against multiresistant micro-organisms from the family Enterobacteriaceae, and genus Pseudomonas.  

PubMed

The antimicrobial activity of twenty beta-lactams was determined against multiresistant micro-organisms from the Enterobacteriaceae family (450) and the genus Pseudomonas (90). The antimicrobial susceptibility was assessed by the disk diffusion method. The most effective antibiotics were cephalosporins of the second and third generation, and non-classical beta-lactams (imipenem and moxalactam). A pronounced resistance was found to carbenicillin, ampicillin, cephalotin and cefazolin. These resistance patterns corresponded to a high consumption of these antibiotics. PMID:7700163

Niebla, A; González, I; Vallín, C

1994-01-01

212

Antimicrobial activity of new porphyrins of synthetic and natural origin  

NASA Astrophysics Data System (ADS)

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%.

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

2012-03-01

213

Antimicrobial activity of chitosan derivatives containing N-quaternized moieties in its backbone: a review.  

PubMed

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

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

2014-01-01

214

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

PubMed Central

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

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

2014-01-01

215

Antimicrobial activity of three Mexican Gnaphalium species.  

PubMed

The antibacterial activity of the hexane, ethyl acetate and methanol extracts of the flowers, leaves and stems of Gnaphalium oxyphyllum var. oxyphyllum, G. liebmannii var. monticola and G. viscosum was investigated. The hexane extracts showed in all cases the higher inhibitions, G. oxyphyllum flower extract exhibiting the wider spectrum of activity. PMID:11543972

Villagómez-Ibarra, J R; Sánchez, M; Espejo, O; Zúñiga-Estrada, A; Torres-Valencia, J M; Joseph-Nathan, P

2001-08-01

216

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)

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.

Alyar, Saliha; Adem, ?evki

2014-10-01

217

Antimicrobial activity of silver nanoparticles impregnated wound dressing  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

218

Spermicidal Activity of the Safe Natural Antimicrobial Peptide Subtilosin  

PubMed Central

Bacterial vaginosis (BV), a condition affecting millions of women each year, is primarily caused by the gram-variable organism Gardnerella vaginalis. A number of organisms associated with BV cases have been reported to develop multidrug resistance, leading to the need for alternative therapies. Previously, we reported the antimicrobial peptide subtilosin has proven antimicrobial activity against G. vaginalis, but not against the tested healthy vaginal microbiota of lactobacilli. After conducting tissue sensitivity assays using an ectocervical tissue model, we determined that human cells remained viable after prolonged exposures to partially-purified subtilosin, indicating the compound is safe for human use. Subtilosin was shown to eliminate the motility and forward progression of human spermatozoa in a dose-dependent manner, and can therefore be considered a general spermicidal agent. These results suggest subtilosin would be a valuable component in topical personal care products aimed at contraception and BV prophylaxis and treatment. PMID:18923673

Sutyak, Katia E.; Anderson, Robert A.; Dover, Sara E.; Feathergill, Kenneth A.; Aroutcheva, Alla A.; Faro, Sebastian; Chikindas, Michael L.

2008-01-01

219

Towards general design rules for membrane active antimicrobials  

NASA Astrophysics Data System (ADS)

Membrane active antimicrobials are short amphipathic peptides that selectively disrupt and lyse bacterial cell membranes. While it is believed that the combination of peptide hydrophobicity and cationic charge is essential for function, the detailed molecular mechanism of selective membrane permeation remains unclear. We use synchrotron small angle x-ray scattering (SAXS) to investigate the interaction of model bacterial and eukaryotic cell membranes with archetypes from each of the three defensin subfamilies found in mammals. The relationship between membrane composition and peptide induced changes in membrane curvature and topology is examined. By comparing the membrane rearrangement and corresponding phase behavior induced by these different peptides we will discuss the importance of amino acid composition and placement on antimicrobial peptide design.

Sanders, Lori; Schmidt, Nathan; Mishra, Abhijit; Gordon, Vernita; Wong, Gerard

2010-03-01

220

Antimicrobial effect of alexidine and chlorhexidine against Enterococcus faecalis infection  

PubMed Central

A previous study demonstrated that alexidine has greater affinity for the major virulence factors of bacteria than chlorhexidine. The aim of this study was to compare the antimicrobial activity of 1% alexidine with that of 2% chlorhexidine using Enterococcus faecalis-infected dentin blocks. Sixty bovine dentin blocks were prepared and randomly divided into six groups of 10 each. E. faecalis was inoculated on 60 dentin blocks using the Luppens apparatus for 24 h and then the dentin blocks were soaked in 2% chlorhexidine or 1% alexidine solutions for 5 and 10 min, respectively. Sterile saline was used as a control. The antimicrobial efficacy was assessed by counting the number of bacteria adhering to the dentin surface and observing the degradation of bacterial shape or membrane rupture under a scanning electron microscope. Significantly fewer bacteria were observed in the 2% chlorhexidine- or 1% alexidine-soaked groups than in the control group (P<0.05). However, there was no significant difference in the number of bacteria adhering to the dentinal surface between the two experimental groups or between the two soaking time groups (P>0.05). Ruptured or antiseptic-attached bacteria were more frequently observed in the 10-min-soaked chlorhexidine and alexidine groups than in the 5-min-soaked chlorhexidine and alexidine groups. In conclusion, 10-min soaking with 1% alexidine or 2% chlorhexidine can be effective against E. faecalis infection. PMID:23492900

Kim, Hyun-Shik; Woo Chang, Seok; Baek, Seung-Ho; Han, Seung Hyun; Lee, Yoon; Zhu, Qiang; Kum, Kee-Yeon

2013-01-01

221

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

PubMed

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

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

2013-12-01

222

In vitro antimicrobial activity of ethanolic fractions of Cryptolepis sanguinolenta  

PubMed Central

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

2012-01-01

223

Characteristics and antimicrobial activity of copper-based materials  

NASA Astrophysics Data System (ADS)

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 suffi

Li, Bowen

224

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

PubMed Central

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

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

2012-01-01

225

Novel composite plastics containing silver(i) acylpyrazolonato additives display potent antimicrobial activity by contact.  

PubMed

New silver(I) acylpyrazolonato derivatives displaying a mononuclear, polynuclear, or ionic nature, as a function of the ancillary azole ligands used in the synthesis, have been fully characterized by thermal analysis, solution NMR spectroscopy, solid-state IR and NMR spectroscopies, and X-ray diffraction techniques. These derivatives have been embedded in polyethylene (PE) matrix, and the antimicrobial activity of the composite materials has been tested against three bacterial strains (E.?coli, P.?aeruginosa, and S.?aureus): Most of the composites show antimicrobial action comparable to PE embedded with AgNO3 . Tests by contact and release tests for specific migration of silver from PE composites clearly indicate that, at least in the case of the PE, for composites containing polynuclear silver(I) additives, the antimicrobial action is exerted by contact, without release of silver ions. Moreover, PE composites can be re-used several times, displaying the same antimicrobial activity. Membrane permeabilization studies and induced reactive oxygen species (ROS) generation tests confirm the disorganization of bacterial cell membranes. The cytotoxic effect, evaluated in CD34(+) cells by MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazoliumbromide) and CFU (colony forming units) assays, indicates that the PE composites do not induce cytotoxicity in human cells. Studies of ecotoxicity, based on the test of Daphnia magna, confirm tolerability of the PE composites by higher organisms and exclude the release of Ag(+) ions in sufficient amounts to affect water environment. PMID:25358838

Marchetti, Fabio; Palmucci, Jessica; Pettinari, Claudio; Pettinari, Riccardo; Condello, Francesca; Ferraro, Stefano; Marangoni, Mirko; Crispini, Alessandra; Scuri, Stefania; Grappasonni, Iolanda; Cocchioni, Mario; Nabissi, Massimo; Chierotti, Michele R; Gobetto, Roberto

2015-01-01

226

Antimicrobial Activities of Three Medicinal Plants and Investigation of Flavonoids of Tripleurospermum disciforme  

PubMed Central

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

Tofighi, Zahra; Molazem, Maryam; Doostdar, Behnaz; Taban, Parisa; Shahverdi, Ahmad Reza; Samadi, Nasrin; Yassa, Narguess

2015-01-01

227

Antimicrobial Activities of Three Medicinal Plants and Investigation of Flavonoids of Tripleurospermum disciforme.  

PubMed

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

Tofighi, Zahra; Molazem, Maryam; Doostdar, Behnaz; Taban, Parisa; Shahverdi, Ahmad Reza; Samadi, Nasrin; Yassa, Narguess

2015-01-01

228

Effect of Antimicrobial Peptide-Amide: Indolicidin on Biological Membranes  

PubMed Central

Indolicidin, a cationic antimicrobial tridecapeptide amide, is rich in proline and tryptophan residues. Its biological activity is intensively studied, but the details how indolicidin interacts with membranes are not fully understood yet. We report here an in situ atomic force microscopic study describing the effect of indolicidin on an artificial supported planar bilayer membrane of dipalmitoyl phosphatidylcholine (DPPC) and on purple membrane of Halobacterium salinarum. Concentration dependent interaction of the peptide and membranes was found in case of DPPC resulting the destruction of the membrane. Purple membrane was much more resistant against indolicidin, probably due to its high protein content. Indolicidin preferred the border of membrane disks, where the lipids are more accessible. These data suggest that the atomic force microscope is a powerful tool in the study of indolicidin-membrane interaction. PMID:21765635

Végh, Attila Gergely; Nagy, Krisztina; Bálint, Zoltán; Kerényi, Ádám; Rákhely, Gábor; Váró, György; Szegletes, Zsolt

2011-01-01

229

Enhancing antibiofilm efficacy in antimicrobial photodynamic therapy: effect of microbubbles  

NASA Astrophysics Data System (ADS)

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.

Kishen, Anil; George, Saji

2013-02-01

230

Water Soluble Usnic Acid-Polyacrylamide Complexes with Enhanced Antimicrobial Activity against Staphylococcus epidermidis  

PubMed Central

Usnic acid, a potent antimicrobial and anticancer agent, poorly soluble in water, was complexed to novel antimicrobial polyacrylamides by establishment of strong acidic-base interactions. Thermal and spectroscopic analysis evidenced a molecular dispersion of the drug in the polymers and a complete drug/polymer miscibility for all the tested compositions. The polymer/drug complexes promptly dissolved in water and possessed a greater antimicrobial activity against Staphylococcus epidermidis than both the free drug and the polymer alone. The best results were obtained with the complex based on the lowest molecular weight polymer and containing a low drug content. Such a complex showed a larger inhibition zone of bacterial growth and a lower minimum inhibitory concentration (MIC) with respect to usnic acid alone. This improved killing effect is presumably due to the reduced size of the complexes that allows an efficient cellular uptake of the antimicrobial complexes. The killing effect extent seems to be not significantly dependent on usnic acid content in the samples. PMID:23549269

Francolini, Iolanda; Taresco, Vincenzo; Crisante, Fernanda; Martinelli, Andrea; D’Ilario, Lucio; Piozzi, Antonella

2013-01-01

231

Synergized antimicrobial activity of eugenol incorporated polyhydroxybutyrate films against food spoilage microorganisms in conjunction with pediocin.  

PubMed

Biopolymers and biopreservatives produced by microorganisms play an essential role in food technology. Polyhydroxyalkanoates and bacteriocins produced by bacteria are promising components to safeguard the environment and for food preservation applications. Polyhydroxybutyrate (PHB)-based antimicrobial films were prepared incorporating eugenol, from 10 to 200 ?g/g of PHB. The films were evaluated for antimicrobial activity against foodborne pathogens, spoilage bacteria, and fungi such as Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Bacillus cereus, Aspergillus flavus, Aspergillus niger, Penicillium sp., and Rhizopus sp. The synergistic antimicrobial activity of the films in the presence of crude pediocin was also investigated. The broth system containing pediocin (soluble form) as well as antimicrobial PHB film demonstrated an extended lag phase and a significant growth reduction at the end of 24 h against the bacteria. Crude pediocin alone could not elicit antifungal activity, while inhibition of growth and sporulation were observed in the presence of antimicrobial PHB film containing eugenol (80 ?g/g) until 7 days in the case of molds, i.e., A. niger, A. flavus, Penicillium sp., and Rhizopus sp. in potato dextrose broth. In the present study, we identified that use of pediocin containing broth in conjunction with eugenol incorporated PHB film could function in synergized form, providing effective hurdle toward food contaminating microorganisms. Furthermore, tensile strength, percent crystallinity, melting point, percent elongation to break, glass transition temperature, and seal strength of the PHB film with and without eugenol incorporation were investigated. The migration of eugenol on exposure to different liquid food simulants was also analyzed using Fourier transform infrared spectroscopy. The study is expected to provide applications for pediocin in conjunction with eugenol containing PHB film to enhance the shelf life of foods in the food industry. PMID:23666640

Narayanan, Aarthi; Neera; Mallesha; Ramana, Karna Venkata

2013-07-01

232

Magainins, a Class of Antimicrobial Peptides from Xenopus Skin: Isolation, Characterization of Two Active Forms, and Partial cDNA Sequence of a Precursor  

Microsoft Academic Search

A family of peptides with broad-spectrum antimicrobial activity has been isolated from the skin of the African clawed frog Xenopus laevis. It consists of two closely related peptides that are each 23 amino acids and differ by two substitutions. These peptides are water soluble, nonhemolytic at their effective antimicrobial concentrations, and potentially amphiphilic. At low concentrations they inhibit growth of

Michael Zasloff

1987-01-01

233

Nanoencapsulation of essential oils to enhance their antimicrobial activity in foods  

Microsoft Academic Search

This work focuses on the encapsulation of essential oils into nanometric delivery systems for incorporation into fruit juices, in order to enhance their antimicrobial activity while minimizing the impact on the quality attributes of the final product. A terpenes mixture and d-limonene were encapsulated into nanoemulsions based on food-grade ingredients, prepared by high pressure homogenization at 300 MPa.The effect of the

Francesco Donsì; Marianna Annunziata; Mariarenata Sessa; Giovanna Ferrari

2011-01-01

234

LL-37 complexation with glycosaminoglycans in cystic fibrosis lungs inhibits antimicrobial activity, which can be restored by hypertonic saline.  

PubMed

There is an abundance of antimicrobial peptides in cystic fibrosis (CF) lungs. Despite this, individuals with CF are susceptible to microbial colonization and infection. In this study, we investigated the antimicrobial response within the CF lung, focusing on the human cathelicidin LL-37. We demonstrate the presence of the LL-37 precursor, human cathelicidin precursor protein designated 18-kDa cationic antimicrobial protein, in the CF lung along with evidence that it is processed to active LL-37 by proteinase-3. We demonstrate that despite supranormal levels of LL-37, the lung fluid from CF patients exhibits no demonstrable antimicrobial activity. Furthermore Pseudomonas killing by physiological concentrations of exogenous LL-37 is inhibited by CF bronchoalveolar lavage (BAL) fluid due to proteolytic degradation of LL-37 by neutrophil elastase and cathepsin D. The endogenous LL-37 in CF BAL fluid is protected from this proteolysis by interactions with glycosaminoglycans, but while this protects LL-37 from proteolysis it results in inactivation of LL-37 antimicrobial activity. By digesting glycosaminoglycans in CF BAL fluid, endogenous LL-37 is liberated and the antimicrobial properties of CF BAL fluid restored. High sodium concentrations also liberate LL-37 in CF BAL fluid in vitro. This is also seen in vivo in CF sputum where LL-37 is complexed to glycosaminoglycans but is liberated following nebulized hypertonic saline resulting in increased antimicrobial effect. These data suggest glycosaminoglycan-LL-37 complexes to be potential therapeutic targets. Factors that disrupt glycosaminoglycan-LL-37 aggregates promote the antimicrobial effects of LL-37 with the caveat that concomitant administration of antiproteases may be needed to protect the now liberated LL-37 from proteolytic cleavage. PMID:19542465

Bergsson, Gudmundur; Reeves, Emer P; McNally, Paul; Chotirmall, Sanjay H; Greene, Catherine M; Greally, Peter; Murphy, Philip; O'Neill, Shane J; McElvaney, Noel G

2009-07-01

235

Evaluation of three medicinal plants for anti-microbial activity  

PubMed Central

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

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

2012-01-01

236

Natural antimicrobials: Effect of Microgard™ and nisin against Listeria innocua in liquid cheese whey  

Microsoft Academic Search

Antimicrobial activity of Microgard™ individually or in combination with nisin against Listeria innocua in liquid cheese whey (LCW) was investigated. Microgard™ did not reduce the initial count of L. innocua during storage at 7, 12, 20 and 25°C, and showed a response similar to the untreated whey. In comparison, nisin exhibited an immediate bactericidal effect that was followed by regrowth

Mariana von Staszewski; Rosa J. Jagus

2008-01-01

237

Design of nanoemulsion-based delivery systems of natural antimicrobials: Effect of the emulsifier  

Microsoft Academic Search

This work aims at investigating the effect of the nanoemulsion delivery systems on the antimicrobial activity of different essential oil components.Carvacrol, limonene and cinnamaldehyde were encapsulated in the sunflower oil droplets of nanoemulsions prepared by high pressure homogenization and stabilized by different emulsifiers: (a) lecithin, (b) pea proteins, (c) sugar ester and (d) a combination of Tween 20 and glycerol

Francesco Donsì; Marianna Annunziata; Mariarosaria Vincensi; Giovanna Ferrari

238

PHMB: an effective antimicrobial in wound bioburden management.  

PubMed

The effective management of bacterial bioburden is an essential element of wound care. Recent years have seen the increased use of topical antimicrobial dressings to control colonisation and infection, yet there is concern that some may inhibit wound healing and may have systemic sequelae (World Union of Wound Healing Societies (WUWHS), 2008). This article focuses on the safety and effectiveness of PHMB, an antimicrobial compound that is relatively underused in the UK, and argues that it is an effective option for the management of bacterial colonisation and infection. PMID:22875372

Butcher, Martyn

239

Antimicrobial activity of essential oils from Mediterranean aromatic plants against several foodborne and spoilage bacteria.  

PubMed

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

Silva, Nuno; Alves, Sofia; Gonçalves, Alexandre; Amaral, Joana S; Poeta, Patrícia

2013-12-01

240

Pharmacological Assessment of the Medicinal Potential of Acacia mearnsii De Wild.: Antimicrobial and Toxicity Activities  

PubMed Central

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) ?g/mL, gram-negative bacteria (39.1–625) ?g/mL and fungal isolates (625–5000) ?g/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 ?g/mL and 500 ?g/mL and the LC50 value (112.36 ?g/mL) indicates that the extract was nontoxic in the brine shrimp lethality assay (LC50 > 100 ?g/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

Olajuyigbe, Olufunmiso O.; Afolayan, Anthony J.

2012-01-01

241

In vitro antimicrobial activity of an experimental dentifrice based on Ricinus communis.  

PubMed

This study evaluated the antimicrobial activity of a Ricinus communis-based experimental dentifrice for denture hygiene against the following standard strains: Staphylococcus aureus, Escherichia coli, Streptococcus mutans, Enterococcus faecalis, Candida albicans and Candida glabrata. The minimum inhibitory concentration (MIC) assay was performed with R. communis in pure oil at 2.5%. Only E. coli was not inhibited by R. communis, but the MIC (0.0781%) was effective against the other microorganisms. From these results it was determined the R. communis concentrations for experimental dentifrices, 1, 2, 5 and 10%, which were evaluated by the test-well diffusion in agar. The commercial dentifrices Colgate, Trihydral and Corega Brite were tested for comparative purposes. The diameter of the zones of bacterial growth inhibition produced around the wells was measured (in mm) with a rule under reflected light. Data were analyzed statistically by analysis of variance and Tukey's post-hoc test (?=0.05). Neither the commercial nor the experimental dentifrices were effective against E. coli. The experimental dentifrices containing R. communis at 2, 5 and 10% presented action against S. mutans, S. aureaus and E. faecallis. The experimental dentifrices showed no antimicrobial activity against Candida spp. and E. coli in any of the tested concentrations. Trihydral was the most effective. Comparing the experimental dentifrices, the product with 10% R. communis produced the largest zones of bacterial growth inhibition and had similar antimicrobial activity to the commercial dentifrices, except against S. aureus. PMID:25252252

Leite, Vanessa Maria Fagundes; Pinheiro, Juliana Barchelli; Pisani, Marina Xavier; Watanabe, Evandro; de Souza, Raphael Freitas; Paranhos, Helena de Freitas Oliveira; Lovato-Silva, Cláudia Helena

2014-01-01

242

Antimicrobial activity of Chinese medicine herbs against common bacteria in oral biofilm. A pilot study.  

PubMed

Twenty traditional Chinese medicines (TCM) were evaluated for their antimicrobial activity against four common oral bacteria. TCMs were tested for sensitivity against Streptococcus mitis, Streptococcus sanguis, Streptococcus mutans and Porphyromonas gingivalis. Aliquots of suspension of each bacterial species were inoculated onto a horse blood agar plate with TCMs soaked separately on 6mm paper disks. The plates were incubated for 48h anaerobically and the mean diameters of growth inhibition of three different areas obtained. 0.2% (w/v) chlorhexidine was used as a positive control. Broth microdilution assay was used to determine minimum inhibitory concentration and minimum bactericidal concentration. Fructus armeniaca mume was effective against all four bacteria. Thirteen TCMs demonstrated antimicrobial activity against Porphyromonas gingivalis, including Cortex magnoliae officinalis, Cortex phellodendri, Flos caryophylli, Flos lonicerae japonicae, Fructus armeniaca mume, Fructus forsythiae suspensae, Herba cum radice violae yedoensitis, Herba menthae haplocalycis, Pericarpium granati, Radix et rhizoma rhei, Radix gentianae, Ramulus cinnamomi cassia and Rhizoma cimicifugae. Cortex phellodendri showed antimicrobial activity against Streptococcus mutans, while Radix et rhizoma rhei was effective against Streptococcus mitis and Streptococcus sanguis. Fructus armeniaca mume had inhibitory effects against Streptococcus mitis, Streptococcus sanguis, Streptococcus mutans and Porphyromonas gingivalis in vitro. PMID:20418062

Wong, R W K; Hägg, U; Samaranayake, L; Yuen, M K Z; Seneviratne, C J; Kao, R

2010-06-01

243

Novel Expression Vector for Secretion of Cecropin AD in Bacillus subtilis with Enhanced Antimicrobial Activity?  

PubMed Central

Cecropin AD, a chimeric antimicrobial peptide obtained from cecropins, is effective at killing specific microorganisms. However, a highly efficient expression system is still needed to allow for commercial application of cecropin AD. For the exogenous expression of cecropin AD, we fused the cecropin AD gene with a small ubiquitin-like modifier (SUMO) gene and a signal peptide of SacB, while a Bacillus subtilis expression system was constructed based on Bacillus subtilis cells genetically modified by the introduction of an operon including an isopropyl-?-d-thiogalactopyranoside (IPTG)-inducible Spac promoter, a signal peptide of amyQ, and the SUMO protease gene. The recombinant cecropin AD was expressed, and 30.6 mg of pure recombinant protein was purified from 1 liter of culture supernatant. The purified cecropin AD displayed antimicrobial activity against some pathogens, such as Staphylococcus aureus and Escherichia coli, and was especially effective toward Staphylococcus aureus, with MICs of <0.05 ?M (0.2 ?g/ml). Stability analysis results showed that the activity of cecropin AD was not influenced by temperatures as high as 55°C for 20 min; however, temperatures above 85°C (for 20 min) decreased the antimicrobial activity of cecropin AD. Varying the pH from 4.0 to 9.0 did not appear to affect the activity of cecropin AD, but some loss of potency was observed at pH values lower than pH 4.0. Under the challenge of several proteases (proteinase K, trypsin, and pepsin), cecropin AD maintained functional activity. The results indicated that the recombinant product expressed by the designed Bacillus subtilis expression system was a potent antimicrobial agent and could be applied to control infectious diseases of farm animals or even humans. PMID:19546372

Chen, Xiang; Zhu, Faming; Cao, Yunhe; Qiao, Shiyan

2009-01-01

244

Synthesis of Cu/CNTs nanocomposites for antimicrobial activity  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

245

Anthelmintic and antimicrobial activity of methanolic and aqueous extracts of Euphorbia helioscopia L.  

PubMed

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

Lone, Bashir A; Bandh, Suhaib A; Chishti, Mohammad Zahoor; Bhat, Fayaz Ahmad; Tak, Hidayatullah; Nisa, Humeera

2013-03-01

246

Isolation, identification and antimicrobial activity of propolis-associated fungi.  

PubMed

Propolis is a natural product widely known for its medicinal properties. In this work, fungi present on propolis samples were isolated, identified and tested for the production of antimicrobial metabolites. Twenty-two fungal isolates were obtained, some of which were identified as Alternaria alternata, Aspergillus flavus, Bipolaris hawaiiensis, Fusarium merismoides, Lasiodiplodia theobromae, Penicillium citrinum, Penicillium crustosum, Penicillium janthinellum, Penicillium purpurogenum, Pestalotiopsis palustris, Tetracoccosporium paxianum and Trichoderma koningii. These fungi were grown in liquid media to obtain crude extracts that were evaluated for their antibiotic activity against pathogenic bacteria, yeast and Cladosporium cladosporioides and A. flavus. The most active extract was obtained from L. theobromae (minimum inhibitory concentration = 64 ?g/mL against Listeria monocitogenes). Some extracts showed to be more active than the positive control in the inhibition of Staphylococcus aureus and L. monocitogenes. Therefore, propolis is a promising source of fungi, which produces active agents against relevant food poisoning bacteria and crop-associated fungi. PMID:23439233

de Souza, Giovanni Gontijo; Pfenning, Ludwig Heinrich; de Moura, Fabiana; Salgado, Mírian; Takahashi, Jacqueline Aparecida

2013-01-01

247

Distinct antimicrobial activities in aphid galls on Pistacia atlantica  

PubMed Central

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

Yoram, Gerchman; Inbar, Moseh

2011-01-01

248

Comparative Antimicrobial Activities of Aerosolized Sodium Hypochlorite, Chlorine Dioxide, and Electrochemically Activated Solutions Evaluated Using a Novel Standardized Assay  

PubMed Central

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

Thorn, R. M. S.; Robinson, G. M.

2013-01-01

249

Antimicrobial activities of LL-37 and its truncated variants against Burkholderia thailandensis.  

PubMed

Antimicrobial peptides (AMPs) are essential host defence molecules found in a wide variety of species and are promising antibacterial therapeutic candidates. Focusing on the human cathelicidin peptide LL-37, the aim of the present study was to explore the mechanisms of action and antimicrobial activities of a library of LL-37 fragments using Burkholderia thailandensis E264 as a model. The results revealed that IG-19 was the shortest fragment within LL-37 that exhibited antibacterial activity. LL-31, missing six residues at the C-terminus of LL-37, exhibited the strongest killing effect. Freeze-fracture electron microscopy of bacterial cells treated with either LL-37 or LL-31 revealed irregular bacterial surfaces with bleb projections, indicating that these peptides disrupted the integrity of the membrane. In addition, these peptides induced leakage of cell components, including nucleotides and even proteins. Altogether, the results obtained indicate the potential of using LL-31 as a new AMP to combat Burkholderia spp. PMID:20685090

Kanthawong, Sakawarat; Bolscher, Jan G M; Veerman, Enno C I; van Marle, Jan; Nazmi, Kamran; Wongratanacheewin, Surasakdi; Taweechaisupapong, Suwimol

2010-11-01

250

Biosynthesis and Antimicrobial Activity of Semiconductor Nanoparticles against Oral Pathogens  

PubMed Central

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

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

2014-01-01

251

Preliminary phytochemical screening, antimicrobial and antioxidant activities of Euphorbia milli.  

PubMed

Euphorbia milii is a Pakistani herb used for various infectious diseases. In this study we have carried out phytochemical, antibacterial and antioxidant investigation of different extracts/fractions. Phytochemical studies showed the presence of cardiac glycosides, steroids/phytosterols, anthocyanin, proteins, terpenoids, flavonoids and tannins. Susceptibility testing by well diffusion assay of its chloroform and methanol fractions revealed good antimicrobial activity against Klebsiella pneumonia and Staph epidermis. Ethyl acetate fraction of roots also exhibited considerable antimicrobial activity against most of tested pathogens. Various fractions (Hexane, chloroform, methanol and water) of E. milii were screen for their antioxidant potential using DPPH radical scavenging assay at different concentrations among these, chloroform fraction exhibited good scavenging activity. The IR spectroscopy of the various extracts/fractions indicated the presence of OH, saturated CH stretching, C=C, C=O, NO2, C-N, Ar-O, C-O- and R-O-Stretching respectively. The findings provide helpful evidence for the use of E. milii in traditional medicines. PMID:25015465

Rauf, Abdur; Khan, Ajmal; Uddin, Nizam; Akram, Muhammad; Arfan, Mohammad; Uddin, Ghias; Qaisar, Muhammad

2014-07-01

252

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

PubMed

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

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

2012-01-01

253

The in vitro antimicrobial activities of the essential oils of some Lamiaceae species from Turkey.  

PubMed

In this study, antimicrobial activities of the essential oils obtained by using the hydrodistillation method from some lamiaceous plants--Mentha longifolia (L.) Hudson ssp. longifolia, M. longifolia (L.) Hudson ssp. typhoides (Briq.) Harley var. typhoides, Mentha pulegium L., Salvia fruticosa Miller, Salvia tomentosa Miller, Calamintha nepeta (L.) Savi ssp. glandulosa (Req.) P.W. Ball, Nepeta cadmea Boiss., Lavandula stoechas L. ssp. stoechas, and Ziziphora tenuior L.--were determined by using the disc diffusion method. The plants used in this study were collected from different localities of Mu?la Province, Turkey. All the essential oils isolated from the plants were very effective against Gram-positive and Gram-negative bacteria, which included multiple-antibiotic resistant strains, except Pseudomonas aeruginosa ATCC 27853 and Pseudomonas fluorescens MU 87. The essential oils of the plant species, except S. tomentosa and S. fruticosa, were very effective against Candida albicans. The antimicrobial activities varied depending on the species, subspecies, or variety. In fact, essential oils of some plants belonging to the same taxa but collected from different localities showed different levels of antimicrobial activities. PMID:19735193

Sarac, Nurdan; Ugur, Aysel

2009-08-01

254

Antimicrobial and antioxidant activities of Cortex Magnoliae Officinalis and some other medicinal plants commonly used in South-East Asia  

PubMed Central

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

Chan, Lai Wah; Cheah, Emily LC; Saw, Constance LL; Weng, Wanyu; Heng, Paul WS

2008-01-01

255

Antimicrobial Activity of Nanoparticle Calcium Hydroxide against Enterococcus Faecalis: An In Vitro Study  

PubMed Central

Introduction: Enterococcus faecalis (E. faecalis) has the ability to invade the dentinal tubules and resist high pH levels. As a result, calcium hydroxide (CH) is not much effective on this bacterium. In theory, nanoparticle calcium hydroxide (NCH) has smaller size and high surface area that enables it to penetrate into the deeper layers of dentin and be more effective on E. faecalis. This in vitro study was designed to compare the antimicrobial activity of NCH and CH against E. faecalis. Methods and Materials: The antimicrobial activity of NCH against E. faecalis was evaluated by two independent tests: the minimum inhibitory concentration (MIC) of intracanal medicament and agar diffusion test (ADT). The efficiency of the medicament in dentinal tubules was evaluated on 23 human tooth blocks that were inoculated with E. faecalis. The tooth blocks were assigned to one control group (saline irrigation) and two experimental groups receiving CH and NCH as intracanal medication. The optical density in each group was assessed with spectrophotometer after collecting samples from dentin depths of 0, 200 and 400 µm. Data were analyzed by SPSS software ANOVA, Kruskal-Wallis and Dunnett’s test. Results: The MIC for NCH was 1/4 of the MIC for CH. NCH with distilled water (DW) produced the greatest inhibition zone in agar diffusion test. NCH had greater antimicrobial activity in dentin samples from depths of 200 and 400 µm compared to CH. Conclusion: The antimicrobial activity of NCH was superior to CH in culture medium. In dentinal tubules the efficacy of NCH was again better than CH on the 200- and 400-µm samples. PMID:25598808

Dianat, Omid; Saedi, Sara; Kazem, Majid; Alam, Mostafa

2015-01-01

256

Essential oils and isolated compounds from Lippia alba leaves and flowers: antimicrobial activity and osteoclast apoptosis.  

PubMed

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

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

257

Enhanced cellular uptake by "pharmaceutically oriented devices" of new simplified analogs of Linezolid with antimicrobial activity.  

PubMed

The aim of the present study was to enhance cellular uptake of simplified analogs of Linezolid by their incorporation into suitable delivery devices in order to improve the antimicrobial activity of these novel synthesized oxazolidin-2-one derivatives. The oxazolidin-2-one derivatives were synthesized by developing a rather simple one-pot reaction starting from oxiranylmethanol and several primary amines. Three delivery devices were prepared by following different synthetic approaches, such as single-step free radical grafting, precipitation polymerization and nano-emulsion. Finally, the antimicrobial activity of the novel synthesized compounds, without any vehicle and after their incorporation into the delivery devices, was evaluated against Escherichia coli and Saccharomyces cerevisiae by performing time-kill analyses. The synthesized oxazolidinones exhibited modest antimicrobial activity against E. coli and S. cerevisiae (MIC 16 ?g/mL). A good activity was, instead, highlighted after their incorporation into the prepared delivery devices (lecithin-based nano-emulsion, poly(N-vinyl-pyrrolidone)-methacrylic acid grafted copolymer and spherical polymeric nanoparticles) (MIC?4 ?g/mL). The incorporation into suitable vehicles, indeed, reduced by 4 times the normal MICs of the newly synthesized oxazolilidin-2-ones and represents an effective strategy to overcome cellular penetration constraints. PMID:24296047

Parisi, Ortensia Ilaria; Fiorillo, Marco; Caruso, Anna; Cappello, Anna Rita; Saturnino, Carmela; Puoci, Francesco; Panno, Antonella; Dolce, Vincenza; El-Kashef, Hussein; Sinicropi, Maria Stefania

2014-01-30

258

Antimicrobial activity of metal based nanoparticles against microbes associated with diseases in aquaculture.  

PubMed

The emergence of diseases and mortalities in aquaculture and development of antibiotics resistance in aquatic microbes, has renewed a great interest towards alternative methods of prevention and control of diseases. Nanoparticles have enormous potential in controlling human and animal pathogens and have scope of application in aquaculture. The present investigation was carried out to find out suitable nanoparticles having antimicrobial effect against aquatic microbes. Different commercial as well as laboratory synthesized metal and metal oxide nanoparticles were screened for their antimicrobial activities against a wide range of bacterial and fungal agents including certain freshwater cyanobacteria. Among different nanoparticles, synthesized copper oxide (CuO), zinc oxide (ZnO), silver (Ag) and silver doped titanium dioxide (Ag-TiO2) showed broad spectrum antibacterial activity. On the contrary, nanoparticles like Zn and ZnO showed antifungal activity against fungi like Penicillium and Mucor species. Since CuO, ZnO and Ag nanoparticles showed higher antimicrobial activity, they may be explored for aquaculture use. PMID:24888333

Swain, P; Nayak, S K; Sasmal, A; Behera, T; Barik, S K; Swain, S K; Mishra, S S; Sen, A K; Das, J K; Jayasankar, P

2014-09-01

259

Antimicrobial Activity of Terminalia catappa, Manilkara zapota and Piper betel Leaf Extract  

PubMed Central

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

Nair, R.; Chanda, Sumitra

2008-01-01

260

Antimicrobial activity of cobalt imidazolate metal-organic frameworks.  

PubMed

Two cobalt imidazolate metal-organic frameworks were evaluated as a bactericidal material against the growth of the Gram-negative bacteria Pseudomonas putida and Escherichia coli. Under the most unfavourable conditions, within the exponential growth phase and in the culture media for both microorganisms, the growth inhibition reached over 50% for concentrations of biocidal material in the 5-10mgL(-1) range. The release of metal gives excellent durability with the antibacterial effect persisting after 3months. Both cobalt-based materials can be prepared with simple, cheap and easily accessible commercial ligands, leading to a more affordable possible future application as antimicrobial materials. PMID:25065809

Aguado, Sonia; Quirós, Jennifer; Canivet, Jerome; Farrusseng, David; Boltes, Karina; Rosal, Roberto

2014-10-01

261

Effect of tea tree (Melaleuca alternifolia) oil as a natural antimicrobial agent in lipophilic formulations.  

PubMed

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 ?-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

Mantil, Elisabeth; Daly, Grace; Avis, Tyler J

2015-01-01

262

Bioprotective properties of Dragon's blood resin: In vitro evaluation of antioxidant activity and antimicrobial activity  

PubMed Central

Background Food preservation is basically done to preserve the natural characteristics and appearance of the food and to increase the shelf life of food. Food preservatives in use are natural, chemical and artificial. Keeping in mind the adverse effects of synthetic food preservatives, there is a need to identify natural food preservatives. The aims of this study were to evaluate in vitro antioxidant and antimicrobial activities of Dragon's blood resin obtained from Dracaena cinnabari Balf f., with a view to develop safer food preservatives. Methods In this study, three solvents of varying polarity were used to extract and separate the medium and high polarity compounds from the non-polar compounds of the Dragon's blood resin. The extracts were evaluated for their antimicrobial activity against the food borne pathogens. The antioxidant activities of the extracts were assessed using DPPH and ABTS radical scavenging, FRAP, metal chelating and reducing power assays. Total phenolics, flavonoids and flavonols of extracts were also estimated using the standard methods. Results Phytochemical analysis of extracts revealed high phenolic content in CH2Cl2 extract of resin. Free radical scavenging of CH2Cl2 extract was found to be highest which is in good correlation with its total phenolic content. All test microorganisms were also inhibited by CH2Cl2 extract. Conclusions Our result provide evidence that CH2Cl2 extract is a potential source of natural antioxidant compounds and exhibited good inhibitory activity against various food borne pathogens. Thus, CH2Cl2 extract of Dragon's blood resin could be considered as possible source of food preservative. PMID:21329518

2011-01-01

263

Curvularia Haloperoxidase: Antimicrobial Activity and Potential Application as a Surface Disinfectant  

PubMed Central

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

Hansen, Eva H.; Albertsen, Line; Schäfer, Thomas; Johansen, Charlotte; Frisvad, Jens C.; Molin, Søren; Gram, Lone

2003-01-01

264

Probing Membrane Insertion Activity of Antimicrobial Polymers via Coarse-grain Molecular Dynamics  

PubMed Central

Knowledge of the mechanism of action of antimicrobial agents is crucial for the development of new compounds to combat microbial pathogens. To this end, computational studies on the interaction of known membrane-active antimicrobial polymers with phospholipid bilayers reveal spontaneous membrane insertion and cooperative action at low and high concentrations, respectively. In late-stage attack, antimicrobials cross the membrane core and occasionally align to provide a stepping-stone pathway for water permeation; this suggests a possible new mode of action that does not depend on pore formation for transport to and across the inner leaflet. The computations rationalize the observed activity of a new class of antimicrobial compounds. PMID:18985168

Lopez, Carlos F.; Nielsen, Steven O.; Srinivas, Goundla; DeGrado, William F.; Klein, Michael L.

2008-01-01

265

Antimicrobial activities and usage in folkloric medicine of some Lamiaceae species growing in Mugla, Turkey  

Microsoft Academic Search

In this study; 23 selected plant species belonging to the Lamiaceae family, used in traditional treatments, were collected from different localities of Mugla, dried and extracted with ethanol using the soxhlet extraction apparatus. The antimicrobial activities of the plant extracts on the various test microorganisms, including multiple antibiotic resistant bacteria, were investigated. Antimicrobial activities of the extracts were determined by

Nurdan Sarac; Aysel Ugur

2007-01-01

266

Antiproliferative, antimicrobial and apoptosis inducing effects of compounds isolated from Inula viscosa.  

PubMed

The antiproliferative and antimicrobial effects of thirteen compounds isolated from Inula viscosa (L.) were tested in this study. The antiproliferative activity was tested against three cell lines using the MTT assay. The microdilution method was used to study the antimicrobial activity against two Gram positive bacteria, two Gram negative bacteria and one fungus. The apoptotic activity was determined using a TUNEL colorimetric assay. Scanning electron microscopy was used to study the morphological changes in treated cancer cells and bacteria. Antiproliferative activity was observed in four flavonoids (nepetin, 3,3'-di-O-methylquercetin, hispidulin, and 3-O-methylquercetin). 3,3'-di-O-Methylquercetin and 3-O-methylquercetin showed selective antiproliferative activity against MCF-7 cells, with IC(50) values of 10.11 and 11.23 µg/mL, respectively. Both compounds exert their antiproliferative effect by inducing apoptosis as indicted by the presence of DNA fragmentation, nuclear condensation, and formation of apoptotic bodies in treated cancer cells. The antimicrobial effect of Inula viscosa were also noticed in 3,3'-di-O-methylquercetin and 3-O-methyquercetin that inhibited Bacillus cereus at MIC of 62.5 and 125 µg/mL, respectively. Salmonella typhimurium was inhibited by both compounds at MIC of 125 µg/mL. 3,3'-di-O-Methylquercetin induced damage in bacterial cell walls and cytoplasmic membranes. Methylated quercetins isolated from Inula viscosa have improved anticancer and antimicrobial properties compared with other flavonoids and are promising as potential anticancer and antimicrobial agents. PMID:22418930

Talib, Wamidh H; Zarga, Musa H Abu; Mahasneh, Adel M

2012-01-01

267

In vitro antimicrobial activity of phytotherapic Uncaria tomentosa against endodontic pathogens.  

PubMed

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

Herrera, Daniel R; Tay, Lidia Y; Rezende, Eluise C; Kozlowski, Vitoldo A; Santos, Elizabete B dos

2010-09-01

268

Antimicrobial and inhibitory enzyme activity of N-(benzyl) and quaternary N-(benzyl) chitosan derivatives on plant pathogens.  

PubMed

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

Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M

2014-10-13

269

Effects of ionic strength on the antimicrobial photodynamic efficiency of methylene blue.  

PubMed

Antimicrobial photodynamic therapy (APDT) may become a useful clinical tool to treat microbial infections, and methylene blue (MB) is a well-known photosensitizer constantly employed in APDT studies, and although MB presents good efficiency in antimicrobial studies, some of the MB photochemical characteristics still have to be evaluated in terms of APDT. This work aimed to evaluate the role of MB solvent's ionic strength regarding dimerization, photochemistry, and photodynamic antimicrobial efficiency. Microbiological survival fraction assays on Escherichia coli were employed to verify the solution's influence on MB antimicrobial activity. MB was evaluated in deionized water and 0.9% saline solution through optical absorption spectroscopy; the solutions were also analysed via dissolved oxygen availability and reactive oxygen species (ROS) production. Our results show that bacterial reduction was increased in deionized water. Also we demonstrated that saline solution presents less oxygen availability than water, the dimer/monomer ratio for MB in saline is smaller than in water and MB presented a higher production of ROS in water than in 0.9% saline. Together, our results indicate the importance of the ionic strength in the photodynamic effectiveness and point out that this variable must be taken into account to design antimicrobial studies and to evaluate similar studies that might present conflicting results. PMID:24496397

Núñez, Silvia Cristina; Garcez, Aguinaldo Silva; Kato, Ilka Tiemy; Yoshimura, Tania Mateus; Gomes, Laércio; Baptista, Maurício Silva; Ribeiro, Martha Simões

2014-03-01

270

Effects of pH and salinity on the antimicrobial properties of clavanins.  

PubMed Central

Clavanins are histidine-rich, amidated alpha-helical antimicrobial peptides that were originally isolated from the leukocytes (hemocytes) of a tunicate, Styela clava. The activities of clavanin A amide and clavanin A acid against Escherichia coli, Listeria monocytogenes, and Candida albicans were substantially greater at pH 5.5 than at pH 7.4. In contrast, clavanin AK, a synthetic variant of clavanin A acid containing 4 histidine-->lysine substitutions exerted substantial activity at both pH 7.4 and pH 5.5. Each of these three clavanins permeabilized the outer and inner membranes of E. coli very effectively at pH 5.5, but only clavanin AK did so at pH 7.4. Unlike magainin 1 and cecropin P1, alpha-helical antimicrobial peptides from frog skin and porcine intestine, respectively, clavanins were broadly effective against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, as well as gram-negative organisms. Because clavanins exert substantial antimicrobial activity in 0.1 to 0.3 M NaCl, they provide templates for designing broad-spectrum peptide antibiotics intended to function in extracellular environments containing normal or elevated NaCl concentrations. The pH-dependent properties of histidine-rich antimicrobial peptides may allow the design of agents that would function selectively in acidic compartments, such as the gastric lumen, or within phagolysosomes. PMID:9199465

Lee, I H; Cho, Y; Lehrer, R I

1997-01-01

271

An amino acid composition criterion for membrane active antimicrobials  

NASA Astrophysics Data System (ADS)

Membrane active antimicrobials (AMPs) are short amphipathic peptides with broad spectrum anti microbial activity. While it is believed that their hydrophobic and cationic moieties are responsible for membrane-based mechanisms of action, membrane disruption by AMPs is manifested in a diversity of outcomes, such as pore formation, blebbing, and budding. This complication, along with others, have made a detailed, molecular understanding of AMPs difficult. We use synchrotron small angle xray scattering to investigate the interaction of model bacterial and eukaryotic cell membranes with archetypes from beta-sheet AMPs (e.g. defensins) and alpha-helical AMPs (e.g. magainins). The relationship between membrane composition and peptide induced changes in membrane curvature and topology is examined. By comparing the membrane rearrangement and phase behavior induced by these different peptides we will discuss the importance of amino acid composition on AMP design.

Schmidt, Nathan; Hwee Lai, Ghee; Mishra, Abhijit; Bong, Dennis; McCray, Paul, Jr.; Selsted, Michael; Ouellette, Andre; Wong, Gerard

2011-03-01

272

Chemical analysis of Greek pollen - Antioxidant, antimicrobial and proteasome activation properties  

PubMed Central

Background Pollen is a bee-product known for its medical properties from ancient times. In our days is increasingly used as health food supplement and especially as a tonic primarily with appeal to the elderly to ameliorate the effects of ageing. In order to evaluate the chemical composition and the biological activity of Greek pollen which has never been studied before, one sample with identified botanical origin from sixteen different common plant taxa of Greece has been evaluated. Results Three different extracts of the studied sample of Greek pollen, have been tested, in whether could induce proteasome activities in human fibroblasts. The water extract was found to induce a highly proteasome activity, showing interesting antioxidant properties. Due to this activity the aqueous extract was further subjected to chemical analysis and seven flavonoids have been isolated and identified by modern spectral means. From the methanolic extract, sugars, lipid acids, phenolic acids and their esters have been also identified, which mainly participate to the biosynthetic pathway of pollen phenolics. The total phenolics were estimated with the Folin-Ciocalteau reagent and the total antioxidant activity was determined by the DPPH method while the extracts and the isolated compounds were also tested for their antimicrobial activity by the dilution technique. Conclusions The Greek pollen is rich in flavonoids and phenolic acids which indicate the observed free radical scavenging activity, the effects of pollen on human fibroblasts and the interesting antimicrobial profile. PMID:21699688

2011-01-01

273

Structure-activity study of macropin, a novel antimicrobial peptide from the venom of solitary bee Macropis fulvipes (Hymenoptera: Melittidae).  

PubMed

A novel antimicrobial peptide, designated macropin (MAC-1) with sequence Gly-Phe-Gly-Met-Ala-Leu-Lys-Leu-Leu-Lys-Lys-Val-Leu-NH2 , was isolated from the venom of the solitary bee Macropis fulvipes. MAC-1 exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria, antifungal activity, and moderate hemolytic activity against human red blood cells. A series of macropin analogs were prepared to further evaluate the effect of structural alterations on antimicrobial and hemolytic activities and stability in human serum. The antimicrobial activities of several analogs against pathogenic Pseudomonas aeruginosa were significantly increased while their toxicity against human red blood cells was decreased. The activity enhancement is related to the introduction of either l- or d-lysine in selected positions. Furthermore, all-d analog and analogs with d-amino acid residues introduced at the N-terminal part of the peptide chain exhibited better serum stability than did natural macropin. Data obtained by CD spectroscopy suggest a propensity of the peptide to adopt an amphipathic ?-helical secondary structure in the presence of trifluoroethanol or membrane-mimicking sodium dodecyl sulfate. In addition, the study elucidates the structure-activity relationship for the effect of d-amino acid substitutions in MAC-1 using NMR spectroscopy. PMID:24616110

Monincová, Lenka; Veverka, Václav; Slaninová, Ji?ina; Bud?šínský, Miloš; Fu?ík, Vladimír; Bednárová, Lucie; Straka, Jakub; Ce?ovský, Václav

2014-06-01

274

Antioxidant capacity, radical scavenger activity, lipid oxidation protection analysis and antimicrobial activity of red grape extracts from different varieties cultivated in Portugal.  

PubMed

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

Correia, Ana C; Jordão, António M

2015-03-01

275

Antimicrobial Activity of Thin Solid Films of Silver Doped Hydroxyapatite Prepared by Sol-Gel Method  

PubMed Central

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

Iconaru, Simona Liliana; Chapon, Patrick; Le Coustumer, Philippe; Predoi, Daniela

2014-01-01

276

Antimicrobial effect of silver-doped phosphate-based glasses.  

PubMed

In this study a range of phosphate-based glasses (PBG) doped with silver have been investigated for their antimicrobial activities. In disk diffusion assays, these compositions demonstrated microbistatic effects against a range of organisms including Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans. The data obtained from the above studies allowed for an additional range of PBG containing lower amounts of silver to be studied for their effects on the growth and viability of S. aureus, E. coli, and C. albicans. PBG containing 3 and 5 mol % Ag were bactericidal for S. aureus and E. coli and significantly decreased the growth rate of C. albicans. A decrease in the dissolution rates of the glasses was seen with increasing Ag content over the range of concentrations investigated. Overall, 3 mol % Ag incorporated into the PBG investigated was sufficient to mount a potent antibacterial effect against the test organisms, and these compositions also gave excellent long-term release of Ag ions into the medium. PMID:16826601

Ahmed, I; Ready, D; Wilson, M; Knowles, J C

2006-12-01

277

Contact-active antimicrobial and potentially self-polishing coatings based on cellulose.  

PubMed

A contact-active antimicrobial coating is described that is only degraded in the presence of cellulase, which is an extracellular enzyme of numerous microbial strains. Antimicrobial DDA was grafted to a cellulose backbone via a polymeric spacer. The antimicrobial activity of the coatings, their biodegradability and their self-polishing potential were investigated. It was found that all coatings were antimicrobially active against Staphylococcus aureus. Coatings with high DS and long polymeric spacers degraded in water, while coatings with low DS and short spacers were not hydrolyzed even in the presence of cellulase. One coating was found to be selectively degradable by cellulase and recovered most of its antimicrobial activity after overloading and subsequent treatment with cellulase. PMID:20945436

Bieser, Arno M; Thomann, Yi; Tiller, Joerg C

2011-01-10

278

In vitro evaluation of the antimicrobial activities of selected lozenges.  

PubMed

The in vitro antimicrobial activities of 10 lozenges (Merothol, Merocets, Merocaine, Strepsils (two varieties), Dequacaine, Dequacets, Zensyls, Tyrozets, and Labosept) were determined by use of a microtiter counting method with Streptococcus pyogenes, Staphylococcus aureus, and Candida albicans as the test organisms. Merothol, Merocets, Merocaine, and both Strepsils formulations all reduced the counts of both S. aureus and S. pyogenes suspensions by approximately 6 log cycles within 5 and 20 min, respectively. Merothol, Merocets, and Merocaine also caused a reduction in the counts of the C. albicans suspension approximately 5 log cycles within 40 min, but no other lozenge formulation showed rapid and marked activity against C. albicans. Dequacaine and Dequacets showed marked but much slower activities against this yeast. Zensyls caused an approximately 6-log-cycle reduction in bacterial counts within 40 min, and Dequacaine, Dequacets, and Tyrozets showed marked but slower antibacterial activities. This work confirmed by a statistically sound in vitro method the in vivo antibacterial activities reported for Merothol, Merocets, and Merocaine, demonstrated equivalent antibacterial activities for Strepsils, and indicated that Merothol, Merocets, and Merocaine also showed marked activities against C. albicans. PMID:8308699

Richards, R M; Xing, D K

1993-12-01

279

Antimicrobial polymers - The antibacterial effect of photoactivated nano titanium dioxide polymer composites  

SciTech Connect

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.

Huppmann, T., E-mail: teresa.huppmann@tum.de; Leonhardt, S., E-mail: stefan.leonhardt@mytum.de, E-mail: erhard.krampe@tum.de; Krampe, E., E-mail: stefan.leonhardt@mytum.de, E-mail: erhard.krampe@tum.de; Wintermantel, E., E-mail: wintermantel@tum.de [Institute of Medical and Polymer Engineering, Technische Universität München (Germany); Yatsenko, S., E-mail: s.yatsenko@skz.de; Radovanovic, I., E-mail: i.radovanovic@skz.de, E-mail: m.bastian@skz.de; Bastian, M., E-mail: i.radovanovic@skz.de, E-mail: m.bastian@skz.de [SKZ- German Plastics Center, Würzburg (Germany)

2014-05-15

280

Antimicrobial polymers - The antibacterial effect of photoactivated nano titanium dioxide polymer composites  

NASA Astrophysics Data System (ADS)

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.

Huppmann, T.; Yatsenko, S.; Leonhardt, S.; Krampe, E.; Radovanovic, I.; Bastian, M.; Wintermantel, E.

2014-05-01

281

Antimicrobial stewardship programs - cost-minimizing or cost-effective?  

PubMed

Antimicrobial stewardship programs (ASPs) are aimed to improve patient care and health care outcomes. It is encouraging to find ASP interventions to be cost-saving in many cost-minimization analyses in literature. Nevertheless, the cost-effectiveness of ASP interventions, measured in cost per quality-adjusted life-years, is less well-established. This Editorial aims to explore the barriers in assessing clinical effectiveness of ASPs and provide suggestions to conduct cost-effectiveness analysis of ASPs. PMID:25331093

You, Joyce

2015-02-01

282

Antimicrobial activity of clove oil and its potential in the treatment of vaginal candidiasis.  

PubMed

In the present study, we evaluated antimicrobial activity of clove oil against a range of fungal pathogens including that responsible for urogenital infection. Clove oil was found to possess strong antifungal activity against opportunistic fungal pathogens such as Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus, etc. The oil was found to be extremely successful in the treatment of experimental murine vaginitis in model animals. On evaluating various formulations, topical administration of the liposomized clove oil was found to be most effective against treatment of vaginal candidiasis. PMID:16390816

Ahmad, N; Alam, M K; Shehbaz, A; Khan, A; Mannan, A; Hakim, S Rashid; Bisht, D; Owais, M

2005-12-01

283

Antimicrobial activity of artemisinin and precursor derived from in vitro plantlets of Artemisia annua L.  

PubMed

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

Appalasamy, Suganthi; Lo, Kiah Yann; Ch'ng, Song Jin; Nornadia, Ku; Othman, Ahmad Sofiman; Chan, Lai-Keng

2014-01-01

284

Alarin but not its alternative-splicing form, GALP (Galanin-like peptide) has antimicrobial activity  

SciTech Connect

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.

Wada, Akihiro, E-mail: a-wada@nagasaki-u.ac.jp [Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan)] [Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan); Wong, Pooi-Fong [Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia)] [Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Hojo, Hironobu [Department of Applied Biochemistry, Institute of Glycoscience, Tokai University, Kanagawa 2591292 (Japan)] [Department of Applied Biochemistry, Institute of Glycoscience, Tokai University, Kanagawa 2591292 (Japan); Hasegawa, Makoto [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Shiga 5260829 (Japan)] [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Shiga 5260829 (Japan); Ichinose, Akitoyo [Electron Microscopy Shop Central Laboratory, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan)] [Electron Microscopy Shop Central Laboratory, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan); Llanes, Rafael [Institute Pedro Kouri, Havana (Cuba)] [Institute Pedro Kouri, Havana (Cuba); Kubo, Yoshinao [Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 8528523 (Japan)] [Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 8528523 (Japan); Senba, Masachika [Department of Pathology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan)] [Department of Pathology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan); Ichinose, Yoshio [Kenya Research Station, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan)] [Kenya Research Station, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan)

2013-05-03

285

Antimicrobial Activity of Artemisinin and Precursor Derived from In Vitro Plantlets of Artemisia annua L.  

PubMed Central

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

Appalasamy, Suganthi; Lo, Kiah Yann; Ch'ng, Song Jin; Nornadia, Ku; Othman, Ahmad Sofiman; Chan, Lai-Keng

2014-01-01

286

Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions.  

PubMed

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 and chitosan were incorporated with AIT and used to coat one side of the film. The films were subjected to different storage conditions (storage time, storage temperature, and packed or unpacked) and handling conditions (washing, abrasion, and air blowing), and the antimicrobial activity of the films against Salmonella Stanley in tryptic soy broth was determined. The films (8.16 ?l of AIT per cm(2) of surface area) significantly (P < 0.05) inhibited the growth of Salmonella during 24 h of incubation at 22°C, while the populations of Salmonella in controls increased from ca. 4 to over 8 log CFU/ml, indicating a minimum inactivation of 4 log CFU/ml on films in comparison to the growth on controls. Statistical analyses indicated that storage time, storage temperature, and surface abrasion affected the antimicrobial activity of the films significantly (P < 0.05). However, the differences in microbial reduction between those conditions were less than 0.5 log cycle. The results suggest that the films' antimicrobial properties are stable under practical storage and handling conditions and that these antimicrobial films have potential applications in food packaging. PMID:23212023

Li, Weili; Liu, Linshu; Jin, Tony Z

2012-12-01

287

Curcumin reduces the antimicrobial activity of ciprofloxacin against Salmonella Typhimurium and Salmonella Typhi  

E-print Network

Curcumin reduces the antimicrobial activity of ciprofloxacin against Salmonella Typhimurium fragmentation, SOS response and reactive oxygen species (ROS) in the bacterial cell. Curcumin, an active research aimed at investigating whether curcumin modulates the action of ciprofloxacin. Method: We

Srinivasan, N.

288

Chemical composition of commercial citrus fruit essential oils and evaluation of their antimicrobial activity acting alone or in combined processes  

Microsoft Academic Search

The present investigation reports on the chemical composition of three commercial citrus fruit essential oils (orange [Citrus sinensis], lemon [Citrus lemon] and Mandarin [Citrus reticulata]) from Spain, and examines their antimicrobial activity against spoiling and pathogenic microorganisms, as well as possible synergistic lethal effects in combination with mild heat. Gas chromatography-mass spectrometry analysis allowed for the identification of 65 compounds

Laura Espina; María Somolinos; Susana Lorán; Pilar Conchello; Diego García; Rafael Pagán

2011-01-01

289

Scolopendin 2, a cationic antimicrobial peptide from centipede, and its membrane-active mechanism.  

PubMed

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?M to 100?M. Circular dichroism analysis showed that the peptide has an ?-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 4.8nm and 5.0nm. 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

Lee, Heejeong; Hwang, Jae-Sam; Lee, Jaeho; Kim, Jae Il; Lee, Dong Gun

2015-02-01

290

Antimicrobial activity of a new vaginal contraceptive NIM76 from neem oil (Azadirachta indica)  

Microsoft Academic Search

Efficacy of NIM-76, a spermicidal fraction from neem oil, was investigated for its antimicrobial action against certain bacteria, fungi and Polio virus as compared to whole neem oil. The NIM-76 preparation showed stronger anti-microbial activity than the whole neem oil. It inhibited growth of various pathogens tested including Escherichia coli and Kleibsiella pneumoniae which were not affected by the whole

M SaiRam; G Ilavazhagan; S. K Sharma; S. A Dhanraj; B Suresh; M. M Parida; A. M Jana; Kumar Devendra; W Selvamurthy

2000-01-01

291

Carrier herbal medicine: an evaluation of the antimicrobial and anticancer activity in some frequently used remedies  

Microsoft Academic Search

The antimicrobial properties of some traditional Carrier herbal preparations were evaluated using an agar dilution method. Pitch preparations were screened against known human pathogens: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus fumigatus. The results indicated definite antimicrobial activity in the pitch preparations of Picea glauca and Pinus contorta and provide a starting point for pharmacognostic evaluation of

E. M. Ritch-Krc; N. J. Turner; G. H. N. Towers

1996-01-01

292

Examination of antimicrobial activity of selected non-antibiotic drugs.  

PubMed

A variety of pharmaceutical preparations, which are applied in the management of non-infectious diseases, have shown in vitro some antimicrobial activity. These drugs are called "non-antibiotics". The aim of this study was to detect and characterize the antimicrobial activity of non-antibiotic drugs, selected from the preparations analysed during state control performed in the National Institute of Public Health in Poland. Over 180 of pharmaceutical preparations were randomly chosen from different groups of drugs. A surveillance study was performed on standard ATCC microbial strains used for drug control: S. aureus, E. coli, P. aeruginosa and C. albicans. It was shown that the drugs listed below inhibited growth of at least one of the examined strains: Actonel 5 mg tabl. (risedronate), Aldan 10 mg tabl. (amlodipine), Aleras 10 mg tabl. (cetirisine), Aspicam 15 mg tabl. (meloxicam), Baikadent 6 mg/g gel (flavons of Scutellariae), Debretin 100 mg tabl. (trimebutine), Ferro-Duo 100 mg tabl. (ferrum), Gastrovent 145 mg caps. (bismuth citrate), Ibum 200 mg caps., Upfen 200 mg tabl. (ibuprofen), Lastet 100 mg caps. (etoposide), Legalon 70 mg tabl. (sylimarin), Madopar 125 tabl. (benserazide, levodopa), Moxenil 100 mg tabl. (nimesulide), Neurotin 800 mg tabl. (gabapentin), Propranolol 40 mg tabl. (propranolol), Rexetin 20 mg tabl. (paroxetine), Salipax 20 mg caps. (fluoxetine), Selofen 10 mg caps. (zaleplon) Stenorol 0.6% powder (halofuginone), Stimuloton 50 mg tabl. (sertraline), Superoptim 0.3 mg tabl. (hipericine), Uversan 50 mg tabl. (arbutine from Arctostaphylos uva ursi). S. aureus strain was susceptible to the most of the drugs listed above. The lowest inhibitory concentration was found for sertraline and hipericine (0.16 and 0.075 mg/mL, respectively). PMID:15909927

Kruszewska, Hanna; Zareba, Tomasz; Tyski, Stefan

2004-12-01

293

Antimicrobial activity of N-phthaloylamino acid hydroxamates.  

PubMed

Antibacterial and antifungal activity of N-phthaloylamino acid hydroxamates [C6H4(CO)2N-X-CONHOH, X=amino acid residues of glycine, beta-alanine or D-phenylglycine], was examined against 44 strains of Gram-positive and Gram-negative bacteria, and 10 species of yeasts. The level of antimicrobial activity was established using the in vitro agar assay and the standard broth dilution susceptibility test. N-phthaloyl-D-phenylglycine-hydroxa- mic acid , the substance with the highest lipophilicity (log P), showed the best antibacterial activity, especially against Gram-negative bacteria. Minimum inhibitory concentration of was 0.008 mg mL-1 in the activity against Yersinia enterocolitica O3, confirmed by a large inhibition zone (30 mm) by the diffusion test. Hydroxamates inhibit growth by chelation of the PDF enzyme metal in both Gram-positive and Gram-negative bacteria, and LpxC enzyme in Gram-negative enzyme. Phthalimides appear to contribute to inhibition by destabilizing m-RNA. Antifungal activity of substances is not very expressed. PMID:16375828

Matijevi?-Sosa, Julija; Cvetni?, Zdenka

2005-12-01

294

Mosquito larvicidal and antimicrobial activity of protein of Solanum villosum leaves  

PubMed Central

Background Mosquitoes are associated with the transmission of malaria, dengue, Japanese encephalitis, filariasis and other viral diseases throughout the globe, apart from being a nuisance pest. Biological control alone or as a part of integrated vector management stands to be a better alternative to the chemical controls aimed against pest mosquitoes. At the same time it is necessary to control bacteria by synthetic or natural means (plant products). Hence the present study was designed to screen the effect of mosquito larvicidal and antimicrobial activitiy of protein isolated from matured leaves of Solanum villosum against mosquito immatures and some pathogenic bacteria. Methods Aqueous solvent extract of fresh mature leaves of S. villosum was tested against 3rd instar larvae of Anopheles stephensi, Culex quinquefasciatus and Stegomyia aegypti mosquitoes and against four pathogenic bacteria. The protein fraction was isolated and tested for mosquitocidal and antibacterial activities. Amino acid analysis was performed on isolated protein using PICO.TAG amino acid system. SDS-PAGE was also done to detect the bands of amino acid on the basis of their molecular weights. Results Proteins isolated from mature leaves of S. villosum were found to have larvicidal and antimicrobial properties. Analysis of the isolated protein identified fifteen amino acids of which eight were essential amino acids. SDS-PAGE detected seven bands corresponding to different molecular weights in the range of 69–109 KDa. Conclusion Proteins of mature leaves of S. villosum exhibited moderate larvicidal and antimicrobial activities. The study provides considerable scope in exploiting local indigenous resources for isolation of antimicrobial and mosquito larvicidal proteins. PMID:19061512

Chowdhury, Nandita; Laskar, Subrata; Chandra, Goutam

2008-01-01

295

Amphiphilic Poly(phenyleneethynylene)s Can Mimic Antimicrobial Peptide Membrane Disordering Effect by  

E-print Network

Amphiphilic Poly(phenyleneethynylene)s Can Mimic Antimicrobial Peptide Membrane Disordering Effect: Antimicrobial peptides (AMPs) are a class of peptides that are innate to various organisms and function. This study demonstrates that mPEs can mimic AMP's membrane disordering. Introduction Antimicrobial peptides

Lee, Ka Yee C.

296

Underlying Mechanism of Antimicrobial Activity of Chitosan Microparticles and Implications for the Treatment of Infectious Diseases  

PubMed Central

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

Jeon, Soo Jin; Oh, Manhwan; Yeo, Won-Sik; Galvão, Klibs N.; Jeong, Kwang Cheol

2014-01-01

297

Effect of naturally occurring antimicrobials and chemical preservatives on the growth of Aspergillus Parasiticus.  

PubMed

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?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

Pillai, Prathesha; Ramaswamy, K

2012-04-01

298

Draft Genome Sequence of Paenibacillus sp. Strain MSt1 with Broad Antimicrobial Activity, Isolated from Malaysian Tropical Peat Swamp Soil  

PubMed Central

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

Ong, Kuan Shion; Yule, Catherine M.; Gan, Han Ming; Lee, Sui Mae

2014-01-01

299

Physicochemical properties, cytotoxicity, and antimicrobial activity of sulphated zirconia nanoparticles  

PubMed Central

Nanoparticle sulphated zirconia with Brønsted acidic sites were prepared here by an impregnation reaction followed by calcination at 600°C for 3 hours. The characterization was completed using X-ray diffraction, thermal gravimetric analysis, Fourier transform infrared spectroscopy, Brunner-Emmett-Teller surface area measurements, scanning electron microscopy with energy dispersive X-ray spectroscopy, and transmission electron microscopy. Moreover, the anticancer and antimicrobial effects were investigated for the first time. This study showed for the first time that the exposure of cancer cells to sulphated zirconia nanoparticles (3.9–1,000 ?g/mL for 24 hours) resulted in a dose-dependent inhibition of cell growth, as determined by (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Similar promising results were observed for reducing bacteria functions. In this manner, this study demonstrated that sulphated zirconia nanoparticles with Brønsted acidic sites should be further studied for a wide range of anticancer and antibacterial applications.

Mftah, Ae; Alhassan, Fatah H; Al-Qubaisi, Mothanna Sadiq; El Zowalaty, Mohamed Ezzat; Webster, Thomas J; Sh-eldin, Mohammed; Rasedee, Abdullah; Taufiq-Yap, Yun Hin; Rashid, Shah Samiur

2015-01-01

300

Antimicrobial activities of silver dressings: an in vitro comparison.  

PubMed

A range of silver-coated or -impregnated dressings are now commercially available for use but comparative data on their antimicrobial efficacies are limited. The antibacterial activities of five commercially available silver-coated/impregnated dressings were compared against nine common burn-wound pathogens, namely methicillin-sensitive and -resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Proteus vulgaris, Acinetobacter baumannii and a multi-drug-efflux-positive Acinetobacter baumannii (BM4454), using a broth culture method. The rapidity and extent of killing of these pathogens under in vitro conditions were evaluated. All five silver-impregnated dressings investigated exerted bactericidal activity, particularly against Gram-negative bacteria, including Enterobacter species, Proteus species and E. coli. The spectrum and rapidity of action, however, ranged widely for different dressings. Acticoat and Contreet had a broad spectrum of bactericidal activities against both Gram-positive and -negative bacteria. Contreet was characterized by a very rapid bactericidal action and achieved a reduction of > or =10,000 c.f.u. ml(-1) in the first 30 min for Enterobacter cloacae, Proteus vulgaris, Pseudomonas aeruginosa and Acinetobacter baumanii. Other dressings demonstrated a narrower range of bactericidal activities. Understanding the characteristics of these dressings may enable them to be targeted more appropriately according to the specific requirements for use of a particular dressing, as in for prophylaxis in skin grafting or for an infected wound with MRSA. PMID:16388031

Ip, Margaret; Lui, Sau Lai; Poon, Vincent K M; Lung, Ivan; Burd, Andrew

2006-01-01

301

Membrane disruptive antimicrobial activities of human ?-defensin-3 analogs.  

PubMed

Human beta defensin-3 (H?D-3) is a host-defense protein exhibiting antibacterial activity towards both Gram-negative and Gram-positive bacteria. There is considerable interest in the function of this protein due to its increased salt tolerance and activity against Gram-positive Staphylococcus aureus. In this study, analogs of H?D-3 devoid of N and C terminal regions are investigated to determine the influence of specific structural motif on antimicrobial activity and selectivity between Gram-positive and Gram-negative bacteria. Circular dichroism, fluorescence and solid-state NMR experiments have been used to investigate the conformation and mode of action of H?D3 analogs with various model membranes to mimic bacterial inner and outer membranes and also mammalian membranes. Our studies specifically focused on determining four major characteristics: (i) interaction of H?D3 analogs with phospholipid vesicles composed of zwitterionic PC or anionic PE:PG vesicles and LPS; (ii) conformation of H?D3-peptide analogs in the presence of PC or PE:PG vesicles; (iii) ability of H?D3 analogs to permeate phospholipid vesicles composed of PC or PE:PG; and (iv) activities on bacteria cells and erythrocytes. Our results infer that the linear peptide L25P and its cyclic form C25P are more active than L21P and C21P analogs. However, they are less active than the parent peptide, thus pointing towards the importance of the N terminal domain in its biological activity. The variation in the activities of L21P/C21P and L25P/C25P also suggest the importance of the positively charged residues at the C terminus in providing selectivity particularly to Gram-negative bacteria. PMID:25112689

Sudheendra, U S; Dhople, Vishnu; Datta, Aritreyee; Kar, Rajiv K; Shelburne, Charles E; Bhunia, Anirban; Ramamoorthy, Ayyalusamy

2015-02-16

302

Surface-engineered core-shell nano-size ferrites and their antimicrobial activity  

SciTech Connect

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.

Baraliya, Jagdish D., E-mail: jdbaraliya@yahoo.co.in; Joshi, Hiren H., E-mail: jdbaraliya@yahoo.co.in [Department of Physics, Saurashtra University, Rajkot - 360 005, Gujarat (India)

2014-04-24

303

Effects of the antimicrobial sulfamethoxazole on groundwater bacterial enrichment  

USGS Publications Warehouse

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.

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

304

Comparative antimicrobial activity and mechanism of action of bovine lactoferricin-derived synthetic peptides.  

PubMed

Lactoferricin B (LfcinB), a 25 residue peptide derived from the N-terminal of bovine lactoferrin (bLF), causes depolarization of the cytoplasmic membrane in susceptible bacteria. Its mechanism of action, however, still needs to be elucidated. In the present study, synthetic LfcinB (without a disulfide bridge) and LfcinB (C-C; with a disulfide bridge) as well as three derivatives with 15-, 11- and 9-residue peptides were prepared to investigate their antimicrobial nature and mechanisms. The antimicrobial properties were measured via minimum inhibitory concentration (MIC) determinations, killing kinetics assays and synergy testing, and hemolytic activities were assessed by hemoglobin release. Finally, the morphology of peptide-treated bacteria was determined by atomic force microscopy (AFM). We found that there was no difference in MICs between LfcinB and LfcinB (C-C). Among the derivatives, only LfcinB15 maintained nearly the same level as LfcinB, in the MIC range of 16-128 ?g/ml, and the MICs of LfcinB11 (64-256 ?g/ml) were 4 times more than LfcinB, while LfcinB9 exhibited the lowest antimicrobial activity. When treated at MIC for 1 h, many blebs were formed and holes of various sizes appeared on the cell surface, but the cell still maintained its integrity. This suggested that LfcinB had a major permeability effect on the cytoplasmic membrane of both Gram-positive and Gram-negative bacteria, which also indicated it may be a possible intracellular target. Among the tested antibiotics, aureomycin increased the bactericidal activity of LfcinB against E. coli, S. aureus and P. aeruginosa, but neomycin did not have such an effect. We also found that the combination of cecropin A and LfcinB had synergistic effects against E. coli. PMID:21607695

Liu, Yifan; Han, Feifei; Xie, Yonggang; Wang, Yizhen

2011-12-01

305

Evaluation of antimicrobial effectiveness of C-8 xylitol monoester as an alternative preservative for cosmetic products.  

PubMed

Xylitol is a natural sugar derived from plants, fruits and vegetables, whose antimicrobial properties are described in the literature. This study aimed to evaluate the antimicrobial effectiveness of C-8 xylitol monoester, for its use as a preservative in cosmetic formulations. The minimum inhibitory concentration (MIC) was determined by the broth macrodilution method, and the antimicrobial effectiveness of C-8 xylitol monoester was determined by using challenge test method. The results obtained in the determination of minimum inhibitory concentration are between 1.0% and 1.25% for Staphylococcus aureus, Escherichia coli and Candida albicans and between 1.0% and 1.5% for Pseudomonas aeruginosa and Aspergillus niger. The amount of 1% of C-8 xylitol monoester was added to the lotion used in the challenge test, observing a rapid decline in the number of CFU g(-1) in stages of evaluation after contamination of the product by all bacteria. The same occurs in relation to C. albicans, which shows a 90% reduction in the number of CFU g(-1). Regarding A. niger, similar reduction is observed when pH value of the lotion is adjusted from 5.5 to 7.0. The results indicate that under the tests conditions, C-8 xylitol monoester has antimicrobial activity and could be considered as an alternative preservative for cosmetic formulations. PMID:21338375

Amaral, L F B; Camilo, N S; Pereda, M D C V; Levy, C E; Moriel, P; Mazzola, P G

2011-10-01

306

Antimicrobial and Antioxidant Activities of Plants from Northeast of Mexico  

PubMed Central

Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalis and two Staphylococcus aureus strains), and seven clinically isolated yeasts (Candida albicans, C. krusei, C. tropicalis, C. parapsilosis and C. glabrata); their antioxidant activity was tested using a DPPH free radical assay. No activity against Gram-negative bacteria was observed with any extract up to the maximum concentration tested, 1000??g?ml?1. We report here for the first time activity of Ceanothus coeruleus against S. aureus (flowers, minimal inhibitory concentration (MIC) 125??g?ml?1), C. glabrata (MICs 31.25??g?ml?1) and C. parapsilosis (MICs between 31.25 and 125??g?ml?1); Chrysanctinia mexicana against C. glabrata (MICs 31.25 ?g ml?1); Colubrina greggii against E. faecalis (MICs 250??g?ml?1) and Cordia boissieri against C. glabrata (MIC 125 ?g ml?1). Furthermore, this is the first report about antioxidant activity of extracts from Ceanothus coeruleus, Chrysanctinia mexicana, Colubrina greggii and Cyperus alternifolius. Some correlation could exist between antioxidant activity and antiyeast activity against yeasts in the species Ceanothus coeruleus, Schinus molle, Colubrina greggii and Cordia boissieri. PMID:19770266

Salazar-Aranda, Ricardo; Pérez-López, Luis Alejandro; López-Arroyo, Joel; Alanís-Garza, Blanca Alicia; Waksman de Torres, Noemí

2011-01-01

307

Antimicrobial and antioxidant activities of three Mentha species essential oils.  

PubMed

The present study describes the antimicrobial activity and free radical scavenging capacity (RSC) of essential oils from Mentha aquatica L., Mentha longifolia L., and Mentha piperita L. The chemical profile of each essential oil was determined by GC-MS and TLC. All essential oils exhibited very strong antibacterial activity, in particularly against Esherichia coli strains. The most powerful was M. piperita essential oil, especially towards multiresistant strain of Shigella sonei and Micrococcus flavus ATTC 10,240. All tested oils showed significant fungistatic and fungicidal activity [expressed as minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values, respectively], that were considerably higher than those of the commercial fungicide bifonazole. The essential oils of M. piperita and M. longifolia were found to be more active than the essential oil of M. aquatica. Especially low MIC (4 microL/mL) and MFC (4 microL/mL) were found with M. piperita oil against Trichophyton tonsurans and Candida albicans (both 8 microL/mL). The RSC was evaluated by measuring the scavenging activity of the essential oils on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and OH radicals. All examined essential oils were able to reduce DPPH radicals into the neutral DPPH-H form, and this activity was dose-dependent. However, only the M. piperita oil reduced DPPH to 50 % (IC50 = 2.53 microg/mL). The M. piperita essential oil also exhibited the highest OH radical scavenging activity, reducing OH radical generation in the Fenton reaction by 24 % (pure oil). According to GC-MS and TLC (dot-blot techniques), the most powerful scavenging compounds were monoterpene ketones (menthone and isomenthone) in the essential oils of M. longifolia and M. piperita and 1,8-cineole in the oil of M. aquatica. PMID:12802721

Mimica-Duki?, Neda; Bozin, Biljana; Sokovi?, Marina; Mihajlovi?, Biserka; Matavulj, Milan

2003-05-01

308

Search of antimicrobial activity of selected non-antibiotic drugs.  

PubMed

A variety of pharmaceutical preparations, which are applied in the management of non-infectious diseases, have shown in vitro some antimicrobial activity. These drugs are called "non-antibiotics". The aim of this study was to detect and characterise the antimicrobial activity of non-antibiotic drugs. selected from the preparations analysed during state control performed at the Drug Institute in Poland. Over 160 pharmaceutical preparations were randomly chosen from different groups of drugs. The surveillance study was performed on standard ATCC microbial strains used for drug control: S aureus, E. coil, P. aeruginosa and C. albicans. It was shown that the drugs listed below inhibited growth of at least one of the examined strains:acyclovir (Awirol 5%, cream), alendronate (Alenato 5 mg, tabl.), alverine (Meteospasmyl 20 mg, caps.), butorphanole (Butamidor 10 mg/ml, amp.), clodronate (Sindronat 400 mg, caps), diclofenac (Olfen 75 mg, amp.), emadastine (Emadine 0.05%, eye dr.), etodolac (Febret 200 mg, caps.), fluvastatine (Lescol 40 mg, tabl.), ketamine (Ketamidor 10%, amp.), levocabastine (Histimet 0.5 mg/ml, eye dr.), losartan (Lorista 50 mg, tabl.), matipranolol (Betaman 0.3% eye dr.), mesalazine (Pentasa 1%, susp.), naproxen (Nalgesin 550 mg, tabl.), oxaprosine (Reumax 600 mg, tabl.), oxymethazoline (Nasivin 0.025%, nose dr.), proxymetacaine (Alcaine 0.5%, eye dr.), ribavirin (Rebetol 200 mg, caps.), rutoside with ascorbic acid (Cerutin 20+200 mg, tabl.), sulodexide (Vessel due F, 250 LSU, caps.), tegaserole (Zelmac 50 mg, tabl.), telmisartan (Pritor 20 mg, tabl.), temosolomide (Temodal 100 mg, caps.), ticlopidine (Ticlid 250 mg, tabl.), tolfenamic acid (Migea rapid 200 mg, tabl.), tramadole (Tramundin 100 mg, tabl.), tropicamide (Tropicamidum 1%, eye dr.). Staphylococcus aureus was susceptible to most of the drugs listed above. Ticlopidine showed activity against S. aureus, E. coli and C. albicans (MICs equal to: 0.45; 0.45 and 0.65 mg/ml, respectively). Oxymetazoline showed activity against S. aureus and E. coli (MICs: 0.005 and 0.025 mg/ml, respectively). Pseudomonas aeruginosa was sensitive to alendronate, clondronate, oxaprozine, ribavirin and tramadole (MICs: 10, 63, 60, 3 and 43 mg/ml, respectively). PMID:12669766

Kruszewska, Hanna; Zareba, Tomasz; Tyski, Stefan

2002-01-01

309

Evaluation of the Antimicrobial Activity of Lysostaphin-Coated Hernia Repair Meshes?  

PubMed Central

Bacterial infections by antibiotic-resistant Staphylococcus aureus strains are among the most common postoperative complications in surgical hernia repair with synthetic mesh. Surface coating of medical devices/implants using antibacterial peptides and enzymes has recently emerged as a potentially effective method for preventing infections. The objective of this study was to evaluate the in vitro antimicrobial activity of hernia repair meshes coated by the antimicrobial enzyme lysostaphin at different initial concentrations. Lysostaphin was adsorbed on pieces of polypropylene (Ultrapro) mesh with binding yields of ?10 to 40% at different coating concentrations of between 10 and 500 ?g/ml. Leaching of enzyme from the surface of all the samples was studied in 2% (wt/vol) bovine serum albumin in phosphate-buffered saline buffer at 37°C, and it was found that less than 3% of adsorbed enzyme desorbed from the surface after 24 h of incubation. Studies of antibacterial activity against a cell suspension of S. aureus were performed using turbidity assay and demonstrated that the small amount of enzyme leaching from the mesh surface contributes to the lytic activity of the lysostaphin-coated samples. Colony counting data from the broth count (model for bacteria in wound fluid) and wash count (model for colonized bacteria) for the enzyme-coated samples showed significantly decreased numbers of CFU compared to uncoated samples (P < 0.05). A pilot in vivo study showed a dose-dependent efficacy of lysostaphin-coated meshes in a rat model of S. aureus infection. The antimicrobial activity of the lysostaphin-coated meshes suggests that such enzyme-leaching surfaces could be efficient at actively resisting initial bacterial adhesion and preventing subsequent colonization of hernia repair meshes. PMID:21709102

Satishkumar, Rohan; Sankar, Sriram; Yurko, Yuliya; Lincourt, Amy; Shipp, John; Heniford, B. Todd; Vertegel, Alexey

2011-01-01

310

In vitro antimicrobial activity of ten medicinal plants against clinical isolates of oral cancer cases  

PubMed Central

Background Suppression of immune system in treated cancer patients may lead to secondary infections that obviate the need of antibiotics. In the present study, an attempt was made to understand the occurrence of secondary infections in immuno-suppressed patients along with herbal control of these infections with the following objectives to: (a) isolate the microbial species from the treated oral cancer patients along with the estimation of absolute neutrophile counts of patients (b) assess the in vitro antimicrobial activity medicinal plants against the above clinical isolates. Methods Blood and oral swab cultures were taken from 40 oral cancer patients undergoing treatment in the radiotherapy unit of Regional Cancer Institute, Pt. B.D.S. Health University, Rohtak, Haryana. Clinical isolates were identified by following general microbiological, staining and biochemical methods. The absolute neutrophile counts were done by following the standard methods. The medicinal plants selected for antimicrobial activity analysis were Asphodelus tenuifolius Cav., Asparagus racemosus Willd., Balanites aegyptiaca L., Cestrum diurnum L., Cordia dichotoma G. Forst, Eclipta alba L., Murraya koenigii (L.) Spreng. , Pedalium murex L., Ricinus communis L. and Trigonella foenum graecum L. The antimicrobial efficacy of medicinal plants was evaluated by modified Kirby-Bauer disc diffusion method. MIC and MFC were investigated by serial two fold microbroth dilution method. Results Prevalent bacterial pathogens isolated were Staphylococcus aureus (23.2%), Escherichia coli (15.62%), Staphylococcus epidermidis (12.5%), Pseudomonas aeruginosa (9.37%), Klebsiella pneumonia (7.81%), Proteus mirabilis (3.6%), Proteus vulgaris (4.2%) and the fungal pathogens were Candida albicans (14.6%), Aspergillus fumigatus (9.37%). Out of 40 cases, 35 (87.5%) were observed as neutropenic. Eight medicinal plants (A. tenuifolius, A. racemosus, B. aegyptiaca, E. alba, M. koenigii, P. murex R. communis and T. foenum graecum) showed significant antimicrobial activity (P < .05) against most of the isolates. The MIC and MFC values were ranged from 31 to 500 ?g/ml. P. aeruginosa was observed highest susceptible bacteria (46.6%) on the basis of susceptible index. Conclusion It can be concluded that treated oral cancer patients were neutropenic and prone to secondary infection of microbes. The medicinal plant can prove as effective antimicrobial agent to check the secondary infections in treated cancer patients. PMID:21599889

2011-01-01

311

pH modulates the activity and synergism of the airway surface liquid antimicrobials ?-defensin-3 and LL-37  

PubMed Central

The pulmonary airways are continuously exposed to bacteria. As a first line of defense against infection, the airway surface liquid (ASL) contains a complex mixture of antimicrobial factors that kill inhaled and aspirated bacteria. The composition of ASL is critical for antimicrobial effectiveness. For example, in cystic fibrosis an abnormally acidic ASL inhibits antimicrobial activity. Here, we tested the effect of pH on the activity of an ASL defensin, human ?-defensin-3 (hBD-3), and the cathelicidin-related peptide, LL-37. We found that reducing pH from 8.0 to 6.8 reduced the ability of both peptides to kill Staphylococcus aureus. An acidic pH also attenuated LL-37 killing of Pseudomonas aeruginosa. In addition, we discovered synergism between hBD-3 and LL-37 in killing S. aureus. LL-37 and lysozyme were also synergistic. Importantly, an acidic pH reduced the synergistic effects of combinations of ASL antibacterials. These results indicate that an acidic pH reduces the activity of individual ASL antimicrobials, impairs synergism between them, and thus may disrupt an important airway host defense mechanism. PMID:25512526

Abou Alaiwa, Mahmoud H.; Reznikov, Leah R.; Gansemer, Nicholas D.; Sheets, Kelsey A.; Horswill, Alexander R.; Stoltz, David A.; Zabner, Joseph; Welsh, Michael J.

2014-01-01

312

Pharmacological properties of Moringa oleifera. 1: Preliminary screening for antimicrobial activity.  

PubMed

The antimicrobial activities of Moringa oleifera leaves, roots, bark and seeds were investigated in vitro against bacteria, yeast, dermatophytes and helminths pathogenic to man. By a disk-diffusion method, it was demonstrated that the fresh leaf juice and aqueous extracts from the seeds inhibit the growth of Pseudomonas aeruginosa and Staphylococcus aureus and that extraction temperatures above 56 degrees C inhibited this activity. No activity was demonstrated against four other pathogenic Gram-positive and Gram-negative bacteria and Candida albicans. By a dilution method, no activity was demonstrated against six pathogenic dermatophytes. A method was standardized for studying the effect of aqueous extracts on Ascaris lumbricoides eggs, but no activity was exhibited by any part of the tree in contrast to Chenopodium ambrosioides leaf extracts. PMID:1921416

Cáceres, A; Cabrera, O; Morales, O; Mollinedo, P; Mendia, P

1991-07-01

313

Characterization of ?-carrageenan films incorporated plant essential oils with improved antimicrobial activity.  

PubMed

Antioxidant and antimicrobial kappa-carrageenan-based films containing different concentrations of Zataria multiflora Boiss (ZEO) and Mentha pulegium (MEO) essential oils were developed, and their water vapor permeability (WVP), optical, microstructure, antioxidant and antimicrobial properties were characterized. ZEO and MEO decreased the WVP of the emulsified films; for example, 3% ZEO reduced WVP by around 80%. Increasing the content of ZEO or MEO from 1% to 3% (v/v) increased values for elongation at break from 37.43% to 44.74% and from 36.09% to 41.25% respectively. Carrageenan-composite films were less resistant to breakage, more flexible and more opaque with lower gloss. These properties were related to the film's microstructure as analyzed by atomic force microscopy and scanning electron microscopy. ZEO affected the antioxidant properties of the films more markedly than MEO, e.g., ZEO containing films showed DPPH radical scavenging of 80.6% which were two-fold higher than those having MEO. The films' antimicrobial activities were increased by incorporating essential oils, particularly ZEO, which were more effective against the bacteria in the direct-contact method than a vapor phase. S. aureus was found to be the most sensitive bacterium to either ZEO or MEO, followed by B. cereus and E. coli. A highest inhibition zone of 544.05 mm(2) was observed for S. aureus around the films incorporated with 3% (v/v) ZEO. The total inhibitory zone of 3% (v/v) MEO formulated films was 20.43 for S. typhimurium and 10.15 mm(2) for P. aeruginosa. These results revealed that ZEO and MEO have good potential to be incorporated into ?-carrageenan to make antimicrobial and antioxidant edible films for food applications. PMID:24299814

Shojaee-Aliabadi, Saeedeh; Hosseini, Hedayat; Mohammadifar, Mohammad Amin; Mohammadi, Abdorreza; Ghasemlou, Mehran; Hosseini, Seyede Marzieh; Khaksar, Ramin

2014-01-30

314

In vitro evaluation of antimicrobial activity of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937).  

PubMed

The antimicrobial activity of five crude extracts (aqueous, methanol, ethyl acetate, acetone and methylene chloride) of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937) was evaluated in vitro by using microdilution method against eight bacterial and eight fungal strains for the first time. The extracts were proven to be active in varying degrees against all the bacteria and fungi tested. O. rotunda methanol extract exhibited the highest antibacterial activity (minimum inhibitory concentration (MIC) 7.5-15.0 ?g/mL and minimum bactericidal concentration 15-30 ?g/mL), while its acetone extract exhibited the most promising antifungal activity (MIC 7.5-45.0 ?g/mL and minimum fungicidal concentration 15-60 ?g/mL). The extracts were more effective against the bacteria and fungi screened compared with the positive controls (streptomycin and ampicillin for bacteria and bifonazole and ketoconazole for fungi, respectively). According to the experimental data obtained, this deepwater sponge species may be considered as a gold mine of new antimicrobial substances with significant and broad-range activity. PMID:24804931

Pejin, Boris; Talevski, Aleksandra; Ciric, Ana; Glamoclija, Jasmina; Nikolic, Milos; Talevski, Trajce; Sokovic, Marina

2014-01-01

315

Antimicrobial activity of some Pacific Northwest woods against anaerobic bacteria and yeast.  

PubMed

Extracts of woods commonly used for animal bedding were tested for antimicrobial activity. Essential oils from Alaska cedar (Chamaecyparis nootkatensis), western juniper (Juniperus occidentalis) and old growth Douglas fir (Pseudotsuga menziesii) as well as methanol extracts of wood from these trees plus western red cedar (Thuja plicata) and ponderosa pine (Pinus ponderosa) were tested for antimicrobial activity against anaerobic bacteria and yeast. The test microbes included Fusobacterium necrophorum, Clostridium perfringens, Actinomyces bovis and Candida albicans which are common to foot diseases and other infections in animals. The essential oils and methanol extracts were tested using a standardized broth assay. Only extracts of Alaska cedar and western juniper showed significant antimicrobial activity against each of the microbes tested. The essential oil of Douglas fir did show antimicrobial activity against A. bovis at the concentrations tested. The methanol extracts of the heartwood of Douglas fir and the sapwood of ponderosa pine showed no antimicrobial activity. The major chemical components of western juniper (cedrol and alpha- and beta-cedrene) and Alaska cedar (nootkatin) were also tested. In western juniper, alpha- and beta-cedrene were found to be active components. Nootkatin showed activity only against C. albicans. The inhibitory activity in Alaska cedar oil was high enough to justify further efforts to define the other chemical components responsible for the antimicrobial activity. PMID:11746838

Johnston, W H; Karchesy, J J; Constantine, G H; Craig, A M

2001-11-01

316

Effect of naturally occurring antimicrobials and chemical preservatives on the growth of Aspergillus Parasiticus  

Microsoft Academic Search

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\\u000a guaiacol, vanillin, anethol, potassium sorbate and sorbic acid). The results demonstrate that colony diameter (mm) exhibited\\u000a a constant increase with time (zero order kinetics) for all

Prathesha Pillai; K. Ramaswamy

317

Functional Divergence among Silkworm Antimicrobial Peptide Paralogs by the Activities of Recombinant Proteins and the Induced Expression Profiles  

PubMed Central

Antimicrobial peptides are small-molecule proteins that are usually encoded by multiple-gene families. They play crucial roles in the innate immune response, but reports on the functional divergence of antimicrobial peptide gene families are rare. In this study, 14 paralogs of antimicrobial peptides belonging to cecropin, moricin and gloverin families were recombinantly expressed in pET expression systems. By antimicrobial activity tests, peptides representing paralogs in the same family of cecropin and moricin families, displayed remarkable differences against 10 tested bacteria. The evolutionary rates were relatively fast in the two families, which presented obvious functional divergence among paralogs of each family. Four peptides of gloverin family had similar antimicrobial spectrum and activity against tested bacteria. The gloverin family showed similar antimicrobial function and slow evolutionary rates. By induced transcriptional activity, genes encoding active antimicrobial peptides were upregulated at obviously different levels when silkworm pupae were infected by three types of microbes. Association analysis of antimicrobial activities and induced transcriptional activities indicated that the antimicrobial activities might be positively correlated with induced transcriptional activities in the cecropin and moricin families. These results suggest that representative BmcecB6, BmcecD and Bmmor as the major effector genes have broad antimicrobial spectrum, strong antimicrobial activity and high microbe-induced expression among each family and maybe play crucial roles in eliminating microbial infection. PMID:21479226

Ye, Mingqiang; Deng, Xiaojuan; Yi, Huiyu; Huang, Yadong; Tan, Xiang; Han, Dong; Wang, Bo; Xiang, Zhonghuai; Cao, Yang; Xia, Qingyou

2011-01-01

318

Seasonal variations of antimicrobial activity and chemical composition of essential oils extracted from three Citrus limon L. Burm. cultivars.  

PubMed

In order to investigate the seasonal variations of antimicrobial properties and chemical composition of essential oils (EOs), three different cultivars of Citrus limon L. Burm. spp. (Femminello Santa Teresa, Monachello and Femminello Continella) were collected at 6-week intervals, from December 2012 to April 2013, for a total of four harvests. The EOs were extracted from lemon peel by hydro-distillation. The antimicrobial activity, tested by paper disc diffusion method, was evaluated against common food-related pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica and Enterobacter spp.). EOs were more effective against Gram-positive than Gram-negative bacteria at each collection time, but a strong strain dependence was evidenced. Monachello EOs showed the highest inhibition power. The chemical characterisation of the EOs performed by gas chromatography/mass spectrometry identified from 36 to 42 molecules. The chemical difference registered among samples and seasons may explain the different antimicrobial efficacies recorded. PMID:24443967

Settanni, L; Randazzo, W; Palazzolo, E; Moschetti, M; Aleo, A; Guarrasi, V; Mammina, C; San Biagio, P L; Marra, F P; Moschetti, G; Germanà, M A

2014-01-01

319

The essential oil of Senecio graveolens (Compositae): chemical composition and antimicrobial activity tests.  

PubMed

The chemical composition of the essential oil obtained from Senecio graveolens (Compositae) was analyzed by GLC-MS and the components identified were: isovaleraldehyde, alpha-pinene, alpha-phellandrene, alpha-terpinene, p-cymene, sabinene, gamma-terpinene, 1-methyl-4-isopropenylbenzene, terpinolene, terpinen-4-ol, piperitenone, alpha- and beta-eudesmol. The investigation by the agar-well diffusion method of the antimicrobial activity of the essential oil proved that it has antibacterial effects on Micrococcus luteus ATCC 9341, oxacillin-sensitive and oxacillin-resistant Staphylococcus aureus, as well as antifungal effects on clinically isolated Candida albicans. The minimal inhibitory concentration (MIC) values for M. luteus, oxacillin-sensitive S. aureus and C. albicans were 8.73, 10.91 and 2.13 x 10(-2) mg/ml, respectively. The antimicrobial activity related to known antibiotics was calculated. These results would be compatible with a potential concentration-dependent selectivity of antifungal effect of S. graveolens essential oil. Minimal bactericidal concentration (MBC) is above 87.3 mg/ml. Thus the MBC:MIC ratio would be clearly higher than 1 (above 8), indicating a bacteriostatic effect of the essential oil. PMID:10432213

Pérez, C; Agnese, A M; Cabrera, J L

1999-07-01

320

Investigation of antimicrobial activity of photothermal therapeutic gold/copper sulfide core/shell nanoparticles to bacterial spores and cells  

PubMed Central

Background Au/CuS core/shell nanoparticles (NPs) were designed as a new type of transducer agent for photothermal therapy (PTT), with attractive features of easy preparation, low cost and small size for targeting. This paper studied for the first time the intrinsic antimicrobial activity of Au/CuS NPs to B. anthracis spores and cells in addition to its PTT effect. Results It was found that Au/CuS NPs were highly efficient in inactivating B. anthracis cells, but not effective to the spores. Treatment with NPs at ~0.83 ?M for 30 min achieved a 7 log reduction in viable cells. The antimicrobial effect was both NPs concentration and treatment time dependent. SEM imaging and the efflux of DNA test demonstrated the damage of cell membrane after NPs treatment, yet further research is necessary to fully understand the precise inactivation mechanism. Conclusions The Au/CuS NPs had strong antimicrobial activity to B. anthracis cells, which showed a great potential to be an effective antimicrobial agent to bacterial cells. PMID:24963345

2014-01-01

321

Short communication: Combined antimicrobial activity of reuterin and diacetyl against foodborne pathogens.  

PubMed

Reuterin (?-hydroxypropionialdehyde) is a broad-spectrum antimicrobial substance produced by some strains of Lactobacillus reuteri during anaerobic fermentation of glycerol. Some of these strains are able to survive and produce reuterin in cheese and yogurt when added as adjuncts to the starter. Similarly, in fermented dairy foods, other inhibitory compounds such as lactic acid and diacetyl are produced during fermentation. In this work, we studied the combined effect of reuterin and diacetyl under different pH conditions against Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. Results from agar spot assays showed that the antimicrobial activity of reuterin-producing strains against the gram-negative bacteria tested was enhanced as the concentration of diacetyl increased to 50 mg/kg, and was higher under acidic conditions (pH 5.0) for the 3 pathogenic strains. The combination of reuterin and diacetyl had an additive effect against L. monocytogenes only at diacetyl concentrations of 50 mg/kg and pH 5.0. In addition, growth kinetics studies showed that the combination of 1 activity unit (AU)/mL of reuterin with 100mg/kg diacetyl increased the lag time of the 3 pathogens. In milk, synergistic antimicrobial activity was observed with the combination of 1 AU/mL reuterin and 50 or 100 mg/kg of diacetyl on the gram-negative strains tested, and with 1 AU/mL reuterin and 100 mg/kg of diacetyl on L. monocytogenes. The greatest inhibition of the 3 pathogens was achieved in acidified milk at pH 5.0 with reuterin (1 AU/mL) and diacetyl (100 mg/kg). Based on these results, the combination of reuterin and diacetyl in acidified dairy products could be a promising strategy to control food pathogens in these products. PMID:25087026

Langa, S; Martín-Cabrejas, I; Montiel, R; Landete, J M; Medina, M; Arqués, J L

2014-10-01

322

Altered activity and physicochemical properties of short cationic antimicrobial peptides by incorporation of arginine analogues.  

PubMed

The incorporation of nongenetically encoded amino acids is a well established strategy to alter the behavior of several types of promising cationic antimicrobial peptides. Generally, these elements have been improved mimics of the hydrophobic amino acids yielding peptides with increased stability and potency. In this initial study, the effect of systematic replacement of Arg in a well-defined moderately antimicrobial tripeptide library is described. It is shown that the arginine analogues need to display a strong basicity to produce active peptides. It is further revealed that the hydrophobic units needed for activity in these peptides can be effectively incorporated in the direct vicinity of the cationic charge to produce compounds with improved antibacterial properties. A well-defined facial amphiphilic structure, which remains intact upon introduction of hydrophobic elements in the cationic side chains, is seen for the majority of the tested peptides. Microcalorimetric studies revealed a peptide binding to large anionic unilamellar vesicles (LUVs) mimicking the Gram-positive bacterial membrane as well as a potentially competitive binding to human serum albumin in the low- to mid-micromolar range. No considerable alterations in binding to either albumin or the LUVs were seen for the analogue containing peptides. A neutral LUV mimicking the eukaryotic cell membrane showed no significant binding to any of the peptides. The oral absorption of this class of short lactoferricin based peptides was investigated for the first time and revealed that incorporation of weaker bases than Arg produced peptides with much improved permeability in a recently developed permeation model, the phospholipid vesicle based barrier assay. Collectively, the results presented here show that there is ample room to toggle the activity and physical properties of short cationic antimicrobial peptides by incorporation of arginine analogues. PMID:19341291

Svenson, Johan; Karstad, Rasmus; Flaten, Gøril E; Brandsdal, Bjørn-Olav; Brandl, Martin; Svendsen, John S

2009-01-01

323

Antimicrobial activity of essential oils against Staphylococcus aureus biofilms.  

PubMed

The present study was aimed to evaluate the potential of essential oils to remove the foodborne pathogen Staphylococcus aureus from food-processing facilities. The effectiveness of 19 essential oils against planktonic cells of S. aureus was firstly assessed by minimal inhibitory concentration. Planktonic cells showed a wide variability in resistance to essential oils, with thyme oil as the most effective, followed by lemongrass oil and then vetiver oil. The eight essential oils most effective against planktonic cells were subsequently tested against 48-h-old biofilms formed on stainless steel. All essential oils reduced significantly (p?effective, but high concentrations were needed to achieve logarithmic reductions over 4 log CFU/cm(2) after 30?min exposure. Alternatively, the use of sub-lethal doses of thyme oil allowed to slow down biofilm formation and to enhance the efficiency of thyme oil and benzalkonium chloride against biofilms. However, some cellular adaptation to thyme oil was detected. Therefore, essential oil-based treatments should be based on the rotation and combination of different essential oils or with other biocides to prevent the emergence of antimicrobial-resistant strains. PMID:25280938

Vázquez-Sánchez, Daniel; Cabo, Marta L; Rodríguez-Herrera, Juan J

2014-10-01

324

Endophytic fungi isolated from wheat (Triticum durum Desf.): evaluation of their antimicrobial activity, antioxidant activity and host growth promotion.  

PubMed

The emergence of antibiotic-resistant micro-organisms calls for inventive research and development strategies. The screening for antimicrobial compounds from endophytes is a promising way to meet the increasing threat of drug-resistant strains of human and plant pathogens. Endophytes may be defined as "microbes that colonize living, internal tissues of plants without causing any immediate, overt negative effects". Endophytes are relatively unstudied as potential sources of novel natural products for exploitation in medicine, agriculture, and industry. The purpose of this study was to evaluate several isolated fungi from wheat (Triticum durum Desf.) Mohamed Ben Bachir variety and to select endophytic fungi for further evaluation of its antimicrobial, antioxidant activities and host growth promotion. A total of 20 endophytic fungi have been isolated. Antimicrobial activity was evaluated for crude ethyl acetate extracts using an agar diffusion assay. All extracts showed inhibitory activity on at least one or more pathogenic microorganism, with an average zone of inhibition varied between 7 mm to 25 mm, a large zone of 23 and 25mm against candida albicans and Escherichia coli respectively. The antioxidant capacity of the extracts was evaluated by beta-carotene/linoleic acid assay. Results showed that 70% of these extracts have antioxidant activity, exhibiting 50, 57% to 78, 96% inhibitions. While 30% from them, their inhibitory activity for oxidation of linoleic acid Were less than 50%. Growth promotion ability of these endophytes was tested on seed germination among ten isolates tested, two isolates showed significant growth promotion effects on wheat seeds. From the present work we can conclude that these microorganisms could be promising source of bioactive compounds, growth promotion and warrant further study. PMID:23878980

Harzallah, Daoud; Sadrati, Nouari; Zerroug, Amina; Dahamna, Saliha; Bouharati, Saddek

2012-01-01

325

Antimicrobial activity of Bauhinia tomentosa and Bauhinia vahlii roots  

PubMed Central

The hexane, ethylacetate and methanol extracts from Bauhinia tomentosa and Bauhinia vahlii roots were tested for their antimicrobial activity against Gram-positive bacteria (four strains), Gram-negative bacteria (three strains) and three fungi strains using microdilution methods, for the determination of minimal inhibition concentration (MIC) and the minimal microbicidal concentration (MMC). The MIC values of hexane extracts of B. tomentosa and B. vahlii roots were more than 250 µg/ml. The MIC values of ethylacetate and methanol extracts of B. tomentosa roots varied from 7.81 to 31.25 µg/ml and 31.25 to 62.50 µg/ml, respectively. The MIC values of ethylacetate and methanol extracts of B. vahlii roots varied from 15.63 to 62.5 µg/ml and 62.5 to 250 µg/ml, respectively. MMC values obtained are two times greater than the corresponding MIC values. The activities of ethylacetate extracts are attributed to the presence of flavonoids and that of methanol extracts are attributed to the presence of tannins. PMID:20931080

Dugasani, Swarnalatha; Balijepalli, Madhu Katyayani; Tandra, Satyanarayana; Pichika, Mallikarjuna Rao

2010-01-01

326

Synthesis, characterization and antimicrobial activity of some novel benzimidazole derivatives  

PubMed Central

A series of novel N-((1H-benzoimidazol-1-yl) methyl)-4-(1-phenyl-5-substituted-4, 5-dihydro-1-benzoimidazol-1-yl) methyl)-4-(1-phenyl-5-substituted-4, 5-dihydro-1H-pyrazol-3-yl) benzenamine were synthesized by treating various 1-(4-((1H-benzoimidazol-1-yl) methylamino) phenyl)-3-substitutedprop-2-en-1-one with phenyl hydrazine in the presence of sodium acetate through a simple ring closure reaction. The starting material, 1-(4-((1H-benzoimidazol-1-yl) methylamino) phenyl)-3-substitutedprop-2-en-1-one,-benzoimidazol-1-yl) methylamino) phenyl)-3-substitutedprop-2-en-1-one, was synthesized from o-phenylenediamine by a multistep synthesis. All the synthesized compounds were characterized by spectroscopic means and elemental analyses. The title compounds were investigated for in vitro antibacterial and antifungal properties against some human pathogenic microorganisms by employing the agar streak dilution method using Ciprofloxacin and Ketoconazole as standard drugs. All title compounds showed activity against the entire strains of microorganism. Structural activity relationship studies reveal that compounds possessing an electron-withdrawing group display better activity than the compounds containing electron-donating groups, whereas the unsubstituted derivatives display moderate activity. Based on the results obtained, N-((1H-benzoimidazol-1-yl) methyl)-4-(1-phenyl-5-(4-(trifluoromethyl) phenyl)-4,5-dihydro-1H-pyrazol-3-yl) benzenamine 5i was found to be very active compared with the rest of the compounds and standard drugs that were subjected to antimicrobial assay. PMID:24696814

Krishnanjaneyulu, Immadisetty Sri; Saravanan, Govindaraj; Vamsi, Janga; Supriya, Pamidipamula; Bhavana, Jarugula Udaya; Sunil Kumar, Mittineni Venkata

2014-01-01

327

Antimicrobial Activity of Selected Phytochemicals against Escherichia coli and Staphylococcus aureus and Their Biofilms  

PubMed Central

Abstract Bacteria can be resistant to multiple antibiotics and we are fast approaching a time when antibiotics will not work on some bacterial infections. New antimicrobial compounds are urgently necessary. Plants are considered the greatest source to obtain new antimicrobials. This study aimed to assess the antimicrobial activity of four phytochemicals—7-hydroxycoumarin (7-HC), indole-3-carbinol (I3C), salicylic acid (SA) and saponin (SP)—against Escherichia coli and Staphylococcus aureus, either as planktonic cells or as biofilms. These bacteria are commonly found in hospital-acquired infections. Some aspects on the phytochemicals mode of action, including surface charge, hydrophobicity, motility and quorum-sensing inhibition (QSI) were investigated. In addition, the phytochemicals were combined with three antibiotics in order to assess any synergistic effect. 7-HC and I3C were the most effective phytochemicals against E. coli and S. aureus. Both phytochemicals affected the motility and quorum-sensing (QS) activity, which means that they can play an important role in the interference of cell-cell interactions and in biofilm formation and control. However, total biofilm removal was not achieved with any of the selected phytochemicals. Dual combinations between tetracycline (TET), erythromycin (ERY) and ciprofloxacin (CIP) and I3C produced synergistic effects against S. aureus resistant strains. The overall results demonstrates the potential of phytochemicals to control the growth of E. coli and S. aureus in both planktonic and biofilm states. In addition, the phytochemicals demonstrated the potential to act synergistically with antibiotics, contributing to the recycling of old antibiotics that were once considered ineffective due to resistance problems. PMID:25437810

Monte, Joana; Abreu, Ana C.; Borges, Anabela; Simões, Lúcia Chaves; Simões, Manuel

2014-01-01

328

Chemical Composition and Antimicrobial Activity of the Essential Oil of Kumquat (Fortunella crassifolia Swingle) Peel  

PubMed Central

The aim of this study was to determine the main constituents of the essential oil isolated from Fortunella crassifolia Swingle peel by hydro-distillation, and to test the efficacy of the essential oil on antimicrobial activity. Twenty-five components, representing 92.36% of the total oil, were identified by GC-MS analysis. The essential oil showed potent antimicrobial activity against both Gram-negative (E. coli and S. typhimurium) and Gram-positive (S. aureus, B. cereus, B. subtilis, L. bulgaricus, and B. laterosporus) bacteria, together with a remarkable antifungal activity against C. albicans. In a food model of beef extract, the essential oil was observed to possess an effective capacity to control the total counts of viable bacteria. Furthermore, the essential oil showed strongly detrimental effects on the growth and morphological structure of the tested bacteria. It was suggested that the essential oil from Fortunella crassifolia Swingle peel might be used as a natural food preservative against bacteria or fungus in the food industry. PMID:22489157

Wang, Yong-Wei; Zeng, Wei-Cai; Xu, Pei-Yu; Lan, Ya-Jia; Zhu, Rui-Xue; Zhong, Kai; Huang, Yi-Na; Gao, Hong

2012-01-01

329

Antimicrobial effects of essential oils in combination with chlorhexidine digluconate.  

PubMed

The aim of the present study was to compare antimicrobial effects of essential oils alone and in combination with chlorhexidine digluconate against planktonic and biofilm cultures of Streptococcus mutans and Lactobacillus plantarum. The essential oils included cinnamon, tea-tree (Melaleuca alternifola), manuka (Leptospermum scoparium), Leptospermum morrisonii, arnica, eucalyptus, grapefruit, the essential oil mouthrinse Cool Mint Listerine and two of its components, menthol and thymol. Cinnamon exhibited the greatest antimicrobial potency (1.25-2.5 mg/ml). Manuka, L. morrisonii, tea-tree oils, and thymol also showed antimicrobial potency but to a lesser extent. The combination effect of the essential oil-chlorhexidine was greater against biofilm cultures of both S. mutans and L. plantarum than against planktonic cultures. The amount of chlorhexidine required to achieve an equivalent growth inhibition against the biofilm cultures was reduced 4-10-fold in combination with cinnamon, manuka, L. morrisonii, thymol, and Listerine. We conclude that there may be a role for essential oils in the development of novel anticaries treatments. PMID:15943766

Filoche, S K; Soma, K; Sissons, C H

2005-08-01

330

Antimicrobial Activity of a Chelatable Poly(Arginyl-Histidine) Produced by the Ergot Fungus Verticillium kibiense  

PubMed Central

We have recently developed a convenient method of screening a broad range of microorganisms that produce ?-poly-l-lysine (M. Nishikawa and K. Ogawa, Appl. Environ. Microbiol. 68:3575-3581, 2002). Using this method, we found an ergot fungus that secretes a charged polypeptide other than ?-poly-l-lysine. It was identified as a new species on the basis of its 28S rRNA sequence and was named Verticillium kibiense (formerly Epichloe kibiensis). Peptide sequencing and mass spectrometry revealed that the polypeptide is a linear peptide composed of repeated units of arginyl-histidine. The numbers of repeated units were in most cases five and in some cases four or six. This peptide showed activity against a broad range of bacteria and fungi but lost its activity under conditions of high ionic strength. Zinc and copper ions specifically changed the circular dichroism spectra of the peptide and restored the antimicrobial activity from abrogation under high ionic conditions, although these ions had no reinforcing effect on antimicrobial activity when they were added to solutions at a low ionic strength. The peptide labeled with fluorescein was able to permeate the cell membranes of target microbes, but its ability to permeate cell membranes decreased under conditions of high ionic strength. This decreased ability was partially recovered specifically by the addition of zinc and copper ions. These results indicate that poly(arginyl-histidine) is a cationic polypeptide characterized by specific metal binding and resistance to salts. PMID:14693544

Nishikawa, Masanobu; Ogawa, Ken'ichi

2004-01-01

331

Synthesis of lipophilic tyrosyl esters derivatives and assessment of their antimicrobial and antileishmania activities  

PubMed Central

Background Preparation of tyrosyl lipophilic derivatives was carried out as a response to the food, cosmetic and pharmaceutical industries' increasing demand for new lipophilic antioxidants. Results A large series of tyrosyl esters (TyC2 to TyC18:1) with increasing lipophilicity was synthesized in a good yield using lipase from Candida antarctica (Novozyme 435). Spectroscopic analyses of purified esters showed that the tyrosol was esterified on the primary hydroxyl group. Synthetized compounds were evaluated for either their antimicrobial activity, by both diffusion well and minimal inhibition concentration (MIC) methods, or their antileishmanial activity against Leishmania major and Leishmania infantum parasite species. Among all the tested compounds, our results showed that only TyC8, TyC10 and TyC12 exhibited antibacterial and antileishmanial activities. When MIC and IC50 values were plotted against the acyl chain length of each tyrosyl derivative, TyC10 showed a parabolic shape with a minimum value. This nonlinear dependency with the increase of the chain length indicates that biological activities are probably associated to the surfactant effectiveness of lipophilic derivatives. Conclusion These results open up potential applications to use medium tyrosyl derivatives surfactants, antioxidants, antimicrobial and antileishmanial compounds in cosmetic, food and pharmaceutical industries. PMID:22264330

2012-01-01

332

Design, synthesis, antimicrobial activity and molecular modeling studies of novel benzofuroxan derivatives against Staphylococcus aureus.  

PubMed

Molecular modification is a quite promising strategy in the design and development of drug analogs with better bioavailability, higher intrinsic activity and less toxicity. In the search of new leads with potential antimicrobial activity, a new series of 14 4-substituted [N'-(benzofuroxan-5-yl)methylene]benzohydrazides, nifuroxazide derivatives, were synthesized and tested against standard and multidrug-resistant Staphylococcus aureus strains. The selection of the substituent groups was based on physicochemical properties, such as hydrophobicity and electronic effect. These properties were also evaluated through the lipophilic and electrostatic potential maps, respectively, considering the compounds with better biological profile. Twelve compounds exhibited similar bacteriostatic activity against standard and multidrug-resistant strains. The most active compound was the 4-CF(3) substituted derivative, which presented a minimum inhibitory concentration (MIC) value of 14.6-13.1 microg/mL, and a ClogP value of 1.87. The results highlight the benzofuroxan derivatives as potential leads for designing new future antimicrobial drug candidates. PMID:19324556

Jorge, Salomão Dória; Masunari, Andrea; Rangel-Yagui, Carlota Oliveira; Pasqualoto, Kerly Fernanda Mesquita; Tavares, Leoberto Costa

2009-04-15

333

Myrtus communis essential oil: chemical composition and antimicrobial activities against food spoilage pathogens.  

PubMed

Myrtus communis is a typical plant of the Mediterranean area, which is mainly used as animal and human food and, in folk medicine, for treating some disorders. In the present study, we evaluated in vitro antibacterial and antifungal properties of the essential oils of Myrtus communis (McEO), as well as its phytochemical composition. The GC/MS analysis of the essential oil revealed 17 compounds. Myrtenyl acetate (20.75%), 1,8-cineol (16.55%), ?-pinene (15.59%), linalool (13.30%), limonene (8.94%), linalyl acetate (3.67%), geranyl acetate (2.99%), and ?-terpineol (2.88%) were the major components. The antimicrobial activity of the essential oil was also investigated on several microorganisms. The inhibition zones and minimal inhibitory concentration (MIC) values of bacterial strains were in the range of 16-28?mm and 0.078-2.5?mg/ml, respectively. The inhibitory activity of the McEO against Gram-positive bacteria was significantly higher than against Gram-negative. It also exhibited remarkable activity against several fungal strains. The investigation of the mode of action of the McEO by the time-kill curve against Listeria monocytogenes (food isolate) showed a drastic bactericidal effect after 5?min using a concentration of 312??g/ml. These results evidence that the McEO possesses antimicrobial properties, and it is, therefore, a potential source for active ingredients for food and pharmaceutical industries. PMID:24706627

Ben Hsouna, Anis; Hamdi, Naceur; Miladi, Ramzi; Abdelkafi, Slim

2014-04-01

334

PLASMOSE - antimicrobial effects of modular atmospheric plasma sources.  

PubMed

The technological potential of non-thermal plasmas for the antimicrobial treatment of heat sensitive materials is well known and has been documented in a great number of research activities, but the realisation of industrial plasma-based decontamination processes remains a great challenge. One of the reasons for this situation is the fact that an antimicrobial treatment process needs to consider all properties of the product to be treated as well as the requirements of the complete procedure, e.g. a reprocessing of a medical instrument. The aim of the BMBF-funded network project PLASMOSE is to demonstrate the applicability of plasma-based processes for the antimicrobial treatment on selected, heat sensitive products. Modular and selective plasma sources, driven at atmospheric pressure are used. This basic approach shall combine the technological advantages of atmospheric pressure plasmas (avoidance of vacuum devices and batch processing) with the flexibility and handling properties of modular devices. TWO DIFFERENT OBJECTIVES WERE SELECTED: the outer surface treatment of medical products and the treatment of hollow packaging for pharmaceutical products. The outer surface treatment of medical products, in particular catheters for intracardial electrophysiological studies, is investigated by means of RF-driven plasma jets in argon. Due to its compact design they are predestined for modularisation and can be adapted to nearly any complex 3-dimensional structure as given by the medical products. The realisation of an antimicrobial treatment process of hollow packaging for pharmaceutical products has quite different demands. Such a process is needed to be implemented in in-line filling procedures and to work without additional process gases. The idea is to use an atmospheric air, microwave-driven self propagating discharge. The plasma process is optimized for the decontamination of 200 ml bottles by field simulation studies combined with optical emissions spectroscopy and micro-biological tests. PMID:20204116

Ehlbeck, Jörg; Brandenburg, Ronny; von Woedtke, Thomas; Krohmann, Udo; Stieber, Manfred; Weltmann, Klaus-Dieter

2008-01-01

335

PLASMOSE - antimicrobial effects of modular atmospheric plasma sources  

PubMed Central

The technological potential of non-thermal plasmas for the antimicrobial treatment of heat sensitive materials is well known and has been documented in a great number of research activities, but the realisation of industrial plasma-based decontamination processes remains a great challenge. One of the reasons for this situation is the fact that an antimicrobial treatment process needs to consider all properties of the product to be treated as well as the requirements of the complete procedure, e.g. a reprocessing of a medical instrument. The aim of the BMBF-funded network project PLASMOSE is to demonstrate the applicability of plasma-based processes for the antimicrobial treatment on selected, heat sensitive products. Modular and selective plasma sources, driven at atmospheric pressure are used. This basic approach shall combine the technological advantages of atmospheric pressure plasmas (avoidance of vacuum devices and batch processing) with the flexibility and handling properties of modular devices. Two different objectives were selected: the outer surface treatment of medical products and the treatment of hollow packaging for pharmaceutical products. The outer surface treatment of medical products, in particular catheters for intracardial electrophysiological studies, is investigated by means of RF-driven plasma jets in argon. Due to its compact design they are predestined for modularisation and can be adapted to nearly any complex 3-dimensional structure as given by the medical products. The realisation of an antimicrobial treatment process of hollow packaging for pharmaceutical products has quite different demands. Such a process is needed to be implemented in in-line filling procedures and to work without additional process gases. The idea is to use an atmospheric air, microwave-driven self propagating discharge. The plasma process is optimized for the decontamination of 200 ml bottles by field simulation studies combined with optical emissions spectroscopy and micro-biological tests. PMID:20204116

Ehlbeck, Jörg; Brandenburg, Ronny; von Woedtke, Thomas; Krohmann, Udo; Stieber, Manfred; Weltmann, Klaus-Dieter

2008-01-01

336

Surface-Bonded Antimicrobial Activity of an Organosilicon Quaternary Ammonium Chloride  

PubMed Central

The hydrolysis product of 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride exhibited antimicrobial activity against a broad range of microorganisms while chemically bonded to a variety of surfaces. The chemical was not removed from surfaces by repeated washing with water, and its antimicrobial activity could not be attributed to a slow release of the chemical, but rather to the surface-bonded chemical. Images PMID:4650597

Isquith, A. J.; Abbott, E. A.; Walters, P. A.

1972-01-01

337

Antimicrobial and anti-inflammatory activity of chitosan-alginate nanoparticles: a targeted therapy for cutaneous pathogens  

PubMed Central

Advances in nanotechnology have demonstrated potential application of nanoparticles for effective and targeted drug delivery. Here, we investigated the antimicrobial and immunological properties and the feasibility of using nanoparticles to deliver antimicrobial agents to treat a cutaneous pathogen. Nanoparticles synthesized with chitosan and alginate demonstrated a direct antimicrobial activity in vitro against Propionibacterium acnes, the bacterium linked to the pathogenesis of acne. By electron microscopy imaging, chitosan-alginate nanoparticles were found to induce disruption of the P. acnes cell membrane, providing a mechanism for the bactericidal effect. The chitosan-alginate nanoparticles also exhibited anti-inflammatory properties as they inhibited P. acnes induced inflammatory cytokine production in human monocytes and keratinocytes. Furthermore, benzoyl peroxide, a commonly used anti-acne drug, was effectively encapsulated in the chitosan-alginate nanoparticles and demonstrated superior antimicrobial activity against P. acnes compared to benzoyl peroxide alone while demonstrating less toxicity to eukaryotic cells. Together, these data suggest the potential utility of topical delivery of chitosan-alginate nanoparticle encapsulated drug therapy for the treatment of dermatologic conditions with infectious and inflammatory components. PMID:23190896

Friedman, Adam J; Phan, Jenny; Schairer, David; Champer, Jackson; Qin, Min; Pirouz, Aslan; Blecher, Karin; Oren, Ami; Liu, Phil; Modlin, Robert L; Kim, Jenny

2012-01-01

338

Sesquiterpene lactones from Centaurea zuccariniana and their antimicrobial activity.  

PubMed

Twenty-nine compounds were isolated from the aerial parts of the Greek plant C. zuccariniana DC. The structures of the isolated compounds were established by means of NMR- ((1) H,(1) H-COSY, (1) H,(13) C-HSQC, HMBC, NOESY, and ROESY) and mass-spectral analyses. These compounds comprise 13 sesquiterpene lactones, 14 flavonoids, two lignans, and one simple lactone. Among the isolated sesquiterpene lactones, three are new, namely one heliangolide, (1E,4Z)-15-hydroxy-8?-O-(4'-acetoxy-3'-hydroxy-2'-methylidenebutanoyl)-6?H,7?H-germacra-1,4,11(13)-trien-6,12-olide; and two eudesmanolides, 8?-(4',5'-diacetoxyangeloyl)sonchucarpolide and one unusual eudesmanolide with an oxygenated bridge linking C(1) and C(4), named zuccarinin. The main sesquiterpene lactones were malacitenolide, cnicin, and 4'-O-acetylcnicin. These results are in agreement with those obtained from the previously studied Greek Centaurea sp. belonging to the section Acrolophus (Cass.) DC.; this finding could be of chemotaxonomic significance for the genus Centaurea. The in vitro antimicrobial activities of the isolated new sesquiterpene lactones were against eight bacteria and eight fungal species. A 96-well microbioassay procedure for fast and easy evaluation of antibacterial and antifungal activities was applied to compare these compounds with commercial antibiotic and fungicide standards, and with previously isolated analogous sesquiterpene lactones tested by the same bioassay. All of the compounds tested showed moderate antibacterial, but significant antifungal activities; the present results corroborate with previous data, indicating that these types of compounds exhibit low or moderate antibacterial, but potent antifungal activities. The unusual eudesmanolide zuccarinin proved to be the most potent among the present tested sesquiterpene lactones, as well as among all previously tested eudesmanolides isolated from Greek Centaurea sp. PMID:23255452

Ciri?, Ana; Karioti, Anastasia; Koukoulitsa, Catherine; Sokovi?, Marina; Skaltsa, Helen

2012-12-01

339

Plant-based hydrocarbon esters from Tragia involucrata possess antimicrobial and anti-inflammatory activities.  

PubMed

Antimicrobial and anti-inflammatory activities of hydrocarbon esters obtained from Tragia involucrata were evaluated by disk-diffusion (250 µg/ml), and broth-dilution (500-7.8 µg/ml), methods against bacteria. Among the compounds, shellsol showed the most potent activity against Burkholderia pseudomallei (KHW), Aeromonas hydrophila, Staphylococcus aureus, Bacillus subtilis, Streptococcus pyogenes, Klebsiella pneumoniae, Proteus mirabilis, and Streptococcus pneumoniae. Interestingly, vinyl hexylether was active against food-spoilage bacteria (Bacillus cereus and Proteus vulgaris), 2, 4-methyl hexane also exerted antimicrobial activity against K. pneumoniae, S. pyogenes, B. pseudomallei, Alcaligens viscolactis, and Pseudomonas aeruginosa. 2-methylnonane and 2, 6-dimethyl heptane showed only weak activity. For example, shellsol showed bacteriostatic effect (MIC of 7.8 µg/ml) against A. hydrophila, vinyl hexylether (MIC of 15.6 µg/ml) against P. mirabilis, and 2, 4-methyl hexane (MIC of 31.25 µg/ml) on B. pseudomallei. Cytotoxic effects of compounds were assayed in human skin and monkey kidney cells (62.5-2000 µg/ml) by an XTT assay. The vinyl hexylether, 2, 4-dimethyl hexane and shellsol did not show any toxicity up to 1000 µg/ml concentrations. The 2-methylnonane and 2, 6-dimethyl heptane induced morphological changes (e.g. cell disintegration and lysis) of both cell types at a 2000 µg/ml. The vinyl hexylether, 2, 4-dimethyl hexane and shellsol were devoid of toxic effects; however, 2-methylnonane induced weight loss and severe necrosis as evidenced by histopathological and serum biochemical analysis in rats. Interestingly, shellsol showed the maximum inhibition of carrageenan-induced, paw oedema in rats. In conclusion, findings of this study clearly indicate that biologically active hydrocarbon esters, such as shellsol, vinyl hexylether, and 2, 4-dimethyl hexane isolated from T. involucrata, may effectively control the growth of certain food-borne and food-spoilage pathogens. PMID:23713670

Samy, Ramar Perumal; Sethi, Gautam; Chow, Vincent T K; Stiles, Bradley G

2013-04-01

340

The effects of postexercise feeding on saliva antimicrobial proteins.  

PubMed

The purpose of this study was to determine the effects of a carbohydrate (CHO) and protein (PRO) drink consumed immediately after endurance exercise on saliva antimicrobial proteins known to be important for host defense. Eleven male runners ran for 2 hr at 75% VO2max on 2 occasions and immediately postexercise were provided, in randomized order, either a placebo solution (CON) or a CHO-PRO solution containing 1.2 g CHO/kg body mass (BM) and 0.4 g PRO/kg BM (CHO-PRO). The solutions were flavor and volume equivalent (12 ml/kg BM). Saliva flow rate, lysozyme, ?-amylase, and secretory (S) IgA concentrations were determined from unstimulated saliva samples collected preexercise, immediately postexercise, and every 30 min until 180 min postexercise. CHO-PRO ingestion immediately postexercise resulted in a lower saliva flow rate than with CON at 30 and 60 min postexercise. Saliva lysozyme concentration increased immediately postexercise in both trials compared with preexercise (p< .05), and CHO-PRO ingestion immediately postexercise resulted in a higher saliva lysozyme concentration in the first hour of recovery than with CON (125% greater at 30 min, 94% greater at 60 min; p< .01). Saliva SIgA concentration decreased below preexercise concentrations 90-150 min postexercise (p< .001), with no effect of CHO-PRO. Saliva ?-amylase activity was unaffected by exercise or CHO-PRO refeeding. CHO-PRO refeeding did not alter the secretion rates of any saliva variables during recovery. In conclusion, immediate refeeding with CHO-PRO evoked a greater saliva lysozyme concentration during the first hour of recovery after prolonged exercise than ingestion of placebo but had minimal impact on saliva ?-amylase and SIgA responses. PMID:22693239

Costa, Ricardo J S; Fortes, Matthew B; Richardson, Katharine; Bilzon, James L J; Walsh, Neil P

2012-06-01

341

Poly-lysine peptidomimetics having potent antimicrobial activity without hemolytic activity.  

PubMed

Diversity of sequence and structure in naturally occurring antimicrobial peptides (AMPs) limits their intensive structure-activity relationship (SAR) study. In contrast, peptidomimetics have several advantages compared to naturally occurring peptide in terms of simple structure, convenient to analog synthesis, rapid elucidation of optimal physiochemical properties and low-cost synthesis. In search of short antimicrobial peptides using peptidomimetics, which provide facile access to identify the key factors involving in the destruction of pathogens through SAR study, a series of simple and short peptidomimetics consisting of multi-Lys residues and lipophilic moiety have been prepared and found to be active against several Gram-negative and Gram-positive bacteria containing methicillin-resistant Staphylococcus aureus (MRSA) without hemolytic activity. Based on the SAR studies, we found that hydrophobicity, +5 charges of multiple Lys residues, hydrocarbon tail lengths and cyclohexyl group were crucial for antimicrobial activity. Furthermore, membrane depolarization, dye leakage, inner membrane permeability and time-killing kinetics revealed that bacterial-killing mechanism of our peptidomimetics is different from the membrane-targeting AMPs (e. g. melittin and SMAP-29) and implied our peptidomimetics might kill bacteria via the intracellular-targeting mechanism as done by buforin-2. PMID:24961649

Ahn, Mija; Jacob, Binu; Gunasekaran, Pethaiah; Murugan, Ravichandran N; Ryu, Eun Kyoung; Lee, Ga-hyang; Hyun, Jae-Kyung; Cheong, Chaejoon; Kim, Nam-Hyung; Shin, Song Yub; Bang, Jeong Kyu

2014-09-01

342

Antimicrobial activity of the major components of the essential oil of Melaleuca alternifolia.  

PubMed

Tea tree oil, or the essential oil of Melaleuca alternifolia, is becoming increasingly popular as a naturally occurring antimicrobial agent. The antimicrobial activity of eight components of tea tree oil was evaluated using disc diffusion and broth microdilution methods. Attempts were also made to overcome methodological problems encountered with testing compounds which have limited solubility in aqueous media. After assessing media with and without solubilizing agents, the disc diffusion method was used to determine the susceptibility of a range of micro-organisms to 1,8-cineole, 1-terpinen-4-ol, rho-cymene, linalool, alpha-terpinene, gamma-terpinene, alpha-terpineol and terpinolene. While the disc diffusion method lacked reproducibility, it was considered useful as a procedure for screening for antimicrobial activity. Terpinen-4-ol was active against all the test organisms while rho-cymene demonstrated no antimicrobial activity. Linalool and alpha-terpineol were active against all organisms with the exception of Pseudomonas aeruginosa. Minimum inhibitory and minimum cidal concentrations of each component against Candida albicans, Escherichia coli and Staphylococcus aureus were determined using a broth microdilution method. Modifications to this method overcame solubility and turbidity problems associated with the oil components and allowed the antimicrobial activity of each of the components to be quantified reproducibly. There was reasonable agreement between minimum inhibitory concentrations and zones of inhibition. These results may have significant implications for the future development of tea tree oil as an antimicrobial agent. PMID:7730203

Carson, C F; Riley, T V

1995-03-01

343

A study of antimicrobial activity, acute toxicity and cytoprotective effect of a polyherbal extract in a rat ethanol-HCl gastric ulcer model  

PubMed Central

Background The decoction of the aerial parts of Rhynchosia recinosa (A.Rich.) Bak. [Fabaceae] is used in combination with the stem barks of Ozoroa insignis Del. (Anacardiaceae), Maytenus senegalensis (Lam.) Excell. [Celastraceae] Entada abyssinica Steud. ex A.Rich [Fabaceae] and Lannea schimperi (Hochst.)Engl. [Anacardiaceae] as a traditional remedy for managing peptic ulcers. However, the safety and efficacy of this polyherbal preparation has not been evaluated. This study reports on the phytochemical profile and some biological activities of the individual plant extracts and a combination of extracts of the five plants. Methods A mixture of 80% ethanol extracts of R. recinosa, O. insignis, M. senegalensis, E. abyssinica and L. schimperi at doses of 100, 200, 400 and 800 mg/kg body wt were evaluated for ability to protect Sprague Dawley rats from gastric ulceration by an ethanol-HCl mixture. Cytoprotective effect was assessed by comparison with a negative control group given 1% tween 80 in normal saline and a positive control group given 40 mg/kg body wt pantoprazole. The individual extracts and their combinations were also tested for antibacterial activity against four Gram negative bacteria; Escherichia coli (ATCC 25922), Salmonella typhi (NCTC 8385), Vibrio cholerae (clinical isolate), and Klebsiella pneumoniae (clinical isolate) using the microdilution method. In addition the extracts were evaluated for brine shrimp toxicity and acute toxicity in mice. Phytochemical tests were done using standard methods to determine the presence of tannins, saponins, steroids, cardiac glycosides, flavonoids, alkaloids and terpenoids in the individual plant extracts and in the mixed extract of the five plants. Results The combined ethanolic extracts of the 5 plants caused a dose-dependent protection against ethanol/HCl induced ulceration of rat gastric mucosa, reaching 81.7% mean protection as compared to 87.5% protection by 40 mg/kg body wt pantoprazole. Both the individual plant extracts and the mixed extracts of 5 plants exhibited weak to moderate antibacterial activity against four G-ve bacteria. Despite Ozoroa insignis being toxic to mice at doses above 1000 mg/kg body wt, the other plant extracts and the combined extract of the 5 plants were tolerated by mice up to 5000 mg/kg body wt. The brine shrimp test results showed the same pattern of toxicity with Ozoroa insignis being the most toxic (LC50?=?10.63 ?g/ml). Phytochemical tests showed that the combined extract of the five plants contained tannins, saponins, steroids, cardiac glycosides, flavonoids and terpenoids. Flavonoids, tannins and terpenoids are known to have antioxidant activity. Conclusion The combined extract of the five plants exhibited a dose-dependent protective activity in the rat ethanol-HCl gastric ulcer model. The extracts also exhibited weak antibacterial activity against four Gram negative bacteria and low acute toxicity in mice and brine shrimps. Although the results support claims by traditional healers who use a decoction of the five plants for treatment of peptic ulcers, more models of gastric ulceration and proper animal toxicity studies are needed to validate possible clinical use of the polyherbal extract. It is also evident that the doses of the crude extracts showing protection of the gastric mucosa are too large for realistic translation to direct clinical application, but further studies using bioassay guided fractionation are important to either identify more practical fractions or active compound/s. PMID:23031266

2012-01-01

344

Antimicrobial and cell-penetrating properties of penetratin analogs: effect of sequence and secondary structure.  

PubMed

Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well as octaarginine and different Tat sequences. The effects of peptide length, guanidinium content, and sequence of non-cationic residues were assessed in mammalian and bacterial cells. The arginine (Arg) content in the penetratin analogs was found to influence eukaryotic cell uptake efficiency, antimicrobial activity towards both Gram-positive and Gram-negative bacteria as well as eukaryotic cell viability. All examined analogs retained the ability to cross eukaryotic membranes giving rise to a distribution within the vacuolar apparatus. Interestingly, a series of shuffled analogs of penetratin with the cationic residues in conserved positions, attain the same ?-helical conformation as native penetratin in the presence of cholesterol-containing liposomes, while conformational differences were observed in the presence of highly anionic liposomes. While the antibacterial effect of the two groups of peptides was similar, the eukaryotic cellular uptake of the shuffled analogs was noticeably lower than for native penetratin. Moreover, a point substitution of Met to Leu in native penetratin had no influence on eukaryotic cellular uptake and antimicrobial effect, and only a minor effect on cytotoxicity, in contrast to the fact that the same substitution in the shuffled analog gave rise to reduced eukaryotic cellular uptake while increasing the antibacterial effect and cytotoxicity. PMID:23085001

Bahnsen, Jesper Søborg; Franzyk, Henrik; Sandberg-Schaal, Anne; Nielsen, Hanne Mørck

2013-02-01

345

Antimicrobial and antioxidant activities of clove essential oil and eugenyl acetate produced by enzymatic esterification.  

PubMed

This work reports the maximization of eugenyl acetate production by esterification of essential oil of clove in a solvent-free system using Novozym 435 as catalyst. The antimicrobial and antioxidant activities of clove essential oil and eugenyl acetate produced were determined. The conditions that maximized eugenyl acetate production were 60 °C, essential oil of clove to acetic anhydride ratio of 1:5, 150 rpm, and 10 wt% of enzyme, with a conversion of 99.87 %. A kinetic study was performed to assess the influence of substrates' molar ratio, enzyme concentration, and temperature on product yield. Results show that an excess of anhydride, enzyme concentration of 5.5 wt%, 50 °C, and essential oil of clove to acetic anhydride ratio of 1:5 afforded nearly a complete conversion after 2 h of reaction. Comparing the antibacterial activity of the essential oil of clove before and after esterification, we observed a decrease in the antimicrobial activity of eugenyl acetate, particularly with regard to minimum inhibitory concentration (MIC). Both eugenyl acetate and clove essential oil were most effective to the gram-negative than gram-positive bacteria group. The results showed a high antioxidant potential for essential oil before and particularly after the esterification reaction thus becoming an option for the formulation of new antioxidant products. PMID:25104002

Vanin, Adriana B; Orlando, Tainara; Piazza, Suelen P; Puton, Bruna M S; Cansian, Rogério L; Oliveira, Debora; Paroul, Natalia

2014-10-01

346

Antimicrobial activity of Tunisian quince (Cydonia oblonga Miller) pulp and peel polyphenolic extracts.  

PubMed

Quince (Cydonia oblonga Miller) fruit aqueous acetone extracts were evaluated. High-performance liquid chromatography-diode array detection and electrospray ionization-mass spectrometry were used for the identification and quantification of the phenolic compounds. The total phenolic content of the pulp and peel parts ranged from 37 to 47 and 105 to 157 mg/100 g of fresh weight, respectively. Chlorogenic acid (5-O-caffeoylquinic acid) was the most abundant phenolic compound in the pulp (37%), whereas rutin (quercetin 3-O-rutinoside) was the main one in the peel (36%). The radical scavenging potential of the extracts was determined and compared with that of synthetic antioxidants. The stronger properties corresponded to those obtained from peel material with a 70-80% inhibitory effect on DPPH radicals. The antimicrobial activity of the extracts against different microorganism strains was also investigated. Quince peel extract was the most active for inhibiting bacteria growth with minimum inhibitory and bactericide concentrations in the range of 102-5 x 103 microg polyphenol/mL. It seems that chlorogenic acid acts in synergism with other components of the extracts to exhibit their total antimicrobial activities. PMID:17263500

Fattouch, Sami; Caboni, Pierluigi; Coroneo, Valentina; Tuberoso, Carlo I G; Angioni, Alberto; Dessi, Sandro; Marzouki, Nejib; Cabras, Paolo

2007-02-01

347

Biosynthesis of silver nanoparticles using Alternanthera sessilis (Linn.) extract and their antimicrobial, antioxidant activities.  

PubMed

The present work focuses the use of the aqueous extract of Alternanthera sessilis Linn. (Amaranthaceae) in producing silver nanoparticles (AgNPs) from silver nitrate aqueous. Phytochemical analysis of the extract revealed the presence of alkaloid, tannins, ascorbic acid, carbohydrates and proteins and they serve as effective reducing and capping agents for converting silver nitrate into nanoparticles. The synthesized silver nanoparticles (AgNPs) were also tested for proteins and ascorbic acid. Its pH was also determined (5.63). The AgNPs obtained was characterized by UV-vis spectroscopy, FT-IR spectroscopy, SEM, Zeta sizer and TG-DSC. SEM images which revealed the presence of various shapes and sizes. FT-IR spectrum showed the AgNPs having a coating of proteins indicating a dual role of bio-molecules responsible for capping and efficient stabilization of the silver nanoparticles. Presence of impurities and melting point profile were screened by TG-DSC analyzer. AgNPs were synthesized from the silver nitrate through the reducing power of ascorbic acid present in A. sessilis leaves. In this study, we also investigated antimicrobial and antioxidant activity of green synthesized AgNPs. The antimicrobial activity is investigated by Bauer et al.'s method. Antioxidant activity was done by DPPH method. PMID:23006568

Niraimathi, K L; Sudha, V; Lavanya, R; Brindha, P

2013-02-01

348

Laurel leaf extracts for honeybee pest and disease management: antimicrobial, microsporicidal, and acaricidal activity.  

PubMed

A diverse set of parasites and pathogens affects productivity and survival of Apis mellifera honeybees. In beekeeping, traditional control by antibiotics and molecules of synthesis has caused problems with contamination and resistant pathogens. In this research, different Laurus nobilis extracts are tested against the main honeybee pests through an integrated point of view. In vivo effects on bee survival are also evaluated. The ethanol extract showed minimal inhibitory concentration (MIC) values of 208 to 416 ?g/mL, having the best antimicrobial effect on Paenibacillus larvae among all substances tested. Similarly, this leaf extract showed a significant antiparasitic activity on Varroa destructor, killing 50 % of mites 24 h after a 30-s exposure, and on Nosema ceranae, inhibiting the spore development in the midgut of adult bees ingesting 1?×?10(4) ?g/mL of extract solution. Both ethanol extract and volatile extracts (essential oil, hydrolate, and its main component) did not cause lethal effects on adult honeybees. Thus, the absence of topical and oral toxicity of the ethanol extract on bees and the strong antimicrobial, microsporicidal, and miticidal effects registered in this study place this laurel extract as a promising integrated treatment of bee diseases and stimulates the search for other bioactive phytochemicals from plants. PMID:24288051

Damiani, Natalia; Fernández, Natalia J; Porrini, Martín P; Gende, Liesel B; Álvarez, Estefanía; Buffa, Franco; Brasesco, Constanza; Maggi, Matías D; Marcangeli, Jorge A; Eguaras, Martín J

2014-02-01

349

Antimicrobial activity of bacterial isolates from different floral sources of honey.  

PubMed

More than two thousand bacterial strains isolated from six US domestic honeys and two manuka honeys from New Zealand were screened for production of antimicrobial compounds. A high incidence of antimicrobial inhibition determined by deferred inhibition assays was observed with the bacterial isolates from all eight honey samples. In total, 2217 isolates out of 2398 strains (92.5% of total isolates) exhibited antimicrobial activity against at least one of the tested microorganisms. Antifungal activity by bacterial isolates originating from the eight honeys ranged from 44.4% to 98.0%. Bacterial isolates from manuka honey (MH1) exhibited antimicrobial activity against Bacillus subtilis ATCC 6633 and Bacillus cereus F4552, at 51.5% and 53.3% of the isolates, respectively. However, less than 30% of the bacterial isolates from the other manuka honey (MH2) and six domestic honey sources exhibited anti-Bacillus activity. Listeria monocytogenes F2-586 1053 showed higher overall rates of sensitivity to between 11 and 66% of the bacterial isolates. The high rate of antimicrobial activity exhibited by the bacterial strains isolated from different honey sources could provide potential sources of novel antimicrobial compounds. PMID:18538876

Lee, Hyungjae; Churey, John J; Worobo, Randy W

2008-08-15

350

Quantification, antioxidant and antimicrobial activity of phenolics isolated from different extracts of Capsicum frutescens (Pimenta Malagueta).  

PubMed

This paper presents the quantification, antioxidant and antimicrobial activity of capsaicin, dihydrocapsaicin and the flavonoid chrysoeriol isolated from different extracts (hexane and acetonitrile extracts from whole fruit, peel and seed) of Capsicum frutescens (pimenta malagueta). The acetonitrile extract of the seeds, peel and whole fruits contained capsaicin as a major component, followed in abundance by dihydrocapsaicin and chrysoeriol. The antimicrobial activity of the isolated compounds against seven microorganisms showed chrysoeriol was the most active compound. In the antioxidant test, the acetonitrile extract from the whole fruit showed the highest activity. The antioxidant activity of pimenta malagueta may be correlated with its phenolic content, principally with the most active compound, capsaicin. PMID:24879587

Nascimento, Patrícia L A; Nascimento, Talita C E S; Ramos, Natália S M; Silva, Girliane R; Gomes, José Erick Galindo; Falcão, Rosângela E A; Moreira, Keila A; Porto, Ana L F; Silva, Tania M S

2014-01-01

351

Antimicrobial Prophylaxis in Adults  

PubMed Central

Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement, and bite wounds. Perioperative antimicrobial prophylaxis is recommended for various surgical procedures to prevent surgical site infections. Optimal antimicrobial agents for prophylaxis should be bactericidal, nontoxic, inexpensive, and active against the typical pathogens that can cause surgical site infection postoperatively. To maximize its effectiveness, intravenous perioperative prophylaxis should be administered within 30 to 60 minutes before the surgical incision. Antimicrobial prophylaxis should be of short duration to decrease toxicity and antimicrobial resistance and to reduce cost. PMID:21719623

Enzler, Mark J.; Berbari, Elie; Osmon, Douglas R.

2011-01-01

352

Antimicrobial activity of seven root canal sealers. Results of agar diffusion and agar dilution tests.  

PubMed

A comparative study of the antimicrobial action of seven root canal sealers: Traitement Spad, Endométhasone, N2 Universal, Diaket-A, AH26 with silver, Tubli Seal, and Sealapex was done with 120 strains of Staphylococcus aureus. Two antimicrobial susceptibility tests were used: the agar dilution test and the agar diffusion test. The Diaket-A and Traitement Spad sealer cements showed the highest efficiency in the dilution test, whereas Diaket-A was in fourth place in the diffusion test, only better than the antimicrobial activity of the Tubli Seal and Sealapex sealers. PMID:1508532

Pumarola, J; Berastegui, E; Brau, E; Canalda, C; Jiménez de Anta, M T

1992-08-01

353

Anti-Leishmanial, Anti-Inflammatory and Antimicrobial Activities of Phenolic Derivatives from Tibouchina paratropica.  

PubMed

A new phenolic derivative, 2,8-dihydroxy-7H-furo[2,3-f]chromen-7-one (1), together with isoquercitrin (2), was isolated from the aerial parts of Tibouchina paratropica. Compound structures were elucidated by spectroscopic methods. Both compounds show antimicrobial activity towards a panel of bacterial and fungal pathogens, and compound 1 displayed potent anti-parasitic activity against Leishmania donovani (IC50 ?=?0.809?µg/mL). In addition, an 85% reduction in the secretion of the pro-inflammatory cytokine IL-6 was recorded when macrophages challenged with lipopolysaccharide were exposed to compound 1, but no effect on the anti-inflammatory IL-10 was observed. Compound 2 showed neither anti-parasitic nor anti-inflammatory properties. In addition, no cytotoxic activities were observed against the human-derived macrophage THP-1 cells. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25417600

Tracanna, María I; Fortuna, Antonio M; Contreras Cárdenas, Angel V; Marr, Alexandra K; McMaster, W Robert; Gómez-Velasco, Anaximandro; Sánchez-Arreola, Eugenio; Hernández, Luis Ricardo; Bach, Horacio

2014-11-24

354

Physicochemical properties, cytotoxicity, and antimicrobial activity of sulphated zirconia nanoparticles.  

PubMed

Nanoparticle sulphated zirconia with Brønsted acidic sites were prepared here by an impregnation reaction followed by calcination at 600°C for 3 hours. The characterization was completed using X-ray diffraction, thermal gravimetric analysis, Fourier transform infrared spectroscopy, Brunner-Emmett-Teller surface area measurements, scanning electron microscopy with energy dispersive X-ray spectroscopy, and transmission electron microscopy. Moreover, the anticancer and antimicrobial effects were investigated for the first time. This study showed for the first time that the exposure of cancer cells to sulphated zirconia nanoparticles (3.9-1,000 ?g/mL for 24 hours) resulted in a dose-dependent inhibition of cell growth, as determined by (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Similar promising results were observed for reducing bacteria functions. In this manner, this study demonstrated that sulphated zirconia nanoparticles with Brønsted acidic sites should be further studied for a wide range of anticancer and antibacterial applications. PMID:25632233

Mftah, Ae; Alhassan, Fatah H; Al-Qubaisi, Mothanna Sadiq; El Zowalaty, Mohamed Ezzat; Webster, Thomas J; Sh-Eldin, Mohammed; Rasedee, Abdullah; Taufiq-Yap, Yun Hin; Rashid, Shah Samiur

2015-01-01

355

Silver Nanoparticle Impregnated Bio-Based Activated Carbon with Enhanced Antimicrobial Activity  

NASA Astrophysics Data System (ADS)

The present study involves the production of silver nanoparticles using a novel yeast strain Saccharomyces cerevisiae BU-MBT CY-1 isolated from coconut cell sap. The biological reduction of silver nitrate by the isolate was deducted at various time intervals. The yeast cells after biological silver reduction were harvested and subjected to carbonization at 400°C for 1 h and its properties were analyzed using Fourier transform infra-red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscopy. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells (CCY) did not contain any particles on its surface. The carbonized silver nanoparticles containing yeast cells (CSY) were made into bioactive emulsion and tested for its efficacy against various pathogenic Gram positive and Gram negative bacteria. The antimicrobial activity studies indicated that CSY bioactive nanoemulsion was effective against Gram negative organisms than Gram positive organism.

Selvakumar, R.; Suriyaraj, S. P.; Jayavignesh, V.; Swaminathan, K.

2013-08-01

356

The antimicrobial activity of honey against common equine wound bacterial isolates.  

PubMed

Delayed healing associated with distal limb wounds is a particular problem in equine clinical practice. Recent studies in human beings and other species have demonstrated the beneficial wound healing properties of honey, and medical grade honey dressings are available commercially in equine practice. Equine clinicians are reported to source other non-medical grade honeys for the same purpose. This study aimed to assess the antimicrobial activity of a number of honey types against common equine wound bacterial pathogens. Twenty-nine honey products were sourced, including gamma-irradiated and non-irradiated commercial medical grade honeys, supermarket honeys, and honeys from local beekeepers. To exclude contaminated honeys from the project, all honeys were cultured aerobically for evidence of bacterial contamination. Aerobic bacteria or fungi were recovered from 18 products. The antimicrobial activity of the remaining 11 products was assessed against 10 wound bacteria, recovered from the wounds of horses, including methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa. Eight products were effective against all 10 bacterial isolates at concentrations varying from <2% to 16% (v/v). Overall, the Scottish Heather Honey was the best performing product, and inhibited the growth of all 10 bacterial isolates at concentrations ranging from <2% to 6% (v/v). Although Manuka has been the most studied honey to date, other sources may have valuable antimicrobial properties. Since some honeys were found to be contaminated with aerobic bacteria or fungi, non-sterile honeys may not be suitable for wound treatment. Further assessment of gamma-irradiated honeys from the best performing honeys would be useful. PMID:23962613

Carnwath, R; Graham, E M; Reynolds, K; Pollock, P J

2014-01-01

357

Antimicrobial effects of silver zeolite, silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms  

PubMed Central

Objective To evaluate the antimicrobial activities of silver inorganic materials, including silver zeolite (AgZ), silver zirconium phosphate silicate (AgZrPSi) and silver zirconium phosphate (AgZrP), against oral microorganisms. In line with this objective, the morphology and structure of each type of silver based powders were also investigated. Methods The antimicrobial activities of AgZ, AgZrPSi and AgZrP were tested against Streptococcus mutans, Lactobacillus casei, Candida albicans and Staphylococcus aureus using disk diffusion assay as a screening test. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the modified membrane method. Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials. Results All forms of silver inorganic materials could inhibit the growth of all test microorganisms. The MIC of AgZ, AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0–60.0 g/L. In terms of morphology and structure, AgZrPSi and AgZrP had smaller sized particles (1.5–3.0 µm) and more uniformly shaped than AgZ. Conclusions Silver inorganic materials in the form of AgZ, AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers. These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection. PMID:23570016

Saengmee-anupharb, Sirikamon; Srikhirin, Toemsak; Thaweboon, Boonyanit; Thaweboon, Sroisiri; Amornsakchai, Taweechai; Dechkunakorn, Surachai; Suddhasthira, Theeralaksna; Kamaguchi, Arihide

2013-01-01

358

Heat stable antimicrobial activity of Allium ascalonicum against bacteria and fungi.  

PubMed

To study antimicrobial activity of shallot in comparison with that of garlic and onion against 23 strains of fungi and bacteria, water extracts of garlic, shallot and onion bulbs were prepared. Each extract was studied in different forms for their antimicrobial activity viz., fresh extract, dry extract and autoclaved extract. Minimal inhibitory concentration and minimal lethal concentrations of these extracts were determined against all organisms by broth dilution susceptibility test. Fresh extract of garlic showed greater antimicrobial activity as compared to similar extracts of onion and shallot. However, dried and autoclaved extracts of shallot showed more activity than similar extracts of onion and garlic. Fungi were more sensitive to shallot extract than bacteria. Amongst bacteria, B. cereus was most sensitive (MIC=5 mg ml(-1)). The lowest minimum bactericidal concentration of shallot extract amongst bacteria tested was 5 mg ml(-1) for B. cereus. Amongst fungi, Aureobasidium pullulans and Microsporum gypseum were most sensitive (MIC= 0.15 mg ml(-1)). The lowest minimum lethal concentration was 2.5 mg ml(-1) for Microsporum gypseum and Trichophyton mentagrophytes. It was therefore, expected that the antimicrobial principle of shallot was different than the antimicrobial compounds of onion and garlic. In addition, the antimicrobial component of the shallot extract was stable at 121 degrees C. PMID:16121720

Amin, M; Kapadnis, B P

2005-08-01

359

Antimicrobial effects of helix D-derived peptides of human antithrombin III.  

PubMed

Antithrombin III (ATIII) is a key antiproteinase involved in blood coagulation. Previous investigations have shown that ATIII is degraded by Staphylococcus aureus V8 protease, leading to release of heparin binding fragments derived from its D helix. As heparin binding and antimicrobial activity of peptides frequently overlap, we here set out to explore possible antibacterial effects of intact and degraded ATIII. In contrast to intact ATIII, the results showed that extensive degradation of the molecule yielded fragments with antimicrobial activity. Correspondingly, the heparin-binding, helix D-derived, peptide FFFAKLNCRLYRKANKSSKLV (FFF21) of human ATIII, was found to be antimicrobial against particularly the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Fluorescence microscopy and electron microscopy studies demonstrated that FFF21 binds to and permeabilizes bacterial membranes. Analogously, FFF21 was found to induce membrane leakage of model anionic liposomes. In vivo, FFF21 significantly reduced P. aeruginosa infection in mice. Additionally, FFF21 displayed anti-endotoxic effects in vitro. Taken together, our results suggest novel roles for ATIII-derived peptide fragments in host defense. PMID:25202017

Papareddy, Praveen; Kalle, Martina; Bhongir, Ravi K V; Mörgelin, Matthias; Malmsten, Martin; Schmidtchen, Artur

2014-10-24

360

On the antimicrobial activity of various Peptide-based dendrimers of similar architecture.  

PubMed

Antimicrobial drug resistance is a major human health threat. Among the many attempts to tackle this problem, the synthesis of antimicrobial compounds that mimic natural antimicrobial peptides appears as a promising approach. Peptide-based dendrimers can be designed to have higher potency than natural antimicrobial peptides and at the same time they can evade the bacterial defense system. Novel dendrimers with similar chemical structure but varying potency in terms of minimum inhibitory concentration were designed. The dependency between dendrimer structure and antibacterial activity as well as their capacity to attack model cell membranes was studied. The data suggests that supramolecular structure in terms of charge distribution and amphiphilicity, rather than net charge, is the main driver for disruption of cellular membranes and this correlates well with dendrimer hemolytic activity. PMID:25574818

Lind, Tania K; Polcyn, Piotr; Zielinska, Paulina; Cárdenas, Marité; Urbanczyk-Lipkowska, Zofia

2014-01-01

361

Factors affecting antimicrobial activity of MUC7 12-mer, a human salivary mucin-derived peptide  

PubMed Central

Background MUC7 12-mer (RKSYKCLHKRCR), a cationic antimicrobial peptide derived from the human low-molecular-weight salivary mucin MUC7, possesses potent antimicrobial activity in vitro. In order to evaluate the potential therapeutic application of the MUC7 12-mer, we examined the effects of mono- and divalent cations, EDTA, pH, and temperature on its antimicrobial activity. Methods Minimal Inhibitory Concentrations (MICs) were determined using a liquid growth inhibition assay in 96-well microtiter plates. MUC7 12-mer was added at concentrations of 1.56–50 ?M. MICs were determined at three endpoints: MIC-0, MIC-1, and MIC-2 (the lowest drug concentration showing 10%, 25% and 50% of growth, respectively). To examine the effect of salts or EDTA, a checkerboard microdilution technique was used. Fractional inhibitory concentration index (FICi) was calculated on the basis of MIC-0. The viability of microbial cells treated with MUC7 12-mer in the presence of sodium or potassium was also determined by killing assay or flow cytometry. Results The MICs of MUC7 12-mer against organisms tested ranged from 6.25–50 ?M. For C. albicans, antagonism (FICi 4.5) was observed for the combination of MUC7 12-mer and calcium; however, there was synergism (FICi 0.22) between MUC7 12-mer and EDTA, and the synergism was retained in the presence of calcium at its physiological concentration (1–2 mM). No antagonism but additivity or indifference (FICi 0.55–2.5) was observed for the combination of MUC7 12-mer and each K+, Na+, Mg2+, or Zn2+. MUC7 12-mer peptide (at 25 ?M) also exerted killing activity in the presence of NaCl, (up to 25 mM for C. albicans and up to 150 mM for E. coli, a physiological concentration of sodium in the oral cavity and serum, respectively) and retained candidacidal activity in the presence of KCl (up to 40 mM). The peptide exhibited higher inhibitory activity against C. albicans at pH 7, 8, and 9 than at pH 5 and 6, and temperature up to 60°C did not affect the activity. Conclusion MUC7 12-mer peptide is effective anticandidal agent at physiological concentrations of variety of ions in the oral cavity. These results suggest that, especially in combination with EDTA, it could potentially be applied as an alternative therapeutic agent for the treatment of human oral candidiasis. PMID:17996119

Wei, Guo-Xian; Campagna, Alexander N; Bobek, Libuse A

2007-01-01

362

Evaluation of Composition and Antimicrobial Activity of Supercritical Fluid Extract of Leaves of Vitex negundo  

PubMed Central

Supercritical fluid extract of leaves of Vitex negundo was tested for its antimicrobial potential and was compared with that of ethanol extract, ether extract and hydrodistilled oil of leaves. The chemical constituents of extracts were studied by chromatographic techniques. Extracts were evaluated for antimicrobial potential against bacterial strains like Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and yeast Candida albicans. Extracts showed prominent antibacterial activity against Bacillus subtilis and Staphylococcus aureus. Supercritical fluid extract exhibited good antibacterial potential. PMID:21695000

Nagarsekar, K. S.; Nagarsenker, M. S.; Kulkarni, S. R.

2010-01-01

363

Activities of LL37, a Cathelin-Associated Antimicrobial Peptide of Human Neutrophils  

Microsoft Academic Search

Human neutrophils contain two structurally distinct types of antimicrobial peptides, b-sheet defensins (HNP-1 to HNP-4) and the a-helical peptide LL-37. We used radial diffusion assays and an improved National Committee for Clinical Laboratory Standards-type broth microdilution assay to compare the antimicrobial properties of LL-37, HNP-1, and protegrin (PG-1). Although generally less potent than PG-1, LL-37 showed considerable activity (MIC, <10

JEFFREY TURNER; YOON CHO; NHU-NGUYEN DINH; ALAN J. WARING; ROBERT I. LEHRER

1998-01-01

364

Antimicrobial Activities of Amphiphilic Peptides Covalently Bonded to a Water-Insoluble Resin  

Microsoft Academic Search

A series of polymer-bound antimicrobial peptides was prepared, and the peptides were tested for their antimicrobial activities. The immobilized peptides were prepared by a strategy that used solid-phase peptide synthesis that linked the carboxy-terminal amino acid with an ethylenediamine-modified polyamide resin (PepsynK). The acid-stable, permanent amide bond between the support and the nascent peptide renders the peptide resistant to cleavage

SHARON L. HAYNIE; GRACE A. CRUM; ANDBRUCE A. DOELE

1995-01-01

365

In vitro assessment of the antimicrobial activity of wound dressings: influence of the test method selected and impact of the pH.  

PubMed

Antibacterial activity of dressings containing antimicrobials is mostly evaluated using in vitro tests. However, the various methods available differ significantly in their properties and results obtained are influenced by the method selected, micro-organisms used, and extraction method, the degree of solubility or the diffusability of the test-compounds. Here, results on antimicrobial activity of silver-containing dressings obtained by agar diffusion test (ADT), challenge tests (JIS L 1902, AATCC 100), and extraction-based methods (microplate laser nephelometry (MLN), luminescent quantification of bacterial ATP (LQbATP)) using Staphylococcus aureus and Pseudomonas aeruginosa were evaluated. Furthermore, the effect of the pH on antibacterial efficacy of these dressings was investigated. All silver-containing dressings exerted antimicrobial activity in all in vitro tests and results correlated considerably well. Differences were observed testing the agent-free basic materials. They did not exhibit any antimicrobial effects in the ADT, MLN or LQbATP, since these methods depend on diffusion/extraction of an active agent. However, they showed a strong antimicrobial effect in the challenge tests as they possess a high absorptive capacity, and are able to bind and sequester micro-organisms present. Therefore, it seems recommendable to choose several tests to distinguish whether a material conveys an active effect or a passive mechanism. In addition, it could be shown that release of silver and its antimicrobial efficacy is partially pH-dependent, and that dressings themselves affect the pH. It can further be speculated that dressings' effects on pH and release of silver ions act synergistically for antimicrobial efficacy. PMID:25578697

Wiegand, Cornelia; Abel, Martin; Ruth, Peter; Elsner, Peter; Hipler, Uta-Christina

2015-01-01

366

P10 ALTERNATIVE USES AND COLLATERAL EFFECTS OF ANTIMICROBIALS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Throughout history and nature, antimicrobials have had applications in addition to treating diseases. Certain insects use antimicrobials as disinfectants. Ancient Nubians incorporated antibiotics in the manufacture of ‘booza’, a traditional alcoholic beverage in their culture. For the last four d...

367

Self-assembly and antimicrobial activity of long-chain amide-functionalized ionic liquids in aqueous solution.  

PubMed

Surface active amide-functionalized ionic liquids (ILs) consisting of a long alkyl chain (C6C14) connected to a polar head group (methylimidazolium or pyridinium cation) via an amide functional group were synthesized and their thermal stability, micellar properties and antimicrobial activity in aqueous solution investigated. The incorporation of an amide group increased the thermal stability of the functionalized ionic liquids compared to simple alkyl chain substituted ionic liquids. The surface activity and aggregation behaviour in aqueous solution of amide-functionalized ionic liquids were examined by tensiometry, conductivity and spectrofluorimetry. Amide-functionalized ILs displayed surface activity and their critical micelle concentration (cmc) in aqueous media decreased with the elongation of the alkyl side chain as occurs for typical surfactants. Compared to non-functionalized ILs bearing the same alkyl chain, ionic liquids with an amide moiety possess higher surface activity (pC20) and lower cmc values. The introduction of an amide group in the hydrophobic chain close to the polar head enhances adsorption at the air/water interface and micellization which could be attributed to the H-bonding in the headgroup region. The antimicrobial activity was evaluated against a panel of representative Gram-negative and Gram-positive bacteria and fungi. Amide-functionalized ILs with more than eight carbon atoms in the side chain showed broad antimicrobial activity. Antibacterial activities were found to increase with the alkyl chain length being the C12 homologous the most effective antimicrobial agents. The introduction of an amide group enhanced significantly the antifungal activity as compared to non-functionalized ILs. PMID:25277287

Garcia, M Teresa; Ribosa, Isabel; Perez, Lourdes; Manresa, Angeles; Comelles, Francesc

2014-11-01

368

Chemical composition and antimicrobial activities of the essential oils from three ecotypes of Zataria multiflora  

PubMed Central

Background: Zataria multiflora Boiss. is a traditional and popular spice in Iran. The effects of 3 ecotypes (ECTPs) of Z. multiflora essential oils (EOs) against most common causes of food-borne and nosocomial infections were evaluated. Materials and Methods: The antimicrobial activities of the EOs were examined by broth microdilution method as recommended by the Clinical and Laboratory Standards Institute (CLSI). The chemical compositions of the EOs from 3 ECTPs of Z. multiflora have been analyzed by gas chromatography–mass spectrometry. Results: Analysis of the EOs indicated that 3 chemotypes were present in Z. multiflora, including carvacrol, thymol-carvacrol, and linalool, whereas previous studies have only found carvacrol and thymol. Inhibition studies showed that the tested EOs entirely inhibited the growth of yeasts at concentrations of less than 1 ?L/mL. Moreover, the oils exhibited significant bacteriostatic and bactericidal activities against Gram-positive and Gram-negative bacteria at concentrations ranging from 0.12 to 8 ?L/mL. Conclusion: These results suggest that the EOs from Z. multiflora should be investigated further for possible use in antimicrobial products and food preservatives. PMID:21472080

Zomorodian, K.; Saharkhiz, M. J.; Rahimi, M. J.; Bandegi, A.; Shekarkhar, G.; Bandegani, A.; Pakshir, K.; Bazargani, A.

2011-01-01

369

Synthesis of poly acrylic acid modified silver nanoparticles and their antimicrobial activities.  

PubMed

Poly acrylic acid modified silver (Ag/PAA) nanoparticles (NPs) have been successfully synthesized in the aqueous solution by using tannic acid as a reductant. The structure, morphology and composition of Ag/PAA NPs were characterized by various techniques such as X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible absorption spectroscopy (UV-vis) and thermogravimetry analysis (TGA). The results show that PAA/Ag NPs have a quasi-ball shape with an average diameter of 10 nm and exhibit well crystalline, and the reaction conditions have some effect on products morphology and size distribution. In addition, the as-synthesized Ag/PAA NPs antimicrobial activities against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) were evaluated by the methods of broth dilution, cup diffusion, optical density (OD600) and electron microscopy observation. The as-synthesized Ag/PAA NPs exhibit excellent antibacterial activity. The antimicrobial mechanism may be attributed to the damaging of bacterial cell membrane and causing leakage of cytoplasm. PMID:24907758

Ni, Zhihui; Wang, Zhihua; Sun, Lei; Li, Binjie; Zhao, Yanbao

2014-08-01

370

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

PubMed Central

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

Dziuba, Bart?omiej; Dziuba, Marta

2014-01-01

371

In vitro evaluation of antimicrobial effect of miswak against common oral pathogens  

PubMed Central

Background and Objective: Miswak is a natural tooth cleaning tool which is being used in many parts of the world since ancient times. It is known to be useful in prevention of dental caries. But still it is not used as frequently as other oral hygiene tools. This research was designed to scientifically establish antimicrobial effect of miswak in vitro against common oral pathogens. Methods: This was a cross-sectional study involving 100 health care workers. This research was carried out in Microbiology section of Dow Diagnostic Research & Reference Laboratory. A questionnaire was designed to test oral hygiene habits of study subjects. Oral swabs were taken and microorganisms were identified by standard bacteriological methods. Test material included four different types of miswaks i.e. (1) root of the peelu (Salvadora persica) tree (in packing) (2) root of the peelu tree (without packing) (3) stem of the peelu tree & (4) stem of the neem (Azadirechta indica) tree. These miswaks were tested against three different types of microorganisms isolated from oral swabs: Staphylococcus aureus, Streptococcus mutans & Candida albicans by agar diffusion method. Inhibition zone was measured after 24 hrs of incubation at 37oC. Results: Among the miswaks used, root of the peelu tree in both packing and without packing exhibited strong antimicrobial effect against all three tested microorganisms. However miswak taken from the stem of the peelu and neem tree did not show any antimicrobial activity against all three types of the tested microorganisms. Conclusion: Miswak taken from the root of the peelu tree exhibited antimicrobial activity against all the common oral pathogens and could be a good oral hygiene tool in combating dental caries. PMID:24772151

Naseem, Saima; Hashmi, Khursheed; Fasih, Fatima; Sharafat, Shaheen; Khanani, Rafiq

2014-01-01

372

Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae), isolated compounds and semi-synthetic derivatives against endodontic bacteria.  

PubMed

This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of ?-amyrin, ?-amyrin, and ?-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC) using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis. PMID:24031892

Dos Santos, Fernanda M; de Souza, Maria Gorete; Crotti, Antônio E Miller; Martins, Carlos H G; Ambrósio, Sérgio R; Veneziani, Rodrigo C S; E Silva, Márcio L Andrade; Cunha, Wilson R

2012-04-01

373

Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae), isolated compounds and semi-synthetic derivatives against endodontic bacteria  

PubMed Central

This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of ?-amyrin, ?-amyrin, and ?-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC) using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis. PMID:24031892

dos Santos, Fernanda M.; de Souza, Maria Gorete; Crotti, Antônio E. Miller; Martins, Carlos H. G.; Ambrósio, Sérgio R.; Veneziani, Rodrigo C. S.; e Silva, Márcio L. Andrade; Cunha, Wilson R.

2012-01-01

374

Antimicrobial activity of crude extracts from plant parts and corresponding calli of Bixa orellana L.  

PubMed

Ethanol extracts from the different parts of B. orellana showed differential antimicrobial activity. It was found that the extracts of in vitro leaves showed maximum activity against Bacillus pumilus followed by the extracts from the roots and hypocotyls. The callus derived from different explants too showed antimicrobial activity. The leaf callus showed maximum activity. The zone of inhibition for the diluted extracts of in vitro hypocotyls and roots and their corresponding calli showed minimum zone of inhibition at concentration 24 mg/ml, whereas the diluted extract of in vitro leaves and leaf derived callus showed minimum zone of inhibition at 16 mg/ml. PMID:12974400

Castello, Marie-Claire; Phatak, Anita; Chandra, Naresh; Sharon, Madhuri

2002-12-01

375

Reevaluation of antimicrobial and antioxidant activity of Thymus spp. extracts before and after encapsulation in liposomes.  

PubMed

The antioxidant and antimicrobial activity of four Thymus species (boissieri, longicaulis, leucospermus, and ocheus) extracts were determined. Two methods (Rancimat and malondialdehyde by high-performance liquid chromatography) were used to measure the antioxidant action in comparison with common commercial antioxidants, including butylated hydroxytoluene and alpha-tocopherol. The extracts that presented high antioxidant activity were encapsulated in liposomes and their antioxidant action was again estimated. Thermal-oxidative decomposition of the samples (pure liposomes and encapsulating extracts) was studied using the differential scanning calorimetry method. The modification of the main transition temperature for the lipid mixture and the splitting of the calorimetric peak in the presence of the antioxidants were also demonstrated by differential scanning calorimetry. All extracts showed antioxidant and antimicrobial activities. Some extracts showed superior or equal antioxidant activity to alpha-tocopherol. When the extracts were encapsulated in liposomes, their antioxidant as well as antimicrobial activities proved to be superior from the same extracts in pure form. PMID:17186670

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

2006-12-01

376

Synthesis, Characterization and Antimicrobial Activity of Certain Novel Aryl Hydrazone Pyrazoline-5-Ones Containing Thiazole Moiety  

PubMed Central

Purpose: The aim of this article is to synthesize, characterize and evaluate the antimicrobial activity of certain novel 3-methyl-5-oxo-4-(phenyl hydrazono)-4,5-dihydro-pyrazol-1-yl]-acetic acid N|-(4-substituted thiazol-2-yl)-hydrazides. Methods: The synthesized compounds were characterized by elemental analysis and IR, NMR and mass spectral data. The antimicrobial activity of novel compounds was evaluated by broth dilution method. Results: XVe, XVf and XVg have shown better antibacterial activity than other compounds of the series. XVa, XVc, XVd and XVe have shown better antifungal activity than the other compounds of the series. Conclusion: All compounds were found to exhibit fair degree of antimicrobial activity. PMID:24312829

Reddy, Maliki Reddy Dastagiri; Prasad, Aluru Raghavendra Guru; Spoorthy, Yadati Narasimha; Ravindranath, Lakshmana Rao Krishna Rao

2013-01-01

377

Effect of the amino chain length and the transformation into citric acid salts of aryl-diphenyl-butenes and ferrocenyl-diphenyl-butenes bearing two dimethylaminoalkyl chains on their antimicrobial activities.  

PubMed

In a previous work we have demonstrated the antimicrobial activity of ferrocenyl or phenyl derivatives of diphenyl butene series. This finding has opened a new area of applications of organometallic compounds. In order to improve these activities, we have synthesized new organic and organometallic diaryl butene compounds with different lengths of their amino chains. These new compounds, and also their ammonium salts, were tested against man pathogenic microorganisms Escherichia coli (ATCC 10536), Pseudomonas aeruginosa (ATCC 15442), Staphylococcus aureus (ATCC 6538) and Enterococcus hirae (ATCC 10541). It emerged from the tests that the Gram+ bacteria are more sensitive to the compounds than Gram-, and the compounds with 3 carbon amino chains have a better antimicrobial activity than the one having a chain of 2 or 4 carbons. The transformation of compounds to citrate salts was accompanied by a significant regression of antibacterial activity against Pseudomonas aeruginosa, for both organic and ferrocenic molecules. This resistance problem has been solved using hydrochlorides salts rather than citrates one. PMID:24133651

Jellali, Karim; Pigeon, Pascal; Trigui, Fatma; Top, Siden; Aifa, Sami; Jaouen, Gérard; El Arbi, Mehdi

2013-01-01

378

Evaluation of the Antimicrobial Activities of Plant Oxylipins Supports Their Involvement in Defense against Pathogens1[W  

PubMed Central

Plant oxylipins are a large family of metabolites derived from polyunsaturated fatty acids. The characterization of mutants or transgenic plants affected in the biosynthesis or perception of oxylipins has recently emphasized the role of the so-called oxylipin pathway in plant defense against pests and pathogens. In this context, presumed functions of oxylipins include direct antimicrobial effect, stimulation of plant defense gene expression, and regulation of plant cell death. However, the precise contribution of individual oxylipins to plant defense remains essentially unknown. To get a better insight into the biological activities of oxylipins, in vitro growth inhibition assays were used to investigate the direct antimicrobial activities of 43 natural oxylipins against a set of 13 plant pathogenic microorganisms including bacteria, oomycetes, and fungi. This study showed unequivocally that most oxylipins are able to impair growth of some plant microbial pathogens, with only two out of 43 oxylipins being completely inactive against all the tested organisms, and 26 oxylipins showing inhibitory activity toward at least three different microbes. Six oxylipins strongly inhibited mycelial growth and spore germination of eukaryotic microbes, including compounds that had not previously been ascribed an antimicrobial activity, such as 13-keto-9(Z),11(E),15(Z)-octadecatrienoic acid and 12-oxo-10,15(Z)-phytodienoic acid. Interestingly, this first large-scale comparative assessment of the antimicrobial effects of oxylipins reveals that regulators of plant defense responses are also the most active oxylipins against eukaryotic microorganisms, suggesting that such oxylipins might contribute to plant defense through their effects both on the plant and on pathogens, possibly through related mechanisms. PMID:16299186

Prost, Isabelle; Dhondt, Sandrine; Rothe, Grit; Vicente, Jorge; Rodriguez, Maria José; Kift, Neil; Carbonne, Francis; Griffiths, Gareth; Esquerré-Tugayé, Marie-Thérèse; Rosahl, Sabine; Castresana, Carmen; Hamberg, Mats; Fournier, Joëlle

2005-01-01

379

Chemical composition and in vitro antimicrobial activity of the essential oil of Cyclotrichium leucotrichum from Iran.  

PubMed

The objective of this study was to investigate in vitro antimicrobial activity and composition of the essential oil of Cyclotrichium leucotrichum growing wild in Iran. The essential oil was obtained by hydro-distillation and analysed by GC-FID and GC/MS. Fifty-nine components representing 98.9% of the total oil were characterised. The essential oil which has 1,8-cineol (14.8%), elemol (12.6%), spathulenol (9.4%), E-caryophyllene (5.7%) and hinesol (5.7%) as its main components, exhibited moderate activity against seven bacteria and a yeast, Candida albicans, with minimum inhibitory concentration values ranging from 0.5 to 64 mg mL(-1) and minimum bactericidal concentration values ranging from 2 to >64 mg mL(-1), respectively. The best inhibitory effects were against three gram-positive bacteria and tested yeast, C. albicans. PMID:22455838

Mirjalili, M H; Hadian, J; Aliahmadi, A; Kanani, M R; Sonboli, A

2013-01-01

380

Antimicrobial activity of the surface coatings on TiAlZr implant biomaterial.  

PubMed

This study is devoted to antimicrobial activity of new surface coatings on TiAlZr. Ti alloys such as TiAlZr are used as implant biomaterials, but, despite the good behavior of such alloys in simulated conditions, bacterial infections appear after the introduction of an implant into the body. The infections are typically caused by the adherence and colonization of bacteria on the surfaces of the implants. The study presents preparation and surface morphology characterization of coatings obtained via anodizing, as well as biomimetic coatings with hydroxyapatite and silver ions with and without antibiotic. The percentage inhibition of Escherichia coli bacteria growth was evaluated for each of the studied coating, and a Trojan-horse model of silver nanoparticles (nAg) antibacterial activity at interface was proposed. Such coatings could be more important taking into account that antibacterial treatments with antibiotics are becoming less effective due to their intensive use. PMID:21889399

Ionita, Daniela; Grecu, Mihaela; Ungureanu, Camelia; Demetrescu, Ioana

2011-12-01

381

Antimicrobial activity of apple, hibiscus, olive, and hydrogen peroxide formulations against Salmonella enterica on organic leafy greens.  

PubMed

Salmonella enterica is one of the most common bacterial pathogens implicated in foodborne outbreaks involving fresh produce in the last decade. In an effort to discover natural antimicrobials for use on fresh produce, the objective of the present study was to evaluate the effectiveness of different antimicrobial plant extract-concentrate formulations on four types of organic leafy greens inoculated with S. enterica serovar Newport. The leafy greens tested included organic romaine and iceberg lettuce, and organic adult and baby spinach. Each leaf sample was washed, dip inoculated with Salmonella Newport