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1

Effect of pulmonary surfactant on antimicrobial activity in vitro.  

PubMed

Time-kill curve experiments were performed with linezolid, doripenem, tigecycline, moxifloxacin, and daptomycin against Staphylococcus aureus and with colistin, moxifloxacin, and doripenem against Pseudomonas aeruginosa to evaluate the effect of porcine pulmonary surfactant on antimicrobial activity. Pulmonary surfactant significantly impaired the activities of moxifloxacin and colistin. When antibiotics are being developed for respiratory tract infections, the method described here might be used to preliminarily quantify the effect of pulmonary surfactant on antimicrobial activity. PMID:23877678

Schwameis, R; Erdogan-Yildirim, Z; Manafi, M; Zeitlinger, M A; Strommer, S; Sauermann, R

2013-10-01

2

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

3

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

4

Antimicrobial activity of some plant extracts having hepatoprotective effects  

Microsoft Academic Search

The antimicrobial activity of hot water and ethanolic extracts of six plant extracts, utilized in Pakistan for the cure of liver damage, were studied. The extracts of Acacia arabica, Nymphaea lotus, Sphareranthus hirtus, Emblica officinalis, Cinchorium intybus and Cardus marianum were tested in vitro against seven bacterial species and two fungal species by well-diffusion method and micro- dilution methods. The

Ammara Hassan; Salma Rahman; Farah Deeba; Shahid Mahmud

5

Effects of Dimerization on the Structure and Biological Activity of Antimicrobial Peptide Ctx-Ha  

PubMed Central

It is well known that cationic antimicrobial peptides (cAMPs) are potential microbicidal agents for the increasing problem of antimicrobial resistance. However, the physicochemical properties of each peptide need to be optimized for clinical use. To evaluate the effects of dimerization on the structure and biological activity of the antimicrobial peptide Ctx-Ha, we have synthesized the monomeric and three dimeric (Lys-branched) forms of the Ctx-Ha peptide by solid-phase peptide synthesis using a combination of 9-fluorenylmethyloxycarbonyl (Fmoc) and t-butoxycarbonyl (Boc) chemical approaches. The antimicrobial activity assay showed that dimerization decreases the ability of the peptide to inhibit growth of bacteria or fungi; however, the dimeric analogs displayed a higher level of bactericidal activity. In addition, a dramatic increase (50 times) in hemolytic activity was achieved with these analogs. Permeabilization studies showed that the rate of carboxyfluorescein release was higher for the dimeric peptides than for the monomeric peptide, especially in vesicles that contained sphingomyelin. Despite different biological activities, the secondary structure and pore diameter were not significantly altered by dimerization. In contrast to the case for other dimeric cAMPs, we have shown that dimerization selectively decreases the antimicrobial activity of this peptide and increases the hemolytic activity. The results also show that the interaction between dimeric peptides and the cell wall could be responsible for the decrease of the antimicrobial activity of these peptides.

Lorenzon, E. N.; Cespedes, G. F.; Vicente, E. F.; Nogueira, L. G.; Bauab, T. M.; Castro, M. S.

2012-01-01

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

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

PubMed

d-Limonene has been considered to be a safer alternative compared to synthetic antimicrobial food additives. However, its hydrophobic and oxidative nature has limited its application in foods. The purpose of this research was to study effects of nisin on the antimicrobial activity of d-limonene and its nanoemulsion and develop a novel antimicrobial delivery system by combining the positive effect of these two antibacterial agents at the same time. By the checkerboard method, both the synergistic and additive effects of d-limonene and nisin were found against four selected food-related microorganisms. Then, d-limonene nanoemulsion with or without nisin was prepared by catastrophic phase inversion method, which has shown good droplet size and stability. The positive effects and outstanding antimicrobial activity of d-limonene nanoemulsion with nisin were confirmed by MICs comparison, scanning electron microscopy and determination of cell constituents released. Overall, the research described in the current article would be helpful in developing a more effective antimicrobial system for the production and preservation of foods. PMID:24360455

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

2014-05-01

8

Effect of Fatty Acid Conjugation on Antimicrobial Peptide Activity.  

National Technical Information Service (NTIS)

Two peptides, YGAAKKAAKAA2 (AKK), and YGAKAKAAKA2 (KAK) were conjugated to fatty acids and tested for the effect on their structure, antibacterial activity, and eukaryotic cell toxicity. In the presence of bacteria-mimicking phospholipid vesicles fatty ac...

A. F. Chu-Kung K. N. Bozzelli R. Nguyen M. V. Tirrell

2004-01-01

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.

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

Direct and indirect antimicrobial effects and antioxidant activity of Cordia gilletii De Wild (Boraginaceae).  

PubMed

Cordia gilletii De Wild (Boraginaceae) root bark is traditionally used in Democratic Republic of Congo (DRC) for the treatment of various disorders, including malaria, diarrhea, wounds and skin diseases; part of these activities may rely on antimicrobial and antioxidant properties. Successive extracts of root barks powder with n-hexane, dichloromethane, ethyl acetate, methanol and water were tested for antimicrobial activity, both direct and indirect (antibiotic resistance reversal), against 10 strains of bacteria and 1 strain of fungi by broth microdilution and agar diffusion methods. The eventual synergy between plant extracts and antibiotics was investigated by the determination of the fractional inhibitory concentration index (FIC index). The methanol extract showed direct antimicrobial activity against all tested microorganisms with minimum inhibitory concentrations (MIC) ranging between 125 and 1000 microg/ml, whereas the ethyl acetate and the dichloromethane extracts showed activity on four and three strains, respectively. 200 microg/ml of n-hexane and dichloromethane extracts decreased the MICs of penicillin and streptomycin 4-64-fold for methicillin-resistant Staphylococcus aureus. A synergistic effect was found between the methanol extract and tetracycline, whereas additive effects were observed for the other combinations tested. The methanol and dichloromethane extracts showed the greater antioxidant activity by scavenging the free radical DPPH with IC(50) values of 3.2 and 8.1 microg/ml, respectively. These results support the use of the plant in the treatment of infectious diseases and wounds; they warrant further studies as to the nature of active compounds. PMID:17537602

Okusa, P N; Penge, O; Devleeschouwer, M; Duez, P

2007-07-25

11

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, Agnčs; Echairi, Abdelwahad; Meunier, Philippe; Vervandier-Fasseur, Dominique; Adrian, Marielle

2014-01-01

12

Effects of Positively Selected Sequence Variations in Human and Macaca fascicularis ?-Defensins 2 on Antimicrobial Activity  

PubMed Central

The evolution of orthologous genes coding for ?-defensin 2 (BD2) in primates has been subject to positive selection during the divergence of the platyrrhines from the catarrhines and of the Cercopithecidae from the Hylobatidae, great apes, and humans. Three peptides have been selected for a functional analysis of the effects of sequence variations on the direct antimicrobial activity: human BD2 (hBD2), Macaca fascicularis BD2 (mfaBD2), and a variant of the human peptide lacking Asp4, (?D)hBD2, which is characteristic only of the human/great ape peptides. hBD2 and mfaBD2 showed a significant difference in specificity, the former being more active towards Escherichia coli and the later towards Staphylococcus aureus and Candida albicans. Asp4 in the human peptide appears to be important, as (?D)hBD2 was less structured and had a markedly lower antimicrobial activity. The evolution of ?-defensin 2 in primates may thus have been driven, at least in part, by different environmental pressures so as to modulate antimicrobial activity.

Antcheva, Nikolinka; Boniotto, Michele; Zelezetsky, Igor; Pacor, Sabrina; Falzacappa, Maria Vittoria Verga; Crovella, Sergio; Tossi, Alessandro

2004-01-01

13

Effect of Glucocorticoids and Catecholamiens on Macrophage Antimicrobial Activity.  

National Technical Information Service (NTIS)

The effects of stress hormones on antibacterial and antiviral functions of resident peritoneal macrophages (MO) were determined. All studies were performed using a serum-free, chemically defined, medium, which eliminates complications which may arise as t...

P. S. Morahan W. L. Dempsey

1989-01-01

14

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

PubMed Central

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

Galvao, Livia Camara de Carvalho; Furletti, Vivian Fernandes; Bersan, Salete Meyre Fernandes; da Cunha, Marcos Guilherme; Ruiz, Ana Lucia Tasca Gois; de Carvalho, Joao Ernesto; Sartoratto, Adilson; Rehder, Vera Lucia Garcia; Figueira, Glyn Mara; Teixeira Duarte, Marta Cristina; Ikegaki, Masarahu; de Alencar, Severino Matias; Rosalen, Pedro Luiz

2012-01-01

15

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

PubMed

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

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

2012-01-01

16

Antitumor effects, cell selectivity and structure–activity relationship of a novel antimicrobial peptide polybia-MPI  

Microsoft Academic Search

A novel antimicrobial peptide, polybia-MPI, was purified from the venom of the social wasp Polybia paulista. It has potent antimicrobial activity against both Gram-positive and Gram-negative bacteria, but causing no hemolysis to rat erythrocytes. To date, there is no report about its antitumor effects on any tumor cell lines. In this study we synthesized polybia-MPI and studied its antitumor efficacy

Kai-rong Wang; Bang-zhi Zhang; Wei Zhang; Jie-xi Yan; Jia Li; Rui Wang

2008-01-01

17

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.

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

2013-01-01

18

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

PubMed

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

19

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

20

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

PubMed

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

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

2008-02-15

21

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.

Bali, Elif Burcu; Ac?k, Leyla; Akca, Gulcin; Sarper, Meral; Elci, Mualla P?nar; Avcu, Ferit; Vural, Mecit

2014-01-01

22

Quaternary ammonium functionalized poly(propylene imine) dendrimers as effective antimicrobials: structure-activity studies.  

PubMed

Quaternary ammonium functionalized poly(propyleneimine) dendrimers were synthesized and their antibacterial properties were evaluated using a bioluminescence method. These quaternary ammonium dendrimers are very potent biocides. The antibacterial properties depend on the size of the dendrimer, the length of hydrophobic chains in the quaternary ammonium groups, and the counteranion. Since these dendrimers are well characterized and monodisperse, they also serve as an effective system to study the structure-activity relationship. The antimicrobial properties of these dendrimer biocides have a parabolic dependence on molecular weight, which is different from the bell-shaped molecular weight dependence of conventional polymer biocides. The dependence on the hydrophobic chain of the quaternary ammonium structure is similar to conventional polymer biocides, and shows a parabolic relationship with dendrimer biocides carrying C10 hydrophobes the most potent. The antimicrobial properties of these novel biocides with bromide anions are more potent than those with chloride anions. Biocides derived from hyperbranched polymers were also synthesized and found to possess somewhat lower effectiveness. PMID:11710139

Chen, C Z; Beck-Tan, N C; Dhurjati, P; van Dyk, T K; LaRossa, R A; Cooper, S L

2000-01-01

23

Engineering antimicrobial peptides with improved antimicrobial and hemolytic activities.  

PubMed

The rapid rise of antibiotic resistance in pathogens becomes a serious and growing threat to medicine and public health. Naturally occurring antimicrobial peptides (AMPs) are an important line of defense in the immune system against invading bacteria and microbial infection. In this work, we present a combined computational and experimental study of the biological activity and membrane interaction of the computationally designed Bac2A-based peptide library. We used the MARTINI coarse-grained molecular dynamics with adaptive biasing force method and the umbrella sampling technique to investigate the translocation of a total of 91 peptides with different amino acid substitutions through a mixed anionic POPE/POPG (3:1) bilayer and a neutral POPC bilayer, which mimic the bacterial inner membrane and the human red blood cell (hRBC) membrane, respectively. Potential of mean force (PMF, free energy profile) was obtained to measure the free energy barrier required to transfer the peptides from the bulk water phase to the water-membrane interface and to the bilayer interior. Different PMF profiles can indeed identify different membrane insertion scenarios by mapping out peptide-lipid energy landscapes, which are correlated with antimicrobial activity and hemolytic activity. Computationally designed peptides were further tested experimentally for their antimicrobial and hemolytic activities using bacteria growth inhibition assay and hemolysis assay. Comparison of PMF data with cell assay results reveals a good correlation of the peptides between predictive transmembrane activity and antimicrobial/hemolytic activity. Moreover, the most active mutants with the balanced substitutions of positively charged Arg and hydrophobic Trp residues at specific positions were discovered to achieve the improved antimicrobial activity while minimizing red blood cell lysis. Such substitutions provide more effective and cooperative interactions to distinguish the peptide interaction with different lipid bilayers. This work provides a useful computational tool to better understand the mechanism and energetics of membrane insertion of AMPs and to rationally design more effective AMPs. PMID:24279498

Zhao, Jun; Zhao, Chao; Liang, Guizhao; Zhang, Mingzhen; Zheng, Jie

2013-12-23

24

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

PubMed

Active packaging is an emerging food technology to improve the quality and safety of food products. Many works have been developed to study the antimicrobial activity of essential oils. Essential oils have been traditionally used as flavorings in food, so they have an important odor impact but they have as well antimicrobial properties that could be used to protect the food. Recent developments in antimicrobial active packaging showed the efficiency of essential oils versus bread and bakery products among other applications. However, one of the main problems to face is the odor and taste they could provide to the packaged food. Using some aromas to mask the odor could be a good approach. That is why the main objective of this paper is to develop an antimicrobial packaging material based on the combination of the most active compounds of essential oils (hydrocinnamaldehyde, oregano essential oil, cinnamaldehyde, thymol, and carvacrol) together with some aromas commonly used in the food industry. A study of the concentration required to get the antimicrobial properties, the organoleptic compatibility with typical aroma present in many food systems (vanilla, banana, and strawberry), and the right combination of both systems has been carried out. Antimicrobial tests of both the mentioned aromas, the main components of some essential oils, and the combination of both groups were carried out against bacteria (Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Salmonella choleraesuis, Yersinia enterocolitica, Escherichia coli), yeasts (Candida albicans, Debaryomyces hansenii, Zygosaccharomyces rouxii), and molds (Botrytis cinerae, Aspergillus flavus, Penicillium roqueforti, Eurotium repens, Penicillium islandicum, Penicillium commune, Penicillium nalgiovensis). The sensory properties of the combinations were evaluated with a triangular test and classification was by an order test; the odor threshold of the aroma compounds was also studied. The results reveal that none of the aromas had antimicrobial properties. The most antimicrobial compounds are thymol, carvacrol, and cinnamaldehyde, but none of them could be combined with banana aroma, whereas only thymol with strawberry aroma gave the right combined organoleptic profile. All of the antimicrobials under study could be combined with vanilla aroma, providing both antimicrobial property and the odor expected. PMID:19711918

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

2009-09-23

25

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

26

Antimicrobial activity in gorgonian corals (Coelenterata, Octocorallia)  

NASA Astrophysics Data System (ADS)

Coral surfaces are often colonized by bacteria and other microbes that may be pathogenic as well as surface-fouling. To test the hypothesis that corals possess antimicrobial properties, both polar and non-polar extracts from eight species of gorgonian corals were assayed against five species of bacteria. Antimicrobial activity was most apparent in the non-polar fractions, which inhibited bacterial growth in all but one of the 40 interactions assayed (8 coralsx5 bacteria). Polar extracts were effective in less than 40% (14/40) of the interactions assayed. The levels of antimicrobial activity varied significantly among the gorgonian corals and was also dependent on the species of bacteria. Generally, marine bacteria were less sensitive to the extracts than were non-marine species. Differences in selerite content among the gorgonians did not influence the levels of extract antimicrobial activity.

Kim, K.

1994-05-01

27

Antimicrobial activities of squalamine mimics.  

PubMed Central

We investigated the antimicrobial properties of compounds with structural features that were designed to mimic those of squalamine, an antibiotic isolated from the stomach of the dogfish shark. The mimics, like squalamine, are sterol-polyamine conjugates. Unlike squalamine, the mimics were simple to prepare, at high yield, from readily available starting materials. Several squalamine mimics showed activity against gram-negative rods, gram-positive cocci including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and fungi. Some had little or no hemolytic activity. The hydrophobicity of the sterol backbone and the length and the cationic charge of the side chains appeared to be critical determinants of activity. One of the squalamine mimics, SM-7, was bactericidal against Escherichia coli, Pseudomonas aeruginosa, and S. aureus; its activity was decreased by divalent or monovalent cations and by bovine serum albumin. Subinhibitory concentrations of SM-7 markedly enhanced the antimicrobial activity of rifampin against gram-negative rods. These results suggest that the compounds may disrupt an outer membrane of gram-negative rods. Squalamine mimics are a new class of broad-spectrum antimicrobial agents. The antagonism of their activity by serum and albumin and their hemolytic properties may limit their use as systemic agents. The squalamine mimics, because of their potencies, broad spectra of antimicrobial activity, and potential for systemic toxicity, appear to be good candidates for development as topical antimicrobial agents.

Kikuchi, K; Bernard, E M; Sadownik, A; Regen, S L; Armstrong, D

1997-01-01

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

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

Microsoft Academic Search

The efficacy of gamma irradiation as a method of decontamination for food and herbal materials is well established. In the present study, Glycyrrhiza glabra roots were irradiated at doses 5, 10, 15, 20 and 25kGy in a cobalt-60 irradiator. The irradiated and un-irradiated control samples were evaluated for phenolic contents, antimicrobial activities and DPPH scavenging properties. The result of the

Khanzadi Fatima Khattak; Thomas James Simpson

2010-01-01

30

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

PubMed

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

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

2009-09-01

31

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).

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

2014-01-01

32

Effect of dietary supplementation on the antimicrobial activity of blood leukocytes isolated from Holstein heifers.  

PubMed

The purpose of this investigation was to evaluate the effect of an immunostimulating feed supplement (OmniGen-AF®) on the antimicrobial properties of blood leukocytes in dairy heifers in an attempt to prevent mastitis. Blood leukocytes from supplemented and unsupplemented controls were used. Phagocytic activity and reactive oxygen species (ROS) production were studied on d 0 (prior to feed supplementation) and on days 30 and 60 after supplementation. L-selectin and IL-8R mRNA expressions on blood leukocytes were evaluated on d 0 (prior to feed supplementation) and monthly thereafter for 15 mo. On d 30 after supplementation, neutrophils from treated heifers exhibited greater binding and internalization of Escherichia coli and greater ROS production compared with unsupplemented controls. L-selectin mRNA expression was increased in supplemented heifers vs. controls; however, IL-8R mRNA expression was not different. Results support the continued study of dietary supplementation as an additional management tool to enhance udder health in dairy heifers. PMID:24094469

Ryman, V E; Nickerson, S C; Kautz, F M; Hurley, D J; Ely, L O; Wang, Y Q; Forsberg, N E

2013-12-01

33

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

Microsoft Academic Search

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,

Z. Jiang; B. J. Kullberg; H van der Lee; A. I. Vasil; J. D. Hale; C. T. Mant; R. E. Hancock; M. L. Vasil; M. G. Netea; R. S. Hodges

2008-01-01

34

?-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.

Mohanram, Harini; Bhattacharjya, Surajit

2014-01-01

35

Antimicrobial activities of Vernonia tenoreana  

Microsoft Academic Search

The antimicrobial activity of Vernonia tenoreana was investigated. Crude extracts and solvent fractions of the leaf and bark of V. tenoreana were obtained using methanol and distilled water (2:3, v:v), ethylacetate, chloroform, and n-hexane as solvents of extraction. The crude and solvent fractions showed broad spectrum activities against Staphylococcus aureus, Streptococcus faecalis, Bacillus subtilis, B. cereus, Shigella dysenteriae, Klebsiella pneumonia,

A. O. OGUNDARE; F. C. ADETUYI; F. A. AKINYOSOYE

2006-01-01

36

Antimicrobial activity of superoxidized water  

Microsoft Academic Search

We tested the antimicrobial activity of superoxidized water against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, Escherichia coli, Pseudomonas aeruginosa and Burkholderia cepacia. The number of bacteria was reduced below detection limit following incubation in superoxidized water for 10s. The bactericidal activity of superoxidized water was similar to that of 80% ethanol, but superior to that of

H. Tanaka; Y. Hirakata; M. Kaku; R. Yoshida; H. Takemura; R. Mizukane; K. Ishida; K. Tomono; H. Koga; S. Kohno; S. Kamihira

1996-01-01

37

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

38

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

39

[Antimicrobial activity exerted by sodium dichloroisocyanurate].  

PubMed

Sodium dichloroisocyanurate is a chlorinated cleaner. It was used for swimming pool sanitation and for the sterilisation of linen. Not recently ago sodium dichloroisocyanurate has substituted hypochlorite for the sterilisation of infant feeding bottles and teats. Sodium dichloroisocyanurate is soluble in water; this condition causes the hydrolysis of sodium dichloroisocyanurate in hypochlorous acid, that is the active agent, isocyanurate and isocyanurate chlorine. These compounds form a chlorine protein that carry out microbicidal activity. In a toxicology study has been shown that no severe changes in the normal metabolic function occurred, furthermore sodium dichloroisocyanurate has not shown teratogenic effects at the concentration of 200 mg/kg. The antimicrobial activity of sodium dichloroisocyanurate was evaluated against Gram negative bacteria such as E. coli or Salmonella typhimurium and against some fungi. This study illustrates a rapid antimicrobial activity using concentrations. Our study concentrated on the antimicrobial activity of sodium dichloroisocyanurate in some experimental conditions. We tested 66 strains of fungi, 28 Gram positive bacteria and 29 Gram negative bacteria. We also evaluated the antimicrobial activity of sodium dichloroisocyanurate against protozoa such as Trichomonas vaginalis. The antimicrobial activity was evaluated in cultural conditions and non cultural conditions; in these experiments we observed similar action in both the commercial product and pure substance. In cultural conditions sodium dichloroisocyanurate shows a good activity against fungi and bacteria, moreover it can be observed that the serum didn't interfere with its activity. In a non cultural condition the Candida was killed rapidly by the sodium dichloroisocyanurate but this activity is influenced by the growth phase of the yeast. Against mycelial form such as Penicillium and Aspergillus the sodium dichloroisocyanurate needs a longer contact time than yeast form for its activity. It is interesting to note that well known bacteria, that are resistant to the common antimicrobial agents, such as Pseudomonas aeruginosa, were inhibited by sodium dichloroisocyanurate in a rapid bactericidal action. Our data demonstrates that no significant adverse influence on the activity of sodium dichloroisocyanurate was shown by pH and by temperature even if in some experimental conditions increased activity was noticed at pH = 6.6. The sodium dichloroisocyanurate has demonstrated good activity against Trichomonas vaginalis. This fact extends the broad-spectrum activity of sodium dichloroisocyanurate to the protozoa. In conclusion, sodium dichloroisocyanurate has demonstrated a good activity against all tested strains, furthermore its activity did not decrease in the presence of 1% of organic substance (serum etc.).(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2484478

D'Auria, F D; Simonetti, G; Strippoli, V

1989-01-01

40

Antimicrobial activity of bovine psoriasin  

Microsoft Academic Search

Human psoriasin (S100A7) has originally been described as a member of the family of S100 calcium-binding proteins which is overexpressed in patients suffering from psoriasis. The bovine homolog was first identified as a cow-derived respiratory allergen. As Escherichia coli mastitis is a common problem in dairy cattle, and human psoriasin was found to exhibit antimicrobial activity preferentially against E. coli,

Petra Regenhard; Matthias Leippe; Sabine Schubert; Rainer Podschun; Ernst Kalm; Joachim Grötzinger; Christian Looft

2009-01-01

41

In-vitro antimicrobial activity and synergistic/antagonistic effect of interactions between antibiotics and some spice essential oils.  

PubMed

Spices and herbs have been used for many years by different cultures. The aim of the present study is (1) to investigate in-vitro antimicrobial effects of different spices and herbs (5 species: Rosmarinus officinalis (Rosemary), Coriandrum sativum (coriander), Micromeria fruticosa (L.) Druce subsp. Brachycalyx P.H. Davis (White micromeria), Cumium cyminum (cumin), Mentha piperita (Peppermint) against different bacteria and fungi species, and (2) to discuss the in-vitro possible effects between the plants and antibiotics. The microorganisms used were Micrococcus luteus LA 2971, Bacillus megaterium NRS, Bacillus brevis FMC 3, Enterococcus faecalis ATCC 15753, Pseudomonas pyocyaneus DC 127, Mycobacterium smegmatis CCM 2067, Escherichia coil DM, Aeromonas hydrophila ATCC 7966, Yersinia enterocolitica AU 19, Staphylococcus aureus Cowan 1, Streptococcus faecalis DC 74 bacteria, and Saccharomyces cerevisiae WET 136, Kluvyeromyces fragilis DC 98 fungi in this study. The results indicated that essential oils of Rosmarinus officinalis, Coriandrum sativum L., Micromeria fruticosa (L.) Druce subsp. brachycalyx P.H. Davis, Cumium cyminum L., Mentha piperita L. were shown antimicrobial activity in the range of 7-60 mm 2 microl(-1) inhibition zone to the microorganisms tested, using disc diffusion method. Standard antibiotic such as Gentamicin (10 microg), Cephalothin (30 microg), Ceftriaxone (10 microg), Nystatin (10 U) discs were used for comparison with the antimicrobial activities of essential oils of these plants. In addition, antibacterial activity of essential oils of these plants was researched by effects when it was used together with these standard antibiotics in vitro. However, antibacterial activity changed also by in vitro interactions between these standard antibiotics and essential oils of these plants. Synergic, additive or antagonist effects were observed in antibacterial activity. PMID:21888227

Toroglu, Sevil

2011-01-01

42

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

43

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.

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

44

Effect of repetitive lysine-tryptophan motifs on the bactericidal activity of antimicrobial peptides.  

PubMed

Previous studies identified lysine- and tryptophan-rich sequences within various cationic antimicrobial peptides. In the present study, we synthesized a series of peptides composed of lysine (K)-tryptophan (W) repeats (KW)( n ) (where n equals 2, 3, 4 or 5) with amidation of the C-terminal to increase cationicity. We found that increases in chain length up to (KW)(4) enhanced the peptides' antibacterial activity; (KW)(5) exhibited somewhat less bactericidal activity than (KW)(4). Cytotoxicity, measured as lysis of human red blood cells, also increased with increasing chain length. With (KW)(5), reduced antibacterial activity and increased cytotoxicity correlated with greater hydrophobicity and self-aggregation in the aqueous environment. The peptides acted by inducing rapid collapse of the bacterial transmembrane potential and induction of membrane permeability. The mode of interaction of the peptides and the phosphate groups of lipopolysaccharide was dependent upon the peptides' ability to permeate the membrane. Longer peptides [(KW)(4) and (KW)(5)] but not shorter peptides [(KW)(2) and (KW)(3)] strongly bound and partially inserted into negatively charged, anionic lipid bilayers. These longer peptides also induced membrane permeabilization and aggregation of lipid vesicles. The peptides had a disordered structure in aqueous solution, and only (KW)(4) and (KW)(5) displayed a folded conformation on lipid membranes. Moreover, (KW)(4) destroyed and agglutinated bacterial cells, demonstrating its potential as an antimicrobial agent. Collectively, the results show (KW)(4) to be the most efficacious peptide in the (KW)( n ) series, exhibiting strong antibacterial activity with little cytotoxicity. PMID:22914980

Gopal, Ramamourthy; Seo, Chang Ho; Song, Peter I; Park, Yoonkyung

2013-02-01

45

Magnesium Based Materials and their Antimicrobial Activity  

NASA Astrophysics Data System (ADS)

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

Robinson, Duane Allan

46

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

PubMed Central

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

Sestras, Radu E.; Jantschi, Lorentz; Bolboaca, Sorana D.

2012-01-01

47

Antimicrobial activity of glucoprotamin-containing disinfectants.  

PubMed

Introduction of a new antimicrobial agent as a drug--for treatment of infections or as a disinfectant and antiseptic, may result in the occurrence of resistance mechanisms against this agent among microorganisms. Two disinfectants of different composition--Incidin Plus for surface disinfection and Sekusept Plus for medical devices disinfection, both containing glucoprotamin as the active substance, were investigated in this study in order to analyze their antimicrobial activity. Standard bacterial and fungal strains recommended by European Standards, established by European Standardization Committee for testing bactericidal and fungicidal activity of chemical disinfectants were used in the study. Furthermore, 60 clinical bacterial strains with different susceptibility to antibiotics and chemotherapeutics, mostly multiresistant, isolated from different specimens from hospitalized patients were analyzed. In addition, 184 fungal clinical strains isolated from hospitalized patients and outpatients were also included in this study. Antimicrobial activity was evaluated according to EN 1040:2005 --using bacterial strains and according to EN 1275:2005--using fungal strains. Glucoprotamin proved to be a very effective and rapidly acting bactericidal and fungicidal agent. Low concentration of glucoprotamin--0.5% showed to be very effective (1 min) against clinical bacterial isolates. Incidin Plus was also very effective (5 min) against clinical fungal isolates. PMID:20380145

Tyski, Stefan; Grzybowska, Wanda; Grzeszczuk, Sabina; Leszczy?ski, Piotr; Staniszewska, Monika; Röhm-Rodowald, Ewa; Jakimiak, Bozena

2009-01-01

48

Effects of hydrophobicity on the antifungal activity of ?-helical antimicrobial peptides  

PubMed Central

We utilized a series of analogs of D-V13K (a 26-residue amphipathic ?-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 6-fold 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 5-fold 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 to 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 nonpolar 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 to D4 and represents a unique approach to control specificity while maintaining high hydrophobicity in the two hydrophobic segments on the nonpolar face of D5.

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

2009-01-01

49

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

50

Antimicrobial activity of South African medicinal plants.  

PubMed

This paper reviews the antimicrobial research undertaken on South African medicinal plants during the period 1997-2008. Antimicrobial methods (disc diffusion, minimum inhibitory concentration (MIC), bio-autography) are briefly discussed and an analysis of the publications reviewed indicates that the majority of papers use MIC assays for antimicrobial determination. Antimicrobial investigations on extracts are presented where the most active plants are identified from screening publications. A summary of some bioactive compounds are given with data restricted to papers reporting quantitative antimicrobial activity equivalent to or below 200 microg/ml. Antimicrobial activities on the essential oils of indigenous medicinal aromatic plants are also reviewed. An overview is given on what activities (extracts, compounds and oils) should be considered noteworthy for publication. Studies focusing on geographical ethnobotany, specific pathogenesis, formulation aspects and in vivo investigations are examined. Future recommendations to consider include pathogen selection, interactive studies and dosage administrations. PMID:18582553

van Vuuren, S F

2008-10-28

51

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

52

Effect of Ring Size on Conformation and Biological Activity of Cyclic Cationic Antimicrobial Peptides  

PubMed Central

In a series of cyclic peptides based on GS10, an analog of gramicidin S (GS), the ring size was varied from 10 to 16 amino acids. Alternative addition of basic and hydrophobic amino acids to the original GS10 construct generated a variety of even-numbered rings, i.e. GS10 [cyclo-(VKLdYPVKLdYP)], GS12 [cyclo-(VKLKdYPKVKLdYP)], GS14 [cyclo-(VKLKVdYPLKVKLdYP), and GS16 [cyclo-(VKLKVKdYPKLKVKLdYP)] (d stands for D-enantiomers). The odd-numbered analogs (11, 13 and 15-mers) were derived from these four peptides either by addition or deletion of single basic (Lys) or hydrophobic (Leu or Val) amino acids. The resulting peptides, divided into three groups on the basis of peptide ring size (10- to 12-meric, 13- and 14-meric, and 15- and 16-meric) illustrated a diverse spectrum of biological activity correlated to their ring size, degree of ?-structure disruption, charge, hydrophobicity, amphipathicity and affinity for lipid membranes. Two of these peptides with potent antimicrobial activities and high therapeutic indexes (4.5–10 folds compared with GS) are promising candidates for development of broad-spectrum antibiotics.

Jelokhani-Niaraki, Masoud; Kondejewski, Leslie H.; Wheaton, Laura C.; Hodges, Robert S.

2009-01-01

53

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

54

Antimicrobial activity of Leucas aspera flowers  

Microsoft Academic Search

The methanol extract of Leucas aspera flowers, its fractions, the alkaloidal residue and the expressed flower juice, tested for antimicrobial activity, showed good antibacterial activity for methanol extract and methanol fraction with maximum activity for the alkaloidal residue.

K. Mangathayaru; J. Lakshmikant; N. Shyam Sundar; R. Swapna; X. Fatima Grace; J. Vasantha

2005-01-01

55

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

56

Screening and Identification of Effective Thermotolerant Lactic Acid Bacteria Producing Antimicrobial Activity Against Escherichia coli and Salmonella sp. Resistant to Antibiotics  

Microsoft Academic Search

Two hundred fifty six isolates of lactic acid bacteria (LAB) displaying antimicrobial activity were isolated from chicken intestine. Twenty effective isolates of LAB show bacteriocin - like activity (BLA) against the target strains resistant to antibiotics ( Escherichia coli and Salmonella sp.) to varying degrees. Broad spectrum inhibition specific (SIS) were found from 6 h cultivation while the longer cultivation

Sunee Nitisinprasert; Veeraphol Nilphai; Phunjai Bunyun; Prakit Sukyai; Katsumi Doi; Kenji Sonomoto

57

A novel beta-defensin antimicrobial peptide in Atlantic cod with stimulatory effect on phagocytic activity.  

PubMed

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, Bĺrd Ove; Fernandes, Jorge M O

2013-01-01

58

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.

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

2013-01-01

59

Effects of Slime Produced by Clinical Isolates of Coagulase-Negative Staphylococci on Activities of Various Antimicrobial Agents  

Microsoft Academic Search

A novel in vitro semiquantitative method was developed to investigate the influence of staphylococcal slime on the activities of 22 antimicrobial agents. Pefloxacin, teicoplanin, and vancomycin demonstrated remarkable decreases in efficacy: 30, 52, and 63%, respectively. The activity of rifampin was not significantly reduced (0.99%), whereas all other agents tested were modestly affected (<15% decrease). These data could be influential

MARIA SOULI; HELEN GIAMARELLOU

1998-01-01

60

Antimicrobial activity of selected Peruvian medicinal plants.  

PubMed

The antimicrobial activity of 36 ethanol extracts from 24 plants, all of them currently used in the Peruvian traditional medicine for the treatment of several infectious and inflammatory disorders, was tested by means of the agar-well diffusion assay against four bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and four fungi (Candida albicans, Trichophyton mentagrophytes, Microsporum gypseum and Sporothrix schenckii). Twenty-five (69%) extracts showed some degree of antimicrobial activity against at least one microorganism. The plants with the greatest antimicrobial activity were Cestrum auriculatum L. Heritier (Solanaceae), Iryanthera lancifolia Ducke Suesseng (Myristicaceae), Lepechinia meyenii (Walp.) Epling (Lamiaceae) and Ophryosporus peruvianus (Gmelin) King & H. Rob. (Asteraceae). PMID:12963143

Rojas, Rosario; Bustamante, Beatriz; Bauer, José; Fernández, Irma; Albán, Joaquina; Lock, Olga

2003-10-01

61

Effects of Net Charge and the Number of Positively Charged Residues on the Biological Activity of Amphipathic ?-Helical Cationic Antimicrobial Peptides  

PubMed Central

In our previous study, we utilized a 26-residue amphipathic ?-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 ?g/ml to <7.8 ?g/ml, respectively).

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

2009-01-01

62

The Antimicrobial Activity of Porphyrin Attached Polymers  

Microsoft Academic Search

We are interested in testing the antimicrobial activity of a porphyrin that is attached to a polymer. The porphyrin (5-(4-carboxyphenyl)-10,15,20-tris-(4-pryridyl)) was synthesized from methyl 4-formyl benzoate, 4-pyridinecarboxaldehyde, and pyrrole and attached to a copolymer of polystyrene\\/poly(vinyl benzyl chloride), which was synthesized by free radical polymerization. The antimicrobial activity of the polymer-attached porphyrin was then determined for gram-negative E. Coli grown

Lesley Thompson

2008-01-01

63

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

PubMed

Recent investigations in the anti-microbial properties of the functional polymers are predominantly focused on the structure of the cationic moieties. In the present study, we investigated that the nature of the anion present in polysulfobetaines affects activity against certain microorganisms and their anti-microbial properties have been rationalized in terms of the structure-activity relationship. Vinyl imidazolium-based polysulfobetaines were prepared by the quaternization of poly(N-vinyl imidazole) with sodium salt of 2-bromo ethanesulfonic acid. The bromide counter anion of the resulting polymer was exchanged with different anions to generate a series of polymers. These were characterized by FTIR, DSC, XRD, SEM, elemental analysis (C, H, N and S) and viscosity measurements. The anti-microbial activity studies were carried against three fungi (Aspergillus niger, Byssochlamys fulva and Mucor circenelliods) and two bacteria (Bacillus coagulans BTS-3 and Pseudomonas aeruginosa BTS-2). The nature of the anion affects the structure of polysulfobetaine by realignment of polymer chains. The anion-dependent anti-microbial properties of polysulfobetaines result from the interaction of the microbes at the polymer interface. PMID:20060120

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

2010-04-01

64

Antimicrobial activity of antiseptic-coated orthopaedic devices.  

PubMed

Antimicrobial coating of medical devices, including fracture fixation devices, has evolved as a potentially effective method for preventing device-related infections. We examined the in vitro antimicrobial activity of titanium cylinders coated with the antiseptic combination of chlorhexidine and chloroxylenol. The coated devices provided zones of inhibition against Staphylococcus epidermidis, S. aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans, at baseline and up to 8 weeks after incubation of the coated cylinders in human serum at 37 degrees C. This durable antimicrobial activity was attributed to the relatively slow leaching of chlorhexidine and chloroxylenol from the coated cylinders as measured by high-performance liquid chromatography. These results suggest that antiseptic-coated orthopaedic devices may provide broad-spectrum and durable antimicrobial protection against device-related infection. PMID:9624548

Darouiche, R O; Green, G; Mansouri, M D

1998-04-01

65

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

PubMed

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

Al-Waili, Noori S

2004-01-01

66

Peptides and proteins with antimicrobial activity.  

PubMed

The increase of microbial resistance to antibiotics has led to a continuing search for newer and more effective drugs. Antimicrobial peptides are generally found in animals, plants, and microorganisms and are of great interest to medicine, pharmacology, and the food industry. These peptides are capable of inhibiting pathogenic microorganisms. They can attack parasites, while causing little or no harm to the host cells. The defensins are peptides found in granules in the polymorphonuclear neutrophils (PMNs) and are responsible for the defense of the organism. Several animal defensins, like dermaseptin, antileukoprotease, protegrin, and others, have had their activities and efficacy tested and been shown to be effective against bacteria, fungi, and protists; there are also specific defensins from invertebrates, e.g., drosomycin and heliomicin; from plants, e.g., the types A and B; and the bacteriocins, e.g., acrocin, marcescin, etc. The aim of the present work was to compile a comprehensive bibliographic review of the diverse potentially antimicrobial peptides in an effort to systematize the current knowledge on these substances as a contribution for further researches. The currently available bibliography does not give a holistic approach on this subject. The present work intends to show that the mechanism of defense represented by defensins is promising from the perspective of its application in the treatment of infectious diseases in human, animals and plants. PMID:21264153

Coutinho, Henrique Douglas Melo; Lôbo, Katiuscia Menezes; Bezerra, Denise Aline Casimiro; Lôbo, Inalzuir

2008-01-01

67

Peptides and proteins with antimicrobial activity  

PubMed Central

The increase of microbial resistance to antibiotics has led to a continuing search for newer and more effective drugs. Antimicrobial peptides are generally found in animals, plants, and microorganisms and are of great interest to medicine, pharmacology, and the food industry. These peptides are capable of inhibiting pathogenic microorganisms. They can attack parasites, while causing little or no harm to the host cells. The defensins are peptides found in granules in the polymorphonuclear neutrophils (PMNs) and are responsible for the defense of the organism. Several animal defensins, like dermaseptin, antileukoprotease, protegrin, and others, have had their activities and efficacy tested and been shown to be effective against bacteria, fungi, and protists; there are also specific defensins from invertebrates, e.g., drosomycin and heliomicin; from plants, e.g., the types A and B; and the bacteriocins, e.g., acrocin, marcescin, etc. The aim of the present work was to compile a comprehensive bibliographic review of the diverse potentially antimicrobial peptides in an effort to systematize the current knowledge on these substances as a contribution for further researches. The currently available bibliography does not give a holistic approach on this subject. The present work intends to show that the mechanism of defense represented by defensins is promising from the perspective of its application in the treatment of infectious diseases in human, animals and plants.

Coutinho, Henrique Douglas Melo; Lobo, Katiuscia Menezes; Bezerra, Denise Aline Casimiro; Lobo, Inalzuir

2008-01-01

68

Synergistic effect and antibiofilm activity between the antimicrobial peptide coprisin and conventional antibiotics against opportunistic bacteria.  

PubMed

Coprisin is a 43-mer defensin-like peptide from the dung beetle, Copris tripartitus. In this study, we tested its minimum inhibitory concentration and performed combination assays to confirm the antibacterial susceptibility of coprisin and synergistic effects with antibiotics. The synergistic effects were evaluated by testing the effects of coprisin in combination with ampicillin, vancomycin, and chloramphenicol. The results showed that coprisin possessed antibacterial properties and had synergistic activities with the antibiotics. To understand the synergistic mechanism(s), we conducted hydroxyl radical assays. Coprisin alone and in combination with antibiotics generated hydroxyl radicals, which are highly reactive oxygen forms and the major property of bactericidal agents. Furthermore, the antibiofilm effect of coprisin alone and in combination with antibiotics was investigated. Biofilm formation is the source of many relentless and chronic bacterial infections. The results indicated that coprisin alone and in combination with antibiotics also had antibiofilm activity. Therefore, we conclude that coprisin has the potential to be used as a combinatorial therapeutic agent for the treatment of infectious diseases caused by bacteria. PMID:23053486

Hwang, In-sok; Hwang, Jae-Sam; Hwang, Ji Hong; Choi, Hyemin; Lee, Eunjung; Kim, Yangmee; Lee, Dong Gun

2013-01-01

69

Medicinal plants and antimicrobial activity  

Microsoft Academic Search

In the present paper, we analyze the past, present and future of medicinal plants, both as potential antimicrobial crude drugs as well as a source for natural compounds that act as new anti-infection agents. In the past few decades, the search for new anti-infection agents has occupied many research groups in the field of ethnopharmacology. When we reviewed the number

J. L. Ríos; M. C. Recio

2005-01-01

70

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.

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

2013-01-01

71

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

72

Antimicrobial activity of Hymenodictyon parvifolium.  

PubMed

Methanol extract of the stem bark of Hymenodictyon parvifolium was tested for its antifungal and antibacterial activity. The extract was found to have inhibitory effect against all the pathogens tested. PMID:12385880

Kariba, R M

2002-10-01

73

Multidrug Pump Inhibitors Uncover Remarkable Activity of Plant Antimicrobials  

PubMed Central

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

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

2002-01-01

74

The Antimicrobial Activity of Porphyrin Attached Polymers  

NASA Astrophysics Data System (ADS)

We are interested in testing the antimicrobial activity of a porphyrin that is attached to a polymer. The porphyrin (5-(4-carboxyphenyl)-10,15,20-tris-(4-pryridyl)) was synthesized from methyl 4-formyl benzoate, 4-pyridinecarboxaldehyde, and pyrrole and attached to a copolymer of polystyrene/poly(vinyl benzyl chloride), which was synthesized by free radical polymerization. The antimicrobial activity of the polymer-attached porphyrin was then determined for gram-negative E. Coli grown to 0.80 OD. In this procedure, glass slides were coated with polymer-attached porphyrin via dip-coating, and the E. Coli bacteria were plated in Luria Broth media. The plates were subsequently exposed to light overnight before they were incubated as porphyrins act as photo-sensitizers when irradiated with light. The polymer-attached porphyrin did exhibit antimicrobial activity and parameters that affect its efficiency will be discussed.

Thompson, Lesley

2008-03-01

75

Synthesis and antimicrobial activity of some anthranilic acid derivatives.  

PubMed

The synthesis of eight derivatives of anthranilic acid is described. Investigation of their antimicrobial activity showed that four of the compounds, viz; anthranilohydrazide, 3,4-dihydro-4-oxo-1,2,3-benzotriazine, triazine-beta-naphthol adduct and N-phenyl anthranilic acid showed significant antibacterial activity. None of the compounds showed any noticeable antifungal effect. PMID:7433494

Kar, A; Gugnani, H C; Madumere, U A

1980-08-01

76

Protease inhibitors from plants with antimicrobial activity.  

PubMed

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

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

2009-06-01

77

Lipidated Peptidomimetics with Improved Antimicrobial Activity  

PubMed Central

We report a series of lipidated ?-AApeptides that mimic the structure and function of natural antimicrobial lipopeptides. Several short lipidated ?-AApeptides show broad-spectrum activity against a range of clinically related Gram-positive and Gram-negative bacteria as well as fungus. Their antimicrobial activity and selectivity are comparable or even superior to the clinical candidate pexiganan as well as previously reported linear ?-AApeptides. The further development of lipidated ?-AApeptides will lead to a new class of antibiotics to combat drug resistance.

2012-01-01

78

Use of rosemary, oregano, and a commercial blend of essential oils in broiler chickens: in vitro antimicrobial activities and effects on growth performance.  

PubMed

The present study was conducted to characterize the in vitro antimicrobial activities of 3 essential oils [oregano, rosemary, and a commercial blend of essential oils (BEO)] against pathogenic and nonpathogenic bacteria and to evaluate their effects on broiler chicken performances. The chemical composition of the essential oils was determined using the gas chromatography interfaced with a mass spectroscopy. The disc diffusion method, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) were applied for the determination of antimicrobial activities of essential oils. In vivo study, a total of seven hundred fifty 1-d-old male broiler chickens were assigned to 6 dietary treatment groups: basal diet (control; CON), CON + 44 mg of avilamycin/kg (A), CON + 100 mg of rosemary essential oil/kg (ROS), CON + 100 mg of oregano essential oil/kg (OR), CON + 50 mg of rosemary and 50 mg of oregano essential oils/kg (RO), and CON + 1,000 mg of BEO/kg (essential oil mixture, EOM). The essential oils isolated from rosemary and oregano were characterized by their greater content of 1,8-cineole (49.99%) and carvacrol (69.55%), respectively. The BEO was mainly represented by the aldehyde (cinnamaldehyde) and the monoterpene (1,8-cineole) chemical groups. The results of the disc diffusion method indicated that the rosemary essential oil had antibacterial activity (P ? 0.05) against only 3 pathogenic bacteria, Escherichia coli (8 mm), Salmonella indiana (11 mm), and Listeria innocua (9 mm). The essential oil of oregano had antimicrobial activities (P ? 0.05) on the same bacteria as rosemary but also on Staphylococcus aureus (22 mm) and Bacillus subtilis (12 mm). Oregano essential oil had greater (P ? 0.05) antimicrobial activities against pathogenic bacteria than rosemary essential oil but they had no synergism between them. The BEO showed an increased antimicrobial activity (P ? 0.05) against all studied bacteria (pathogenic and nonpathogenic bacteria) except for Lactobacillus rhamnosus. The supplementation of the basal diet with avilamycin or essential oils improved (P ? 0.05) broiler chicken BW, BW gain, and G:F compared with the CON diet. There were no differences in growth performances among birds fed A, ROS, OR, RO, or EOM diets. In general, essential oils contained in rosemary, oregano, and BEO can substitute for growth promoter antibiotics. Although the 3 essential oils had different antimicrobial activities, they exhibited the same efficiency in broiler chickens. PMID:22064737

Mathlouthi, N; Bouzaienne, T; Oueslati, I; Recoquillay, F; Hamdi, M; Urdaci, M; Bergaoui, R

2012-03-01

79

Antimicrobial activity of various extracts of Ocimum basilicum L. and observation of the inhibition effect on bacterial cells by use of scanning electron microscopy.  

PubMed

The antimicrobial activities of chloroform, acetone and two different concentrations of methanol extracts of Ocimum basilicum L. were studied. These extracts were tested in vitro against 10 bacteria and 4 yeasts strains by the disc diffusion method. The results indicated that the methanol extracts of O. basilucum exhibited the antimicrobial activity against tested microorganisms. While the chloroform and acetone extracts had no effect, the methanol extracts showed inhibition zones against strains of Pseudomonas aeruginosa, Shigella sp., Listeria monocytogenes, Staphylococcus aureus and two different strains of Escherichia coli. The cells of microorganisms, which were treated and untreated with plant extracts, were observed by using the scanning electron microscope. It was observed that the treated cells were damaged. PMID:20161958

Kaya, Ilhan; Yigit, Nazife; Benli, Mehlika

2008-01-01

80

Nitric oxide produced in Peyer's patches exhibits antiapoptotic activity contributing to an antimicrobial effect in murine salmonellosis.  

PubMed

Salmonella species normally infect hosts via the oral-fecal route. We previously reported that NO had potent host defense functions in murine salmonellosis, not only via a direct antibacterial effect but also because it was cytoprotective for infected host cells. Here, we used an oral route to infect iNOS-deficient mice infected with S. enterica serovar Typhimurium to further investigate the cytoprotective role of NO in preventing damage caused by Salmonella organisms in PP. Oral bacterial challenge (2 x 10(5) CFU, or >100 LD(50)) produced a more severe infection and greater lethality in iNOS-deficient mice than in iNOS-competent mice. We used specific antibodies to S. enterica Typhimurium, neutrophils, iNOS, nitrotyrosine, and dendritic cells (CD11c-positive) in histochemical and immunohistochemical studies to examine infected PP tissues. S. enterica Typhimurium colonization in PP from iNOS-deficient mice was significantly higher than that in wild-type mice. Histochemical assays showed extensive cellular damage in PP. We then examined PP tissues for apoptosis by means of in situ TUNEL analysis and by measuring caspase-3 specific activity in tissue homogenates. Increased numbers of TUNEL-positive cells and severe granulomatous inflammation with increased infiltration of neutrophils and macrophages were observed during infection in iNOS-deficient mice compared with wild-type mice. iNOS-deficient mice had increased numbers of dendritic cells and significantly higher caspase-3-specific activity in PP. These data confirm that NO exerts its protective function not only through direct antibacterial action, but also by preventing apoptosis and thereby contributing to antimicrobial defense during salmonellosis. PMID:18426394

Alam, Mohammad S; Zaki, Mohammad H; Sawa, Tomohiro; Islam, Sabrina; Ahmed, Khandaker A; Fujii, Shigemoto; Okamoto, Tatsuya; Akaike, Takaaki

2008-04-01

81

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

82

Antimicrobial activity of some natural dyes  

Microsoft Academic Search

The present study was taken up as an exploratory study to test if some natural dyes have inherent antimicrobial activity with a view to develop protective clothing from these. Four natural dyes Acacia catechu, Kerria lacca, Quercus infectoria, Rubia cordifolia and Rumex maritimus were tested against common pathogens Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa. Quercus

Rajni Singh; Astha Jain; Shikha Panwar; Deepti Gupta; S. K. Khare

2005-01-01

83

Antimicrobial activities of tocklai vegetative tea clones.  

PubMed

Thirty-one Tocklai vegetative (TV) tea clones contained caffeine and total catechin 44.39 and 227.55 mg/g dry weight of leaves, respectively. The (-)-epigallocatechin gallate (EGCG) was the most abundant (109.60 mg/g) followed by -(-)-epigallocatechin (EGC, 44.54 mg/g), (-)-epicatechin gallate (ECG, 41.74 mg/g), (-)-epicatechin (EC, 27.42 mg/g) and +catechin (4.25 mg/g). Total catechins were highest in TV 20 (509.7 mg/g) and lowest in TV 6 (71.7 mg/g). The tea clones that contain high level of total catechin exhibited the strongest antimicrobial activity. Among caffeine and flavanol compounds, theaflavins (TF) present in black tea possess a similar antimicrobial potency as EC present in fresh leaves, and that the conversion of catechins to TF during fermentation in making black tea tends to alter their antimicrobial activities. The bioactive molecules other than catechins present in tea leaves may also contribute towards antimicrobial activity. PMID:23024406

Thakur, D; Das, S C; Sabhapondit, S; Tamuly, P; Deka, D K

2011-10-01

84

In vitro antimicrobial activity of Achyranthes coynei Sant.  

PubMed Central

Objective To validate the traditional use of Achyranthes coynei (A. coynei) Sant. as an antimicrobial in treatment of various infectious diseases. Methods Leaf extracts of A. coynei obtained through successive solvent extraction using petroleum ether, dichrloromethane, chloroform and methanol were used to screen the antimicrobial activity on five Gram positive, five Gram negative bacteria and two fungi. Minimum inhibitory concentration (MIC) was determined by two fold tube-dilution method. Results Methanolic leaf extract was more effective than other three extracts on the tested bacteria. Methanolic extract was efficient on Staphylococcus epidermis, Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa with MIC values (0.62±0.00) mg/mL. The fungal organisms were less susceptible against extracts tested. Conclusions These results support the traditional use of leaf extracts of A. coynei as they have antimicrobial potential. Further studies are needed for establishing safety, toxicity and pharmacological activity with phytochemical investigation.

Ankad, Gireesh; Upadhya, Vinayak; Pai, Sandeep R.; Hegde, Harsha V.; Roy, Subarna

2013-01-01

85

Influence of abiotic factors on the antimicrobial activity of chitosan.  

PubMed

In an effort to bypass the adverse secondary effects attributed to the traditional therapeutic approaches used to treat skin disorders (such as atopic dermatitis), alternative antimicrobials have recently been suggested. One such antimicrobial is chitosan, owing to the already proved biological properties associated with its use. However, the influence of abiotic factors on such activities warrants evaluation. This research effort assessed the antimicrobial activity of chitosan upon skin microorganisms (Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli) in vitro when subject to a combination of different abiotic factors such as pH, ionic strength, organic acids and free fatty acids. Free fatty acids, ionic strength and pH significantly affected chitosan's capability of reducing the viable numbers of S. aureus. This antimicrobial action was potentiated in the presence of palmitic acid and a lower ionic strength (0.2% NaCl), while a higher ionic strength (0.4% NaCl) favored chitosan's action upon the reduction of viable numbers of S. epidermidis and E. coli. Although further studies are needed, these preliminary results advocate that chitosan can in the future be potentially considered as an antimicrobial of choice when handling symptoms associated with atopic dermatitis. PMID:24330167

Tavaria, Freni K; Costa, Eduardo M; Gens, Eduardo J; Malcata, Francisco Xavier; Pintado, Manuela E

2013-12-01

86

Novel ?-MSH Peptide Analogues with Broad Spectrum Antimicrobial Activity  

PubMed Central

Previous investigations indicate that ?-melanocyte-stimulating hormone (?-MSH) and certain synthetic analogues of it exert antimicrobial effects against bacteria and yeasts. However, these molecules have weak activity in standard microbiology conditions and this hampers a realistic clinical use. The aim in the present study was to identify novel peptides with broad-spectrum antimicrobial activity in growth medium. To this purpose, the Gly10 residue in the [DNal(2?)-7, Phe-12]-MSH(6–13) sequence was replaced with conventional and unconventional amino acids with different degrees of conformational rigidity. Two derivatives in which Gly10 was replaced by the residues Aic and Cha, respectively, had substantial activity against Candida strains, including C. albicans, C. glabrata, and C. krusei and against gram-positive and gram-negative bacteria. Conformational analysis indicated that the helical structure along residues 8–13 is a key factor in antimicrobial activity. Synthetic analogues of ?-MSH can be valuable agents to treat infections in humans. The structural preferences associated with antimicrobial activity identified in this research can help further development of synthetic melanocortins with enhanced biological activity.

Auriemma, Luigia; Limatola, Antonio; Di Maro, Salvatore; Merlino, Francesco; Mangoni, Maria Luisa; Luca, Vincenzo; Di Grazia, Antonio; Gatti, Stefano; Campiglia, Pietro; Gomez-Monterrey, Isabel; Novellino, Ettore; Catania, Anna

2013-01-01

87

Novel ?-MSH peptide analogues with broad spectrum antimicrobial activity.  

PubMed

Previous investigations indicate that ?-melanocyte-stimulating hormone (?-MSH) and certain synthetic analogues of it exert antimicrobial effects against bacteria and yeasts. However, these molecules have weak activity in standard microbiology conditions and this hampers a realistic clinical use. The aim in the present study was to identify novel peptides with broad-spectrum antimicrobial activity in growth medium. To this purpose, the Gly10 residue in the [DNal(2')-7, Phe-12]-MSH(6-13) sequence was replaced with conventional and unconventional amino acids with different degrees of conformational rigidity. Two derivatives in which Gly10 was replaced by the residues Aic and Cha, respectively, had substantial activity against Candida strains, including C. albicans, C. glabrata, and C. krusei and against gram-positive and gram-negative bacteria. Conformational analysis indicated that the helical structure along residues 8-13 is a key factor in antimicrobial activity. Synthetic analogues of ?-MSH can be valuable agents to treat infections in humans. The structural preferences associated with antimicrobial activity identified in this research can help further development of synthetic melanocortins with enhanced biological activity. PMID:23626703

Grieco, Paolo; Carotenuto, Alfonso; Auriemma, Luigia; Limatola, Antonio; Di Maro, Salvatore; Merlino, Francesco; Mangoni, Maria Luisa; Luca, Vincenzo; Di Grazia, Antonio; Gatti, Stefano; Campiglia, Pietro; Gomez-Monterrey, Isabel; Novellino, Ettore; Catania, Anna

2013-01-01

88

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

PubMed

This study evaluated four food-derived peptides with known antihypertensive activities for antimicrobial activity against pathogenic microorganisms, and assessed structure-function relationships using alanine analogues. The peptides (EVSLNSGYY, barley; PGTAVFK, soybean; TTMPLW, ?-casein; VHLPP, ?-zein) and the six alanine substitution peptides of PGTAVFK were synthesised, characterised and evaluated for antimicrobial activity using the bacteria, Escherichia coli, Staphylococcus aureus, and Micrococcus luteus and the yeast, Candida albicans. The peptides TTMPLW and PGTAVFK inhibited growth of all four microorganisms tested, with activities of a similar order of magnitude to ampicillin and ethanol controls. EVSLNSGYY inhibited the growth of the bacteria, but VHLPP showed no antimicrobial activity. The alanine analogue, PGAAVFK showed the highest overall antimicrobial activity and PGTAVFA showed no activity; overall, the activities of the analogues were consistent with their structures. Some peptides with antihypertensive activity also show antimicrobial activity, suggesting that food-derived peptides may exert beneficial effects via a number of mechanisms. PMID:24176365

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

2014-03-01

89

The Antimicrobial Activity of Liposomal Lauric Acids Against Propionibacterium acnes  

PubMed Central

This study evaluated the antimicrobial activity of lauric acid (LA) and its liposomal derivatives against Propionibacterium acnes (P. acnes), the bacterium that promotes inflammatory acne. First, the antimicrobial study of three free fatty acids (lauric acid, palmitic acid and oleic acid) demonstrated that LA gives the strongest bactericidal activity against P. acnes. However, a setback of using LA as a potential treatment for inflammatory acne is its poor water solubility. Then the LA was incorporated into a liposome formulation to aid its delivery to P. acnes. It's demonstrated that the antimicrobial activity of LA was not only well maintained in its liposomal derivatives but also enhanced at low LA concentration. In addition, the antimicrobial activity of LA-loaded liposomes (LipoLA) mainly depended on the LA loading concentration per single liposomes. Further study found that the LipoLA could fuse with the membranes of P. acnes and release the carried LA directly into the bacterial membranes, thereby killing the bacteria effectively. Since LA is a natural compound that is the main acid in coconut oil and also resides in human breast milk and liposomes have been successfully and widely applied as a drug delivery vehicle in the clinic, the LipoLA developed in this work holds great potential of becoming an innate, safe and effective therapeutic medication for acne vulgaris and other P. acnes associated diseases.

Yang, Darren; Pornpattananangkul, Dissaya; Nakatsuji, Teruaki; Chan, Michael; Carson, Dennis; Huang, Chun-Ming; Zhang, Liangfang

2009-01-01

90

Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species  

PubMed Central

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

Mitrovic, Tatjana; Stamenkovic, Slavisa; Cvetkovic, Vladimir; Tosic, Svetlana; Stankovic, Milan; Radojevic, Ivana; Stefanovic, Olgica; Comic, Ljiljana; ?acic, Dragana; Curcic, Milena; Markovic, Snezana

2011-01-01

91

Antimicrobial activity of o-carboranylalanine.  

PubMed

Functionalized polyhedral carboranes, including amino acid analogs, have unique physicochemical properties and are used as experimental anticancer agents. However, our current knowledge on their effect in nonmammalian biological systems is limited. We investigated the activity spectrum in vitro of o-carboranylalanine (o-Cba), considered to be a highly lipophilic analog of phenylalanine, against representative plant pathogenic bacteria and fungi of various taxonomic position. The antibacterial effect of o-Cba against some species was comparable to that of the widely used agricultural antibiotic, streptomycin. The sensitivity of individual bacterial species to o-Cba within the same genus varied to a greater extent than the average sensitivity of various genera. In general, this carborane-containing amino acid was more toxic to Gram positive bacteria (Bacillus, Corynebacterium, Curtobacterium, Micrococcus, Rhodococcus, and Staphylococcus) than to Gram negative ones (Agrobacterium, Erwinia, Escherichia, Pseudomonas, Rhizobium, and Xanthomonas). Compared to the commercial fungicide, prochloraz, o-Cba was weakly toxic against various fungi (Zygo- and Ascomycota). It was also inferior to the commercial fungicide metalaxyl in inhibiting the vegetative growth of oomyceteous plant pathogens (Pythium irregulare, Phytophthora cryptogea and Plasmopara halstedii). Against the asexual spores of P. halstedii, o-Cba, however, was over a thousandfold more active than tridemorph, a selective zoospore inhibitor fungicide. For all taxonomic groups, the observed antimicrobial effect of o-Cba could be diminished with histidine, but not with phenylalanine. In studies on healthy and mildew-infected sunflower and tobacco plants o-Cba showed neither fungicidal nor phytotoxic effects at 500 ppm. This is the first report on the biological activity spectrum of a carborane-containing amino acid. PMID:10707765

Oros, G; Ujváry, I; Nachman, R J

1999-01-01

92

Antimicrobials  

PubMed Central

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

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

2013-01-01

93

Antimicrobial activity of metronidazole in anaerobic bacteria.  

PubMed

The antimicrobial activity of metronidazole was investigated in anaerobic bacteria by use of time-viability studies. This antimicrobial agent has a rapid onset of bactericidal activity under proper reducing conditions. The bactericidal rates were not affected by inoculum size or nutritional requirements, nor by inhibition of growth and protein synthesis by chloramphenicol. Using supernatant fractions of actively growing cultures of susceptible organisms, we observed a disappearance of metronidazole and a loss of biological activity, but there was no significant change in preparations from resistant bacteria. The decrease in drug concentration with susceptible cells occurred during the time that its bactericidal action was being exerted. Extracts from susceptible organisms rapidly reduced the concentration of metronidazole, confirming previous observations which suggest that the drug acts as a terminal electron acceptor. Radioisotope experiments with [14C]metronidazole revealed that the compound was taken up by both resistant and susceptible bacteria, although there was a difference in rate and extent of accumulation. These studies demonstrate that metronidazole's antimicrobial activity against anaerobic bacteria is bactericidal and independent of growth rate, and that it involves the uptake and metabolism of the compound. PMID:233729

Tally, F P; Goldin, B R; Sullivan, N; Johnston, J; Gorbach, S L

1978-03-01

94

Antimicrobial activity of silicone rubber used in hydrocephalus shunts, after impregnation with antimicrobial substances  

Microsoft Academic Search

Colonisation of cerebrospinal fluid shunts by coagulate-negative staphylococci (Staphylococcus albus) is a serious problem. Because of its possible role in prevention of the condition, the antimicrobial activity of silicone rubber after impregnation with antimicrobial drugs was studied. The method of impregnation used and test methods were found to be important. Formaldehyde-urea condensates gave no activity. Gentamicin sulphate gave activity which

R Bayston; R D Milner

1981-01-01

95

Antimicrobially active isoquinoline alkaloids from Litsea cubeba.  

PubMed

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

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

2009-01-01

96

Macin Family of Antimicrobial Proteins Combines Antimicrobial and Nerve Repair Activities*  

PubMed Central

The tertiary structures of theromacin and neuromacin confirmed the macin protein family as a self-contained family of antimicrobial proteins within the superfamily of scorpion toxin-like proteins. The macins, which also comprise hydramacin-1, are antimicrobially active against Gram-positive and Gram-negative bacteria. Despite high sequence identity, the three proteins showed distinct differences with respect to their biological activity. Neuromacin exhibited a significantly stronger capacity to permeabilize the cytoplasmic membrane of Bacillus megaterium than theromacin and hydramacin-1. Accordingly, it is the only macin that displays pore-forming activity and that was potently active against Staphylococcus aureus. Moreover, neuromacin and hydramacin-1 led to an aggregation of bacterial cells that was not observed with theromacin. Analysis of the molecular surface properties of macins allowed confirmation of the barnacle model as the mechanistic model for the aggregation effect. Besides being antimicrobially active, neuromacin and theromacin, in contrast to hydramacin-1, were able to enhance the repair of leech nerves ex vivo. Notably, all three macins enhanced the viability of murine neuroblastoma cells, extending their functional characteristics. As neuromacin appears to be both a functional and structural chimera of hydramacin-1 and theromacin, the putative structural correlate responsible for the nerve repair capacity in leech was located to a cluster of six amino acid residues using the sequence similarity of surface-exposed regions.

Jung, Sascha; Sonnichsen, Frank D.; Hung, Chien-Wen; Tholey, Andreas; Boidin-Wichlacz, Celine; Haeusgen, Wiebke; Gelhaus, Christoph; Desel, Christine; Podschun, Rainer; Waetzig, Vicki; Tasiemski, Aurelie; Leippe, Matthias; Grotzinger, Joachim

2012-01-01

97

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

98

Antimicrobial activity of Omalanthus nervosus.  

PubMed

The ethanol extracts of Omalanthus nervosus leaves, stem and root barks, were partitioned (petrol, dichloromethane, ethyl acetate). In respect to crude extracts, all fractions demonstrated broader spectrum and higher levels of antibacterial activity, ethyl acetate fractions being in all cases the more active. No fraction was active against tested moulds. PMID:11295305

Khan, M R; Kihara, M; Omoloso, A D

2001-03-01

99

Chemical reactivity and antimicrobial activity of N-substituted maleimides.  

PubMed

Several N-substituted maleimides containing substituents of varying bulkiness and polarity were synthesised and tested for antimicrobial and cytostatic activity. Neutral maleimides displayed relatively strong antifungal effect minimum inhibitory concentrations (MICs in the 0.5-4 µg ml(-1) range); their antibacterial activity was structure dependent and all were highly cytostatic, with IC(50) values below 0.1 µg ml(-1). Low antimicrobial but high cytostatic activity was noted for basic maleimides containing tertiary aminoalkyl substituents. Chemical reactivity and lipophilicity influenced antibacterial activity of neutral maleimides but had little if any effect on their antifungal and cytostatic action. N-substituted maleimides affected biosynthesis of chitin and ?(1,3)glucan, components of the fungal cell wall. The membrane enzyme, ?(1,3)glucan synthase has been proposed as a putative primary target of N-ethylmaleimide and some of its analogues in Candida albicans cells. PMID:21612375

Salewska, Natalia; Boros-Majewska, Joanna; L?cka, Izabela; Chyli?ska, Katarzyna; Sabisz, Micha?; Milewski, S?awomir; Milewska, Maria J

2012-02-01

100

Phenolic antioxidants from clonal oregano ( Origanum vulgare) with antimicrobial activity against Helicobacter pylori  

Microsoft Academic Search

Phenolic phytochemicals consumed via our diet are good sources of natural antioxidants. These phenolic metabolites have beneficial effects on human health, including inhibition of mutagenesis and carcinogenesis. In addition some phenolic phytochemicals have also been shown to have antimicrobial and antifungal activity. Oregano (Origanum vulgare L.) is an important Mediterranean herb rich in phenolic compounds with antioxidant and antimicrobial activity.

Sung-Sook Chun; Dhiraj A. Vattem; Yuan-Tong Lin; Kalidas Shetty

2005-01-01

101

Effect of HMG-CoA reductase inhibitors on antimicrobial susceptibilities for gram-negative rods.  

PubMed

Epidemiologic evidence suggests a beneficial effect of HMG-CoA reductase inhibitors (statins) in sepsis, and in-vitro data exist for antimicrobial activity of statins against some bacteria and fungi. We examined whether statin exposure at physiologic concentrations enhances activity of selected antimicrobials against Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Broth microdilution was performed with and without dose-ranging concentrations of lovastatin, fluvastatin, atorvastatin, pravastatin and simvastatin. No effects on antimicrobial activity were demonstrated. PMID:22736455

Farmer, Aaron R; Murray, Clinton K; Mende, Katrin; Akers, Kevin S; Zera, Wendy C; Beckius, Miriam L; Yun, Heather C

2013-04-01

102

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

PubMed

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

103

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).

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

2014-01-01

104

Diazinium salts with dihydroxyacetophenone skeleton: Syntheses and antimicrobial activity.  

PubMed

Herein we report a feasible study concerning syntheses, structure and antimicrobial activity of some new diazinium salts with dihydroxyacetophenone skeleton. A fast, general, environmentally friendly, and facile method for preparation of diazinium salts under microwave and ultrasounds irradiation is presented. Antimicrobial tests prove that some diazine compounds have a remarkable activity against different microorganisms (germs and fungi), the pyrimidine derivatives being more active. Correlations between structure and antimicrobial activity are reported. PMID:18672317

Balan, Ana Maria; Florea, Ondina; Moldoveanu, Costel; Zbancioc, Gheorghita; Iurea, Dorina; Mangalagiu, Ionel I

2009-05-01

105

Antimicrobial Activity of Indigofera suffruticosa  

PubMed Central

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

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

2006-01-01

106

Synthetic analogs of anoplin show improved antimicrobial activities.  

PubMed

We present the antimicrobial and hemolytic activities of the decapeptide anoplin and 19 analogs thereof tested against methicillin-resistant Staphylococcus aureus ATCC 33591 (MRSA), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), vancomycin-resistant Enterococcus faecium (ATCC 700221) (VRE), and Candida albicans (ATCC 200955). The anoplin analogs contain substitutions in amino acid positions 2, 3, 5, 6, 8, 9, and 10. We use these peptides to study the effect of altering the charge and hydrophobicity of anoplin on activity against red blood cells and microorganisms. We find that increasing the charge and/or hydrophobicity improves antimicrobial activity and increases hemolytic activity. For each strain tested, we identify at least six anoplin analogs with an improved therapeutic index compared with anoplin, the only exception being Enterococcus faecium, against which only few compounds are more specific than anoplin. Both 2Nal(6) and Cha(6) show improved therapeutic index against all strains tested. PMID:24019229

Munk, Jens K; Uggerhřj, Lars Erik; Poulsen, Tanja J; Frimodt-Mřller, Niels; Wimmer, Reinhard; Nyberg, Nils T; Hansen, Paul R

2013-11-01

107

Antimicrobially active alkaloids from Tabernaemontana chippii.  

PubMed

From Tabernaemontana chippii root bark, forty-five alkaloids were isolated; thirty-four were fully characterized by means of their spectral data and/or co-tlc; eight alkaloids were new, four of them being 3-hydroxy derivatives of known dimeric voacamine type alkaloids. Most of the twenty-six known alkaloids belonged to the corynanthean, ibogan, or bisindole classes. The structures of eleven other alkaloids--all minor--were only partially elucidated, most of them being new alkaloids. All the dimeric alkaloids were shown to possess strong antimicrobial activity against gram-positive bacteria and moderate to weak activity against gram-negative bacteria. PMID:4031898

Van Beek, T A; Verpoorte, R; Svendsen, A B; Fokkens, R

1985-01-01

108

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.

Radomska-Lesniewska, Dorota M.; Skopinski, Piotr; Zdanowski, Robert; Lewicki, Slawomir; Kocik, Janusz; Skopinska-Rozewska, Ewa; Stankiewicz, Wanda

2013-01-01

109

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

110

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

111

Comparative antimicrobial activities of Emblica officinalis and Ocimum sanctum.  

PubMed

The aqueous and successive extracts of the fruit pulp of Emblica officinalis and fresh leaves and stems of Ocimum sanctum were prepared and evaluated for antimicrobial activity. The successive extracts such as petroleum ether,chloroform, ethyl acetate and methanol were prepared by successive solvent extraction method and aqueous extract by maceration process and screened for antimicrobial activity against gram positive bacteria Staphylococcus aureus, gram negative bacteria E.coli and fungal strains of Candida species by using agar cup plate method. The extracts showed different degree of activity against pathogenic microbes. The results obtained were compared with standard drugs Amoxicillin (10?g) and Amphotericin B(10?g). The methanolic extract of Emblica officinalis was found to be more effective than the leaf and stem extracts of Ocimum sanctum in inhibiting all the microbial strains. PMID:22557261

Vijayalakshmi, S; Arunkumar, V; Anju, D; Gunasundari, P; Moorthy, P; Chandrasekharan, A K

2007-10-01

112

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

113

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

114

Antimicrobial contact activity of econazole sulfosalicylate.  

PubMed

The aim of this investigation was to compare the contact action of econazole sulfosalicylate (E-SSA) on mycetes (Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, Trichophyton rubrum, T. cutaneum, Pityrosporum sp.), Gram-positive bacteria (Staphylococcus aureus, Streptococcus faecalis) and Gram-negative bacteria (Escherichia coli, Citrobacter freundii) with that exerted by econazole nitrate (E-NIT). The results show E-SSA activity greater than E-NIT (in particular against mycetes and Gram-negative bacteria). The E-SSA contact activity trials illustrated certain properties of this imidazole sulfosolicylate such as: absence of latency time, antimicrobial activity proportional to its concentration, when a high concentration is used, given the limiting influence of pH and ionic strength of the medium. The higher E-SSA contact activity, in relation to E-NIT, can be correlated to its greater lipophylia considering also the lipophylic properties of SSA and the scarce dissociation of E-SSA. PMID:1875229

Simonetti, N; Spignoli, G; D'Auria, F D; Strippoli, V

1991-04-01

115

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.

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

2013-01-01

116

Antimicrobial activity of some medicinal barks used in Peruvian Amazon.  

PubMed

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

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

2007-05-01

117

Antimicrobial Effects of Interferon-Inducible CXC Chemokines against Bacillus anthracis Spores and Bacilli  

Microsoft Academic Search

Based on previous studies showing that host chemokines exert antimicrobial activities against bacteria, we sought to determine whether the interferon-inducible Glu-Leu-Arg-negative CXC chemokines CXCL9, CXCL10, and CXCL11 exhibit antimicrobial activities against Bacillus anthracis. In vitro analysis demon- strated that all three CXC chemokines exerted direct antimicrobial effects against B. anthracis spores and bacilli including marked reductions in spore and bacillus

Matthew A. Crawford; Yinghua Zhu; Candace S. Green; Marie D. Burdick; Patrick Sanz; Farhang Alem; Alison D. O'Brien; Borna Mehrad; Robert M. Strieter; Molly A. Hughes

2009-01-01

118

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) Ĺ 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) Ĺ, Ag-O bond distances of 2.261(4)-2.536(5) Ĺ, 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

119

Antimicrobial activities of some Euphorbia species.  

PubMed

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

Kirbag, Sevda; Erecevit, P?nar; Zengin, Fikriye; Guvenc, Ay?e Nilay

2013-01-01

120

Synergistic Antimicrobial Activities of Folic Acid Antagonists and Nucleoside Analogs?  

PubMed Central

The antimicrobial activities of folic acid antagonists are supposed to be antagonized by elevated extracellular thymidine concentrations in damaged host tissues. Therefore, this study was aimed at screening for nucleoside analogs that impair bacterial thymidine utilization and analyzing the combined antimicrobial activities of nucleoside analogs and folic acid antagonists in the presence of thymidine. Our screening results revealed that different nucleoside analogs, in particular halogenated derivatives of 2?-deoxyuridine, substantially impaired the bacterial utilization of extracellular thymidine in Staphylococcus aureus. Time-kill methods showed that 5-iodo-2?-deoxyuridine enhanced the extent of killing of trimethoprim-sulfamethoxazole (SXT) at 24 h against S. aureus in the presence of thymidine (200 ?g/liter). While SXT (40 mg/liter) alone did not kill bacteria in the presence of thymidine, its combination with the nucleoside analog at a concentration of 8 ?mol/liter showed a bactericidal effect. Moreover, 5-iodo-2?-deoxyuridine combined with SXT in the presence of thymidine showed a broad spectrum of activity against several Gram-positive and Gram-negative bacteria. In conclusion, these data provide evidence that the in vitro antimicrobial activity of SXT in the presence of thymidine can be significantly improved by combination with a nucleoside analog.

Zander, Johannes; Besier, Silke; Ackermann, Hanns; Wichelhaus, Thomas A.

2010-01-01

121

Antimicrobial activity of Caesalpinia pulcherrima, Euphorbia hirta and Asystasia gangeticum.  

PubMed

The ethanolic extracts of the dry fruits of Caesalpinia pulcherrima, aerial parts of Euphorbia hirta and flowers of Asystasia gangeticum were tested for antimicrobial activity. The three plants exhibited a broad spectrum of antimicrobial activity, particularly against Escherichia coli (enteropathogen), Proteus vulgaris, Pseudomonas aeruginosa and Staphylococcus aureus. PMID:16730921

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

2006-07-01

122

Antimicrobial activity of Caesalpinia pulcherrima, Euphorbia hirta and Asystasia gangeticum  

Microsoft Academic Search

The ethanolic extracts of the dry fruits of Caesalpinia pulcherrima, aerial parts of Euphorbia hirta and flowers of Asystasia gangeticum were tested for antimicrobial activity. The three plants exhibited a broad spectrum of antimicrobial activity, particularly against Escherichia coli (enteropathogen), Proteus vulgaris, Pseudomonas aeruginosa and Staphylococcus aureus.

M. Sudhakar; Ch. V. Rao; P. M. Rao; D. B. Raju; Y. Venkateswarlu

2006-01-01

123

Evaluation of antimicrobial activities of Satureja hortensis L  

Microsoft Academic Search

The present study was designated to evaluate the antimicrobial activities of methonol and hexane extracts of Satureja hortensis L. which is an annual herb used as traditional folk medicine in Eastern Anatolia region of Turkey for the treatment of different infectious diseases and disorders. The antimicrobial activities of the extracts against 147 laboratory strains belong to 55 bacterial species, and

F ?ahin; ? Karaman; M Güllüce; H Ö?ütçü; M ?engül; A Ad?güzel; S Öztürk; R Kotan

2003-01-01

124

Antimicrobial activity of Citrox® bioflavonoid preparations against oral microorganisms  

Microsoft Academic Search

Background Citrox® is a formulation of soluble bioflavonoids obtained from citrus fruits. The non-toxic and antimicrobial properties of natural bioflavonoids are well documented, and consequently there has been interest in the therapeutic application of these substances.Objective To determine the antimicrobial activity of two Citrox® formulations (BC30 and MDC30) with different bioflavonoid combinations against a range of oral microorganisms.Methods The antimicrobial

M. A. O. Lewis; M. J. Wilson; D. W. Williams; S. J. Hooper

2011-01-01

125

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.

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

2013-01-01

126

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

127

Synthesis, antimicrobial and anticancer activity of new thiosemicarbazone derivatives.  

PubMed

Thiosemicarbazones of p-aminobenzoic acid (PABA) were synthesized and tested for their antimicrobial and anticancer activity. Hydroxamate derivatives 4a-4l were found to have better antimicrobial and anticancer activity than their acid counterpart. Compound 4d was found to have good antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis with IC(50) value of about 1 µM. Compound 4f showed potent antifungal activity against Candida albicans (IC(50) ?= 1.29 µM) and compound 4h showed potent anticancer activity (IC(50) ?= 0.07 µM). PMID:21290424

Kulandaivelu, Umasankar; Padmini, Valisakka Gari; Suneetha, Kyatham; Shireesha, Boyapati; Vidyasagar, Jannu Vincent; Rao, Tadikonda Rama; K N, Jayaveera; Basu, Arijit; Jayaprakash, Venkatesan

2011-02-01

128

Lactoferrin: Antimicrobial activity and therapeutic potential.  

PubMed

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

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

2013-03-15

129

Conjugated polyelectrolyte capsules: light-activated antimicrobial micro "Roach Motels".  

PubMed

Microcapsules consisting of alternating layers of oppositely charged poly(phenylene ethynylene)-type conjugated polyelectrolytes (CPEs) were prepared via layer-by-layer deposition onto MnCO3 template particles followed by dissolution of the template particles using an ethylenediaminetetraacetate solution. The resulting microcapsules exhibit bright-green fluorescence emission characteristics of the CPEs. Strong antimicrobial activity was observed upon mixing of polyelectrolyte capsules with Cobetia marina or Pseudomonas aeruginosa followed by white-light irradiation. It was demonstrated that the materials act as highly effective light-activated micro "Roach Motels" with greater than 95% kill after exposure to approximately 1 h of white light. PMID:20355752

Corbitt, Thomas S; Sommer, Jonathan R; Chemburu, Sireesha; Ogawa, Katsu; Ista, Linnea K; Lopez, Gabriel P; Whitten, David G; Schanze, Kirk S

2009-01-01

130

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; Joăo Evangelista; Jose Maurício Schneedorf

2005-01-01

131

The antimicrobial activity, toxicity and antimicrobial mechanism of a new type of tris(alkylphenyl)sulfonium.  

PubMed

The antimicrobial activity, toxicity and antimicrobial mechanism of a new type of tris(4-alkylphenyl)sulfonium which has sterically bulky alkyl substituents (bTAPS), were estimated and compared with those of other sulfoniums which we reported previously. Concerning tris {4-(iso-propyl)phenyl}sulfonium (bTAPS-iso3) and tris{4-(tert-butyl)phenyl}sulfonium (bTAPS-tert4), the antimicrobial activity of these compounds tended to be lower than both tri(n-alkyl)sulfoniums (TASs) and tris{4-(n-alkylphenyl)}sulfoniums (TAPSs) at similar ClogP values. However, the activities of tris{4-(cyclohexyl)phenyl}sulfonium (bTAPS-cyclo6) were clearly higher than those of TAS and were almost similar to those of TAPS at similar ClogP values. The mutagenicities of tested bTAPSs were judged to be all negative. Both the acute oral toxicity strength and the acute skin irritation/corrosion toxicity strength tended to follow the order of TAPSs > bTAPSs > TASs. However, only the acute skin irritation/corrosion toxicity strength of bTAPS-cyclo6 was almost as low as that of TAS which has a similar ClogP value to bTAPS-cyclo6. Because bTAPS-cyclo6 has both high antimicrobial activity and low toxicity, this compound might become to be an alternative antimicrobial compound to relatively hazardous antimicrobials which have been widely used in many fields. PMID:22451429

Hirayama, Michiasa

2012-03-01

132

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

133

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

134

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.

2013-01-01

135

Microbial conditions and antimicrobial activity in cultures of two microalgae species, Tetraselmis chuii and Chlorella minutissima, and effect on bacterial load of enriched Artemia metanauplii  

Microsoft Academic Search

The microbial conditions and antimicrobial activity were determined in batch cultures of two microalgae species, Tetraselmis chuii and Chlorella minutissima. The number of bacteria associated with the microalgae cultures showed an exponential growth 2, 10, and 16 days after inoculation, and they were higher in T. chuii in all three sampling points compared with C. minutissima. No presumptive Vibrio strains

Pavlos Makridis; Rita Alves Costa; Maria Teresa Dinis

2006-01-01

136

Antimicrobial activity of saponin fractions of the leaves of Gymnema sylvestre and Eclipta prostrata  

Microsoft Academic Search

The antimicrobial activity of saponin fractions from the leaves of Gymnema sylvestre and Eclipta prostrata was evaluated against pathogenic bacteria and fungi in an in vitro condition. A series of concentrations of crude and pure\\u000a saponin fractions were tested for antimicrobial activity by zone of inhibition method. The pure saponin fractions were found\\u000a to be more effective against tested bacterial pathogens

Venkatesan Gopiesh khanna; Krishnan Kannabiran

2008-01-01

137

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

PubMed

The objective of this study was to compare the antimicrobial activity of sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX) and octenidine hydrochloride (OCT) in different concentrations against endodontic pathogens in vitro. Agar diffusion procedure was used to determine the antimicrobial activity of the tested materials. Enterococcus faecalis, Candida albicans and the mixture of these were used for this study. In the agar diffusion test, 5.25% NaOCl exhibited better antimicrobial effect than the other concentrations of NaOCl for all strains. All concentrations of OCT were effective against C. albicans and E. faecalis. Some 0.2% CHX was ineffective on all microorganisms. Antibacterial effectiveness of all experimental solutions decreased on the mixture of all strains. Decreasing concentrations of NaOCl resulted in significantly reduced antimicrobial effect. PMID:23551508

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

2013-04-01

138

Studies on Anticancer Activities of Antimicrobial Peptides  

PubMed Central

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

Hoskin, David W.; Ramamoorthy, Ayyalusamy

2008-01-01

139

Antimicrobial activity of nanodispersed thymol in tryptic soy broth.  

PubMed

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

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

2013-03-01

140

Comparative evaluation of the antimicrobial activity of ACTICOAT antimicrobial barrier dressing.  

PubMed

This study evaluated the antimicrobial activity of ACTICOAT Antimicrobial Barrier Dressing (Westaim Biomedical Corp, Fort Saskatchewan, Alberta, Canada), a silver-coated wound dressing, and compared it with silver nitrate, silver sulfadiazine, and mafenide acetate. The minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC), zone of inhibition, and killing curves were determined with 5 clinically relevant bacteria. The data indicate that ACTICOAT silver had the lowest MIC and MBC and generated similar zones of inhibition to silver nitrate and silver sulfadiazine. Viable bacteria were undetectable 30 minutes after inoculation with the dressing, whereas it took 2 to 4 hours for silver nitrate and silver sulfadazine to achieve the same result. Mafenide acetate generated the biggest zones of inhibition, but it had the highest MICs and MBCs, and a significant number of bacteria still survived after 6 hours of treatment. The results suggest that ACTICOAT Antimicrobial Barrier Dressing has better antimicrobial performance than either of the existing silver-based products. ACTICOAT dressing killed the bacteria that were tested much faster, which is a very important characteristic for a wound dressing acting as a barrier to invasive infection to have. The study also suggests that a single susceptibility test such as a MIC or zone of inhibition test does not provide a comprehensive profile of antimicrobial activity of a topical antimicrobial agent or dressing. A combination of tests is desirable. PMID:10342470

Yin, H Q; Langford, R; Burrell, R E

1999-01-01

141

Effect of Antimicrobial Edible Additives on Cassava Starch Biobased Films Characterization  

Microsoft Academic Search

Antimicrobial films appear in response of the searching for more competitive and aggregated value packaging. With the aim of developing packages that, besides active are also biodegradable, this work proposes to study the effect of antimicrobial additives (honey, cinnamon powder, clove powder, orange essential oil, pepper and coffee powder) on the characterization of cassava starch biobased films. The biofilms were

Ana C. L. Attarian; Viviane Kechichian; Pricila Veiga-Santos; Cynthia Ditchfield; Carmen C. Tadini

142

Oxygen limitation favors the production of protein with antimicrobial activity in Pseudoalteromonas sp  

PubMed Central

This study examined the effect of dissolved oxygen concentration on the production of biomass and metabolites with antimicrobial activity of Pseudoalteromonas sp cultured at 0, 150, 250, or 450 revolutions per minute (rev. min-1). Dissolved oxygen (D.O) was monitored during the fermentation process, biomass was quantified by dry weight, and antimicrobial activity was assessed using the disk diffusion method. The bacterium Pseudoalteromonas reached similar concentration of biomass under all experimental agitation conditions, whereas antimicrobial activity was detected at 0 and 150 rev. min-1 registering 0% and 12% of D.O respectively corresponding to microaerophilic conditions. Antibiotic activity was severely diminished when D.O was above 20% of saturation; this corresponded to 250 or 450 rev. min-1. SDS-PAGE electrophoresis revealed a protein with a molecular weight of approximately 80 kilodaltons (kDa) with antimicrobial activity. Pseudoalteromonas is capable of growing under oxic and microaerophilic conditions but the metabolites with antimicrobial activity are induced under microaerophilic conditions. The current opinion is that Pseudoalteromonas are aerobic organisms; we provide additional information on the amount of dissolved oxygen during the fermentation process and its effect on antimicrobial activity.

Lopez, Ruth; Monteon, Victor; Chan, Ernesto; Montejo, Rubi; Chan, Manuel

2012-01-01

143

Nanoscalic silver possesses broad-spectrum antimicrobial activities and exhibits fewer toxicological side effects than silver sulfadiazine  

Microsoft Academic Search

Silver has been used successfully for decades as an antibacterial agent and has become a standard treatment for burns and bacterial skin infections. Silver-containing creams, particularly silver sulfadiazine (SSD), possess effective activities against bacteria and fungi. However, there is serious concern that silver ions applied to denuded skin might be absorbed in significant amounts, thus introducing the risk of silver

Oliver Brandt; Michael Mildner; Alexander E. Egger; Michael Groessl; Uwe Rix; Martin Posch; Bernhard K. Keppler; Christian Strupp; Beat Mueller; Georg Stingl

144

Antimicrobial effect of cranberry juice and extracts  

Microsoft Academic Search

The antimicrobial effect of cranberry juice and of three cranberry extracts (water-soluble (E1) and apolar phenolic compounds (E2), and anthocyanins (E3)) was investigated against seven bacterial strains (Enterococcus faecium resistant to vancomycin (ERV), Escherichia coli O157:H7 EDL 933, Escherichia coli ATCC 25922, Listeria monocytogenes HPB 2812, Pseudomonas aeruginosa ATCC 15442, Salmonella Typhimurium SL1344, and Staphylococcus aureus ATCC 29213). Each cranberry

J. Côté; S. Caillet; G. Doyon; D. Dussault; J.-F. Sylvain; M. Lacroix

2011-01-01

145

Synthesis and antimicrobial activity of new adamantane derivatives III.  

PubMed

Some novel ester imides synthesised from trimellitic acid anhydride and 1-adamantanol or 2-adamantanol, were tested as antimicrobial compounds. Unfortunately, these agents showed a modest antibacterial activity (MIC > 6 microg/ml). However, a comparison of these N-substituted adamantylester imides with the series published previously, indicated that the incorporation of L-alanine and L-phenylalanine into the phthalimide moiety was the best choice regardless of the series and leads to antimicrobial activity against Staphylococcus aureus strains. PMID:12361228

Orzeszko, Andrzej; Kami?ska, Beata; Staro?ciak, Bohdan J

2002-08-01

146

Antimicrobial Activity and Synthesis of Quinoline-Based Chalcones  

Microsoft Academic Search

A series of quinoline-based chalcones have been prepared by the condensation of quinoline-3-carbaldehydes with acetophenone and N-substituted-3-acetyl-4-hydroxy-2-quinolones with heterocyclic carbaldehydes. The prepared chalcones have been screened for antimicrobial activities against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtiles, Klebsiellea erogeues, Staphylococcus albus, Aspergillus flavus, Aspergillus niger, Rhodolorula rubera, Lipomyces lopofera and Candida albicans. All the prepared chalcones have shown significant antimicrobial activities.

Muhammad Azad; Munawar Ali Munawar; Hamid Latif Siddiqui

2007-01-01

147

Antimicrobial activity of phenol and benzoic acid derivatives  

Microsoft Academic Search

Vinyl monomers with phenol and benzoic acid as pendant groups were synthesized, and their antimicrobial activities were examined on equal weight basis using the halo zone test. For both bacteria and fungi, the halo zone diameter decreased in the order of p-hydroxyphenyl acrylate (M2)>allyl p-hydroxyphenyl acetate (M1)?p-2-propenoxyphenol (M3). Polymerization of the monomers decreased their antimicrobial activity significantly, but the order

Eun-Soo Park; Woong-Sig Moon; Min-Jin Song; Mal-Nam Kim; Kyoo-Hyun Chung; Jin-San Yoon

2001-01-01

148

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

PubMed

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

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

2014-05-12

149

Emerging rules for effective antimicrobial coatings.  

PubMed

In order to colonize abiotic surfaces, bacteria and fungi undergo a profound change in their biology to form biofilms: communities of microbes embedded into a matrix of secreted macromolecules. Despite strict hygiene standards, biofilm-related infections associated with implantable devices remain a common complication in the clinic. Here, the application of highly dosed antibiotics is problematic in that the biofilm (i) provides a protective environment for microbes to evade antibiotics and/or (ii) can provide selective pressure for the evolution of antibiotic-resistant microbes. However, recent research suggests that effective prevention of biofilm formation may be achieved by multifunctional surface coatings that provide both non-adhesive and antimicrobial properties imparted by antimicrobial peptides. Such coatings are the subject of this review. PMID:24176168

Salwiczek, Mario; Qu, Yue; Gardiner, James; Strugnell, Richard A; Lithgow, Trevor; McLean, Keith M; Thissen, Helmut

2014-02-01

150

Effects of materials containing antimicrobial compounds on food hygiene.  

PubMed

Surfaces with microorganisms may transfer unwanted microorganisms to food through cross-contamination during processing and preparation. A high hygienic status of surfaces that come in contact with food is important in order to reduce the risk of cross-contamination. During the last decade, products containing antimicrobial compounds, such as cutting boards, knives, countertops, kitchen utensils, refrigerators, and conveyor belts, have been introduced to the market, claiming hygienic effects. Such products are often referred to as "treated articles." Here we review various aspects related to treated articles intended for use during preparation and processing of food. Regulatory issues and methods to assess antibacterial effects are covered. Different concepts for treated articles as well as their antibacterial activity are reviewed. The effects of products with antimicrobials on food hygiene and safety are discussed. PMID:21740725

Mřretrř, Trond; Langsrud, Solveig

2011-07-01

151

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

152

Study of the soil isolates for antimicrobial activity.  

PubMed

During the process of screening for a potent antimicrobial compound, a new strain was isolated from the soil sample of Thalaikunda village in Ooty, Tamil Nadu. That organism was name as NK(2). It was found to be antagonistic to both bacterial and fungal test organisms. Production of antibiotic was more in a newly formulated broth. Antibiotic production reached maximum at the end of the 70 h of fermentation by stirred flask culture. The antimicrobial compound was extracted in n-butanol, ethyl acetate and methanol. Antimicrobial compound, which was produced by the soil isolate NK(2) did not showed cytotoxic activity on Vero cell lines. PMID:21369451

Srividya, A R; Saritha, G S; Suresh, B

2008-11-01

153

Peptidotriazoles with antimicrobial activity against bacterial and fungal plant pathogens.  

PubMed

We designed and prepared peptidotriazoles based on the antimicrobial peptide BP100 (LysLysLeuPheLysLysIleLeuLysTyrLeu-NH(2)) by introducing a triazole ring in the peptide backbone or onto the side chain of a selected residue. These compounds were screened for their in vitro growth inhibition of bacterial and fungal phytopathogens, and for their cytotoxic effects on eukaryotic cells and tobacco leaves. Their proteolytic susceptibility was also analyzed. The antibacterial activity and the hemolysis were influenced by the amino acid that was modified with the triazole as well as by the absence of presence of a substituent in this heterocyclic ring. We identified sequences active against the bacteria Xanthomonas axonopodis pv. vesicatoria, Erwinia amylovora, Pseudomonas syringae pv. syringae (MIC of 1.6-12.5 ?M), and against the fungi Fusarium oxysporum (MIC<6.2-12.5 ?M) with low hemolytic activity (0-23% at 50 ?M), high stability to protease digestion and no phytotoxicity. These peptidotriazoles constitute good candidates to design new antimicrobial agents. PMID:22198367

Güell, Imma; Micaló, Lluís; Cano, Laura; Badosa, Esther; Ferre, Rafael; Montesinos, Emilio; Bardají, Eduard; Feliu, Lidia; Planas, Marta

2012-01-01

154

Assessment of the antimicrobial activity of lactic acid bacteria isolated from Borde and Shamita, traditional Ethiopian fermented beverages, on some food- borne pathogens and effect of growth medium on the inhibitory activity  

Microsoft Academic Search

The antimicrobial activity of lactic acid bacteria (LAB) isolated from fermented products on various food borne pathogens is well documented. This prompted the study to evaluate the in-vitro antimicrobial activity of LAB isolated from two traditional Ethiopian fermented beverages on Staphylococcus aureus, Shigella flexneri, Salmonella spp. and Esherichia coli O157:H7. Lactobacillus isolates were separately grown in MRS and LAPTg broths

Girum Tadesse; Eden Ephraim; Mogessie Ashenafi

155

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).

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

2011-01-01

156

Antimicrobial properties of light-activated polyurethane containing indocyanine green.  

PubMed

The aim of this study was to produce novel antimicrobial polymers containing the light-activated antimicrobial agent indocyanine green (ICG). The novel materials were prepared by swelling polyurethane in acetone containing water and ICG, followed by solvent evaporation. The uptake of ICG was dependent upon the ratio of acetone to water. Only at a ratio of 99 parts acetone to 1 part water was there any substantial colouration of the samples. When exposed to laser light from the near infrared spectrum (808 nm), polyurethane-containing ICG exhibited antimicrobial activity against Gram-positive bacteria; a 2 log?? reduction was achieved against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis after 15 min exposure, corresponding to an energy dose of 31.83 J delivered at an energy density of 31.83 J/cm˛. Under the same conditions, Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) appeared to be less susceptible, the viable count being reduced by 0.5 log??. Some of the physical properties of the resulting material were also investigated and it was found that the elasticity (Young's modulus) was reduced by approximately 60%. Furthermore, when the ICG-containing polymer was stretched, the breaking point occurred when the elongation was 6.7 times the initial value, while ICG-free polyurethane samples did not break following a 7-fold elongation. The contact angles for water droplets revealed that the ICG-containing polymer was more hydrophobic than untreated polyurethane. The results of this study show that ICG can be embedded in polyurethane to produce materials which when irradiated with near-infrared light can exert a bactericidal effect particularly against MRSA and S. epidermidis. Such materials may be useful for preparing intravenous catheters, which are often colonized by such organisms. PMID:20008087

Perni, Stefano; Pratten, Jonathan; Wilson, Michael; Piccirillo, Clara; Parkin, Ivan P; Prokopovich, Polina

2011-01-01

157

Antimicrobial activity of truncated alpha-defensin (human neutrophil peptide (HNP)-1) analogues without disulphide bridges.  

PubMed

Antimicrobial peptides play an important role in host defence, particularly in the oral cavity where there is constant challenge by microorganisms. The alpha-defensin antimicrobial peptides comprise 30-50% of the total protein in the azurophilic granules of human neutrophils, the most abundant of which is human neutrophil peptide 1 (HNP-1). Despite its antimicrobial activity, a limiting factor in the potential therapeutic use of HNP-1 is its chemical synthesis with the correct disulphide topology. In the present study, we synthesised a range of truncated defensin analogues lacking disulphide bridges. All the analogues were modelled on the C-terminal region of HNP-1 and their antimicrobial activity was tested against a range of microorganisms, including oral pathogens. Although there was variability in the antimicrobial activity of the truncated analogues synthesised, a truncated peptide named 2Abz(23)S(29) displayed a broad spectrum of antibacterial activity, effectively killing all the bacterial strains tested. The finding that truncated peptides, modelled on the C-terminal beta-hairpin region of HNP-1 but lacking disulphide bridges, display antimicrobial activity could aid their potential use in therapeutic interventions. PMID:17548109

Lundy, Fionnuala T; Nelson, John; Lockhart, Derek; Greer, Brett; Harriott, Pat; Marley, John J

2008-01-01

158

Cytotoxicity and Antimicrobial Activity of Nerium oleander Extracts  

Microsoft Academic Search

El Sawi, N.M., Geweely, N.S., Qusti, S., Mohamed, M. and Kamel, A. 2010. Cytotoxicity and antimicrobial activity of Nerium oleander extracts. J. Appl. Anim. Res., 37: 25–31.The antimicrobial properties of the crude and pure extracts of Nerium oleander were investigated against three Gramve bacteria (Escherichia coli, Pseudomonas aeruginosa and Salmonella enteritidis), three Gram +ve bacteria (Bacillus subtilis, Listeria monocytogenes and

Nagwa M. El Sawi; Neveen S. Geweely; Safaa Qusti; M. Mohamed; A. Kamel

2010-01-01

159

Antimicrobial and Antioxidative Activities of Bioactive Constituents from Hydnophytum formicarum Jack  

Microsoft Academic Search

Hydnophytum formicarum Jack. (Rubiaceae) is a medicinal plant whose tubers possesses cardiovascular, anti-inflammatory and antiparasitic effects and have been used for the treatment of hepatitis, rheumatism and diarrhea. Herein we report the isolation of its active constituents and the testing of their antimicrobial activity against 27 strains of microorganisms using an agar dilution method and of their antioxidative activity using

Supaluk Prachayasittikul; Prasit Buraparuangsang; Apilak Worachartcheewan; Chartchalerm Isarankura-Na-Ayudhya; Somsak Ruchirawat; Virapong Prachayasittikul

2008-01-01

160

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

161

Salusin-?, an Antimicrobially Active Peptide against Gram-Positive Bacteria.  

PubMed

Salusin-? has been detected in numerous mammalian tissues and has been shown to have various effects on the cardiovascular system. In this study, we showed that salusin-? exhibited potent antibacterial activity against Gram-positive microorganisms such as Bacillus subtilis NBRC 3513, Bacillus megaterium ATCC 19213, Staphylococcus aureus NBRC 12732, and Staphylococcus epidermidis NBRC 12933. A cytoplasmic membrane-depolarizing assay using the DiSC3(5) dye revealed that the addition of 4?nmol/mL of salusin-? caused the leakage of fluorescence dye from Staphylococcus aureus NBRC 12732. The antimicrobial potency and circular dichroism (CD) spectroscopy of five analogs related to salusin-? were examined to determine structure-function relationships in its N- and C-terminal regions. The results obtained suggest that the N-terminal sequences of the salusin-? molecule are important for the expression of the potent antimicrobial activity of this peptide. A profile corresponding to that of the ?-helix conformation was observed in the salusin-? solution. PMID:24881665

Kimura, Masahiro; Shindo, Mitsuno; Moriizumi, Toshiyuki; Tagawa, Noriko; Fujinami, Aya; Kato, Ikuo; Uchida, Yoshiki

2014-01-01

162

Evidence for antimicrobial activity associated with common house spider silk  

PubMed Central

Background Spider silk is one of the most versatile materials in nature with great strength and flexibility. Native and synthetically produced silk has been used in a wide range of applications including the construction of artificial tendons and as substrates for human cell growth. In the literature there are anecdotal reports that suggest that native spider silk may also have antimicrobial properties. Findings In this study we compared the growth of a Gram positive and a Gram negative bacterium in the presence and absence of silk produced by the common house spider Tegenaria domestica. We demonstrate that native web silk of Tegenaria domestica can inhibit the growth of the Gram positive bacterium, Bacillus subtilis. No significant inhibition of growth was detected against the Gram negative bacterium, Escherichia coli. The antimicrobial effect against B. subtilis appears to be short lived thus the active agent potentially acts in a bacteriostatic rather than bactericidal manner. Treatment of the silk with Proteinase K appears to reduce the ability to inhibit bacterial growth. This is consistent with the active agent including a protein element that is denatured or cleaved by treatment. Tegenaria silk does not appear to inhibit the growth of mammalian cells in vitro thus there is the potential for therapeutic applications.

2012-01-01

163

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

PubMed

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

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

2008-11-01

164

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

PubMed

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

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

2014-09-22

165

Influence of montmorillonite on antimicrobial activity of tetracycline and ciprofloxacin  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

166

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

167

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

PubMed

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

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

2014-01-01

168

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

PubMed Central

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

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

2014-01-01

169

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

170

Antimicrobial and free radical scavenging activities of Teucrium montanum.  

PubMed

The antimicrobial and free radical scavenging activities of petroleum ether, chloroform, ethyl acetate, n-butanol and water extracts of Teucrium montanum were investigated. Ethyl acetate, chloroform and n-butanol extracts expressed a wide range of inhibiting activity against both Gram (+) and Gram (-) bacteria. n-Butanol extract possessed potent DPPH free radical scavenging activity. PMID:16797876

Djilas, Sonja M; Markov, Sinisa L; Cvetkovi?, Dragoljub D; Canadanovi?-Brunet, Jasna M; Cetkovi?, Gordana S; Tumbas, Vesna T

2006-07-01

171

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

172

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

PubMed

Activated carbon fiber (ACF) filters have a wide range of applications, including air purification, dehumidification, and water purification, due to their large specific surface area, high adsorption capacity and rate, and specific surface reactivity. However, when airborne microorganisms such as bacteria and fungi adhere to the carbon substrate, ACF filters can become a source of microbial contamination, and their filter efficacy declines. Antimicrobial treatments are a promising means of preventing ACF bio-contamination. In this study, we demonstrate the use of Sophora flavescens in antimicrobial nanoparticles coated onto ACF filters. The particles were prepared using an aerosol process consisting of nebulization-thermal drying and particle deposition. The extract from S. flavescens is an effective, natural antimicrobial agent that exhibits antibacterial activity against various pathogens. The efficiency of Staphylococcus epidermidis inactivation increased with the concentration of S. flavescens nanoparticles in the ACF filter coating. The gas adsorption efficiency of the coated antimicrobial ACF filters was also evaluated using toluene. The toluene-removal capacity of the ACF filters remained unchanged while the antimicrobial activity was over 90% for some nanoparticle concentrations. Our results provide a scientific basis for controlling both bioaerosol and gaseous pollutants using antimicrobial ACF filters coated with S. flavescens nanoparticles. PMID:24951887

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

2014-09-15

173

Antimicrobial activity of lipophilic avian eggshell surface extracts.  

PubMed

The avian eggshell cuticle is the waxy outermost layer of the mineralized eggshell in direct contact with the environment. In this study, lipophilic eggshell surface extracts from three domestic species were evaluated for their antimicrobial activity. Chicken and goose extracts demonstrated potent bactericidal activity against both Gram-positive and Gram-negative bacteria, while activity could not be detected for duck eggshell surface extracts. Using the chicken as a model species, evaluation of albumen, fecal material, and uropygial gland extracts eliminated these as a potential source of the observed activity. Results suggest that lipophilic components are incorporated into the egg during its formation and play a role in antimicrobial defense. This study represents the first successful extraction and evaluation of lipophilic antimicrobial components from the avian egg. PMID:20804124

Wellman-Labadie, Olivier; Lemaire, Simon; Mann, Karlheinz; Picman, Jaroslav; Hincke, Maxwell T

2010-09-22

174

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

PubMed

Using natural additives to preserve foods has become popular due to consumer demands for nature and safety. Antimicrobial activity is one of the most important properties in many plant essential oils (EOs). The antimicrobial activity of the essential oil of Litsea cubeba (LC-EO) from Taiwan and the antimicrobial impact of individual volatile components in the oil on pathogens or spoilage microorganisms: Vibrio parahaemolyticus, Listeria monocytogenes, Lactobacillus plantarum, and Hansenula anomala in vitro, and the antimicrobial activity of the LC-EO against these organisms in food systems were studied. The "antimicrobial impact" (AI) is a new term that combines the effects of minimal microbicidal concentration (MMC) and quantity of an antimicrobial substance. The AI can quantitatively reflect the relative importance of individual components of the EO on the entire antimicrobial activity of the EO. The MMCs of the LC-EO against V. parahaemolyticus, L. monocytogenes, L. plantarum, and H. anomala were determined as 750, 750, 1500, and 375 ?g/g, respectively in vitro. The MMCs of the LC-EO were 3000, 6000, and 12,000 ?g/g for L. monocytogenes in tofu stored at 4 °C, 25 °C, and 37 °C, respectively. The temperature affected the bacterial growth which consequently influenced the MMCs of the LC-EO. The MMCs of the LC-EO were 3000, 6000, and 375 ?g/g for Vibrio spp. in oysters, L. plantarum in orange-milk beverage, and H. anomala in soy sauce, respectively. Except for soy sauce, the food systems exhibited marked matrix effects on diminishing the antimicrobial activity of the LC-EO. Averagely, citral accounted for ca 70% of the total AI value for all the tested organisms, and the rest of the AI value of the LC-EO was determined by all the tested compounds (ca 4%) and the unidentified compounds (ca 26%). PMID:22459760

Liu, Tai-Ti; Yang, Tsung-Shi

2012-05-01

175

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

PubMed Central

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

Olli, Sudar; Rangaraj, Nandini; Nagaraj, Ramakrishnan

2013-01-01

176

Screening of some indigenous Qatari medicinal plants for antimicrobial activity.  

PubMed

Aqueous, ethanol and butanol crude extracts of the aerial parts of ten plants exhibited variable degrees of antimicrobial activity against four bacterial and two fungal species. Aqueous extracts had low antimicrobial activity against E.coli, P.aeruginosa, B. cerreus, S.aureus, C.albicans and A.flavus. Avicennia marina (AM) aqueous extract exhibited a moderate antifungal activity. Ethanol and butanol crude extracts exhibited an improved antimicrobial activity. However, butanol exhibited a superior antimicrobial activity compared with aqueous and ethanol crudes. Compared with the standard antibiotics tested the butanol extract had the highest activity. Butanol extracts at 2000 microg/disc of AM, Lotus halophilus (LA), Pulicaria gnaphaloides (PG) and Capparis spinosa (CS) had a very good antibacterial activity against both gram-positive and -negative bacteria as well as moderate to good antifungal activity against C. albicans and A. flavus. Medicago laciniata (ML), Limonium axillare (LA) and (PG) butanol crude extract compared with standard chloramphenicol, tetracycline and nalidixic acid exhibited a superior antifungal activity. PMID:12458480

Mahasneh, Adel M

2002-12-01

177

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.

2013-01-01

178

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.

Luis, Angelo; Breitenfeld, Luiza; Ferreira, Susana; Duarte, Ana Paula; Domingues, Fernanda

2014-01-01

179

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

180

Synthesis and Antimicrobial Activity of Silver-Doped Hydroxyapatite Nanoparticles  

PubMed Central

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

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

2013-01-01

181

Synthetic histatin analogues with broad-spectrum antimicrobial activity.  

PubMed Central

Histatins are salivary histidine-rich cationic peptides, ranging from 7 to 38 amino acid residues in length, that exert a potent killing effect in vitro on Candida albicans. Starting from the C-terminal fungicidal domain of histatin 5 (residues 11-24, called dh-5) a number of substitution analogues were chemically synthesized to study the effect of amphipathicity of the peptide in helix conformation on candidacidal activity. Single substitutions in dh-5 at several positions did not have any effect on fungicidal activity. However, multi-site substituted analogues (dhvar1 and dhvar2) exhibited a 6-fold increased activity over dh-5. In addition, dhvar1 and dhvar2 inhibited the growth of the second most common yeast found in clinical isolates, Torulopsis glabrata, of oral- and non-oral pathogens such as Prevotella intermedia and Streptococcus mutans, and of a methicillin-resistant Staphylococcus aureus. In their broad-spectrum activity, dhvar1 and dhvar2 were comparable to magainins (PGLa and magainin 2), antimicrobial peptides of amphibian origin. Both the fungicidal and the haemolytic activities of dhvar1, dhvar2 and magainins increased at decreasing ionic strength.

Helmerhorst, E J; Van't Hof, W; Veerman, E C; Simoons-Smit, I; Nieuw Amerongen, A V

1997-01-01

182

Antimicrobial activity of chitosan films containing nisin, peptide P34, and natamycin  

Microsoft Academic Search

The antimicrobial effect of edible chitosan films containing nisin, peptide P34, and natamycin was investigated. The activity of chitosan films was tested against Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Clostridium perfringens, Lactobacillus acidophilus, Aspergillus phoenicis, and Penicillium stoloniferum. The addition of nisin and P34 significantly increased the activity against bacteria. Films containing natamycin showed similar inhibition

Nisia Cé; Caciano P. Z. Noreńa; Adriano Brandelli

2012-01-01

183

Antimicrobial activity of submerged cultures of Chilean basidiomycetes.  

PubMed

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

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

2010-10-01

184

Antimicrobial activity of plant extract Ankaferd Blood Stopper.  

PubMed

The in vitro antimicrobial activity of Ankaferd Blood Stopper (ABS) was assessed on 102 clinical isolates from both Gram negative and Gram positive bacteria and four standard strains, including MRSA ATCC 43300, MSSA ATCC 25923, P. aeruginosa ATCC 27853 and E. coli ATCC 35218. ABS was significantly active against all bacteria investigated. PMID:18930120

Tasdelen Fisgin, Nuriye; Tanriverdi Cayci, Yeliz; Coban, Ahmet Yilmaz; Ozatli, Duzgun; Tanyel, Esra; Durupinar, Belma; Tulek, Necla

2009-01-01

185

Screening of some Cuban medicinal plants for antimicrobial activity  

Microsoft Academic Search

The antimicrobial activities of 23 extracts of 12 Cuban plant species reported in traditional medicine were tested. The agar diffusion method was used to assess the activity against four bacteria and one yeast: Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The results, evaluated as the diameter of the inhibition zone of microbial growth, showed that nine

M. J. Martínez; J. Betancourt; N. Alonso-González; A. Jauregui

1996-01-01

186

The Synthesis and Antimicrobial Activity of Heterocyclic Derivatives of Totarol  

PubMed Central

The synthesis and antimicrobial activity heterocyclic analogs 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 analogs with an indole attached exhibit, for the first time, enhanced antimicrobial activity relative to the parent natural product. Preliminary experiments demonstrate that the indole analogs do not target the bacterial cell division protein FtsZ as had been hypothesized for totarol.

Kim, Michelle B.; O'Brien, Terrence E.; Moore, Jared T.; Anderson, David E.; Foss, Marie H.; Weibel, Doug-las B.; Ames, James B.; Shaw, Jared T.

2012-01-01

187

Phytochemical investigation and antimicrobial activity of Psidium guajava L. leaves  

PubMed Central

Psidium guajava L. leaves were subjected to extraction, fractionation and isolation of the flavonoidal compounds. Five flavonoidal compounds were isolated which are quercetin, quercetin-3-O-?-L-arabinofuranoside, quercetin-3-O-?-D-arabinopyranoside, quercetin-3-O-?-D-glucoside and quercetin-3-O-?-D-galactoside. Quercetin-3-O-?-D-arabinopyranoside was isolated for the first time from the leaves. Fractions together with the isolates were tested for their antimicrobial activity. The antimicrobial studies showed good activities for the extracts and the isolated compounds.

Metwally, A. M.; Omar, A. A.; Harraz, F. M.; El Sohafy, S. M.

2010-01-01

188

Antimicrobial activity of crude methanolic extract from Phyllanthus niruri.  

PubMed

The antibacterial efficiency of the methanolic extract of Phyllanthus niruri Linn. was investigated against pathogenic bacteria responsible for common infections of skin, and urinary and gastrointestinal tracts. The extract demonstrated antibacterial activities against all the Gram-positive and Gram-negative bacteria tested. The results obtained suggested that at higher concentrations the extract would eradicate the growth of bacterial cells. The bacterial cells, after exposure to the extract, showed complete alteration in their morphology, followed by collapse of the cells beyond repair. The study revealed that the methanolic extract of P. niruri may be an effective antibacterial agent to treat bacterial infections since the extract exhibited significant antimicrobial potency, comparable with that of the standard antibiotic chloramphenicol. PMID:23738462

Ibrahim, Darah; Hong, Lim Sheh; Kuppan, Ninthianantham

2013-04-01

189

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

PubMed

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

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

2014-06-11

190

Structure-antimicrobial activity relationship between pleurocidin and its enantiomer  

PubMed Central

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

Lee, Juneyoung

2008-01-01

191

Effect of plant age on endophytic bacterial diversity of balloon flower (Platycodon grandiflorum) root and their antimicrobial activities.  

PubMed

Balloon flower (Platycodon grandiflorum) is widely cultivated vegetable and used as a remedy for asthma in East Asia. Experiments were conducted to isolate endophytic bacteria from 1-, 3-, and 6-year-old balloon flower roots and to analyze the enzymatic, antifungal, and anti-human pathogenic activities of the potential endophytic biocontrol agents obtained. Total 120 bacterial colonies were isolated from the interior of all balloon flower roots samples. Phylogenetic analysis based on 16S rRNA gene sequences showed that the population of 'low G + C gram-positive bacteria' (LGCGPB) gradually increased 60.0-80.0% from 1 to 6 years balloon flower sample. On the other hand, maximum hydrolytic enzyme activity showing endophytic bacteria was under LGCGPB, among the bacterial strains, Bacillus sp. (BF1-1 and BF3-8), Bacillus sp. (BF1-2 and BF3-5), and Bacillus sp. (BF1-3, BF3-6, and BF6-4) showed maximum enzyme activities. Besides, Bacillus licheniformis (BF3-5 and BF6-6) and Bacillus pumilus (BF6-1) showed maximum antifungal activity against Phytophthora capsici, Fusarium oxysporum, Rhizoctonia solani, and Pythium ultimum. Moreover, Bacillus licheniformis was found in 3 and 6 years balloon flower roots, but Bacillus pumilus was found only in 6 years sample. It is presumed that older balloon flower plants invite more potential antifungal endophytes for there protection from plant diseases. In addition, Bacillus sp. (BF1-2 and BF3-5) showed maximum anti-human pathogenic activity. So, plant age is presumed to influence diversity of balloon flower endophytic bacteria. PMID:20221603

Asraful Islam, Shah Md; Math, Renukaradhya K; Kim, Jong Min; Yun, Myoung Geun; Cho, Ji Joong; Kim, Eun Jin; Lee, Young Han; Yun, Han Dae

2010-10-01

192

Antimicrobial and antibiofilm activity of designed and synthesized antimicrobial peptide, KABT-AMP.  

PubMed

Lysine-rich peptide, designated as KABT-AMP, was designed and synthesized to supersede the irrational use of chemical antibiotics as standard therapy. KABT-AMP is a 22-amino acid helical cationic peptide (+10) and amphipathic in nature. The antimicrobial kinetics of the peptide was ascertained in the representative strains of gram-positive, gram-negative, and fungal strains, viz., Staphylococcus aureus MTCC 2940, Escherichia coli MTCC 2939, and Candida albicans MTCC 227, respectively. KABT-AMP was synthesized by solid-phase synthesis and purified using reverse-phase high-performance liquid chromatography which resulted in >95 % purity, and matrix-assisted laser desorption/ionization time of flight revealed the mass of the peptide to be 2.8 kDa. KABT-AMP showed significant broad-spectrum antimicrobial activity against the bacterial and fungal strains analyzed in the present study with survivability of 30.8, 30.6, and 31.7 % in E. coli, S. aureus, and C. albicans, respectively, at 6 h. KABT-AMP also demonstrated antibiofilm activity against the tested biofilm forming clinical isolate, Candida tropicalis. The putative membranolytic activity of the peptide was substantiated by electron microscopic analysis. Results reveal that KABT-AMP will exhibit noteworthy antimicrobial activity against multidrug-resistant bacteria and fungus at micromolar concentrations with minimal cytotoxicity and thus could be conceived for biomedical application. PMID:23649308

Thankappan, Bency; Jeyarajan, Sivakumar; Hiroaki, Sakaue; Anbarasu, Kumarasamy; Natarajaseenivasan, Kalimuthusamy; Fujii, Noriko

2013-07-01

193

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

194

Antimicrobial Activity of Extractable Conifer Heartwood Compounds Toward Phytophthora ramorum  

Microsoft Academic Search

Ethyl acetate extracts from heartwood of seven western conifer trees and individual volatile compounds in the extracts were\\u000a tested for antimicrobial activity against Phytophthora ramorum. Extracts from incense and western redcedar exhibited the strongest activity, followed by yellow-cedar, western juniper,\\u000a and Port-Orford-cedar with moderate activity, and no activity for Douglas-fir and redwood extracts. Chemical composition of\\u000a the extracts varied both

Daniel K. Manter; Rick G. Kelsey; Joseph J. Karchesy

2007-01-01

195

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.

Benbelaid, Fethi; Khadir, Abdelmounaim; Abdoune, Mohamed Amine; Bendahou, Mourad

2013-01-01

196

Antimicrobial Susceptibility of Stenotrophomonas maltophilia Isolates from Korea, and the Activity of Antimicrobial Combinations against the Isolates  

PubMed Central

The aim of this study was to determine antimicrobial susceptibility of recent clinical Stenotrophomonas maltophilia isolates from Korea, and to compare the activity levels of several combinations of antimicrobials. A total of 206 non-duplicate clinical isolates of S. maltophilia was collected in 2010 from 11 university hospitals. Antimicrobial susceptibility testing was performed using the Clinical Laboratory Standards Institute agar dilution method. In vitro activity of antimicrobial combinations was tested using the checkerboard method. The susceptibility rates to trimethoprim-sulfamethoxazole and minocycline were 96% and 99%, respectively. The susceptibility rate to levofloxacin was 64%. All of four antimicrobial combinations showed synergy against many S. maltophilia isolates. A combination of trimethoprim-sulfamethoxazole plus ticarcillin-clavulanate was most synergistic among the combinations. None of the combinations showed antagonistic activity. Therefore, some of the combinations may be more useful than individual drugs in the treatment of S. maltophilia infection. Further clinical studies are warranted to validate our in vitro test results.

Chung, Hae-Sun; Kim, Young Ree; Shin, Kyeong Seob; Whang, Dong Hee; Ahn, Jee Young; Park, Yeon-Joon; Uh, Young; Chang, Chulhun L.; Shin, Jong Hee; Lee, Hye Soo; Lee, Kyungwon; Chong, Yunsop

2013-01-01

197

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

PubMed

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

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

2010-02-01

198

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

PubMed

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

Waters, Brian W; Hung, Yen-Con

2014-04-01

199

A multicenter evaluation of linezolid antimicrobial activity in North America  

Microsoft Academic Search

Overall, 141 centers in North America enrolled in this international surveillance study designed to evaluate the in vitro antimicrobial activity and spectrum of linezolid, a new oxazolidinone. Each participant tested the susceptibility of clinical isolates of staphylococcal species (n = 85) against 12 drugs, and enterococcal species (n = 40) against 6 drugs using reference broth microdilution trays; and of

Charles H. Ballow; Ronald N. Jones; Douglas J. Biedenbach

2002-01-01

200

Antimicrobial and antibiofilm activity of pleurocidin against cariogenic microorganisms  

Microsoft Academic Search

Dental caries is a common oral bacterial infectious disease of global concern. Prevention and treatment of caries requires control of the dental plaque formed by pathogens such as Streptococcus mutans and Streptococcus sobrinus. Pleurocidin, produced by Pleuronectes americanus, is an antimicrobial peptide that exerts broad-spectrum activity against pathogenic bacteria and fungi. Moreover, pleurocidin shows less hemolysis and is less toxic

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

2011-01-01

201

Differential activity of innate defense antimicrobial peptides against Nocardia species  

Microsoft Academic Search

BACKGROUND: Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs) in innate defense against Nocardia, the activity of human ?-defensins human neutrophil peptides (HNPs) 1-3, human

Siegbert Rieg; Benjamin Meier; Eva Fähnrich; Anja Huth; Dirk Wagner; Winfried V Kern; Hubert Kalbacher

2010-01-01

202

Antimicrobial activity in subArctic marine invertebrates  

Microsoft Academic Search

In the marine environment, any living or non-living surface is exposed to bacterial colonization. Many invertebrate species in temperate, tropical and Antarctic regions have demonstrated chemical defences against the formation of microbial films. In the present study, the antimicrobial activity of sub-Arctic invertebrates was investigated for the first time. Crude extracts of abundant invertebrates belonging to several taxonomic groups were

H. Lippert; R. Brinkmeyer; T. Mülhaupt; K. Iken

2003-01-01

203

Total syntheses and antimicrobial activities of pyridine alkaloids from Rubiaceae  

Microsoft Academic Search

Pyridine alkaloids from Rubiaceae were prepared by palladium-catalyzed cross-coupling reactions of methyl 5-bromonicotinate (6) with various organometallic reagents. Baker's yeast reduction of the ketone8 gave the levorotatory alcohol (S)-1. On this basis, the naturally occurring alcohol (+)-1 was assigned to be (R)-configurated. The alkaloids1 and4 show weak antimicrobial activities.

F. Bracher; T. Papke

1995-01-01

204

Phytochemical and Antimicrobial Activity of Digera Muricata (L.) Mart  

Microsoft Academic Search

The successive Soxhlet extract of Digera muricata (L.) Mart. (Amaranthaceae) were extracted using petroleum ether, chloroform, ethanol and distilled water in ascending order of the polarity. These extracts were subjected to screening of preliminary phytochemicals tests. The results indicate the presence of alkaloids, flavonoids, phenols, tannins, terpenes and saponins. These extracts further subjected to the antimicrobial activity. Among the bacteria

PRATIMA MATHAD; SUNDAR S. METY

205

Antioxidant and antimicrobial activities of Lycium shawii fruits extract.  

PubMed

Crude extracts from the fruit of Lycium shawii, a plant collected from the south of Tunisia, were screened for their in vitro antioxidant, antimicrobial and antifungal activities. The dried fruits were extracted with EtOH and an aqueous suspension of the obtained EtOH extract was partitioned successively with CHCl3, CH2Cl2, EtOAc and n-BuOH, leaving residual water extract. Total phenolic content of extracts from these fruits were also determined. ?-Carotene bleaching assay and Folin-Ciocalteu reagent were used to determine total antioxidant activity and total phenols of fruit extracts. Total phenolic and flavonoid contents varied from 100 to 377 mg GAE/g DW and 3.3-110.6 mg quercetin/gDW, respectively. Several extracts showed high antioxidant capacity and an antimicrobial activity against different strains. This is, to our knowledge, the first report on the detail chemical composition, antioxidant and antimicrobial activities of L. shawii extracts. The results provided evidence that the studied fruit might indeed be potential sources of natural antioxidant and antimicrobial agents. PMID:23732331

Dahech, Imen; Farah, Wafa; Trigui, Mohamed; Ben Hssouna, Anis; Belghith, Hafedh; Belghith, Karima Srih; Ben Abdallah, Ferjani

2013-09-01

206

Antimicrobial activity of some medicinal plants of the Cerrado, Brazil.  

PubMed

In order to determine the potential of Cerrado plants as sources of antimicrobial activity, the phytochemical screening of ethanol extracts from Virola surinamensis, Qualea grandiflora, Alchornea castaneifolia, Hancornia speciosa and Curatella americana traditionally used in folk medicine are reported. PMID:18350520

Costa, E S; Hiruma-Lima, C A; Lima, E O; Sucupira, G C; Bertolin, A O; Lolis, S F; Andrade, F D P; Vilegas, W; Souza-Brito, A R M

2008-05-01

207

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

208

?-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

209

Antimicrobial activity of aminoreductone against Helicobacter pylori.  

PubMed

Anti-Helicobacter pylori (H. pylori) effects of aminoreductone (AR), a Maillard reaction product, were evaluated in this study. AR effectively inhibited the growth of all 24 strains (19 clinical isolates and 5 isogenic mutants) irrespective of susceptibility to antibiotics and clinical manifestation. The minimum inhibitory concentration (MIC) of AR ranged from 0.5 to 5 mM. A killing assay with multiples of MIC was performed, demonstrating that the killing activity of AR was significantly higher than that of its derived melanoidin, an inhibitor of H. pylori urease-gastric mucin adherence, formed in the final stage of the Maillard reaction. These significant effects of AR on H. pylori were observed even in acidic conditions (pH 3). At most, 25 mM AR effectively exhibited bactericidal activity in all strains. These results rise up the possibility that foods containing AR, such as milk and dairy products, are valuable sources for preventing colonization of H. pylori in the stomach and its associated tissue damages. PMID:19891477

Trang, Vu Thu; Takeuchi, Hiroaki; Kudo, Hayato; Aoki, Akitoshi; Katsuno, Shinya; Shimamura, Tomoko; Sugiura, Tetsuro; Ukeda, Hiroyuki

2009-12-01

210

In vitro antimicrobial activity of methanolic leaf extract of Psidium guajava L.  

PubMed Central

Aim: This study was designed to examine the chemical composition and in vitro antimicrobial potential of methanolic extract of Psidium guajava Linn (Myrtaceae). Materials and Methods: The inhibitory effect of methanolic extract of P. guajava was tested against three bacterial and two fungal strains by using the paper disc diffusion method. Results: The methanolic extract exhibited antibacterial activity against E. coli with minimum inhibitory concentration, 0.78 ?g/ml, minimum bactericidal concentration of 50 ?g/ml, and appreciable antifungal activity with minimum inhibitory concentration of 12.5 ?g/ml. Preliminary phytochemical analysis of methanolic extract revealed the presence of antimicrobial compounds such as flavonoids, steroids, and tannins, which may contribute for the antimicrobial action of P. guajava. Conclusion: The extract was found to be bacteriostatic and fungistatic in action.

Dhiman, Anju; Nanda, Arun; Ahmad, Sayeed; Narasimhan, B.

2011-01-01

211

2-pyrones possessing antimicrobial and cytotoxic activities.  

PubMed

The 2-pyrone sub-unit is found in a number of natural products possessing broad spectrum biological activity. Such compounds are validated as being capable of binding to specific protein domains and able to exert a remarkable range of biological effects. In an effort to identify synthetic 2-pyrones with interesting biological effects, herein we report the synthesis and biological evaluation of 4-substituted-6-methyl-2-pyrones. Synthetic routes to 4-alkyl/alkenyl/aryl/alkynyl-6-methyl-2-pyrones have been developed utilising Sonogashira, Suzuki and Negishi cross-coupling starting from readily available 4-bromo-6-methyl-2-pyrone. Specific conditions for each organometallic protocol were required for successful cross-coupling. In particular, a triethylamine/acetonitrile--base/solvent mixture was crucial to Sonogashira alkynylation of 4-bromo-6-methyl-2-pyrone, whereas thallium carbonate was a mandatory base for the Suzuki cross-coupling of trialkylboranes. The 2-pyrones demonstrate potent inhibitory activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Schizosaccharomyces pombe and Botrytis cinerea. The growth inhibitory activities of selected 2-pyrones were determined in A2780 human ovarian carcinoma and K562 human chronic myelogenous leukaemia cell lines using an in vitro cell culture system (MTT assay). These studies demonstrate that 4-phenylethynyl-, 4-tetrahydropyranylpropargyl ether- and 4-ethynyl-6-methyl-2-pyrones have excellent potential as a new class of anticancer agents. PMID:15246105

Fairlamb, Ian J S; Marrison, Lester R; Dickinson, Julia M; Lu, Feng-Ju; Schmidt, Jan Peter

2004-08-01

212

Mechanisms of selective antimicrobial activity of gaegurin 4.  

PubMed

Gaegurin 4 (GGN4), an antimicrobial peptide isolated from a Korean frog, is five times more potent against Gram-positive than Gram-negative bacteria, but has little hemolytic activity. To understand the mechanism of such cell selectivity, we examined GGN4-induced K(+) efflux from target cells, and membrane conductances in planar lipid bilayers. The K(+) efflux from Gram-positive M. luteus (2.5 microg/ml) was faster and larger than that from Gram-negative E. coli (75 microg/ml), while that from RBC was negligible even at higher concentration (100 microg/ml). GGN4 induced larger conductances in the planar bilayers which were formed with lipids extracted from Gram-positive B. subtilis than in those from E. coli (p<0.01), however, the effects of GGN4 were not selective in the bilayers formed with lipids from E. coli and red blood cells. Addition of an acidic phospholipid, phosphatidylserine to planar bilayers increased the GGN4-induced membrane conductance (p<0.05), but addition of phosphatidylcholine or cholesterol reduced it (p<0.05). Transmission electron microscopy revealed that GGN4 induced pore-like damages in M. luteus and dis-layering damages on the outer wall of E. coli. Taken together, the present results indicate that the selectivity of GGN4 toward Gram-positive over Gram-negative bacteria is due to negative surface charges, and interaction of GGN4 with outer walls. The selectivity toward bacteria over RBC is due to the presence of phosphatidylcholine and cholesterol, and the trans-bilayer lipid asymmetry in RBC. The results suggest that design of selective antimicrobial peptides should be based on the composition and topology of membrane lipids in the target cells. PMID:19885025

Kim, Heejeong; Lee, Byeong Jae; Lee, Mun Han; Hong, Seong Geun; Ryu, Pan Dong

2009-02-01

213

Antimicrobial effectiveness of silver nanoparticles co-stabilized by the bioactive copolymer pluronic F68  

PubMed Central

Background Silver nanoparticles (AgNps) have attracted much interest in biomedical engineering, since they have excellent antimicrobial properties. Therefore, AgNps have often been considered for incorporation into medical products for skin pathologies to reduce the risk of contamination. This study aims at evaluating the antimicrobial effectiveness of AgNps stabilized by pluronic™ F68 associated with other polymers such as polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). Methods AgNps antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method. The action spectrum was evaluated for different polymers associated with pluronic™ F68 against the gram negative bacteria P. aeuroginosa and E. coli and the gram positive bacteria S. Aureus. Results AgNps stabilized with PVP or PVA and co-stabilized with pluronic™ F68 are effective against E. coli and P. aeruginosa microorganisms, with MIC values as low as 0.78% of the concentration of the original AgNps dispersion. The antimicrobial action against S. aureus is poor, with MIC values not lower than 25%. Conclusions AgNps stabilized by different polymeric systems have shown improved antimicrobial activity against gram-negative microorganisms in comparison to unstabilized AgNps. Co-stabilization with the bioactive copolymer pluronic™ F68 has further enhanced the antimicrobial effectiveness against both microorganisms. A poor effectiveness has been found against the gram-positive S. aureus microorganism. Future assays are being delineated targeting possible therapeutic applications.

2012-01-01

214

Antimicrobial peptides (AMP) with antiviral activity against fish nodavirus  

Microsoft Academic Search

Nervous necrosis virus (NNV) is classified as betanodavirus of Nodaviridae, and has caused mass mortality of numerous marine fish species at larval stage. Antimicrobial peptides (AMPs) play an important role of innate immunity either against bacterial pathogens or viruses. Up to date, little is known if any AMP could effectively inhibit fish nodaviruses and its mechanism. In this study, the antiviral

Ta-Jui Chia; Yu-Chi Wu; Jyh-Yih Chen; Shau-Chi Chi

2010-01-01

215

In vitro antimicrobial activity of Cryptolepis sanguinolenta (periplocaceae)  

Microsoft Academic Search

The aim of the present study was to investigate in vitro, the effect of three different preparations of Cryptolepis sanguinolenta, obtained from 2 mg\\/ml each of 70% ethanol, hot and cold aqueous extract, as antimicrobial agents using agar diffusion method. The microbes used in this study consisted of one strain of Salmonella typhimurium, two strains each of Proteus mirabilis, Pseudomonas

Felix C. Mills-Robertson; Frederick A. Aboagye; George Duker-Eshun; Sylvester Kaminta; Samuel Agbeve

216

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

217

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

218

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.

2013-01-01

219

Effect of proline position on the antimicrobial mechanism of buforin II  

PubMed Central

Buforin II (BF2) is a histone-derived antimicrobial peptide that causes cell death by translocating across membranes and interacting with nucleic acids. It contains one proline residue critical for its function. Previous research found that mutations replacing proline lead to decreased membrane translocation and antimicrobial activity as well as increased membrane permeabilization. This study further investigates the role of proline in BF2’s antimicrobial mechanism by considering the effect of changing proline position on membrane translocation, membrane permeabilization, and antimicrobial activity. For this purpose, four mutants were made with proline substitution (P11A) or relocation (P11A/G7P, P11A/V12P, P11A/V15P). These mutations altered the amount of ?-helical content. Although antimicrobial activity correlated with the ?-helical content for the peptides containing proline, membrane translocation did not. This observation suggests that factors in BF2’s bactericidal mechanism other than translocation must be altered by these mutations. To better explain these trends we also measured the nucleic acid binding and membrane permeabilization of the mutant peptides. A comparison of mutant and wild type BF2 activity revealed that BF2 relies principally on membrane translocation and nucleic acid binding for antimicrobial activity, although membrane permeabilization may play a secondary role for some BF2 variants. A better understanding of the role of proline in the BF2 antimicrobial mechanism will contribute to the further design and development of BF2 analogues. Moreover, since proline residues are prevalent among other antimicrobial peptides, this systematic characterization of BF2 provides general insights that can promote our understanding of other systems.

Xie, Yang; Fleming, Eleanor; Chen, Jessica L.; Elmore, Donald E.

2011-01-01

220

The antimicrobial effects of cranberry against Staphylococcus aureus.  

PubMed

The antimicrobial effects of the American cranberry (Vaccinium macrocarpon) on a major food-borne pathogen, Staphylococcus aureus, were investigated using commercially obtained Lakewood® organic cranberry juice and Ocean Spray® cranberry juice cocktail and four other berry fruit extracts (acai berry, strawberry, raspberry, and blueberry). The results showed that cranberry is a potent antimicrobial against S. aureus and the most potent among the berries studied. The order of percentage inhibition of bacterial growth at the same concentration of phenolic materials as gallic acid equivalents was Lakewood cranberry juice?>?Ocean Spray cranberry juice???blueberry?>?acai berry???raspberry???strawberry. The antimicrobial effect was not due to the acidity of the berries as NaOH-neutralized samples were almost as effective in terms of percentage inhibition of viable cell growth. Solid-phase extraction of cranberry juice using C18 solid phase showed that the antimicrobial effects reside exclusively with the C18-bound materials. PMID:22414934

Lian, Poh Yng; Maseko, T; Rhee, M; Ng, K

2012-04-01

221

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.

Bharate, Sandip B.; Thompson, Charles M.

2010-01-01

222

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

223

The antimicrobial activity, hydrophobicity and toxicity of sulfonium compounds, and their relationship.  

PubMed

The sulfonium compound is a kind of cationic surfactant as well as a quaternary ammonium which has been used widely around the globe. This study investigated the antimicrobial activity, the hydrophobicity, the toxicity of several sulfoniums and their relationship with the aim of clarifying their antimicrobial activity and toxicity, and, furthermore, of predicting their usefulness availability as antimicrobials. As a result, the antimicrobial activity, expressed as the minimum inhibitory concentration (MIC) of the sulfoniums examined in this study, tended to decrease with the increase of their hydrophobicity, estimated by ClogP, and their antimicrobial activity against the gram-positive bacteria was higher than that against the gram-negative bacteria used in this study. The antimicrobial activities of several sulfoniums against the gram-positive bacteria were higher than those of some common cationic antimicrobials including quaternary ammoniums such as cetylpyridinium chloride (CPC) and benzalkonium chloride (BKC). In contrast, the antimicrobial activities of the sulfoniums against the gram-negative bacteria were lower than those of some common cationic antimicrobials. Meanwhile the toxicity, in particular, the acute dermal irritation/corrosion of the sulfoniums, tended to be lower than that of common cationic antimicrobials which were toxic in many cases indices. These results suggest that the sulfoniums might become useful antimicrobials which are less hazardous to human health than common cationic antimicrobials. PMID:21467626

Hirayama, Michiasa

2011-03-01

224

Thermodynamics of RTA3 peptide binding to membranes and consequences for antimicrobial activity?  

PubMed Central

RTA3 is an ?-helical, amphipathic peptide with broad-spectrum activity against Gram-negative bacteria and low mammalian cell toxicity. RTA3 contains a cysteine residue, replacement of which with an alanine or serine (RTA3-C15S) virtually abolishes antimicrobial activity. Much of the activity of RTA3 can be recovered in RTA3-C15L, indicating that the C15 residue functions largely as a bulky hydrophobic side chain promoting target cell membrane interactions. The poorly active RTA3-C15S is a useful variant for assessing the mechanistic aspects of RTA3 activity. Binding and membrane perturbation in vesicles containing different proportions of negative surface charge are analyzed in terms of amino acid-specific free energy contributions to interfacial binding, which likely underlie variations in antimicrobial activity amongst RTA3 variants. Comparison with published free energy scales indicates that the reduced electrostatic contribution to binding to membranes having reduced negative surface charge can be compensated in RTA3 (but not RTA3-C15S) by a slightly deeper insertion of the C-terminus of the peptide to maximize hydrophobic contributions to binding. Analysis of inner membrane (IM)- and outer membrane (OM)-selective permeabilization of Escherichiacoli demonstrates a broad similarity between peptide effects on vesicles with low negative surface charge (20% negatively charged lipids), E.coli membrane perturbation, and antimicrobial activity, supporting a role for membrane perturbation in the killing mechanism of RTA3. The results demonstrate that large variations in antimicrobial activity on subtle changes in amino acid sequence in helical amphipathic peptides can be rationalized in terms of the thermodynamics of peptide binding to membranes, allowing a more systematic understanding of antimicrobial activity in these peptides.

Hawrani, Ayman; Howe, Robin A.; Walsh, Timothy R.; Dempsey, Christopher E.

2010-01-01

225

Platelets display potent antimicrobial activity and release human beta-defensin 2.  

PubMed

Platelet-rich plasma (PRP) is a potent agent that improves soft tissue and bone healing. By the release of growth factors and cytokines, PRP is believed to locally boost physiologic healing processes. Recently, antimicrobial activity of PRP has been demonstrated against S. aureus strains. Major scientific effort is being put into the understanding and prevention of infections i.e. by delivery of antimicrobial substances. In previous studies we showed the ideal antibacterial activity-profile of the human beta-defensin 2 (hBD-2) for orthopaedic infections and therefore hypothesized that hBD-2 may be the effector of antimicrobial platelet action. Platelet concentrates were produced from human platelet phresis obtained from a hospital blood bank. They were screened by immunohistochemistry, Western Blot and ELISA for the human beta defensin-2. In vitro susceptibility to PRP was investigated by a standard disc diffusion test with or without pre-incubation of PRP with anti-hBD-2 antibody. SPSS statistical software was used for statistical analysis. PRP contains hBD-2 470?pg/10(9) platelets or 1786?pg/ml, respectively, (ELISA), which was confirmed by immunohistochemistry and Western Blot. In antimicrobial testing, PRP demonstrates effective inhibition of E. coli, B. megaterium, P. aeruginosa, E. faecalis and P. mirabilis. With this study we confirm the previously reported antimicrobial action of platelet concentrates i.e. PRP. In opposition to previously reported effects against gram positive bacteria our study focuses on gram negative and less common gram positive bacteria that do frequently cause clinical complications. We provide a possible molecular mechanism at least for E. coli and P. mirabilis for this effect by the detection of an antimicrobial peptide (hBD-2). This study may advocate the clinical use of PRP by highlighting a new aspect of platelet action. PMID:21913811

Tohidnezhad, Mersedeh; Varoga, Deike; Wruck, Christoph Jan; Podschun, Rainer; Sachweh, Benita Hermanns; Bornemann, Jorg; Bovi, Manfred; Sönmez, Taha Tolga; Slowik, Alexander; Houben, Astrid; Seekamp, Andreas; Brandenburg, Lars Ove; Pufe, Thomas; Lippross, Sebastian

2012-01-01

226

Antimicrobial and antioxidant activities of some Nigerian medicinal plants.  

PubMed

Ten Nigerian plants suggested from their ethnomedical uses to possess antimicrobial and antioxidant activities were studied for their anti-microbial and anti-oxidant properties. Antimicrobial activity was tested against Escherichia coli NCTC 10418, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Candida pseudotropicalis and Trichophyton rubrum (clinical isolate). Trichilia heudelotti leaf extract showed both antibacterial and antifungal activities and was the most active against all the strains of bacteria tested. Boerhavia diffusa, Markhamia tomentosa and T. heudelotti leaf extracts inhibited the gram negative bacteria E. coli and P. aeruginosa strains whereas those of M. tomentosa, T. heudelotti and Sphenoceutrum jollyamum root inhibited at least one of the fungi tested. At a concentration of 312 microg/ml, hexane and chloroform fractions of T. heudelotti extract inhibited 6 and 14% of the fifty multi-drug resistant bacteria isolates from clinical infections, respectively. At < or = 5 mg/ml, the CHCl(3) (64%) and aqueous (22%) fractions of T. heudelotti and those of CHCl(3) (34%) and EtOAC (48%) of M. tomentosa gave the highest inhibition that was stronger than their corresponding methanol extracts. The corresponding EC(50) of the extracts on M. acuminata, T. heudelotti, E. senegalensis and M. tomentosa were 4.00, 6.50, 13.33, and 16.50 ig/ml using the TLC staining and 1,1-dipheyl-2-picry-hydrazyl (DPPH) free radical scavenging assay. Therefore, leaf extracts of M. tomentosa and T. heudelotti, especially the latter, possess strong antimicrobial and antioxidant activities and should be further investigated. These activities justified the ethnomedical uses of these plants. PMID:20162089

Aladesanmi, A J; Iwalewa, E O; Adebajo, A C; Akinkunmi, E O; Taiwo, B J; Olorunmola, F O; Lamikanra, A

2006-01-01

227

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

228

Design of Embedded-Hybrid Antimicrobial Peptides with Enhanced Cell Selectivity and Anti-Biofilm Activity  

PubMed Central

Antimicrobial peptides have attracted considerable attention because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance which is the most common source of failure in bacterial infection treatment along with biofilms. The method to design hybrid peptide integrating different functional domains of peptides has many advantages. In this study, we designed an embedded-hybrid peptide R-FV-I16 by replacing a functional defective sequence RR7 with the anti-biofilm sequence FV7 embedded in the middle position of peptide RI16. The results demonstrated that the synthetic hybrid the peptide R-FV-I16 had potent antimicrobial activity over a wide range of Gram-negative and Gram-positive bacteria, as well as anti-biofilm activity. More importantly, R-FV-I16 showed lower hemolytic activity and cytotoxicity. Fluorescent assays demonstrated that R-FV-I16 depolarized the outer and the inner bacterial membranes, while scanning electron microscopy and transmission electron microscopy further indicated that this peptide killed bacterial cells by disrupting the cell membrane, thereby damaging membrane integrity. Results from SEM also provided evidence that R-FV-I16 inherited anti-biofilm activity from the functional peptide sequence FV7. Embedded-hybrid peptides could provide a new pattern for combining different functional domains and showing an effective avenue to screen for novel antimicrobial agents.

Xu, Wei; Zhu, Xin; Tan, Tingting; Li, Weizhong; Shan, Anshan

2014-01-01

229

Isolation and antimicrobial and antioxidant evaluation of bio-active compounds from eriobotrya japonica stems.  

PubMed

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

230

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

PubMed

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

Stanciuc, A M; Gaspar, A; Moldovan, L; Saviuc, C; Popa, M; M?ru?escu, L

2011-01-01

231

In Vitro Study of Sustained Antimicrobial Activity of a New Silver Alginate Dressing  

PubMed Central

Silver-containing dressings are considered fundamental to the management of infected acute and chronic wounds, specifically burns. The aim of this study was to determine both the spectrum of activity and efficacy of an Alginate/CMC Silver Dressing (ACSP) on planktonic microorganisms by conducting a 21-day repeat-challenge log reduction study. ACSP was found to have a microbiocidal effect, for up to 21 days, on all bacteria and yeast challenged. The results demonstrated an antimicrobial efficacy similar to Hydrofiber Silver Dressing's (HSD)2 up to day 14 for each microorganism tested. However, following a second reinoculation of microorganisms at day 14, ACSP showed antimicrobial efficacy superior to HSD's against a number of opportunistic pathogens, which included Pseudomonas aeruginosa and Candida albicans. The ACSD maintained its antimicrobial action against all microorganisms over the 21-day study period.

Bradford, Colin; Freeman, Richard; Percival, Steven L.

2009-01-01

232

In vitro study of sustained antimicrobial activity of a new silver alginate dressing.  

PubMed

Silver-containing dressings are considered fundamental to the management of infected acute and chronic wounds, specifically burns. The aim of this study was to determine both the spectrum of activity and efficacy of an Alginate/CMC Silver Dressing (ACSP) on planktonic microorganisms by conducting a 21-day repeat-challenge log reduction study. ACSP was found to have a microbiocidal effect, for up to 21 days, on all bacteria and yeast challenged. The results demonstrated an antimicrobial efficacy similar to Hydrofiber Silver Dressing's (HSD) up to day 14 for each microorganism tested. However, following a second reinoculation of microorganisms at day 14, ACSP showed antimicrobial efficacy superior to HSD's against a number of opportunistic pathogens, which included Pseudomonas aeruginosa and Candida albicans. The ACSD maintained its antimicrobial action against all microorganisms over the 21-day study period. PMID:24527131

Bradford, Colin; Freeman, Richard; Percival, Steven L

2009-12-01

233

Preparation and antimicrobial activity of poly (vinyl chloride)/gelatin/montmorillonite biocomposite films.  

PubMed

The aim of this study was using a novel antimicrobial thermoplastic plasticizer based on aliphatic anhydride derivative dodecenyl succinic anhydride (DSA) for blending poly (vinyl chloride), PVC, with gelatin in presence of montmorillonite (MMT) using Brabender via polymer melting technique. This anhydride-based plasticizer blended the membrane ingredients homogenously under melting process. The used plasticizer exhibited high performance antimicrobial potency for some biomedical and industrial applications. The prepared biocomposite films were evaluated for antimicrobial activity using agar disc diffusion method against gram-positive and gram-negative bacteria such as: Staphylococcus aureus (S. aureus), Klebsiella pneumonia (K. pneumonia), Bacillus cereus (B. cereus), Bacillus subtilis (B. subtilis) and Escherichia coli (E. coli). The majority of these biocomposites, except the plasticized PVC with DOP, have shown inhibitory effect at different concentrations (1.0-20) mg/ml against all above mentioned bacteria. However, C. albicans and A. niger were the most resistant strains. PMID:21909641

Haroun, Ahmed A; Ahmed, Eman F; Abd El-Ghaffar, M A

2011-11-01

234

Amino acid substitutions in an alpha-helical antimicrobial arachnid peptide affect its chemical properties and biological activity towards pathogenic bacteria but improves its therapeutic index.  

PubMed

Four variants of the highly hemolytic antimicrobial peptide Pin2 were chemically synthesized with the aim to investigate the role of the proline residue in this peptide, by replacing it with the motif glycine-valine-glycine [GVG], which was found to confer low hemolytic activity in a spider antimicrobial peptide. The proline residue in position 14 of Pin2 was substituted by [V], [GV], [VG] and [GVG]. Only the peptide variant with the proline substituted for [GVG] was less hemolytic compared to that of all other variants. The peptide variant [GVG] kept its antimicrobial activity in Muller-Hilton agar diffusion assays, whereas the other three variants were less effective. However, all Pin2 antimicrobial peptide variants, were active when challenged against a Gram-positive bacteria in Muller-Hilton broth assays suggesting that chemical properties of the antimicrobial peptides such as hydrophobicity is an important indication for antimicrobial activity in semi-solid environments. PMID:20033827

Rodríguez, A; Villegas, E; Satake, H; Possani, L D; Corzo, Gerardo

2011-01-01

235

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.

2012-01-01

236

Enzyme-assisted processing increases antimicrobial and antioxidant activity of bilberry.  

PubMed

The effects of nine cell wall-degrading enzymes on the antimicrobial and antioxidant activities of bilberry were studied. Antimicrobial activity was measured using the human pathogens Salmonella enterica sv. Typhimurium and Staphylococcus aureus as test strains. Enzyme treatments liberated phenolics from the cell wall matrix, which clearly increased the antimicrobial activity of berry juices, press cakes, and berry mashes on the basis of plate counts. Antibacterial effects were stronger against Salmonella than against Staphylococcus bacteria. In general, the increase in activity measured as colony-forming units per milliliter was 3-5 logarithmic units against Salmonella and 1-2 units against Staphylococcus bacteria. Increase in antimicrobial activity was observed only in acidic conditions, which is also the natural environment in various berry products, such as juices. The activity profile of the pectinase preparation affected the chemistry of the phenolics due to the presence of deglycosylating activities in some preparations. The difference in phenolic profiles was reflected in the antimicrobial effects. Bilberry mashes treated with Pectinex Ultra SP-L, Pectinex 3 XL, and Pectinex BE XXL were most efficient against Salmonella bacteria, whereas mashes treated with Pectinex Smash, Pectinex BE 3-L, and Biopectinase CCM showed the strongest antimicrobial activity against Staphylococcus bacteria. Due to the liberation of phenolics from the cell wall matrix the antioxidant activity measured as radical scavenging activity was also increased on average about 30% by the enzymatic treatments. The highest increase in phenolic compounds was about 40%. Highest increases in anthocyanins and in antioxidant activity were observed in berry mash treated with Pectinex Smash XXL enzyme, and the lowest increase was observed after treatment with Pectinex BE 3-L. Enzyme-assisted processing is traditionally used to improve berry and fruit juice yields. However, enzymatic treatments also have an impact on the functional properties of the products. The increased liberation of phenolics from the cell wall matrix can prolong the shelf life of berry products by limiting the growth of contaminants during processing or storage. The increased amount of phenolic compounds may also have a positive effect on gut well-being. PMID:18211029

Puupponen-Pimiä, Riitta; Nohynek, Liisa; Ammann, Sabine; Oksman-Caldentey, Kirsi-Marja; Buchert, Johanna

2008-02-13

237

Antimicrobial activity of broth fermented with kefir grains.  

PubMed

Kefir grains originate from the Caucasus region and are used for preparing beverages using sugar solution, milk, and fruit juice. As long as they are formed by a microbial consortium useful in the intestine, the produced drinks can be called probiotics. The aim of this study was to determine the antimicrobial activity during kefir fermentation in sugar broth. Fermentations with three kinds of carbohydrates (molasses, demerara sugar, and brown sugar) as carbon source were carried out. Brown sugar promoted the greatest antimicrobial activities, producing inhibition halos corresponding to 35, 14, 12, 14, and 14 mm for Candida albicans, Salmonella typhi, Shigella sonnei, Staphylococcus aureus, and Escherichia coli, respectively. Different carbon source concentrations and the time of fermentation influenced the size of the inhibition halos of the pathogenic microorganisms. PMID:18663417

Silva, Karoline R; Rodrigues, Sheila A; Filho, Lauro Xavier; Lima, Alvaro S

2009-02-01

238

Effect of hospitalization and antimicrobial therapy on antimicrobial resistance of colonizing Staphylococcus epidermidis.  

PubMed

Endogenous infections with multi-resistant S. epidermidis are among the leading causes of nosocomial infections. The effect of hospitalization and antimicrobial therapy on antimicrobial resistance of colonizing staphylococci was determined from swabs of the nose, hand, axilla and groin from 157 patients on one day. Hospitalization for >72 hours, compared with <72 hours, was associated with a higher percentage of isolates resistant to oxacillin (56% versus 19%), gentamicin (40% versus 15%), trimethoprim (36% versus 17%), clindamycin (56% versus 17%), and fusidic acid (20% versus 4%; p < 0.01 for all), but not to rifampicin (6% versus 1%) or fosfomycin (43% versus 34%, p > 0.05 for both). Concurrent antimicrobial therapy resulted in increased resistance to oxacillin (61% versus 28%), gentamicin (43% versus 20%), and clindamycin (60% versus 26%; p < 0.01 for all), but not to trimethoprim (39% versus 23%), fusidic acid (19% versus 9%), rifampicin (6% versus 3%), or fosfomycin (46% versus 38%, p > 0.05 for all). The increase in resistant isolates was not independent, since hospitalization and antimicrobial therapy were correlated (p < 0.001). After adjustment for potential risk factors such as diabetes mellitus, central venous catheters, and hemodialysis, the odds ratio for oxacillin resistance was 2.8-3.6. None of the risk factors showed statistically significant results, except for the presence of neoplastic disease, which had a significant interaction (P=0.035). The within-subgroup odds ratios for patients with and without neoplasm were 4.2 (95% CI, 2.3-5.7) and 2.1 (95% CI, 0.78-3.12), respectively. These results show that hospitalization for more than three days, with or without antimicrobial therapy, and the presence of neoplastic disease are associated with increased antimicrobial resistance in colonizing S. epidermidis. PMID:15379145

Knauer, Ariane; Fladerer, Petra; Strempfl, Christina; Krause, Robert; Wenisch, Christoph

2004-07-31

239

Kirenol production in hairy root culture of Siegesbeckea orientalis and its antimicrobial activity  

PubMed Central

Background: Despite the excellent anti-inflammatory and anti-rheumatic efficacy associated with kirenol generation, the content of kirenol in Siegesbeckea orientalis is quite low. Objective: This study was designed to establish a reliable kirenol production protocol by transformed root cultures of S. orientalis and to investigate the antimicrobial activities of kirenol, hairy root, and S. orientalis. Materials and Methods: Transformed root cultures of S. orientalis were established by the transformation of Agrobacterium rhizogenes A4. Transgenic status of the roots was confirmed by polymerase chain reaction (PCR) using rolB specific primers. The biomass and kirenol accumulation of hairy root clones were assessed using four different culture media: MS, MS/2, B5, and white. The antimicrobial activities of kirenol, hairy root, and S. orientalis were evaluated by the disc diffusion method. Results: The optimum media for kirenol synthesis was MS. The content of kirenol in transformed hairy roots made up about 80% of that observed in natural leaves of S. orientalis (1.6 mg/g dry weight). All tested samples displayed antimicrobial activity against Gram-positive pathogens including Staphylococcus epidermidis, Staphylococcus aureus, and Acinetobacter baumannii, with MIC ranging from 78 to 625 ?g/mL. Discussion and Conclusion: The high level of kirenol contents was obtained from hairy roots of S. orientalis. Kirenol was effective against gram-positive bacteria. Interestingly, the extract from hairy roots showed a diverse antimicrobial effect from that of kirenol and S. orientalis.

Wang, Jian-Ping; Zhou, Ya-Ming; Zhang, Yong-Hui

2012-01-01

240

Antioxidant and antimicrobial activity of legume hulls  

Microsoft Academic Search

Antioxidant activity of aqueous hull extracts of commonly consumed legumes in India namely Vigna radiata (mung bean), Cicer arietinum (Bengal gram) and Cajanus cajan (pigeon pea) was studied by several in vitro assays. The extracts showed high phenolic content and excellent DPPH scavenging activity (75–85%) at very low concentration. The IC50 values for superoxide radical scavenging activity was also low

Sweetie R. Kanatt; Arun Sharma

2011-01-01

241

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

242

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

243

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

244

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

PubMed

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

Agnihotri, Supriya; Wakode, S

2010-09-01

245

Phytochemical screening, antioxidant, and antimicrobial activities of the crude leaves' extract from Ipomoea batatas (L.) Lam  

PubMed Central

Background: Ipomoea batatas (L.) Lam., popularly known as sweet potato (SP), has played an important role as an energy and a phytochemical source in human nutrition and animal feeding. Ethnopharmacological data show that SP leaves have been effectively used in herbal medicine to treat inflammatory and/or infectious oral diseases in Brazil. The aim of this research was to evaluate the phytochemical, antioxidant, and antimicrobial activities of the crude leaves’ extract of SP leaves. Materials and Methods: The screening was performed for triterpenes/steroids, alkaloids, anthraquinones, coumarins, flavonoids, saponins, tannins, and phenolic acids. The color intensity or the precipitate formation was used as analytical responses to these tests. The total antioxidant capacity was evaluated by the phosphomolybdenum complex method. Antimicrobial activity was made by agar disk and agar well diffusion tests. Results: The phytochemical screening showed positive results for triterpenes/steroids, alkaloids, anthraquinones, coumarins, flavonoids, saponins, tannins, and phenolic acids. Total contents of 345.65, 328.44, and 662.02 mg were respectively obtained for alkaloids, anthraquinones, and phenolic compounds in 100 g of the dry sample. The total antioxidant capacity was 42.94% as compared to ascorbic acid. For antimicrobial studies, no concentration of the SP freeze dried extract was able to inhibit the growth of Streptococcus mutans, S. mitis, Staphylococcus aureus, and Candida albicans in both agar disk and agar well diffusion tests. Conclusions: SP leaves demonstrated the presence of secondary metabolites with potential biological activities. No antimicrobial activity was observed.

Pochapski, Marcia Thais; Fosquiera, Eliana Cristina; Esmerino, Luis Antonio; dos Santos, Elizabete Brasil; Farago, Paulo Vitor; Santos, Fabio Andre; Groppo, Francisco Carlos

2011-01-01

246

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

247

Antimicrobial activity of silver/starch/polyacrylamide nanocomposite.  

PubMed

A novel silver/starch/polyacrylamide nanocomposite hydrogel was prepared by grafting acrylamide onto starch in presence of silver nitrate by use of ammonium persulphate as an initiator and N,N-methylene-bisacrylamide as a crosslinking agent, then reducing the silver ions enclosed in the hydrogel structure to silver nanoparticles by treating the hydrogel with sodium hydroxide solution. All factors which affect the grafting/crosslinking reaction were optimized and the concentration of silver ion was changed from 0ppm to 50ppm. The produced nanocomposite hydrogel was characterized for its nanosilver content and the UV-spectra showed similar absorption spectra at wavelength 405nm for all AgNO3 concentrations but the plasmon showed increase in the intensity of the absorption peak as AgNO3 concentration incorporated to the hydrogel structure increases. The nanocomposite hydrogel was also characterized for its antimicrobial activity toward two types of bacteria and two types of fungi. The results showed that the hydrogel with 0ppm silver content has no antimicrobial activity, and that the antimicrobial activity expressed as inhibition zone increases as the silver content increases from 5ppm to 50ppm. PMID:24769214

Abdel-Halim, E S; Al-Deyab, Salem S

2014-07-01

248

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

249

Antimicrobial activity of nanoemulsion in combination with cetylpyridinium chloride in multidrug-resistant Acinetobacter baumannii.  

PubMed

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; Alvarez, Rene

2013-08-01

250

Antimicrobial Activity of Human Prion Protein Is Mediated by Its N-Terminal Region  

PubMed Central

Background Cellular prion-related protein (PrPc) is a cell-surface protein that is ubiquitously expressed in the human body. The multifunctionality of PrPc, and presence of an exposed cationic and heparin-binding N-terminus, a feature characterizing many antimicrobial peptides, made us hypotesize that PrPc could exert antimicrobial activity. Methodology and Principal Findings Intact recombinant PrP exerted antibacterial and antifungal effects at normal and low pH. Studies employing recombinant PrP and N- and C-terminally truncated variants, as well as overlapping peptide 20mers, demonstrated that the antimicrobial activity is mediated by the unstructured N-terminal part of the protein. Synthetic peptides of the N-terminus of PrP killed the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the Gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungus Candida parapsilosis. Fluorescence studies of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen after treatment with the “classical” human antimicrobial peptide LL-37. In contrast to LL-37, however, no marked helix induction was detected for the PrP-derived peptides in presence of negatively charged (bacteria-mimicking) liposomes. PrP furthermore showed an inducible expression during wounding of human skin ex vivo and in vivo, as well as stimulation of keratinocytes with TGF-? in vitro. Conclusions The demonstration of an antimicrobial activity of PrP, localisation of its activity to the N-terminal and heparin-binding region, combined with results showing an increased expression of PrP during wounding, indicate that PrPs could have a previously undisclosed role in host defense.

Pasupuleti, Mukesh; Roupe, Markus; Rydengard, Victoria; Surewicz, Krystyna; Surewicz, Witold K.; Chalupka, Anna; Malmsten, Martin; Sorensen, Ole E.; Schmidtchen, Artur

2009-01-01

251

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.

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

2013-01-01

252

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

253

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

SciTech Connect

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

Martinez-Becerra, Francisco [Department of Immunology, Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico, Circuito Escolar s/n, Mexico, DF, CP 04510 (Mexico); Silva, Daniel-Adriano [Department of Biochemistry, Facultad de Medicina, Universidad Nacional Autonoma de Mexico (Mexico); Dominguez-Ramirez, Lenin [Department of Biochemistry, Facultad de Medicina, Universidad Nacional Autonoma de Mexico (Mexico); Mendoza-Hernandez, Guillermo [Department of Biochemistry, Facultad de Medicina, Universidad Nacional Autonoma de Mexico (Mexico); Lopez-Vidal, Yolanda [Departamento de Microbiologia y Parasitologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico (Mexico); Soldevila, Gloria [Department of Immunology, Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico, Circuito Escolar s/n, Mexico, DF, CP 04510 (Mexico); Garcia-Zepeda, Eduardo A. [Department of Immunology, Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico, Circuito Escolar s/n, Mexico, DF, CP 04510 (Mexico)]. E-mail: garciaze@servidor.unam.mx

2007-04-06

254

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; Zúńiga-Estrada, A; Torres-Valencia, J M; Joseph-Nathan, P

2001-08-01

255

Antimicrobial activity of three Mexican Gnaphalium species  

Microsoft Academic Search

The antibacterial activity of the hexane, ethyl acetate and methanol extracts of the flowers, leaves and stems of Gnaphaliumoxyphyllum 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.

J. Roberto Villagómez-Ibarra; Maricruz Sánchez; Ofelia Espejo; Armida Zúńiga-Estrada; J. Mart??n Torres-Valencia; Pedro Joseph-Nathan

2001-01-01

256

Antifeedant and antimicrobial activity of Tylophora indica  

Microsoft Academic Search

Crude and pure extracts of Tylophora indica were investigated in view of antifeedant, antibacterial and antifungal properties. Leaf crude extract showed more antifeedant activity than stem and root against Spodoptera litura, a polyphagous pest on wide ranging crops. Among the pure compounds isolated, Tylophorine showed the highest antifeedant activity followed by Septicine, O-Methyl Tylophorinidine and simple aliphatic acid. Similarly the

B. Krishna Reddy; M. Balaji; P. Uma Reddy; G. Sailaja; K. Vaidyanath; G. Narasimha

2009-01-01

257

Antimicrobial spectrum of activity for meropenem and nine broad spectrum antimicrobials: report from the MYSTIC Program (2002) in North America  

Microsoft Academic Search

The Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program provides susceptibility data for participating medical centers where carbapenems are utilized. The activity of meropenem and nine broad-spectrum antimicrobial agents were assessed against 3,047 bacterial isolates collected during 2002 from 16 North American sites. The overall rank order of susceptibility of the 10 antimicrobial agents tested against Gram-negative isolates was: meropenem

Paul R Rhomberg; Ronald N Jones

2003-01-01

258

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.

2012-02-01

259

N-cholesteryl amino acid conjugates and their antimicrobial activities.  

PubMed

A series of N-cholesteryl amino acid conjugates have been synthesized using a reductive amination protocol in good yield and purity. All the synthesized conjugates were evaluated for their in vitro antimicrobial activities against Gram positive and Gram negative bacteria. Among the conjugates tested, N-cholesteryl GABA 12 showed the highest potency toward the methicillin-resistant Staphylococcus aureus with the lowest MIC value of 2 ?g/mL. Hemolytic activities of the compounds 3, 4, 11, and 12 were determined. All compounds tested had no significant hemolytic activity up to >50 ?g/mL. PMID:23872625

Jadhav, Jyoti R; Kim, Hong-Seok; Kwak, Jin-Hwan

2013-10-01

260

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.

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

2013-01-01

261

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

PubMed

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. (1)H and (13)C 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. PMID:24835932

Alyar, Saliha; Adem, Sevki

2014-10-15

262

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.

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

2008-01-01

263

Chemical composition and antimicrobial activities of the essential oils from Ocimum selloi and Hesperozygis myrtoides.  

PubMed

Ocimum selloi, a traditional medicinal plant from Brazil, is sold in open-air markets at Rio de Janeiro State. Hesperozygis myrtoides is a very aromatic small bush found in the State of Minas Gerais, Brazil, growing at an altitude of 1800m. The chemical composition of both essential oils was analyzed as well as their antimicrobial activity against fungi and bacteria. For all specimens of Ocimum selloi obtained at open-air markets, methylchavicol was major compound found (93.6% to 97.6%) in their essential oils. The major compounds identified in the oil of H. myrtoides were pulegone (44.4%), isomenthone (32.7%), and limonene (3.5%). Both oils displayed antimicrobial activity against all tested microorganisms but Candida albicans was the most susceptible one. Combinations of the two oils in different proportions were tested to verify their antimicrobial effect against C. albicans, which, however, was not modified in any of the concentrations tested. The minimum inhibitory concentration (MIC) was determined to confirm the antimicrobial activity against C. albicans as well as other clinical isolates (C. glabrata, C. krusei, C. parapsilosis and C. tropicalis). PMID:21834250

Martini, Márcia G; Bizzo, Humberto R; Moreira, Davyson de L; Neufeld, Paulo M; Miranda, Simone N; Alviano, Celuta S; Alviano, Daniela S; Leităo, Suzana G

2011-07-01

264

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

PubMed

The volatile oils obtained from the leaves of four pecan cultivars growing in Egypt were evaluated for their chemical composition and antimicrobial activity. The selected cultivars (cv.) were Carya illinoinensis (Wangneh.) K. Koch. cv. Wichita, C. illinoinensis cv. Western Schley, C. illinoinensis cv. Cherokee, and C. illinoinensis cv. Sioux. The gas chromatography-mass spectrometry analyses revealed that the volatile oils from samples of the different cultivars differ in composition and percentage of their components. ?-Curcumene was found as the major constituent of the cv. Wichita oil, whereas germacrene D was the major component of cv. Sioux, cv. Cherokee, and cv. Western Schley. The antimicrobial activity was assayed using the Kirby-Bauer Method by measuring the zone of inhibition of growth. All volatile oils displayed an antimicrobial activity against the tested bacterial strains. On the other hand, only the volatile oil of cv. Wichita showed an antifungal effect on Aspergillus flavus. This work has identified candidates of volatile oils for future in vivo studies to develop antibiotic substitutes for the diminution of human and animal pathogenic bacteria. Nevertheless, the variations of the volatile oil components and antimicrobial potencies of the different studied cultivars, necessitate identifying the cultivars used in future studies. PMID:24180553

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

2013-11-01

265

Antibacterial activity of the soil-bound antimicrobials oxytetracycline and ofloxacin.  

PubMed

Soil contamination of antimicrobials has become an increasing concern because of the potential risks to the soil microbial ecosystem and human health. The present study investigated sorption and desorption behaviors of oxytetracycline (OTC) and ofloxacin (OFL) in 3 typical soils (A, B, and C), and evaluated the antibacterial activity of soil-adsorbed compounds to a pure sensitive strain Escherichia coli ATCC 25922. The results showed different sorption and desorption behaviors of OTC and OFL in the 3 soils, behaviors that were mainly influenced by soil organic matter content and cation exchange capacity (CEC) as well as pH value. In addition, complexation and cation-exchange reactions were shown to be the main sorption mechanisms. Strong adsorption was found in soil B (with a high organic matter content) and in soil C (with high CEC), whereas enhanced desorption was observed in soil A (with low organic matter content). The results also demonstrated that soil-bound antimicrobials retained antibacterial activity toward E. coli. Opposite patterns of antibacterial activity were found for the 2 antimicrobials in the 3 soils: A?>?B?>?C for OFL; and C?>?B?>?A for OTC. This finding suggests that soil-bound antimicrobials could still exert selective pressure on soil bacteria although less effectively in comparison with the dissolved forms. Environ Toxicol Chem 2014;33:776-783. © 2014 SETAC. PMID:24408539

Peng, Feng-Jiao; Zhou, Li-Jun; Ying, Guang-Guo; Liu, You-Sheng; Zhao, Jian-Liang

2014-04-01

266

Isolation, characterization and phylogeny of sponge-associated bacteria with antimicrobial activities from Brazil.  

PubMed

Bacteria associated with marine sponges represent a rich source of bioactive metabolites. The aim of this study was to isolate and characterize bacteria with antimicrobial activities from Brazilian sponges. A total of 158 colony-forming units were isolated from nine sponge species. Among these, 12 isolates presented antimicrobial activities against pathogenic bacteria. Based on comparative sequence analysis of their 16S rRNA genes, the sponge-associated bacterial strains could be subdivided into three phylogenetically different clusters. Five strains were affiliated with Firmicutes (genera Bacillus and Virgibacillus), three with alpha-Proteobacteria (Pseudovibrio sp.) and four with gamma-Proteobacteria (genera Pseudomonas and Stenotrophomonas). The sponge-associated bacterial strains Pseudomonas fluorescens H40 and H41 and Pseudomonas aeruginosa H51 exhibited antimicrobial activity against both Gram-negative and Gram-positive bacteria, including strains such as vancomycin-resistant Enterococcus faecium and multiresistant Klebsiella pneumoniae. Bacillus pumilus Pc31 and Pc32, Pseudovibrio ascidiaceicola Pm31 and Ca31 and Pseudovibrio denitrificans Mm37 strains were more effective against Gram-positive bacteria. These findings suggest that the identified strains may contribute to the search for new sources of antimicrobial substances, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria. PMID:20600863

Santos, Olinda C S; Pontes, Paula V M L; Santos, Juliana F M; Muricy, Guilherme; Giambiagi-deMarval, Marcia; Laport, Marinella S

2010-09-01

267

Antimicrobial activity of four root canal sealers against endodontic pathogens  

Microsoft Academic Search

The antibacterial effects of various types of widely used endodontic sealers have not been compared systematically on facultative or obligate anaerobic endodontic pathogens. The aim of this study was to evaluate the antimicrobial properties of four commonly used endodontic sealers: two epoxy-resin-based sealers (AH26, AH plus), one zinc-oxide eugenol-based sealer (N2), and one calcium hydroxide-based sealer (Sealapex). The testing microbes

Chung-Chih Lai; Fu-Mei Huang; Hui-Wen Yang; You Chan; Min-Sheng Huang; Ming-Yung Chou; Yu-Chao Chang

2001-01-01

268

Antimicrobial Activity of Medicated Soaps Commonly Used By Dar es Salaam Residents in Tanzania  

PubMed Central

An in vitro evaluation of the anti-microbial activity of medicated soaps was conducted using ditch-plate and hand washing techniques. Strains of reference microbes namely Candida albicans (ATCC90028), Staphylococcus aureus (ATCC25923), Pseudomonas aureginosa (ATCC27853) and Escherichia coli (ATCC25922) were tested at three different soaps’ concentrations (1.0, 4.0 and 8.0 mg/ml). A total of 16 medicated soaps were assayed for their antimicrobial efficacy. Of these, 13 were medicated and 3 non-medicated soaps, which served as control. Ciprofloxacin and ketaconazole were employed as positive controls. Label disclosure for the soaps’ ingredients and other relevant information were absorbed. The most common antimicrobial active ingredients were triclosan, trichloroxylenol and trichlorocarbanilide. ANOVA for means of zones of inhibition revealed variability of antimicrobial activity among the medicated soaps. Positive correlation (r=0.318; P<0.01) between zones of inhibition and soaps’ concentrations was evidenced. Hand washing frequencies positively correlated with microbial counts. Roberts® soap exhibited the largest zone of inhibition (34 mm) on S. aureus. Candida albicans was the least susceptible microbe. Regency® and Dalan® exhibited the least zone of inhibition on the tested bacteria. Protex®, Roberts®, Family® and Protector® were equally effective (P<0.01) against S. aureus. In conclusion, majority of the assayed medicated soaps have satisfactory antibacterial activity; though lack antifungal effect with exception of Linda® liquid soap. The hand washing technique has proved to be inappropriate for evaluation of soaps’ antimicrobial efficacy due to presence of the skin microflora.

Mwambete, K. D.; Lyombe, F.

2011-01-01

269

Antimicrobial activity of Wedelia trilobata crude extracts.  

PubMed

A biological screening of activity against Gram-positive and Gram-negative bacteria, yeasts, and fungi of crude extracts from Wedelia trilobata is reported. The n-hexane extract showed antibacterial activity against Bacillus subtilis, Mycobacterium smegmatis, Staphylococcus aureus, and Staphylococcus epidermidis (Gram-positive bacteria); along with Proteus vulgaris, Pseudomonas aeruginosa, Salmonella group C, Salmonella paratyphi, and Shigella sonnei (Gram-negative bacteria). The ethyl acetate extract was active only against Salmonella group C; and the aqueous extract was inactive against the tested bacteria. None of the tested extracts showed biological activity against the yeasts (Candida albicans, Candida tropicalis, Rhodotorula rubra) or the fungi (Aspergillus flavus, Aspergillus niger, Mucor sp., Trichophyton rubrum). PMID:10374253

Taddei, A; Rosas-Romero, A J

1999-05-01

270

Antimicrobial activity of certain Indian medicinal plants used in folkloric medicine  

Microsoft Academic Search

Fifty medicinal plants belonging to 26 families were studied for their antimicrobial activity. Among 50 plants tested, 72% showed antimicrobial activity. About 22 plant extracts from 15 families exhibited activity against both Gram-positive and Gram-negative bacteria. Fourteen plants belonging to 11 families did not show activity against any of the bacteria tested. Only nine plant extracts showed antifungal activity. The

D. Srinivasan; Sangeetha Nathan; T. Suresh; P. Lakshmana Perumalsamy

2001-01-01

271

Natural products from cyanobacteria with antimicrobial and antitumor activity.  

PubMed

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

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

2014-10-01

272

Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration.  

PubMed

The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods. PMID:16831479

Al-Bakri, Amal G; Afifi, Fatma U

2007-01-01

273

Antimicrobial Activity of a Novel Catheter Lock Solution  

PubMed Central

Intravascular catheter-associated bloodstream infections significantly increase rates of morbidity and hospital costs. Microbial colonization and development of biofilms, which are known to be recalcitrant to antibiotic therapy, often lead to the loss of otherwise patent vascular access systems. We evaluated a new taurolidine- and citrate-based catheter lock solution (Neutrolin; Biolink Corporation, Norwell, Mass.) for its activity against planktonic microbes, antimicrobial activity in a catheter model, and biofilm eradication activity. In studies of planktonic microbes, after 24 h of contact, 675 mg of taurolidine-citrate solution per liter caused >99% reductions in the initial counts of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Entercoccus faecalis. A solution of 13,500 mg/liter was cidal for Candida albicans. Ports and attached catheters inoculated with 50 to 600 CFU of these bloodstream isolates per ml were locked with heparin or the taurolidine-citrate solution. After 72 h, there was no growth in the taurolidine-citrate-treated devices but the heparin-treated devices exhibited growth in the range of 6 × 102 to 5 × 106 CFU/ml. Biofilms were developed on silicone disks in modified Robbins devices with broth containing 6% serum (initial counts, 106 to 108 CFU/cm2). The axenic biofilms were treated for 24 h with taurolidine-citrate or heparin. Taurolidine-citrate exposure resulted in a median reduction of 4.8 logs, whereas heparin treatment resulted in a median reduction of 1.7 logs (P < 0.01). No significant differences in the effects of the two treatments against P. aeruginosa and C. albicans were observed. These findings suggest that taurolidine-citrate is a promising combination agent for the prevention and treatment of intravascular catheter-related infections.

Shah, Chirag B.; Mittelman, Marc W.; Costerton, J. W.; Parenteau, Stephen; Pelak, Michael; Arsenault, Richard; Mermel, Leonard A.

2002-01-01

274

Antimicrobial activities of the rhizome extract of Zingiber zerumbet Linn  

PubMed Central

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

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

2011-01-01

275

Chemical composition, antimicrobial and antioxidant activities of essential oil from Ampelopsis megalophylla.  

PubMed

Chemical composition, antimicrobial and antioxidant activities of the essential oil of Ampelopsis megalophylla were evaluated in this research. GC-MS analysis of the essential oil revealed 42 compounds, representing 88.54% of the oil. The major compounds were borneol (10.81%), ?-pinene (6.74%) and ?-elemene (6.23%). The antimicrobial activity of the essential oil was evaluated against 13 micro-organisms using the disc diffusion and broth microdilution methods. Results demonstrated higher effects of this oil against Gram-positive bacteria than the other reference strains tested. The antioxidant effect of the essential oil was evaluated by using 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,20-azinobis-3-ethylbenzthiazoline-6-sulfonate scavenging assays. The essential oil exhibited moderate antioxidant activity. PMID:24524337

Xie, Xian-Fei; Wang, Jian-Wu; Zhang, Han-Ping; Li, Qi-Xiong; Chen, Bang-Yin

2014-01-01

276

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

PubMed

The antimicrobial activity of analogs obtained by substituting arginine and lysine in CL(14-25), a cationic ?-helical dodecapeptide, with alanine against Porphyromonas gingivalis, a periodontal pathogen, varied significantly depending on the number and position of cationic amino acids. The alanine-substituted analogs had no hemolytic activity, even at a concentration of 1 mM. The antimicrobial activities of CL(K20A) and CL(K20A, K25A) were 3.8-fold and 9.1-fold higher, respectively, than that of CL(14-25). The antimicrobial activity of CL(R15A) was slightly lower than that of CL(14-25), suggesting that arginine at position 15 is not essential but is important for the antimicrobial activity. The experiments in which the alanine-substituted analogs bearing the replacement of arginine at position 24 and/or lysine at position 25 were used showed that arginine at position 24 was crucial for the antimicrobial activity whenever lysine at position 25 was substituted with alanine. Helical wheel projections of the alanine-substituted analogs indicate that the hydrophobicity in the vicinity of leucine at position 16 and alanines at positions 18 and/or 21 increased by substituting lysine at positions 20 and 25 with alanine, respectively. The degrees of diSC3 -5 release from P. gingivalis cells and disruption of GUVs induced by the alanine-substituted analogs with different positive charges were not closely related to their antimicrobial activities. The enhanced antimicrobial activities of the alanine-substituted analogs appear to be mainly attributable to the changes in properties such as hydrophobicity and amphipathic propensity due to alanine substitution and not to their extents of positive charge (cationicity). © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 58-68, 2014. PMID:23982951

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

2014-01-01

277

Antimicrobial Activity of Propolis on Oral Microorganisms  

Microsoft Academic Search

.   Formation of dental caries is caused by the colonization and accumulation of oral microorganisms and extracellular polysaccharides\\u000a that are synthesized from sucrose by glucosyltransferase of Streptococcus mutans. The production of glucosyltransferase from oral microorganisms was attempted, and it was found that Streptococcus mutans produced highest activity of the enzyme. Ethanolic extracts of propolis (EEP) were examined whether EEP inhibit

Yong K. Park; Michel H. Koo; José A. S. Abreu; Masaharu Ikegaki; Jaime A. Cury; Pedro L. Rosalen

1998-01-01

278

More effective antimicrobial mastoparan derivatives, generated by 3D-QSAR-Almond and computational mutagenesis.  

PubMed

Antimicrobial peptides are drugs used against a wide range of pathogens which present a great advantage: in contrast with antibiotics they do not develop resistance. The wide spectrum of antimicrobial peptides advertises them in the research and pharmaceutical industry as attractive starting points for obtaining new, more effective analogs. Here we predict the antimicrobial activity against Bacillus subtilis (expressed as minimal inhibitory concentration values) for 33 mastoparan analogs and their new derivatives by a non-aligned 3D-QSAR (quantitative structure-activity relationship) method. We establish the contribution to antimicrobial activity of molecular descriptors (hydrophobicity, hydrogen bond donor and steric), correlated with contributions from the membrane environment (sodium, potassium, chloride). Our best QSAR models show significant cross-validated correlation q(2) (0.55-0.75), fitted correlation r(2) (greater than 0.90) coefficients and standard error of prediction SDEP (less than 0.250). Moreover, based on our most accurate 3D-QSAR models, we propose nine new mastoparan analogs, obtained by computational mutagenesis, some of them predicted to have significantly improved antimicrobial activity compared to the parent compound. PMID:22086548

Avram, Speranta; Buiu, Catalin; Borcan, Florin; Milac, Adina-Luminita

2012-02-01

279

Novel natural food antimicrobials.  

PubMed

Naturally occurring antimicrobial compounds could be applied as food preservatives to protect food quality and extend the shelf life of foods and beverages. These compounds are naturally produced and isolated from various sources, including plants, animals and microorganisms, in which they constitute part of host defense systems. Many naturally occurring compounds, such as nisin, plant essential oils, and natamycin, have been widely studied and are reported to be effective in their potential role as antimicrobial agents against spoilage and pathogenic microorganisms. Although some of these natural antimicrobials are commercially available and applied in food processing, their efficacy, consumer acceptance and regulation are not well defined. This manuscript reviews natural antimicrobial compounds with reference to their applications in food when applied individually or in combination with other hurdles. It also reviews the mechanism of action of selected natural antimicrobials, factors affecting their antimicrobial activities, and future prospects for use of natural antimicrobials in the food industry. PMID:22385168

Juneja, Vijay K; Dwivedi, Hari P; Yan, Xianghe

2012-01-01

280

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.

2012-01-01

281

Antimicrobial activity of the solvent fractions from Bulbine natalensis Tuber.  

PubMed

Bulbine natalensis Baker has been acclaimed to be used as an antimicrobial agent in the folklore medicine of South Africa without scientific evidence to substantiate or refute this claim. In view of this, the in vitro antimicrobial activity of solvent fractions (ethanol, ethyl acetate, n-butanol and water) from Bulbine natalensis Tuber against 4 Gram positive and 12 Gram negative bacteria as well as 3 fungal species were investigated using agar dilution. The ethanolic extract, n-butanol and ethyl acetate fractions inhibited 75, 87.5 and 100% respectively of the bacterial species in this study. The ethanolic, n-butanol and ethyl acetate fractions produced growth inhibition at MIC range of 1-10, 3-10 as well as 1 and 5 mg/ml respectively whereas the water fraction did not inhibit the growth of any of the bacterial species. Again, it was only the ethyl acetate fraction that inhibited the growth of Shigelli flexneri, Staphyloccus aureus and Escherichia coli. The ethanolic, ethyl acetate and n-butanolic fractions dose dependently inhibited the growth of Aspergillus niger and A. flavus whereas the water fraction produced 100% growth inhibition of the Aspergillus species at all the doses investigated. In contrast, no growth inhibition was produced on Candida albicans. The growth inhibition produced by the solvent fractions of B. natalensis Tuber in this study thus justifies the acclaimed use of the plant as an antimicrobial agent. The ethyl acetate fraction was the most potent. PMID:23983381

Yakubu, M T; Mostafa, M; Ashafa, A O T; Afolayan, A J

2012-01-01

282

[Activity of 14 antimicrobials against Eikenella corrodens].  

PubMed

Eikenella corrodens is a gram-negative bacillus that colonizes as normal flora of the mouth, the upper respiratory tract and the gastrointestinal tract. The aim of this study was to determine the susceptibility patterns against fourteen antibiotics of 25 E. corrodens strains isolated at our hospital. MICs were determined by the agar dilution technique using Müeller-Hinton agar with sheep blood (5% v/v) to penicillin, ampicillin, ampicillin-sulbactam, cephalotin, cefoxitin, ceftiaxone, colistin, gentamicin, amikacin, erythromycin, rifampin, ciprofloxacin and clindamycin. The most active antibiotics were ciprofloxacin and ceftriaxone (MIC90 = 0.008 and 0.125 microgram/ml, respectively), whereas eritromycin, gentamicin and amikacin showed less activity. Only one strain was beta lactamase positive, and it was inhibited by sulbactam. Erithromycin, gentamicin and amikacin had poor activity (MIC90 = 16.8 and 64 micrograms/ml, respectively), whereas all the strains were uniformly resistant to clindamycin (MIC > or = 32 micrograms/ml). We suggest about the need of periodical surveys of E. corrodens susceptibility patterns, since strains have been found with decreased susceptibility against antibiotics which are currently being used for the treatment of infectious diseases. PMID:12600009

Vay, C; Almuzara, M; Barberis, C; Rodriguez, C; Togneri, A; Mattera, J; Famiglietti, A

2002-01-01

283

Antimicrobial and antioxidant activities of unripe papaya.  

PubMed

The meat, seed and pulp of Carica papaya Linn., a popular traditional medicinal herb grown in the tropics, was shown by the agar-cup method to be bacteriostatic against several enteropathogens such as Bacillus subtilis, Enterobacter cloacae, Escherichia coli, Salmonella typhi, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The same parts of papaya were unequivocably demonstrated by electron spin resonance spectrometry to scavenge 1,1-diphenyl-2-picrylhydrazyl (5.8 x 10(14) spins/ml), hydroxyl (5.1 x 10(14) spins/ml) and superoxide (1.2 x 10(14) spins/ml) radicals with the seed giving the highest activity at concentrations (IC50) of 2.1, 10.0 and 8.7 mg/ml, respectively. The superoxide dismutase (SOD)-like activity in the meat, seed and pulp amounts to about 32, 98 and 33 units/ml; comparable to those of soybean paste miso, rice bran and baker's yeast. Vitamin C, malic acid, citric acid and glucose are some of the possible antioxidative components in papaya. Our study correlates the bacteriostatic activity of papaya with its scavenging action on superoxide and hydroxyl radicals which could be part of the cellular metabolism of such enteropathogens. This is indicative of the pathophysiological role of these reactive oxygen species in gastrointestinal diseases and papaya's ability to counteract the oxidative stress. PMID:8412504

Osato, J A; Santiago, L A; Remo, G M; Cuadra, M S; Mori, A

1993-01-01

284

Antimicrobial activity and antibiotic resistance of lactic acid bacteria isolated from Armada cheese (a Spanish goats’ milk cheese)  

Microsoft Academic Search

Thirty-one lactic acid bacteria isolated from Armada cheese and previously selected in accordance with their technological properties, were screened for antimicrobial activity one against another. Four strains showed inhibitory activity against 14 strains when tested by well diffusion assay after the effects of organic acid and hydrogen peroxide were eliminated. Extracts of the strains did not show inhibitory activity after

M. A. Herreros; H. Sandoval; L. González; J. M. Castro; J. M. Fresno; M. E. Tornadijo

2005-01-01

285

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

286

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.

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

2012-01-01

287

Antimicrobial activity of carbon fiber fabric modified with a polymer-gentamicin complex  

Microsoft Academic Search

Modified and unmodified carbon fiber supports were treated with solutions of a polymer-gentamicin complex, possessing high\\u000a antimicrobial activity and low toxicity. It was found that the antimicrobial activity of modified carbon fiber fabrics depended\\u000a on the nature of the support and on the immobilization conditions. The highest antimicrobial activity was observed with phosphorus-containing\\u000a carbon fiber ion exchanger in salt form.

M. V. Solovskii; V. I. Dubkova; N. P. Krut’ko; E. F. Panarin; M. Yu. Smirnova; N. A. Belyasova; O. I. Maevskaya

2009-01-01

288

Antioxidant and antimicrobial effects of garlic in chicken sausage  

PubMed Central

The antioxidant and antimicrobial effects of equivalent concentrations of fresh garlic (FG), garlic powder (GP) and garlic oil (GO) were investigated against lipid oxidation and microbial growth in raw chicken sausage during storage at 3°C. The antioxidant activities were compared to that of a standard synthetic antioxidant; butylated hydroxyanisole (BHA). The initial mean levels of thiobarbituric acid (TBA) value and peroxide value (POV) were 0.140 and 6.32, respectively. However after 21 days of storage, TBA and POV ranged from 0.151 to 4.92, respectively, in FG (50 g/kg) formulated samples to 0.214 and 8.64, respectively, in GO (0.06 g/ kg) formulation. Addition of either garlic or BHA (0.1 g/kg) significantly delayed lipid oxidation when compared with control. The antioxidant activities of the various materials added followed the order FG>GP>BHA>GO. On the other hand, the initial aerobic plate count (APC) in the samples was 4.41 log10 CFU/g. Addition of FG (30 g/kg) or GP (9 g/kg) significantly reduced the APC and, subsequently, the shelf-life of the product was extended to 21 days. However, addition of GO or BHA resulted in no significant difference in APC when compared with control. Sensory analysis indicated that FG had a significant stronger flavor than the other sausage formulations. The results suggest that fresh garlic and garlic powder, through their combined antioxidant and antimicrobial effects, are potentially useful in preserving meat products.

Sallam, Kh.I.; Ishioroshi, M.; Samejima, K.

2007-01-01

289

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.

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

2013-01-01

290

Evaluation of three medicinal plants for anti-microbial activity.  

PubMed

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

2012-07-01

291

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.

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

2012-01-01

292

Antimicrobial activity of Acanthus ilicifolius: Skin infection pathogens  

PubMed Central

Objective To investigate the antimicrobial activity of Acanthus ilicifolius against the skin infecting bacterial and fungal pathogens. Through the literature survey, the mangrove plant Acanthus ilicifolius was used in skin infection diseases and have potential anti-inflammatory activity. Methods Antimicrobial activity of the leaf extracts was tested using agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were carried out. Results Among the different extracts, chloroform extract showed maximum activity against the bacterial pathogens methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Candida albicans and Trichophyton rubrum. Methanol and acetone extracts showed maximum activity against Staphylococcus epidermis and Lactobacillus plantarum respectively. Chloroform extracts showed the lowest MIC (0.5 mg/mL) and MBC (2 mg/mL) values against the skin pathogens compared with other extracts. Phytochemical screening revealed the presence of resins, steroids, tannins, glycosides, sugars, carbohydrates, saponins, sterols, terpenoids, phenol, alkaloids, cardiac glycosides and catechol. Conclusions Further, the separation of potential compounds from the crude extracts will be useful for control the skin infection pathogens.

Govindasamy, Chinnavenkataraman; Arulpriya, Mani

2013-01-01

293

In vitro screening for anti-microbial activity of chitosans and chitooligosaccharides, aiming at potential uses in functional textiles.  

PubMed

Antimicrobial finishing of textiles has been found to be an economical way to prevent (or treat) skin disorders. Hence, this research effort was aimed at elucidating the relationship between molecular weight (MW) of chitosan and its antimicrobial activity upon six dermal reference microorganisms, as well as the influence of the interactions with cotton fabrics on said activity. Using 3 chitosans with different MW, as well as two chitooligosaccharide (COS) mixtures, a relevant antimicrobial effect was observed by 24 h for the six microorganisms tested; it was apparent that the antimicrobial effect is strongly dependent on the type of target microorganism and on the MW of chitosan being higher for lower MW in the case of E. coli, K. pneumoniae and P. aeruginosa, and the reverse in the case of both Gram-positive bacteria. Furthermore, a strong anti-fungal effect was detectable upon C. albicans, resembling the action over Gram-positive bacteria. Interactions with cotton fabric resulted in a loss of COS activity when compared with cultured media, relative to the effect over Gram-negative bacteria. However, no significant differences for the efficacy of all the 5 compounds were observed by 4 h. The three chitosans possessed a higher antimicrobial activity when impregnated onto the fabric, and presented a similar effect on both Gram-positive bacteria and yeast, in either matrix. Pseudomonas aeruginosa showed to be the most resistant microorganism to all five compounds. PMID:20208434

Fernandes, Joăo C; Tavaria, Freni K; Fonseca, Susana C; Ramos, Oscar S; Pintado, Manuela E; Malcata, F Xavier

2010-02-01

294

Chitosan-hydroxycinnamic acid conjugates: preparation, antioxidant and antimicrobial activity.  

PubMed

In this study, the antioxidant and antimicrobial activities of chitosan-caffeic acid, chitosan-ferulic acid, and chitosan-sinapic acid conjugates with different grafting ratios were investigated. The synthesized chitosan-hydroxycinnamic acid conjugates were verified by performing (1)H NMR and differential scanning calorimetry analysis. The antioxidant activities of the conjugates were increased compared to the unmodified chitosan, by 1.79-fold to 5.05-fold (2,2-diphenyl-1-picrylhydrazyl scavenging assay), 2.44-fold to 4.12-fold (hydrogen peroxide scavenging assay), 1.34-fold to 3.35-fold (ABTS(+) radical scavenging assay), and also exhibited an increased reducing power. The conjugates also showed excellent lipid peroxidation inhibition abilities in a linoleic acid emulsion system. The conjugates exhibited antimicrobial activity against 15 clinical isolates, two standard methicillin-resistant Staphylococcus aureus (MRSA) and three standard methicillin-susceptible S. aureus strains, as well as eight foodborne pathogens. Additionally, the conjugates showed no cytotoxic activity towards human Chang liver and mouse macrophage RAW264.7 cells. PMID:24262532

Lee, Dae-Sung; Woo, Ji-Young; Ahn, Chang-Bum; Je, Jae-Young

2014-04-01

295

Anti-allergic and anti-microbial activities of some Thai crops  

Microsoft Academic Search

Thirteen Thai crops including banana, okra, jackfruit, germinated rice, rambutan, durian, jampadah, huasa potato, tamarind, coconut, mango, fan palm fruit and dioscorea tuber were tested for anti-allergic effect using RBL-2H3 cells and anti-microbial activity. These 13 crops, some of which included different parts, e.g. skin, flesh, and seed, were extracted with four solvents separately ((95% ethanol (EtOH), 50% EtOH, water

Supinya Tewtrakul; Arunporn Itharat; Piboon Thammaratwasik; Buncha Ooraikul

296

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

Microsoft Academic Search

The chemical composition of the essential oil obtained from Senecio graveolens (Compositae) was analyzed by GLC–MS and the components identified were: isovaleraldehyde, ?-pinene, ?-phellandrene, ?-terpinene, p-cymene, sabinene, ?-terpinene, 1-methyl-4-isopropenylbenzene, terpinolene, terpinen-4-ol, piperitenone, ?- and ?-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

Cristina Pérez; Alicia Mariel Agnese; José Luis Cabrera

1999-01-01

297

Assessment of antimicrobial activity of coffee brewed in three different ways from different origins  

Microsoft Academic Search

The antimicrobial effect against pathogens such as Staphylococcus aureus, Enterecoccus faecalis, Listeria monocytogenes, Pseudomonas aeruginosa, Escherichia coli and Salmonella\\u000a choleraesius was determined in four types of coffee (Coffea arabica L. cv. Colombia, decaffeinated cv. Colombia, cv. Ethiopia and cv. Kenya). Coffee was seen to have significant activity against\\u000a the growth of food spoilage bacteria. Among the Gram-positive bacteria, coffee was

Magdalena Martínez-Tomé; Antonia Ma Jiménez-Monreal; Laura García-Jiménez; Luis Almela; Luis García-Diz; Miguel Mariscal-Arcas; M. Antonia Murcia

298

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

PubMed

AIMS: The aim of this study was to evaluate the antimicrobial effects of five natural substances against 50 clinical isolates of Mycoplasma hominis. METHODS AND RESULTS: The in vitro activity of selected natural compounds, cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene, was investigated against 50 M. hominis isolates cultivated from cervical swabs by the broth dilution method. All showed valuable antimicrobial activity against the tested isolates. Oil from the bark of Cinnamomum zeylanicum (MBC(90) = 500 µg/mL) however was found to be the most effective. Carvacrol (MBC(90) = 600 µg/mL) and eugenol (MBC(90) = 1000 µg/mL) also possessed strong antimycoplasmal activity. CONCLUSIONS: The results indicate that cinnamon bark oil, carvacrol and eugenol have strong antimycoplasmal activity and the potential for use as antimicrobial agents in the treatment of mycoplasmal infections. PMID:23128812

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

2012-10-30

299

Enantioselective synthesis and antimicrobial activities of tetrahydro-?-carboline diketopiperazines.  

PubMed

A series of single isomers tetrahydro-?-carboline diketopiperazines were stereoselectively synthesized starting from l-tryptophan methyl ester hydrochloride and six aldehydes through a four-step reaction including Pictet-Spengler reaction, crystallization-induced asymmetric transformations (CIAT), Schotten-Baumann reaction, and intramolecular ester amidation. The chemical structures were characterized by nuclear magnetic resonance (NMR) and elemental analysis, among which two compounds were determined by x-ray single crystal diffraction. Moreover, antimicrobial activities of all the compounds were also tested. PMID:23861205

Ma, Yangmin; Wu, Hao; Zhang, Jin; Li, Yanchao

2013-10-01

300

Synthesis and antimicrobial activity of new adamantane derivatives I.  

PubMed

A series of fourteen derivatives of adamantane was synthesised. The new compound 4-(adamant-1-ylmethoxycarbonyl)phthalanhydride obtained from 1-adamantane-methanol and trimellitic anhydride chloride appeared very useful for preparation of a number of N-substituted phthalimides. Antimicrobial activity of the newly obtained derivatives such as, for example, 4-(adamant-1-ylmethoxycarbonyl)-N-(5-carboxypentamethylene)p hthalimide or 4-(adamant-1-ylmethoxycarbonyl)-N-(L-alanyl)phthalimide was tested against Staphylococcus aureus, Bacillus sp., Micrococcus flavus and Enterococcus faecium. The minimal inhibitory concentration (MIC) for these compounds against S. aureus were 0.022 and 0.05 microg/ml, respectively. PMID:10961681

Orzeszko, A; Gralewska, R; Staro?ciak, B J; Kazimierczuk, Z

2000-01-01

301

Synthesis and antimicrobial activity of new adamantane derivatives II.  

PubMed

A series of new derivatives of adamantane was synthesised. The new compound 4-(adamant-1-ylethylenoxycarbonyl)phthalanhydride obtained from 1-adamantaneethanol and trimellitic anhydride chloride, as well as 4-(adamant-1-ylmethylenoxycarbonyl)phthalanhydride, appeared very useful for preparation of a number of N-substituted phthalimides. Antimicrobial activity of newly obtained derivatives such as, for example, 4-(adamant-1-ylethylenoxycarbonyl)-N-(L-phenylalanyl)phthalimide or 4-(adamant-1-ylmethylenoxycarbonyl)-N-(L-leucyl)-phthalimide was tested against Staphylococcus aureus, Bacillus sp., Micrococcus flavus and Enterococcus faecium. The minimal inhibitory concentrations for these compounds against Bacillus cereus were 15 and 8 microg/ml, respectively. PMID:11152243

Orzeszko, A; Kami?ska, B; Orzeszko, G; Staro?ciak, B J

2000-01-01

302

Antimicrobial and antifungal effects of tissue conditioners containing a photocatalyst.  

PubMed

This study examined the antimicrobial/antifungal ability of a tissue conditioner containing a photocatalyst for Escherichia coli, Streptococcus mutans, Staphylococcus aureus and Candida albicans. The photocatalyst was mixed with tissue conditioners powders at concentrations of 0, 10, 15, and 20 wt%. Tissue conditioners powders containing a photocatalyst were mixed with liquid to make test specimens. Test specimens inoculated by each microorganism were irradiated by ultraviolet light for 0-, 2- and 4 hours. The antimicrobial/antifungal effects were evaluated by the CFU technique. The CFU values of each microorganism for tissue conditioners containing a photocatalyst showed significant decrease following UV-irradiation. The improvement in antimicrobial/antifungal effects was concomitant with the increase of the mixing ratio and the irradiation time. Therefore, the results indicated that tissue conditioners containing a photocatalyst might have photocatalytic ability. PMID:21946490

Uchimaru, Masayuki; Sakai, Takako; Moroi, Ryoji; Shiota, Susumu; Shibata, Yukie; Deguchi, Mikito; Sakai, Hidetaka; Yamashita, Yoshihisa; Terada, Yoshihiro

2011-01-01

303

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.

Olajuyigbe, Olufunmiso O.; Afolayan, Anthony J.

2012-01-01

304

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

305

Antimicrobial activity of propolis samples from two different regions of Anatolia  

Microsoft Academic Search

Antimicrobial activity of two propolis samples from Kazan and Marmaris regions in Turkey were investigated by the disc diffusion method. Antimicrobial activity was tested with four different ethanolic extracts (30, 50, 70, and 96% ethanol) of each sample against seven Gram positive, four Gram negative bacteria and one fungus culture. The activity was found to be mainly due to caffeic

Murat Kartal; Sulhiye Y?ld?z; Serdar Kaya; Semra Kurucu; Gülaçt? Topçu

2003-01-01

306

Cationic amphipathic peptides, derived from bovine and human lactoferrins, with antimicrobial activity against oral pathogens  

Microsoft Academic Search

Peptides derived from the N-terminal domain that comprises an amphipathic ?-helix in human lactoferrin (LFh 18–31 and LFh 20–38) and bovine lactoferrin (LFb 17–30 and LFb 19–37) were chemically synthesised. Since many positively charged amphipathic ?-helices contain antimicrobial activity, the peptides were tested for their antimicrobial activity against various oral pathogens. Both peptides from bovine lactoferrin had more potent antimicrobial

Jasper Groenink; Els Walgreen-Weterings; Wim van ’t Hof; Enno C. I Veerman; Arie V Nieuw Amerongen

1999-01-01

307

General Principles of Antimicrobial Therapy  

PubMed Central

Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community.

Leekha, Surbhi; Terrell, Christine L.; Edson, Randall S.

2011-01-01

308

Table olives from Portugal: phenolic compounds, antioxidant potential, and antimicrobial activity.  

PubMed

The phenolic compounds composition, antioxidant potential, and antimicrobial activity of different table olives from Portugal, namely, natural black olives "Galega", black ripe olive "Negrinha de Freixo", Protected Designation of Origin (PDO) "Azeitona de Conserva Negrinha de Freixo" olives, and "Azeitona de Conserva de Elvas e Campo Maior" Designation of Origin (DO) olives, were investigated. The analysis of phenolic compounds was performed by reversed-phase HPLC/DAD, and seven compounds were identified and quantified: hydroxytyrosol, tyrosol, 5-O-caffeoilquinic acid, verbascoside, luteolin 7-O-glucoside, rutin, and luteolin. The antioxidant activity was assessed by the reducing power assay, the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals, and the beta-carotene linoleate model system. The antioxidant activity was correlated with the amount of phenolics found in each sample. The antimicrobial activity was screened using Gram-positive (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). PDO and DO table olives revealed a wide range of antimicrobial activity. C. albicans was resistant to all the analyzed extracts. PMID:17061816

Pereira, José Alberto; Pereira, Ana P G; Ferreira, Isabel C F R; Valentăo, Patrícia; Andrade, Paula B; Seabra, Rosa; Estevinho, Letícia; Bento, Albino

2006-11-01

309

Novel expression vector for secretion of cecropin AD in Bacillus subtilis with enhanced antimicrobial activity.  

PubMed

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-beta-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 microM (0.2 microg/ml). Stability analysis results showed that the activity of cecropin AD was not influenced by temperatures as high as 55 degrees C for 20 min; however, temperatures above 85 degrees 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

2009-09-01

310

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.

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

2014-01-01

311

Antimicrobial activity of selected South African medicinal plants  

PubMed Central

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

2012-01-01

312

Antimicrobial activity of cationic peptides in endodontic procedures  

PubMed Central

Objectives: The present study aimed to investigate the antimicrobial and biofilm inhibition activity of synthetic antimicrobial peptides (AMPs) against microbes such as Enterococcus faecalis, Staphylococcus aureus, and Candida albicans which are involved in endodontic infections. Materials and Methods: Agar diffusion test was done to determine the activity of peptides. The morphological changes in E. faecalis and reduction in biofilm formation after treatment with peptides were observed using scanning electron microscope. The efficacy of peptides using an ex vivo dentinal model was determined by polymerase chain reaction and confocal laser scanning microscopy. Platelet aggregation was done to determine the biocompatibility of peptides. Results: Among 11 peptides, two of the amphipathic cationic peptides were found to be highly active against E. faecalis, S. aureus, C. albicans. Efficacy results using dentinal tubule model showed significant reduction in microbial load at 400 ?m depth. The peptides were also biocompatible. Conclusion: These results suggest that synthetic AMPs have the potential to be developed as antibacterial agents against microorganisms involved in dental infections and thus could prevent the spread and persistence of endodontic infections improving treatment outcomes and teeth preservation.

Winfred, Sofi Beaula; Meiyazagan, Gowri; Panda, Jiban J.; Nagendrababu, Venkateshbabu; Deivanayagam, Kandaswamy; Chauhan, Virander S.; Venkatraman, Ganesh

2014-01-01

313

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

314

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.

Yoram, Gerchman; Inbar, Moseh

2011-01-01

315

Chemical constituents, antimicrobial and antimalarial activities of Zanthoxylum monophyllum.  

PubMed

From the leaves and bark of Zanthoxylum monophyllum, a new lignan, 3-methoxy-3',4'-methylenedioxylignan-4,8,9,9'-tetraol (1), has been isolated along with 22 known compounds (2- 23), fifteen of them reported for the first time from Z. monophyllum. Their chemical structures were elucidated using detailed spectroscopic studies and chemical analysis. All compounds were evaluated for antimicrobial and antiprotozoal activities. Alkaloids BIS-[6-(5,6-dihydro-chelerythrinyl)] ether (2) and 6-ethoxy-chelerythrine (4) exhibited strong activity against Aspergillus fumigatus and methicillin-resistant Staphylococcus aureus (MRSA). Compound 4-methoxy-N-methyl-2-quinolone (9) exhibited significant activity against MRSA (IC50 value of 8.0?µM) while compound 5,8,4'-trihydroxy-3,7,3'-trimethoxyflavone (10) showed weak activity against Plasmodium falciparum. PMID:21341176

Rodríguez-Guzmán, Raquel; Fulks, Laura C Johansmann; Radwan, Mohamed M; Burandt, Charles L; Ross, Samir A

2011-09-01

316

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

317

Antimicrobial Activity of Artemisia absinthium Against Surgical Wounds Infected by Staphylococcus aureus in a Rat Model.  

PubMed

The wound infection is one of the frequent complications in patients undergoing surgical operations. Staphylococcus aureus is the most common cause of surgical wounds. Artemisia absinthium has been shown to bear strong antimicrobial activity, especially against Gram-positive pathogens. This study was designed to investigate the antimicrobial effects of A. absinthium against surgical wounds infected by S. aureus in a rat model. Twenty male Sprague-Dawley rats were divided randomly into two equal groups of treated and control rats. A circular incision was created on the dorsal inter-scapular region of each rat. After skin wounding, rats were inoculated locally with 1 × 10(4) CFU of S. aureus at sites of skin wounds. The extract was applied topically twice a day throughout the experiment. Animals of the control group were left untreated. Results have revealed that topical application of A. absinthium extract on the infected wound sites produced significant antibacterial activity against S. aureus. PMID:24293717

Moslemi, Hamid Reza; Hoseinzadeh, Hesamoddin; Badouei, Mahdi Askari; Kafshdouzan, Khatereh; Fard, Ramin Mazaheri Nezhad

2012-12-01

318

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

319

Antimicrobial activity of wool fabric treated with curcumin  

Microsoft Academic Search

Curcumin, a common natural dye used for fabric and food colorations, was used as an antimicrobial finish due to its bactericidal properties on dyed textiles. A common dyeing process, either batch or continuous, could provide textiles with colour as well as antimicrobial properties. The relationship between the sorption of an interesting natural colorant onto wool and the antimicrobial ability of

Shinyoung Han; Yiqi Yang

2005-01-01

320

Selective antimicrobial activity and mode of action of adepantins, glycine-rich peptide antibiotics based on anuran antimicrobial peptide sequences.  

PubMed

A challenge when designing membrane-active peptide antibiotics with therapeutic potential is how to ensure a useful antibacterial activity whilst avoiding unacceptable cytotoxicity for host cells. Understanding their mode of interaction with membranes and the reasons underlying their ability to distinguish between bacterial and eukaryotic cytoplasmic cells is crucial for any rational attempt to improve this selectivity. We have approached this problem by analysing natural helical antimicrobial peptides of anuran origin, using a structure-activity database to determine an antimicrobial selectivity index (SI) relating the minimal inhibitory concentration against Escherichia coli to the haemolytic activity (SI=HC(50)/MIC). A parameter that correlated strongly with SI, derived from the lengthwise asymmetry of the peptides' hydrophobicity (sequence moment), was then used in the "Designer" algorithm to propose novel, highly selective peptides. Amongst these are the 'adepantins', peptides rich in glycines and lysines that are highly selective for Gram-negative bacteria, have an exceptionally low haemolytic activity, and are less than 50% homologous to any other natural or synthetic antimicrobial peptide. In particular, they showed a very high SI for E. coli (up to 400) whilst maintaining an antimicrobial activity in the 0.5-4?M range. Experiments with monomeric, dimeric and fluorescently labelled versions of the adepantins, using different bacterial strains, host cells and model membrane systems provided insight into their mechanism of action. PMID:23196344

Ili?, Nada; Novkovi?, Mario; Guida, Filomena; Xhindoli, Daniela; Benincasa, Monica; Tossi, Alessandro; Jureti?, Davor

2013-03-01

321

In vitro antioxidant and antimicrobial activities of flavonoids from Panax notoginseng flowers.  

PubMed

Panax notoginseng and its flowers are both well-known traditional Chinese medicinal herbs. To date, antimicrobial and antioxidant activities of flavonoids from P. notoginseng flowers (PNF) remain unclear. In this study, antimicrobial and antioxidant activities of flavonoids from PNF were investigated. The crude flavonoids were purified using a column (25 cm × 1.5 cm) packed with AB-8 macroporous adsorption resin. Compared with ascorbic acid, the purified flavonoids excelled in scavenging activities on 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid, superoxide anion and hydroxyl radicals at 0.2-1.0 mg/mL concentration. However, flavonoids exhibited weaker reducing power than ascorbic acid at 20-100 ?g/mL concentration. In addition, the flavonoids exhibited obvious inhibitory effects on Staphylococcus aureus, Aeromonas hydrophila and Pseudomonas aeruginosa. These results clearly indicate that flavonoids from PNF are effective in scavenging free radicals and have the potential to be used as antioxidants and antimicrobial agents, and also provide the theoretical data for supporting the use of PNF in food, pharmaceutical and cosmetics industries. PMID:24666395

Hong, Jun; Hu, Jian-Ye; Liu, Jun-Hong; Zhou, Zheng; Zhao, An-Fang

2014-08-01

322

Antimicrobial activity of the essential oil and extracts of Cordia curassavica (Boraginaceae).  

PubMed

In traditional Mexican medicine Cordia curassavica (Jacq) Roemer & Schultes is used to treat gastrointestinal, respiratory and dermatological disorders in Zapotitlán de las Salinas, Puebla (México). The aim of this work was to investigate antimicrobial activity of the essential oil, obtained by using Clevenger distillation apparatus, and hexane, chloroform and methanol extracts from aerial parts of Cordia curassavica. Antimicrobial activity was evaluated against 13 bacteria and five fungal strains. The oil and extracts exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and five fungal strains. Sarcina lutea and Vibrio cholerae were the strains more sensitive to the essential oil effect (MIC=62 microg/mL) and Vibrio cholerae for the hexane extract (MIC=125 microg/mL). Rhyzoctonia solani was the strain more sensitive to the essential oil effect (IC(50)=180 microg/mL) and Trichophyton mentagrophytes for the hexane extract (IC(50)=230 microg/mL). The essential oil was examined by GC and GC-MS. A total 11 constituents representing 96.28% of the essential oil were identified: 4-methyl,4-ethenyl-3-(1-methyl ethenyl)-1-(1-methyl methanol)cyclohexane (37.34%), beta-eudesmol (19.21%), spathulenol (11.25%) and cadina 4(5), 10(14) diene (7.93%) were found to be the major components. The present study tends to confirm the use in the folk medicine of Cordia curassavica in gastrointestinal, respiratory and dermatological diseases. PMID:17140754

Hernandez, Tzasna; Canales, Margarita; Teran, Barbara; Avila, Olivia; Duran, Angel; Garcia, Ana Maria; Hernandez, Hector; Angeles-Lopez, Omar; Fernandez-Araiza, Mario; Avila, Guillermo

2007-04-20

323

Silanols, a New Class of Antimicrobial Agent.  

National Technical Information Service (NTIS)

Alkyldimethylsilanols, R(CH3)2SiOH, were recently reported to exhibit unexpectedly strong antimicrobial effects. The antimicrobial activities of alkyldimethylsilanols were significantly higher than their analogous alcohols. A study of structural dependenc...

R. H. Baney S. Farrah Y. Kim

2006-01-01

324

In vitro antimicrobial activity of natural toxins and animal venoms tested against Burkholderia pseudomallei  

PubMed Central

Background Burkholderia pseudomallei are the causative agent of melioidosis. Increasing resistance of the disease to antibiotics is a severe problem in treatment regime and has led to intensification of the search for new drugs. Antimicrobial peptides are the most ubiquitous in nature as part of the innate immune system and host defense mechanism. Methods Here, we investigated a group of venoms (snakes, scorpions and honey bee venoms) for antimicrobial properties against two strains of Gram-negative bacteria Burkholderia pseudomallei by using disc-diffusion assay for in vitro susceptibility testing. The antibacterial activities of the venoms were compared with that of the isolated L-amino acid oxidase (LAAO) and phospholipase A2 (PLA2s) enzymes. MICs were determined using broth dilution method. Bacterial growth was assessed by measurement of optical density at the lowest dilutions (MIC 0.25 mg/ml). The cell viability was measured using tetrazolium salts (XTT) based cytotoxic assay. Results The studied venoms showed high antimicrobial activity. The venoms of C. adamanteus, Daboia russelli russelli, A. halys, P. australis, B. candidus and P. guttata were equally as effective as Chloramphenicol and Ceftazidime (30 ?g/disc). Among those tested, phospholipase A2 enzymes (crotoxin B and daboiatoxin) showed the most potent antibacterial activity against Gram-negative (TES) bacteria. Naturally occurring venom peptides and phospholipase A2 proved to possess highly potent antimicrobial activity against Burkholderia pseudomallei. The XTT-assay results showed that the cell survival decreased with increasing concentrations (0.05–10 mg/mL) of Crotalus adamanteus venom, with no effect on the cell viability evident at 0.5 mg/mL. Conclusion This antibacterial profile of snake venoms reported herein will be useful in the search for potential antibacterial agents against drug resistant microorganisms like B. pseudomallei.

Perumal Samy, R; Pachiappan, A; Gopalakrishnakone, P; Thwin, Maung M; Hian, Yap E; Chow, Vincent TK; Bow, Ho; Weng, Joseph T

2006-01-01

325

Vibrational spectra and antimicrobial activity of selected bivalent cation benzoates  

NASA Astrophysics Data System (ADS)

Selected bands of FT-IR spectra of Mg(II), Ca(II), Cu(II) and Zn(II) benzoates of both solid state and water solution, were assigned to appropriate molecular vibrations. Next evaluation of electronic charge distribution in both carboxylic anion and aromatic ring of studied compounds was performed. Classical plate tests and turbidimetry measurements, monitoring growth of bacteria Escherichia coli, Bacillus subtilis and yeasts Pichia anomala and Saccharomyces cerevisiae during 24 h of incubation, in optimal growth conditions (control) and in medium with addition of studied benzoate (concentration of 0.01% expressed as the concentration of benzoic acid), proved antimicrobial activity of studied compounds against investigated micro-organisms. PLS (partially least square) and PCR (principal component regression) techniques were applied to build a model, correlating spectral data reflecting molecular structure of studied compounds, with degree of influence of those compounds on growth of studied micro-organisms. Statistically significant correlation within cross validation diagnostic of PLS-1 calibration was found, when log 1/T of selected spectral regions of water solution samples were used as input data. The correlation coefficients between predicted with PLS calibration based on created 1, 2 or 3 factor models, and actual values of antimicrobial activity were: 0.70; 0.76, 0.81 for P. anomala, B. subtilis, and E. coli, respectively. Log(PRESS) values of appropriate models were 2.10, 2,39 and 3.23 for P. anomala, B. subtilis, and E. coli, respectively.

Borawska, M. H.; Koczo?, P.; Piekut, J.; ?wis?ocka, R.; Lewandowski, W.

2009-02-01

326

Synthesis and Antimicrobial Activity of Some New Quinoxaline Derivatives  

PubMed Central

2-Chloro-3-methylquinoxaline was selected as a nucleus around which various molecular transformations were performed to obtain new compounds expected to possess optimized antimicrobial activity. As very little work regarding attachment of ether linkages replacing chlorine at C-2 has been reported, it was thought worthwhile to synthesize various quinoxaline derivatives by replacing the C2 chlorine with an ether linkage attached to a benzene ring possessing an aldehyde or a free amino group which can be further reacted with aromatic amines and aromatic aldehydes, respectively, to yield new Schiff bases containing quinoxaline moieties. Thus the compounds 4-(2-methylquinoxalinyloxy) benzaldehyde (4), 2-[4-(substituted-benziminomethyl)-phenoxy]-3-methyl quinoxalines 5a–e, 4-(2-methyl-quinoxaline-3-yloxy)benzamine (6) and 4-(2-methylquinoxalin-3-yloxy)-N-substituted benzylidine benzamines 7a–e were synthesized and tested for their antimicrobial activity. The structures of the compounds were confirmed on the basis of their elemental and spectral data.

Singh, Dharmchand Prasad; Deivedi, Sanjay Kumar; Hashim, Syed Riaz; Singhal, Ram Gopal

2010-01-01

327

Antimicrobial activity and composition profile of grape (Vitis vinifera) pomace extracts obtained by supercritical fluids.  

PubMed

The possibility of increasing the aggregated value of the huge amount of residues generated by wineries around the world foment studies using the grape pomace - the residue from the wine production, composed by seed, skin and stems - to obtain functional ingredients. Nowadays, consumers in general prefer natural and safe products mainly for food and cosmetic fields, where the supercritical fluid extraction is of great importance due to the purity of the extracts provided. Therefore, the objective of this work is to evaluate the global extraction yield, the antimicrobial activity and the composition profile of Merlot and Syrah grape pomace extracts obtained by supercritical CO2 (SC-CO2) and CO2 added with co-solvent at pressures up to 300 bar and temperatures of 50 and 60 °C. The results were compared with the ones obtained by Soxhlet and by ultrasound-assisted leaching extraction methods. The main components from the extracts, identified by HPLC, were gallic acid, p-OH-benzoic acid, vanillic acid and epicatechin. The antibacterial and antifungal activities of the extracts were evaluated using four strains of bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa) and three fungi strains (Candida albicans, Candida parapsilosis, Candida krusei). Despite lower extraction yield results, the supercritical fluid extracts presented the highest antimicrobial effectiveness compared to the other grape pomace extracts due to the presence of antimicrobial active compounds. Syrah extracts were less efficient against the microorganisms tested and Merlot extracts were more active against Gram-positive bacteria. PMID:23036924

Oliveira, Daniela A; Salvador, Ana Augusta; Smânia, Artur; Smânia, Elza F A; Maraschin, Marcelo; Ferreira, Sandra R S

2013-04-10

328

Green Synthesis and Characterization of Silver Nanoparticles for Antimicrobial Activity Against Burn Wounds Contaminating Bacteria  

NASA Astrophysics Data System (ADS)

Silver nanoparticles (AgNPs) were prepared from the plant extract of N. arbor-tristis under atmospheric conditions through green synthesis and characterized by various physicochemical techniques like UV-Visible spectroscopy, IR Spectra, energy dispersive X-ray spectrometry (EDS), X-ray diffraction and transmission electron microscopy (TEM) and the results confirmed the synthesis of homogeneous and stable AgNPs by the plant extracts. The antimicrobial activity of AgNPs was investigated against most common bacteria found in burn wound Staphylococcus epidermidis and Pseudomonas aeruginosa. In these tests, Mueller Hinton agar plates were used with AgNPs of various concentrations, supplemented in liquid systems. P. aeruginosa was inhibited at the low concentration of AgNPs, whereas the growth-inhibitory effect on S. epidermidis was mild. These results suggest that AgNPs can be used as effective growth inhibitors of various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.

Rout, Anandini; Jena, Padan K.; Sahoo, Debasish; Parida, Umesh K.; Bindhani, Birendra K.

2014-04-01

329

Antimicrobial activity and cellular toxicity of nanoparticle-polymyxin B conjugates  

NASA Astrophysics Data System (ADS)

We investigate the antimicrobial activity and cytotoxicity to mammalian cells of conjugates of the peptide antibiotic polymyxin B (PMB) to Au nanoparticles and CdTe quantum dots. Au nanoparticles fully covered with PMB are identical in antimicrobial activity to the free drug alone, whereas partially-conjugated Au particles show decreased effectiveness in proportion to the concentration of Au. CdTe-PMB conjugates are more toxic to Escherichia coli than PMB alone, resulting in a flattening of the steep PMB dose-response curve. The effect is most pronounced at low concentrations of PMB, with a greater effect on the concentration required to reduce growth by half (IC50) than on the concentration needed to inhibit all growth (minimum inhibitory concentration, MIC). The Gram positive organism Staphylococcus aureus is resistant to both PMB and CdTe, showing minimal increased sensitivity when the two are conjugated. Measurement of reactive oxygen species (ROS) generation shows a significant reduction in photo-generated hydroxyl and superoxide radicals with CdTe-PMB as compared with bare CdTe. There is a corresponding reduction in toxicity of QD-PMB versus bare CdTe to mammalian cells, with nearly 100% survival in fibroblasts exposed to bactericidal concentrations of QD-PMB. The situation in bacteria is more complex: photoexcitation of the CdTe particles plays a small role in IC50 but has a significant effect on the MIC, suggesting that at least two different mechanisms are responsible for the antimicrobial action seen. These results show that it is possible to create antimicrobial agents using concentrations of CdTe quantum dots that do not harm mammalian cells.

Park, Soonhyang; Chibli, Hicham; Wong, Jody; Nadeau, Jay L.

2011-05-01

330

Curvularia haloperoxidase: antimicrobial activity and potential application as a surface disinfectant.  

PubMed

A presumed antimicrobial enzyme system, the Curvularia haloperoxidase system, was examined with the aim of evaluating its potential as a sanitizing agent. In the presence of hydrogen peroxide, Curvularia haloperoxidase facilitates the oxidation of halides, such as chloride, bromide, and iodide, to antimicrobial compounds. The Curvularia haloperoxidase system caused several-log-unit reductions in counts of bacteria (Pseudomonas spp., Escherichia coli, Serratia marcescens, Aeromonas salmonicida, Shewanella putrefaciens, Staphylococcus epidermidis, and Listeria monocytogenes), yeasts (Candida sp. and Rhodotorula sp.), and filamentous fungi (Aspergillus niger, Aspergillus tubigensis, Aspergillus versicolor, Fusarium oxysporum, Penicillium chrysogenum, and Penicillium paxilli) cultured in suspension. Also, bacteria adhering to the surfaces of contact lenses were killed. The numbers of S. marcescens and S. epidermidis cells adhering to contact lenses were reduced from 4.0 and 4.9 log CFU to 1.2 and 2.7 log CFU, respectively, after treatment with the Curvularia haloperoxidase system. The killing effect of the Curvularia haloperoxidase system was rapid, and 10(6) CFU of E. coli cells/ml were eliminated within 10 min of treatment. Furthermore, the antimicrobial effect was short lived, causing no antibacterial effect against E. coli 10 min after the system was mixed. Bovine serum albumin (1%) and alginate (1%) inhibited the antimicrobial activity of the Curvularia haloperoxidase system, whereas glucose and Tween 20 did not affect its activity. In conclusion, the Curvularia haloperoxidase system is an effective sanitizing system and has the potential for a vast range of applications, for instance, for disinfection of contact lenses or medical devices. PMID:12902249

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

2003-08-01

331

Antimicrobial activity and phytochemical screening of stem bark extracts from Jatropha curcas (Linn)  

Microsoft Academic Search

The in vitro antimicrobial activity of crude ethanolic, methanolic and water extracts of the stem bark of Jatropha curcas were investigated. The extracts exhibited antimicrobial activities with zones of inhibition ranging from 5 to 12, 8 to 20 and 0 to 8 mm for ethanol, methanol and water extracts respect- ively. The minimum inhibitory concentration (MIC) of the ethanol extract

O. O. Igbinosa; E. O. Igbinosa

2009-01-01

332

Phytochemical analysis of Gymnema sylvestre and evaluation of its antimicrobial activity  

Microsoft Academic Search

Gymnema sylvestre (CS 149), known to be a rich source of saponins and other valuable phytochemicals, has been analysed for antimicrobial activity. The chloroform extracts of aerial and root parts of G. sylvestre exhibited higher antimicrobial activity as compared to diethyl ether and acetone. The root extracts of chloroform have shown competitive minimum inhibitory concentration and minimum bactericidal concentration values

Bhuvaneswari Chodisetti; Kiranmayee Rao; Archana Giri

2012-01-01

333

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

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

1972-01-01

334

Preliminary Phytochemical Analysis and Antimicrobial Activity of Some Weeds collected from Marathwada Region  

Microsoft Academic Search

The aqueous and ethanolic extracts of selected weeds such as Portulaca oleracea L. (Portulaceae), Cardiospermum helicacabum L. (Sapindaceae), Euphorbia hirta L. (Euphorbiaceae), Crotalaria retusa L. (Fabaceae) and Euphorbia heterophylla L. (Euphorbiaceae) were screened for phytochemical analysis and antimicrobial activity. The antimicrobial activities were tested against two gram-positive bacteria (Bacillus subtilis, Staphylococus aureus), one gram-negative bacterium (Pseudomonas aeruginosa) and a mould

Dhole JA; Dhole NA; Lone KD; Bodke SS; Rajarshi Shahu

2011-01-01

335

Antimicrobial activity and chemical composition of Thymus vulgaris, Thymus zygis and Thymus hyemalis essential oils  

Microsoft Academic Search

The present study describes the volatile profile and antimicrobial activity of Thymus vulgaris (thymol chemotype), Thymus zygis subsp. gracilis (thymol and two linalool chemotypes) and Thymus hyemalis Lange (thymol, thymol\\/linalool and carvacrol chemotypes) essential oils extracted from seven plants cultivated in Murcia (Spain). Antimicrobial activities of the oils were evaluated for control of growth and survival of 10 pathogenic microorganisms.Gas

María C. Rota; Antonio Herrera; Rosa M. Martínez; Jose A. Sotomayor; María J. Jordán

2008-01-01

336

Anti herpes simplex virus activity of lactoferrin\\/lactoferricin – an example of antiviral activity of antimicrobial protein\\/peptide  

Microsoft Academic Search

.  One of the most common viral infections in humans is caused by the herpes simplex virus (HSV). It was first effectively treated\\u000a in the 1970s with the introduction of acyclovir, which is still the most commonly used treatment. Naturally occurring antimicrobial\\u000a proteins and peptides have also been shown to possess antiviral activity against HSV. This review will focus on the

H. Jenssen

2005-01-01

337

Antimicrobial effect of spices and herbs on Vibrio parahaemolyticus.  

PubMed

The antimicrobial effects of spices and herbs from 18 plant species were examined on a foodborne pathogen, Vibrio parahaemolyticus, with the use of combinations of temperatures and nutrient levels. Basil, clove, garlic, horseradish, marjoram, oregano, rosemary, and thyme exhibited antibacterial activities at incubation of 30 degrees C, while with the exception of horseradish, the same spices and additional 7 species exhibited the activities at 5 degrees C. The lowest MIC (minimum inhibitory concentration) was 0.125% observed in clove and marjoram at 30 degrees C in a nutrient rich medium. Lowering of incubation temperature produced little effect on the MICs except for turmeric. The decreasing of the MIC in turmeric appeared to be basically attributed to the sensitivity of the bacterium to coldness. In nutrient poor medium, the lowest was 0.001 and 0.00025% in marjoram at 30 degrees C and at 5 degrees C, respectively. The sensitivity to several spices and herbs was similar among different clinical serotypes including the emerging strain O3:K6. These results suggest that the spices and herbs can be practical for protecting seafood from the risk of contamination by V. parahaemolyticus and used in hurdle technology with low temperature. PMID:16797760

Yano, Yutaka; Satomi, Masataka; Oikawa, Hiroshi

2006-08-15

338

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

339

Antiradical, antimicrobial and cytotoxic activities of commercial beetroot pomace.  

PubMed

The by-product of food processing is often utilized as feed, and for the preparation of dietary fiber and biofuel. However, these products are also promising sources of bioactive antioxidants and color giving compounds, which could be used as additives in the food, pharmaceutical and cosmetic industry. The aim of this study was to investigate the phytochemical profile, and the antiradical, antimicrobial and cytotoxic activities of industrial beetroot pomace extract (BPE). The content of phenolics (45.68 mg gallic acid equivalents g(-1)), flavonoids (25.89 mg rutin equivalents g(-1)) and betalains (4.09 mg betanin g(-1); 7.32 mg vulgaxanthin I g(-1)) were determined spectrophotometrically. The antiradical activity on DPPH (EC(50)(DPPH·) = 0.0797 mg ml(-1)), hydroxyl (EC(50)(·OH) = 0.0655 mg ml(-1)) and superoxide anion (EC(50)(O2·-) = 1.0625 mg ml(-1)) radicals were measured by electron spin resonance (ESR) spectroscopy. The antimicrobial activity was determined using the agar-well diffusion method. Gram(-) bacteria (Salmonella typhimurium, Citrobacter freundii) and Gram(+) bacteria, (Staphylococcus aureus, Staphylococcus sciuri, Bacillus cereus) showed high susceptibility, while yeasts and moulds were resistant. BPE exhibits cytotoxic properties against Ehrlich carcinoma (EAC) cells in vivo due to induction of oxidative stress. The largest decreases in EAC cell numbers were observed in the pre-treated male (approximately 53%) and female (approximately 47%) mice, and also the EAC cell viability was decreased after administration of BPE. The activities of the antioxidant enzymes, xanthine oxidase (XOD) and peroxidase (Px), were significantly different between the untreated EAC control group and all other groups that were treated with BPE. The XOD and Px activities were very low in untreated malignant cells, but increased significantly after administration of BPE. Our results show that BPE holds promise in the food industry as a source of bioactive compounds. PMID:23423147

Vuli?, Jelena J; Cebovi?, Tatjana N; Canadanovi?, Vladimir M; Cetkovi?, Gordana S; Djilas, Sonja M; Canadanovi?-Brunet, Jasna M; Veli?anski, Aleksandra S; Cvetkovi?, Dragoljub D; Tumbas, Vesna T

2013-04-30

340

Antimicrobial activity of whey protein based edible films incorporated with oregano, rosemary and garlic essential oils  

Microsoft Academic Search

The use of edible films to release antimicrobial constituents in food packaging is a form of active packaging. Antimicrobial properties of spice extracts are well known, however their application to edible films is limited. In this study, antimicrobial properties of whey protein isolate (WPI) films containing 1.0–4.0% (wt\\/vol) ratios of oregano, rosemary and garlic essential oils were tested against Escherichia

A. C. Seydim; G. Sarikus

2006-01-01

341

Bile Acids Improve the Antimicrobial Effect of Rifaximin? †  

PubMed Central

Diarrhea is one of the most common infirmities affecting international travelers, occurring in 20 to 50% of persons from industrialized countries visiting developing regions. Enterotoxigenic Escherichia coli (ETEC) is the most common causative agent and is isolated from approximately half of the cases of traveler's diarrhea. Rifaximin, a largely water-insoluble, nonabsorbable (<0.4%) antibiotic that inhibits bacterial RNA synthesis, is approved for use for the treatment of traveler's diarrhea caused by diarrheagenic E. coli. However, the drug has minimal effect on the bacterial flora or the infecting E. coli strain in the aqueous environment of the colon. The purpose of the present study was to evaluate the antimicrobial effect and bioavailability of rifaximin in aqueous solution in the presence and absence of physiologic concentrations of bile acids. The methods used included growth measurement of ETEC (strain H10407), rifaximin solubility measurements, total bacterial protein determination, and assessment of the functional activity of rifaximin by monitoring inhibition of bacterial ?-galactosidase expression. Solubility studies showed rifaximin to be 70- to 120-fold more soluble in bile acids (approximately 30% in 4 mM bile acids) than in aqueous solution. Addition of both purified bile acids and human bile to rifaximin at subinhibitory and inhibitory concentrations significantly improved the drug's anti-ETEC effect by 71% and 73%, respectively, after 4 h. This observation was confirmed by showing a decrease in the overall amount of total bacterial protein expressed during incubation of rifaximin plus bile acids. Rifaximin-treated samples containing bile acids inhibited the expression of ETEC ?-galactosidase at a higher magnitude than samples that did not contain bile acids. The study provides data showing that bile acids solubilize rifaximin on a dose-response basis, increasing the drug's bioavailability and antimicrobial effect. These observations suggest that rifaximin may be more effective in the treatment of infections in the small intestine, due to the higher concentration of bile in this region of the gastrointestinal tract than in the colon. The water insolubility of rifaximin is the likely explanation for the drug's minimal effects on colonic flora and fecal pathogens, despite in vitro susceptibility.

Darkoh, Charles; Lichtenberger, Lenard M.; Ajami, Nadim; Dial, Elizabeth J.; Jiang, Zhi-Dong; DuPont, Herbert L.

2010-01-01

342

Screening of plant extracts for antimicrobial activity against bacteria and yeasts with dermatological relevance.  

PubMed

There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobial agents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata (dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia officinalis (supercritical carbon dioxide [CO2] extracts). Additionally, the following characteristic plant substances were tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic acid, harpagoside, boswellic acid and gentiopicroside. The extracts and compounds were tested against 29 aerobic and anaerobic bacteria and yeasts in the agar dilution test. U. barbata-extract and usnic acid were the most active compounds, especially in anaerobic bacteria. Usnea CO2-extract effectively inhibited the growth of several Gram-positive bacteria like Staphylococcus aureus (including methicillin-resistant strains - MRSA), Propionibacterium acnes and Corynebacterium species. Growth of the dimorphic yeast Malassezia furfur was also inhibited by Usnea-extract. Besides the Usnea-extract, Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to be effective against a panel of bacteria. It is concluded that due to their antimicrobial effects some of the plant extracts may be used for the topical treatment of skin disorders like acne vulgaris and seborrhoic eczema. PMID:17291738

Weckesser, S; Engel, K; Simon-Haarhaus, B; Wittmer, A; Pelz, K; Schempp, C M

2007-08-01

343

Antimicrobial activity of clove and cinnamon essential oils against Listeria monocytogenes in pasteurized milk.  

PubMed

The antimicrobial activity of essential oils (EOs) of cinnamon bark, cinnamon leaf, and clove against Listeria monocytogenes Scott A were studied in semiskimmed milk incubated at 7 degrees C for 14 days and at 35 degrees C for 24 h. The MIC was 500 ppm for cinnamon bark EO and 3,000 ppm for the cinnamon leaf and clove EOs. These effective concentrations increased to 1,000 ppm for cinnamon bark EO, 3,500 ppm for clove EO, and 4,000 ppm for cinnamon leaf EO when the semiskimmed milk was incubated at 35 degrees C for 24 h. Partial inhibitory concentrations and partial bactericidal concentrations were obtained for all the assayed EOs. The MBC was 3,000 ppm for the cinnamon bark EO, 10,500 ppm for clove EO, and 11,000 ppm for cinnamon leaf EO. The incubation temperature did not affect the MBC of the EOs but slightly increased the MIC at 35 degrees C. The increased activity at the lower temperature could be attributed to the increased membrane fluidity and to the membrane-perturbing action of EOs. The influence of the fat content of milk on the antimicrobial activity of EOs was tested in whole and skimmed milk. In milk samples with higher fat content, the antimicrobial activity of the EOs was reduced. These results indicate the possibility of using these three EOs in milk beverages as natural antimicrobials, especially because milk beverages flavored with cinnamon and clove are consumed worldwide and have been increasing in popularity in recent years. PMID:18095427

Cava, R; Nowak, E; Taboada, A; Marin-Iniesta, F

2007-12-01

344

Exploring of Antimicrobial Activity of Triphala Mashi-an Ayurvedic Formulation.  

PubMed

Triphala Mashi is an ayurvedic formulation that was prepared in our lab. Aqueous and alcoholic extracts of both Triphala and Triphala Mashi were used, to evaluate antimicrobial activity. Comparative phytochemical profile of Triphala and Triphala Mashi was done by preliminary phytochemical screening, total phenolic content and thin layer chromatography (TLC). Antimicrobial activity includes isolation of pathogens from clinical samples, its characterization, testing its multiple drug resistance against standard antibiotics and antimicrobial activity of aqueous and alcoholic extracts of both Triphala and Triphala Mashi against these organisms by using agar gel diffusion method. Triphala Mashi containing phenolic compounds, tannins exhibited comparable antimicrobial activity in relation to Triphala against all the microorganisms tested. It inhibits the dose-dependent growth of Gram-positive and Gram-negative bacteria. In conclusion, it appears that Triphala Mashi has non-specific antimicrobial activity. PMID:18317557

Biradar, Yogesh S; Jagatap, Sheetal; Khandelwal, K R; Singhania, Smita S

2008-03-01

345

Chemical composition and antimicrobial activity of Satureja hortensis and Trachyspermum copticum essential oil  

PubMed Central

Background and Objectives The aim of this study was to evaluate the chemical composition and antimicrobial activity of Satureja hortensis and Trachyspermum copticum essential oils against different kinds of microorganisms in vitro. Material and Methods The antimicrobial activity was evaluated by micro broth dilution assay and the chemical composition of essential oils was analyzed by GC and GC/MS. Results Thymol, p-cymene, ?-terpinene and carvacrol were the main components of S. hortensis oil while thymol, ?-terpinene, and o-cymene were the major components of T. copticum oil. Two essential oils exhibited strong antimicrobial activity but the antimicrobial activity of T. copticum oil was higher than that of S. hortensis oil. Conclusion Thymol as a main component of oils plays an important role in antimicrobial activity.

Mahboubi, M; Kazempour, N

2011-01-01

346

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

347

Chemical composition, and antioxidant and antimicrobial activities of three hazelnut (Corylus avellana L.) cultivars.  

PubMed

Hazelnut (Corylus avellana L.) is a very popular dry fruit in the world being consumed in different form and presentations. In the present work, three hazelnut cultivars (cv. Daviana, Fertille de Coutard and M. Bollwiller) produced in Portugal, were characterized in respect to their chemical composition, antioxidant potential and antimicrobial activity. The samples were analysed for proximate constituents (moisture, fat, crude protein, ash), nutritional value and fatty acids profile by GC/FID. Antioxidant potential was accessed by the reducing power assay, the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and beta-carotene linoleate model system. Their antimicrobial capacity was also checked against Gram positive (Bacillus cereus, B. subtilis, Staphylococcus aureus) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). Results showed that the main constituent of fruits was fat ranging from 56% to 61%, being the nutritional value around 650 kcal per 100 g of fruits. Oleic was the major fatty acid varying between 80.67% in cv. F. Coutard and 82.63% in cv. Daviana, followed by linoleic, palmitic, and stearic acids. Aqueous hazelnut extract presented antioxidant activity in a concentration-dependent way, in general with similar behaviour for all cultivars. Hazelnut extracts revealed a high antimicrobial activity against Gram positive bacteria (MIC 0.1 mg/mL) showing a good bioactivity of these fruits. PMID:18316150

Oliveira, Ivo; Sousa, Anabela; Morais, Jorge Sá; Ferreira, Isabel C F R; Bento, Albino; Estevinho, Letícia; Pereira, José Alberto

2008-05-01

348

Antimicrobial activity of endodontic sealers based on calcium hydroxide and MTA.  

PubMed

The aim of this study was to evaluate the antimicrobial activity of a new root canal sealer containing calcium hydroxide (Acroseal) and the root canal sealer based on MTA (Endo CPM Sealer), in comparison with traditional sealers (Sealapex, Sealer 26 and Intrafill) and white MTA-Angelus, against five different microorganism strains. The materials and their components were evaluated after manipulation, employing the agar diffusion method. A base layer was made using Müller-Hinton agar (MH) and wells were made by removing agar. The materials were placed into the wells immediately after manipulation. The microorganisms used were: Micrococcus luteus (ATCC9341), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (ATCC27853), Candida albicans (ATCC 10231), and Enterococcus faecalis (ATCC 10541). The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37 degrees C for 24 h. The results showed that Sealapex and its base paste, Sealer 26 and its powder, Endo CPM Sealer and its powder, white MTA and its powder all presented antimicrobial activity against all strains. Intrafill and its liquid presented antimicrobial activity against all strains except P. aeruginosa and Acroseal was effective only against M. luteus and S. aureus. PMID:19177851

Tanomaru, Juliane M G; Tanomaru-Filho, Mário; Hotta, Juliana; Watanabe, Evandro; Ito, Izabel Y

2008-01-01

349

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

350

Antimicrobial activity of extracts from Tamarindus indica L. leaves  

PubMed Central

Tamarindus indica L. leaves are reported worldwide as antibacterial and antifungal agents; however, this observation is not completely accurate in the case of Cuba. In this article, decoctions from fresh and sun dried leaves, as well as fluid extracts prepared with 30 and 70% ethanol-water and the pure essential oil from tamarind leaves were microbiologically tested against Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Pseudomona aeruginosa and Candida albicans. Aqueous and fluid extracts were previously characterized by spectrophotometric determination of their total phenols and flavonoids, while the essential oil was chemically evaluated by gas chromatography/mass spectroscopy (GC/MS). Experimental data suggest phenols as active compounds against B. subtilis cultures, but not against other microorganisms. On the other hand, the essential oil exhibited a good antimicrobial spectrum when pure, but its relative low concentrations in common folk preparations do not allow for any good activity in these extracts.

Escalona-Arranz, Julio Cesar; Peres-Roses, Renato; Urdaneta-Laffita, Imilci; Camacho-Pozo, Miladis Isabel; Rodriguez-Amado, Jesus; Licea-Jimenez, Irina

2010-01-01

351

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 1000mg/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

352

Synthesis of 1-isopropyl-3-acyl-5-methyl-benzimidazolone Derivatives and Their Antimicrobial Activity  

PubMed Central

A series of N-acylated analogues of 1-isopropyl-3-acyl-5-methyl-benzimidazolone were synthesized. Bioassay results indicated that analogues 5-07 and 5-19 exhibited the most potency against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Analogues 5-02, 5-07, 5-12, 5-15, 5-19, 5-20 and 5-25 could effectively inhibit the spore germination of Botrytis cinerea. The relationship between structure and their antimicrobial activity (SAR) has also been discussed according to aliphatic acids and aromatic acids derivatives, respectively. This implied that the N-acylated derivatives of 5-methyl-benzimidazolone might be potential antimicrobial agents.

Xu, Nan; Yang, Chunnan; Gan, Xinqi; Wei, Shaopeng; Ji, Zhiqin

2013-01-01

353

Synthesis, biological activity and solution structure of new analogues of the antimicrobial Gramicidin S.  

PubMed

Gramicidin S (GS) is a cyclo-decapeptide antibiotic isolated from Bacillus brevis. The structural studies have shown that GS forms a two-stranded antiparallel ?-sheet imposed by two II' ?-turns. Despite its wide Gram+ and Gram- antimicrobial spectrum, GS is useless in therapy because of its high hemotoxicity in humans. It was found, however, that the analogues of GS-14 (GS with 14 amino acid residues) attained a better antimicrobial selectivity when their amphipatic moments were perturbed. In this study, we report effects of similar perturbations imposed on GS cyclo-decapeptide analogues. Having solved their structures by NMR/molecular dynamics and having tested their activities/selectivities, we have concluded that the idea of perturbation of the amphipatic moment does not work for GS-10_0 analogues. An innovative approach to the synthesis of head-to-tail cyclopeptides was used. PMID:21308877

Kamysz, El?bieta; Mickiewicz, Beata; Kamysz, Wojciech; Bieli?ska, Sylwia; Rodziewicz-Motowid?o, Sylwia; Ciarkowski, Jerzy

2011-03-01

354

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

355

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.

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

2014-01-01

356

Antimicrobial activity of thin solid films of silver doped hydroxyapatite prepared by sol-gel method.  

PubMed

In this work, the preparation and characterization of silver doped hydroxyapatite thin films were reported and their antimicrobial activity was characterized. Silver doped hydroxyapatite (Ag:HAp) thin films coatings substrate was prepared on commercially pure Si disks by sol-gel method. The silver doped hydroxyapatite thin films were characterized by various techniques such as Scanning electron microscopy (SEM) with energy Dispersive X-ray attachment (X-EDS), Fourier transform infrared spectroscopy (FT-IR), and glow discharge optical emission spectroscopy (GDOES). These techniques have permitted the structural and chemical characterisation of the silver doped hydroxyapatite thin films. The antimicrobial effect of the Ag:HAp thin films on Escherichia coli and Staphylococcus aureus bacteria was then investigated. This is the first study on the antimicrobial effect of Ag:HAp thin films obtained by sol-gel method. The results of this study have shown that the Ag:HAp thin films with x(Ag) = 0.5 are effective against E. coli and S. aureus after 24 h. PMID:24523630

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

2014-01-01

357

Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus.  

PubMed

Fatty acids and derivatives (FADs) are resources for natural antimicrobials. In order to screen for additional potent antimicrobial agents, the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay. Monoglycerides of fatty acids were the most potent class of fatty acids, among which monotridecanoin possessed the most potent antimicrobial activity. The conventional quantitative structure-activity relationship (QSAR) and comparative molecular field analysis (CoMFA) were performed to establish two statistically reliable models (conventional QSAR: R(2)=0.942, Q(2)(LOO)=0.910; CoMFA: R(2)=0.979, Q(2)=0.588, respectively). Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structure-activity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents. PMID:22302421

Zhang, Hui; Zhang, Lu; Peng, Li-juan; Dong, Xiao-wu; Wu, Di; Wu, Vivian Chi-Hua; Feng, Feng-Qin

2012-02-01

358

Sequence context induced antimicrobial activity: insight into lipopolysaccharide permeabilization.  

PubMed

Lactoferrampin (WR17, Trp 268-Arg 284), an antimicrobial peptide, is known to have significant antibacterial and candidacidal activities. However, there are no previous studies explaining how WR17 permeabilizes the outer membrane of Gram negative bacteria and neutralizes endotoxins. In this study we used a series of assays like antimicrobial activity, calcein leakage, NPN dye uptake and endotoxin neutralization assay to show that the sequence context of WR17 modulates its multi-faceted activities. We determined the high resolution NMR structure of WR17 in LPS and found that the N-ter region forms a helix (Trp1-Phe11) and orients itself at an angle of 45° into the lipopolysaccharide (LPS) micelle, whereas the C-ter region (Lys13-Arg17) remains as a flexible extended random coil. We also verified this result through in silico molecular modeling simulation. Isothermal titration calorimetry showed that the interaction of WR17 and its analogues with LPS was primarily endothermic in nature. Using several fluorescence techniques such as anisotropy and red edge excitation shift assay we revealed motional restriction for Trp1 of WR17 in LPS. The distance between the indole ring of Trp1 of WR17 and the polar head group of LPS is around 7 Ĺ, as obtained from the depth of insertion assay. Additionally, MD simulation demonstrated that the incorporation of the peptide in LPS is achieved with the help of the K(13)xK(15)xR(17) motif at the C-terminus. This novel anchoring "K(13)NKSR(17)" motif is currently being utilized in our ongoing research to design novel anti-endotoxic molecules. PMID:24714742

Ghosh, Anirban; Datta, Aritreyee; Jana, Jagannath; Kar, Rajiv Kumar; Chatterjee, Chiradip; Chatterjee, Subhrangsu; Bhunia, Anirban

2014-06-01

359

A Fourier Transformation based Method to Mine Peptide Space for Antimicrobial Activity  

PubMed Central

Background Naturally occurring antimicrobial peptides are currently being explored as potential candidate peptide drugs. Since antimicrobial peptides are part of the innate immune system of every living organism, it is possible to discover new candidate peptides using the available genomic and proteomic data. High throughput computational techniques could also be used to virtually scan the entire peptide space for discovering out new candidate antimicrobial peptides. Result We have identified a unique indexing method based on biologically distinct characteristic features of known antimicrobial peptides. Analysis of the entries in the antimicrobial peptide databases, based on our indexing method, using Fourier transformation technique revealed a distinct peak in their power spectrum. We have developed a method to mine the genomic and proteomic data, for the presence of peptides with potential antimicrobial activity, by looking for this distinct peak. We also used the Euclidean metric to rank the potential antimicrobial peptides activity. We have parallelized our method so that virtually any given protein space could be data mined, in search of antimicrobial peptides. Conclusion The results show that the Fourier transform based method with the property based coding strategy could be used to scan the peptide space for discovering new potential antimicrobial peptides.

Nagarajan, Vijayaraj; Kaushik, Navodit; Murali, Beddhu; Zhang, Chaoyang; Lakhera, Sanyogita; Elasri, Mohamed O; Deng, Youping

2006-01-01

360

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

361

Biological activities of commercial bee pollens: antimicrobial, antimutagenic, antioxidant and anti-inflammatory.  

PubMed

Bee pollen is considered, since memorable times, a good source of nourishing substances and energy. The present study aimed to evaluate the biological activities of eight commercial bee pollens purchased from the market. The origin of sample A was not specified in the labeling; samples B, C, D and G were from Portugal and the remaining were from Spain. The sample E presented the highest value of phenolics (32.15±2.12 mg/g) and the H the lowest (18.55±095 mg/g). Sample C had the highest value of flavonoids (10.14±1.57 mg/g) and sample H the lowest (3.92±0.68 mg/g). All the samples exhibited antimicrobial activity, being Staphylococcus aureus the most sensitive and Candida glabrata the most resistant of the microorganisms studied. All the samples exhibited antimutagenic activity, even though some samples were more effective in decreasing the number of gene conversion colonies and mutant colonies. Regarding the antioxidant activity, assessed using two methods, the more effective was sample B. The anti-inflammatory activity, assessed using the hyaluronidase enzyme, was highest in samples B and D. Pearson's correlation coefficients between polyphenols, flavonoids, antioxidant activity and antimicrobial activity were computed. It was also performed a discriminant analysis. PMID:24262487

Pascoal, Ananias; Rodrigues, Sandra; Teixeira, Alfredo; Feás, Xesus; Estevinho, Leticia M

2014-01-01

362

In vitro synergistic activities of antimicrobial peptide brevinin-2CE with five kinds of antibiotics against multidrug-resistant clinical isolates.  

PubMed

Antimicrobial peptides are the promising candidates for withstanding multidrug-resistant bacteria (MDRB) which were caused by the misuse and extensive use of antibiotics. In this research, in vitro activities of one antimicrobial cationic peptide, brevinin-2CE alone and in combination with five kinds of antibiotics were assessed against clinical isolates of extended-spectrum ?-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus. The results showed that most of the combination groups had synergistic effects. Also, it was obvious that brevinin-2CE had more rapid and severe action on the tested MDRBs which demonstrated that brevinin-2CE and the antibiotics had different antimicrobial mechanisms. Thus, it was presumed that the antimicrobial peptides destroyed the bacterial cells via pore formation mechanisms which lead to the increasing of membrane permeability; and then the other compounds like antibiotics might enter into the cells and accomplish the antimicrobial activities more rapidly and efficiently. PMID:24474334

Zhang, Yuan; Liu, Yukun; Sun, Yan; Liu, Qingmei; Wang, Xiaoyan; Li, Zhi; Hao, Jie

2014-06-01

363

In vitro antimicrobial effect of the tissue conditioner containing silver nanoparticles  

PubMed Central

PURPOSE The aim of this study was to identify in vitro antimicrobial activity of the tissue conditioner containing silver nanoparticles on microbial strains, Staphylococcus aureus, Streptococcus mutans and Candida albicans. MATERIALS AND METHODS Experimental disc samples (20.0×3.0 mm) of tissue conditioner (GC Soft-Liner, GC cooperation, Tokyo, Japan) containing 0.1 - 3.0% silver nanoparticles (0%: control) were fabricated. Samples were placed on separate culture plate dish and microbial suspensions (100 µL) of tested strains were inoculated then incubated at 37?. Microbial growth was verified at 24 hrs and 72 hrs and the antimicrobial effects of samples were evaluated as a percentage of viable cells in withdrawn suspension (100 µL). Data were recorded as the mean of three colony forming unit (CFU) numerations and the borderline of the antimicrobial effect was determined at 0.1% viable cells. RESULTS A 0.1% silver nanoparticles combined to tissue conditioner displayed minimal bactericidal effect against Staphylococcus aureus and Streptococcus mutans strains, a 0.5% for fungal strain. Control group did not show any microbial inhibitory effect and there were no statistical difference between 24 hrs and extended 72 hrs incubation time (P > .05). CONCLUSION Within the limitation of this in vitro study, the results suggest that the tissue conditioner containing silver nanoparticles could be an antimicrobial dental material in denture plaque control. Further mechanical stability and toxicity studies are still required.

2011-01-01

364

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

365

Tammar wallaby mammary cathelicidins are differentially expressed during lactation and exhibit antimicrobial and cell proliferative activity.  

PubMed

Cathelicidins secreted in milk may be central to autocrine feedback in the mammary gland for optimal development in addition to conferring innate immunity to both the mammary gland and the neonate. This study exploits the unique reproductive strategy of the tammar wallaby (Macropus eugenii) model to analyse differential splicing of cathelicidin genes and to evaluate the bactericidal activity and effect of the protein on mammary epithelial cell proliferation. Two linear peptides, Con73 and Con218, derived from the heterogeneous carboxyl end of cathelicidin transcripts, MaeuCath1 and MaeuCath7 respectively, were evaluated for antimicrobial activity. Both Con73 and Con218 significantly inhibited the growth of Staphylococcus aureus, Pseudomonas aureginosa, Enterococcus faecalis and Salmonella enterica. In addition both MaeuCath1 and MaeuCath7 stimulated proliferation of primary tammar wallaby mammary epithelial cells (WallMEC). Lactation-phase specific alternate spliced transcripts were determined for MaeuCath1 showing utilisation of both antimicrobial and proliferative functions are required by the mammary gland and the suckled young. The study has shown for the first time that temporal regulation of milk cathelicidins may be crucial in antimicrobial protection of the mammary gland and suckled young and mammary cell proliferation. PMID:21824524

Wanyonyi, Stephen S; Sharp, Julie A; Khalil, Elie; Lefevre, Christophe; Nicholas, Kevin R

2011-11-01

366

Chemical composition, antimicrobial and antioxidant activities of essential oil from Gnaphlium affine.  

PubMed

The chemical composition of the essential oil from Gnaphlium affine was determined, and its antimicrobial and antioxidant activities were evaluated. Twenty-four compounds, representing 94.95% of the amount of total oil, were identified by gas chromatography-mass spectrometry (GC-MS) analysis. Main constituents of the essential oil were found to be eugenol (18.24%), linalool (10.62%), trans-caryophyllene (8.86%), ?-terpineol (5.97%), p-cymene (5.75%), hexadecanoic acid (5.63%), ?-cadinene (4.98%), ?-cadinene (4.22%), ?-humulene (3.22%), and (-)-?-elemene (3.15%). The essential oil revealed a remarkable antimicrobial effect against the tested food-borne microorganisms with the MIC and MBC values in the ranges of 0.2-1.56 ?g/ml and 0.39-3.13 ?g/ml, respectively. The essential oil showed a potent antioxidant activity in ABTS radical scavenging, lipid peroxidation and reducing power assay. It was suggested that the essential oil from G. affine may be a new potential source as natural antimicrobial and antioxidant agents applied in food systems. PMID:21414372

Zeng, Wei-Cai; Zhu, Rui-Xue; Jia, Li-Rong; Gao, Hong; Zheng, Yue; Sun, Qun

2011-06-01

367

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.

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

2014-01-01

368

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

369

Preliminary Screening of Endophytic Fungi from Medicinal Plants in Malaysia for Antimicrobial and Antitumor Activity  

PubMed Central

The screening of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeast and fungi was carried out on isopropanol extracts prepared from 121 isolates of endophytic fungi isolated from medicinal plants in Malaysia. Sensitivity was found to vary among the microorganisms. Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were susceptible to extracts from three, two and two isolates of endophytic fungi, respectively. None were found effective against Salmonella typhimurium. Sixteen endophytic fungal isolates tested were also found to exhibit antitumor activity in the yeast cell-based assay.

Radu, Son; Kqueen, Cheah Yoke

2002-01-01

370

[In vitro antimicrobial activities of quinolones, rifamycins and macrolides against Mycobacterium tuberculosis and M.avium complex: attempt to establish new assay methods which accurately reflect therapeutic effects of test agents in vivo].  

PubMed

Profiles of expression of the antimicrobial activities of LVFX, KRM-1648 (KRM), and CAM against M. tuberculosis (MTB) and M. avium complex (MAC) residing in MONO-MAC-6 human macrophage like cells (MM6-M phi s) and A-549 human type II alveolar pneumocyte cells (A-549 cells) were determined. First, the antimicrobial activities of LVFX, KRM, and CAM against intracellular organisms of MTB Kurono and MAC N-444 strains were examined under conditions in which infected MM6-M phi s and A-549 cells were cultured for up to 7 days or longer in medium containing the antimicrobials at their Cmaxs in the blood, achievable after oral administration of clinical dosages of these drugs. The antimicrobial effects of LVFX and KRM against respectively MTB and MAC within A-549 cells were significantly less than the activities they displayed against the same organisms residing in MM6-M phi s. Notably, it was also found that KRM had a markedly larger MIC (0.25 microgram/ml) for MAC N-444 within A-549 cells than its MIC (0.008 microgram/ml) for the same strain residing in MM6-M phi s. Thus, the profiles of LVFX- and KRM-mediated killing or inhibition of intracellular MTB or MAC organisms in A-549 cells were markedly different from those observed for the organisms residing in MM6-M phi s. Second, invasive and multiplicative phenotypes of MTB and MAC organisms, which had been adapted to either an extracellular or intracellular environment (designated as E- and I-type organisms, respectively), were studied. In the case of MTB, I-type organisms (retrieved from infected MM6-M phi s after bacterial growth within the M phi s during 5-day cultivation) were less efficient than E-type organisms (prepared by cultivating the organisms in 7H9 medium) in entering MM6-M phi s, whereas I-type organisms were more efficient than E-type organisms in invading A-549 cells. On the other hand, in the case of MAC, infectivity of I-type organisms not only in MM6-M phi s but also in A-549 cells was larger than that of E-type organisms. Next, while I-type organisms of MTB and MAC displayed more vigorous replication within MM6-M phi s than E-type organisms, the growth rate of E-type organisms within A-549 cells was more rapid than that of I-type organisms residing in A-549 cells. These findings indicate that there are significant differences between E- and I-type organisms of MTB or MAC in ability to invade and multiply within M phi s (professional phagocytes) and alveolar epithelial cells (nonprofessional phagocytic cells). PMID:10067057

Sato, K; Tomioka, H

1999-01-01

371

Antimicrobial activity of some medicinal plants from Ghana.  

PubMed

The results of a preliminary antimicrobial screening of the methanol extracts of Aframomum melegueta, Piper guineense, Xylopia aethiopica, Zingiber officinale, medicinal plants of Ghana, are reported. PMID:14693222

Konning, G H; Agyare, C; Ennison, B

2004-01-01

372

Antimicrobial activity and phytochemical analysis of crude extracts and essential oils from medicinal plants.  

PubMed

We aimed to establish a phytochemical analysis of the crude extracts and performed GC-MS of the essential oils (EOs) of Eugenia uniflora L. (Myrtaceae) and Asteraceae species Baccharis dracunculifolia DC, Matricaria chamomilla L. and Vernonia polyanthes Less, as well as determining their antimicrobial activity. Establishment of the minimal inhibitory concentrations of the crude extracts and EOs against 16 Staphylococcus aureus and 16 Escherichia coli strains from human specimens was carried out using the dilution method in Mueller-Hinton agar. Some phenolic compounds with antimicrobial properties were established, and all EOs had a higher antimicrobial activity than the extracts. Matricaria chamomilla extract and E. uniflora EO were efficient against S. aureus strains, while E. uniflora and V. polyanthes extracts and V. polyanthes EO showed the best antimicrobial activity against E. coli strains. Staphylococcus aureus strains were more susceptible to the tested plant products than E. coli, but all natural products promoted antimicrobial growth inhibition. PMID:22007687

Silva, N C C; Barbosa, L; Seito, L N; Fernandes, A

2012-01-01

373

In Vitro Antimicrobial, Cytotoxic and Antioxidant Activity of Flower Extract of Saccharum Spontaneum Linn  

Microsoft Academic Search

The research work was conducted to investigate the in vitro antimicrobial, cytotoxic and antioxidant activity of chloroform extract of flower Saccharum spontaneum Linn. (Family- Gramineae). Disc diffusion technique was used for in vitro antibacterial and antifungal screening. Zones of inhibition were observed in disc diffusion for antimicrobial investigation against 4 Gram-positive and 8 Gram negative pathogenic bacteria. The extract showed

Farhana Alam Ripa; Mahmuda Haque

374

Antimicrobial activity of the methanolic extract from the stem bark of tridesmostemon omphalocarpoides (Sapotaceae)  

Microsoft Academic Search

The methanolic extract and fractions from the stem bark of Tridesmostemon omphalocarpoides were investigated for their in vitro antimicrobial properties as well as their phytochemical constituents. The stem bark was collected from Yaoundé, in the Centre Province of Cameroon. The antimicrobial activity of the extract and fractions against two Candida species and seven aerobic bacteria was evaluated on the basis

V. Kuete; J. G. Tangmouo; V. Penlap Beng; F. N. Ngounou; D. Lontsi

2006-01-01

375

Antimicrobial Activity of Lactic Acid Bacteria from Sour Milk Products Narine, Karine, and Matsun  

Microsoft Academic Search

We studied antimicrobial properties of lactic acid bacteria from sour milk products Narine, Karine, and Matsun. The whey of the sour milk products included two major fractions, of sugars and L-lactic acid and its sodium and calcium salts. Antimicrobial activity of Narine, Karine, and Matsun was related to the presence of L-lactic acid and its sodium and calcium salts.

A. O. Martirosyan; Sh. L. Mndzhoyan; L. M. Charyan; L. G. Akopyan; M. N. Nikishchenko

2004-01-01

376

Retention of Antimicrobial Activity in Plaque and Saliva following Mouthrinse Use in vivo  

Microsoft Academic Search

The aim of this study was to determine the contribution of plaque and saliva towards the prolonged activity, also called substantivity, of three antimicrobial mouthrinses (Listerine®, Meridol®, Crest Pro Health®), used in combination with a toothpaste (Prodent Coolmint®). Volunteers brushed for 4 weeks with a toothpaste without antimicrobial claims, while during the last 2 weeks half of the volunteers used

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

2010-01-01

377

Antimicrobial activity of aqueous and methanol extracts of Juniperus oxycedrus L  

Microsoft Academic Search

Aqueous and methanol extracts of the leaves of Juniperus oxycedrus were investigated for their in vitro antimicrobial properties. The plant was collected from Pelitli Village of Gebze, Kocaeli, in the Marmara region of Turkey. Juniperus oxycedrus is widely used as traditional folk medicine in Turkey for treatment of different infectious diseases. The antimicrobial activity of the extracts against 143 laboratory

? Karaman; F ?ahin; M Güllüce; H Ö?ütçü; M ?engül; A Ad?güzel

2003-01-01

378

Bass Hepcidin Synthesis, Solution Structure, Antimicrobial Activities and Synergism, and in Vivo Hepatic Response to  

Microsoft Academic Search

Bass hepcidin was purified from the gill of hybrid striped bass (Morone chrysops Morone saxatilis) based on antimicrobial activity against Escherichia coli. This 21-amino acid peptide has 8 cysteines engaged in 4 di- sulfide bonds and is very similar to human hepcidin, an antimicrobial peptide with iron regulatory properties. To gain insight into potential role(s) of bass hepcidin in innate

Bacterial Infections; Xavier Lauth; Jeffrey J. Babon; Jason A. Stannard; Satendra Singh; Victor Nizet; James M. Carlberg; Vaughn E. Ostland; Michael W. Pennington; Raymond S. Norton; Mark E. Westerman

379

Antimicrobial activity of an endophytic Xylaria sp.YX-28 and identification of its antimicrobial compound 7-amino-4-methylcoumarin  

Microsoft Academic Search

An endophytic Xylaria sp., having broad antimicrobial activity, was isolated and characterized from Ginkgo biloba L. From the culture extracts of this fungus, a bioactive compound P3 was isolated by bioactivity-guided fractionation and\\u000a identified as 7-amino-4-methylcoumarin by nuclear magnetic resonance, infrared, and mass spectrometry spectral data. The compound\\u000a showed strong antibacterial and antifungal activities in vitro against Staphylococcus aureus [minimal

Xiaoli Liu; Mingsheng Dong; Xiaohong Chen; Mei Jiang; Xin Lv; Jianzhong Zhou

2008-01-01

380

Antioxidant and antimicrobial activity of Cissus quadrangularis L.  

PubMed

Extracts of Cissus quadrangularis L. were tested for antioxidant activity by beta-carotene linoleic acid model and also by 1,1-diphenyl-2-picrylhydrazyl model. The ethyl acetate fraction of both fresh and dry stem extracts at a concentration of 100 ppm showed 64.8% antioxidant activity in the beta-carotene linoleic acid system and 61.6% in the 1,1-diphenyl-2-picrylhydrazyl system. This fraction showed the presence of sterols, vitamin C, and tannins as phytoconstituents. The antioxidant activity of methanol extract and aqueous extract were comparatively less significant than that of ethyl acetate extract, and n-hexane extract showed the least activity. The ethyl acetate extract and methanol extract of both fresh and dry stems further exhibited antimicrobial activity against Gram-positive bacteria, including Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Streptococcus species. The resu