Variable Antimicrobial Activity Research Articles

Assessment of antimicrobial activity of hundreds extract of twenty Indian medicinal plants

The antimicrobial activity of 100 extracts of twenty plants Namely Symplocos racemosa, Solanum xanthocapum, Phyllanthus urinaria, Blumea lacera, Acorus calamus, Thevetia nerifolia, Bauhinia purpurea, Jatropha gossypifolia, Pithecellobium dulce, Hydrangea integrifolia, Sphaeranthus indicus, Vitex negundo, Zizyphus xylopyrus, Aconitum heterophyllum, Scoparia dulcis, Callicarpa dichtoma, Adhatoda zylamei, Sphaeralcea angustifolia, Swertia chirayita, Aconitum heterophyllum from Uttar Pradesh, India was tested against twelve pathogenic micro-organisms. The 51 extracts of P. urinaria, B. lacera, B. eriantha, T. nerifolia, J. gossypifolia, P. dulce, H. integrifolia, S. indicus, V. negundo, Z. xylopyrus, A. heterophylum, S. dulcis, C. dichtoma, A. zylamei, S. angustifolia, S. chirayita, A. heterophyllum were found to be inhibiting all the bacterial strains tested, in a range of concentrations by microbroth dilution assay and 0.75 to 48.0 mg/disc by disc diffusion assay. The 37 extracts were found to be active against the fungal strains in arrange of 0.75 to 24.0 mg/ml by microbroth dilution assay. Other plant extracts also exhibited variable antimicrobial activity against one or more species of microorganisms. As the extracts of all the plants which were used in this study effectively controlled the growth of many pathogenic bacteria and fungi, they can be used in the treatment of various infectious diseases. Bioactive compounds from these plants can be employed in the formulation of antimicrobial agents for the treatment of various bacterial and fungal infections.

NATURAL ANTIMICROBIAL ACTIVITY OF LAWSONIA INERMIS AND INDIGO TINCTORIA AGAINST CLINICALLY ISOLATED MICROORGANISMS

Objective: The present study aimed at evaluating the natural antimicrobial activity of Lawsonia inermis (L. inermis) and Indigofera tinctoria (I. tinctoria) against a reference and pathogenic clinically isolated strains compare with some antibiotics.Methods: The antimicrobial activity of Lawsonia inermis (red henna) and Indigo tinctoria (black henna) was evaluated against clinically isolated strains from urinary tract and wounds infected patients. The six tested strains namely were Staphylococcus aureus, Enterococcus fecalis, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans. The antimicrobial activity was evaluated by agar diffusion method and microplate dilution for measuring the minimum inhibitory concentration (MIC). An American Type Culture Collection (ATCC) of bacteria was used as a control for confirming the type of the isolated bacteria.Results: Both red and black henna showed variable antimicrobial activity against tested bacteria and C. albicans. Alcoholic and oily extracts were more effective than water. Staphylococcus epidermis was significantly affected with water extract of black henna (20±1.1) and red henna (11±0.5). Nigella sativa oil extract with black henna had showed significant synergism effects against some microorganisms as Enterococcus fecalis (40±1.5), P. aeruginosa (15±0.9) and Candida albicans (18±0.6).Conclusion: Black and red henna had antibacterial and antifungal activities. They exhibited synergistic effects when mixed with black seed oil.

Antimicrobial Activity of the Ethanolic and Aqueous Extract of Vicia faba L. (Fabaceae) at Three Different Concentrations in the Absence and Presence of Zn(OAc)2.2H2O

The aqueous and ethanolic extract of Passiflora edulis and Vicia faba L. (Fabaceae) exhibited antimicrobial activity against the pathogenic microorganisms: E. coli, S. aureus, K. pneumoniae and C. albicans. This was evaluated using the Disc Diffusion Assay under asceptic conditions. Antimicrobial activity wasn’t induced by the solvent, ethanol nor water. The highest AZOI was 153.9 mm2 and the lowest 12.56 mm2. Negligible Zone of Inhibition, ZOI were observed in several instances. The aqueous extract of the fruit also induced negligible Zone of Inhibition, ZOI. In comparison to the reference, Ampicillin and Nystatin, these values are less. As the concentration of the metal salt, Zn(OAc)2.2H2O and ethanolic extract increases, there seem to be a variation in antimicrobial activity. Zn(OAc)2.2H2O appears to intensify the antimicrobial activity of the plant ethanolic and aqueous extract. Zn (OAc)2.2H2O in the absence of any extracts exhibited antimicrobial activity. The AZOI range from 47.2 mm2 to 117.8 mm2. Antimicrobial selectivity was also observed in several instances.

Therapeutic potentials of Crataegus azarolus var. eu- azarolus Maire leaves and its isolated compounds

BackgroundHyperglycemia is a complicated condition accompanied with high incidence of infection and dyslipidemia. This study aimed to explore the phyto-constituents of Crataegus azarolus var. eu- azarolus Maire leaves, and to evaluate the therapeutic potentials particularly antimicrobial, antihyperglycemic and antihyperlipidemic of the extract and the isolated compound (3β-O-acetyl ursolic acid).MethodsTotal phenolics and flavonoidal contents were measured by RP-HPLC analysis. Free radicals scavenging activity of different extraction solvents was tested in-vitro on DPPH free radicals. The antimicrobial activity of the ethanolic extract and its fractions as well as the isolated compounds were evaluated in-vitro on variable microorganisms. Animal models were used to evaluate the antihyperglycemic and antihyperlipidemic activities of the ethanolic extract along with the isolated compound (3β-O acetyl ursolic acid).ResultsRP- HPLC analysis of the phenolics revealed high content of rutin, salicylic and ellagic acids. Six compounds belonging to triterpenes and phenolics were isolated from chloroform and n-butanol fractions namely: ursolic acid, 3β-O-acetyl ursolic acid, ellagic acid, quercetin 3-O-β methyl ether, rutin and apigenin7-O-rutinoside. Ethanolic extract showed the highest DPPH radical scavenger activity compared to other solvents. Ethanolic extract, hexane fraction, ursolic acid, 3β-O acetyl ursolic acid and quercetin 3-O-methyl ether showed variable antimicrobial activity against E. coli, P. aeruginosa, S. aureus, and C. albicans. Administration of the ethanolic extract or 3β-O acetyl ursolic acid orally to the mice reduced blood glucose significantly in a time- and dose-dependent manner. Ethanolic extract significantly reduced LDL-C, VLDL-C, TC and TG and increased HDL-C in rats. Ethanolic extract and 3β-O acetyl ursolic acid reduced in-vitro activity of pancreatic lipase.ConclusionThis study reveals that Crataegus azarolus var. eu- azarolus Maire has the efficiency to control hyperglycemia with its associated complications. This study is the first to evaluate antihyperglycemic and antihyperlipidemic potentials of 3β-O acetyl ursolic acid.

Role of salt precursors for the synthesis of zinc oxide nanoparticles and in imparting variable antimicrobial activity

Synthesis of nanoparticles (NPs) having unique potentials and properties is of great importance in nanotechnology. The NP synthesis techniques may include the wet chemistry to microbial incubation reduction methods. This work reports generation of ZnO NPs by identical preparation including incubation of different zinc salts i.e. zinc acetate, zinc chloride and zinc sulphate as precursors with cell free extracts of Bacillus circulans MTCC 7906 (Bc7906) and Pleurotus florida (Pf). The synthesized NPs exhibited variation in their absorption peaks in UV-Vis spectra which appeared at 275 nm, 325 nm and 375 nm with P. florida for the three salt precursors respectively while the Bc7906 generated ZnO NPs showed peaks between 300-350 nm. A variation in ZnO NP morphology ranged from 50 to 120 nm in size and spherical, oval, cylindrical to trigonal anisotropic in shape by transmission EM. Further, the rough and corrugated surface topography of ZnO NPs was observed in Scanning EM. The % weight for Zn element surface composition as recorded by SEM-EDS was observed to be highest for zinc acetate (2.34%) and zinc sulphate (7.54 %) on microbial synthesis from Bc7906 and Pf respectively. The antimicrobial potential of the synthesized ZnO NPs on human pathogenic and plant beneficial bacteria was tested and it was observed to be highest for microbially synthesized ZnO NPs using zinc acetate (15 mm) and zinc sulphate (14 mm) as salt precursors @ 10 ppm. This is the first report on differential antimicrobial behavior of ZnO NPs on human pathogenic and plant beneficial microbes.

Characterization of water-types and their influence on the antimicrobial proper-ties of Kombucha ferments against bacteria and yeast

Understanding the relationships between diet, gut microflora, and health is an increasingly important area of research. Recent studies have demonstrated that Kombucha tea provides variable antimicrobial activity against pathogenic microbes. In this study, we tested Kombucha tea for antimicrobial activity against various Gram-positive and Gram-negative bacteria, as well as yeast, using an agar diffusion method. Standard zone of inhibition assays were used to test the hypothesis that variance in antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans may be due to the varying levels of cations, like Ca2+, found in different water-types (well water, artesian water, city water, type-II water and distilled water). Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES) results indicated that high cationic (Ca2+, Mg2+, and Na+) content water (well water) resulted in the largest zone of inhibition against S. aureus, with a 12.3% difference when compared to low cationic content water (type-II water). E. coli maintained a constant zone of inhibition regardless of water-type or batch-type, while C. albicans showed no zones of inhibition. Inhibition is either through a synergistic relationship with the pH conditions, the other cations present (Mg2+, Na+, Si, etc.) or a mix of both, as pH in the range of 4.5 - 3 is not enough to inhibit the growth of S. aureus. These results indicate that a direct relationship exists between cationic concentrations of water used to prepare Kombucha, and antibacterial activity against S. aureus, due to the improved fermentation of the tea with high concentrations of cations. Strong antimicrobial potential exists, particularly against S. aureus, which may be useful in determining novel approaches to synthesize antimicrobial drugs. Further study is needed to assess other S. aureus strains, as well as to determine how this relationship translates to human microbiota interactions and their microbial metabolic profiles.

Bioactive Hydantoin Alkaloids from the Red Sea Marine Sponge Hemimycale arabica.

In the course of our continuing efforts to identify bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge Hemimycale arabica. The antimicrobial fraction of an organic extract of the sponge afforded two new hydantoin alkaloids, hemimycalins A and B (2 and 3), together with the previously reported compound (Z)-5-(4-hydroxybenzylidene)imidazolidine-2,4-dione (1). The structures of the compounds were determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determinations. Hemimycalins A (2) and B (3) represent the first examples of the natural N-alkylated hydantoins from the sponge Hemimycale arabica. Compounds 1–3 displayed variable antimicrobial activities against E. coli, S. aureus, and C. albicans. In addition, compound 1 displayed moderate antiproliferative activity against the human cervical carcinoma (HeLa) cell line. These findings provide further insight into the chemical diversity as well as the biological activity of this class of compounds.

English

The leaves of Persea americana are widely used for ethno-medicinal purposes worldwide. This study assessed the antimicrobial and antioxidant activities of the methanol, ethyl acetate, chloroform and petroleum ether leaves extracts of P. americana. Extracts displayed variable antimicrobial activities that were microorganism-specific. The methanolic extract displayed the most potent antimicrobial activities with the largest zones of inhibition (0-1.8 mm) in the agar diffusion assay and with the lowest minimum inhibitory concentration (MIC) in the broth dilution assay against a panel of microorganisms that included Bacillus subtilis, Escherichia coli, Salmonella typhi, Streptococcus aureus, Pseudomonas aeruginosa and Candida albicans. The ethyl acetate extract exhibited the most potent antioxidant potential with the lowest EC50 of 4.15x10-30 g/ml for the peroxide radical scavenging activities. The data supports the ethnomedicinal use of the leaves of P. americana for the management of infections and for other symptoms whose etiology may be linked to oxidative stress. Key words: Persea americana, antioxidant, antimicrobial, phytochemical screening, minimum inhibitory concentration.

Comparative Evaluation of Antibacterial Efficacy of Six Indian Plant Extracts against Streptococcus Mutans

To assess the antimicrobial efficacy of six plant extracts of Indian origin often used as traditional medicine against standard strains of Streptococcus mutans. The antimicrobial activity of six plant extracts was determined by the agar well diffusion method. The minimum inhibitory concentration (MIC) for the crude (raw), Organic solvent based, aqueous extracts was determined by the agar well diffusion method. Out of all the six extracts evaluated, organic solvent based and aqueous extracts of all the extracts were found to have variable antimicrobial activities against the oral pathogen. The crude extract of Garlic was the most effective against Streptococcus mutans with the highest zone of inhibition (24.62 mm) followed by the aqueous extract of Amla (19.47mm) and organic solvent based extract of Ginger (18.76 mm). Despite of the fact that the extracts were not pure compounds and antimicrobial results were obtained. This recommends the potency of these extracts. The figment of the derivation of antimicrobial compounds from plants seems lucrative as it will lead to the development of a phytomedicine to act against microbes.

<i>In-vitro</i> antibacterial sensitivity of <i>Usnea barbata</i> lichen extracted with methanol and ethyl-acetate against selected <i>Staphylococcus</i> species from milk of cows with mastitis

Abstract. This study aimed at evaluating the antimicrobial potential of Usnea barbata lichen as a medicinal plant against selected Staphylococcus species isolated from raw milk of cows. In-vitro screening of methanol and ethyl-acetate extracts from Usnea barbata lichen were evaluated to determine their antimicrobial activity against thirteen different Staphylococcus species. The selected organisms were isolated from raw bovine milk and identified using several biochemical tests and confirmed with API staph kit. The antimicrobial activity of the extracts were evaluated using both the agar well diffusion method (at 5 mg/ml, 10 mg/ml and 20 mg/ml) and the broth micro-dilution technique to determine the mean zone of inhibition and the minimum inhibitory concentration (MIC), respectively. Both the methanol and ethyl-acetate extracts showed variable antimicrobial activity against the Staphylococcus species with mean zones of inhibition ranging from 0-34 mm in diameter at 5 mg/ml, 10 mg/ml and 20 mg/ml, respectively. Susceptibility by the Staphylococcus species tested in the methanol and the ethyl-acetate extract was 92.31 % and 53.85 %, respectively. The MIC result for the methanol extract ranged from 0.04 to 10 mg/ml, while that of the ethyl-acetate extract ranged from 0.16 to 5 mg/ml. Results from this study revealed the in vitro microbial activity of Usnea barbata extracts which indicate its potential as a medicinal plant.

Altitude and Growth Stage Specific Variations in Antimicrobial Activity of Darjeeling Himalayan Pellia Endiviifolia against Selected Human Pathogens

Antibacterial activity of methanol and ethanol extracts of vegetative and reproductive thalli of the liverwort Pellia endiviifolia from eastern Himalaya were tested against Staphylococcus aureus (ATCC 25923), Shigella dysenteriae (ATCC 9361), Enterobacter cloacae (ATCC 13047), and Serratia marcescens (ATCC 13880) strains by well diffusion assay, minimum inhibitory concentration, and minimum bactericidal concentration. Antibiosis depended on the altitude of growth as well as the tissue type. There was no difference in the bioactivity due to the plant part used in the extract; however, samples collected from higher altitudes showed higher antimicrobial capacity than those from lower altitudes.

Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects.

BackgroundSalivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production.Methodology/Principal FindingsIn this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina’s MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS). A new medium for maximum biomass production buffered with 2-(N-morpholino)ethanesulfonic acid (MES) was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10) and salivaricin G32 (by strain YU10) from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains.ConclusionThe current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for pharmaceuticals and probiotics from S. salivarius generating different lantibiotics. This is relevant for the clinical management of oral cavity and upper respiratory tract in the human population.

Synthesis, antimicrobial and molecular docking studies of enantiomerically pure N-alkylated β-amino alcohols from phenylpropanolamines

Enantiomerically pure N-alkylated β-amino alcohols 1a, 1a′, 1c, 1c′, 1d, 1d′, 1e and 1e′, with ee 100% have been synthesized from phenylpropanolamines 2. Effect of the neighboring chiral environment on the newly formed chiral center has been studied experimentally and concluded that the newly formed chiral center’s absolute configuration is opposite to the adjacent (α- or β-) chiral environment. The antimicrobial activity of the synthesized β-amino alcohols were screened using in vitro disc diffusion method and variable antimicrobial activities were shown for 1a, 1a′, 1c, 1c′, 1d, 1d′, 1e &1e′ and amongst them 1d &1d′ exhibited significant activity against bacteria and fungi. In silico studies revealed all the synthesized β-amino alcohols 1a–e and 1a′–e′ have shown good binding energies ranging from −7.38 to −6.09kJ/mol towards the target receptor DNA topoisomerase IV and 1d′ has shown maximum binding energy −7.38kJ/mol.

The variation in antimicrobial and antioxidant activities of acetone leaf extracts of 12 Moringa oleifera (Moringaceae) trees enables the selection of trees with additional uses

BackgroundThe aim of this study was to evaluate the variation in antimicrobial and antioxidant activities of the leaf acetone extracts of 12 Moringa oleifera trees harvested in order to select the best material for clonal propagation. MethodsA two-fold serial microdilution method was used to determine the minimum inhibitory concentration (MIC) against a panel of fungal (Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans) and bacterial (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa) species. The radical scavenging capacity was determined using 2,2 diphenyl-1-picryhydrazyl (DPPH). ResultsThere was a large variation in antimicrobial activities with MICs between 0.04 and 2.50mg/ml against bacteria and from 0.16 to >2.50mg/ml against fungi. For samples harvested in winter: trees L3 and LP2 had significant activity against E. faecalis (MIC 0.08mg/ml) and E. coli (MIC 0.04mg/ml). Trees L5, LP1 and LP6 had weak activity against E. coli (MICs 1.25 and 2.50mg/ml), S. aureus (MIC 1.25mg/ml), and E. faecalis (MIC 2.50mg/ml), while other samples had moderate activity against the four bacteria (MICs 0.16–0.63mg/ml). From samples collected in summer: L5 (MIC 0.08mg/ml), L6 (MIC 0.08mg/ml after 1h incubation), LP1 (MICs 0.08mg/ml), LP2 (MICs 0.08mg/ml after 1h incubation), LP4 (0.08mg/ml) and LP5 (MICs 0.04 and 0.08mg/ml) had significant activity against E. faecalis (L5, L6, LP1, LP2, LP4, and LP5), S. aureus (LP1, and LP5), and E. coli (LP2, and LP5), respectively. Other extracts had weak antibacterial activity with MICs ranging from 0.16 to 0.63mg/ml. Most of the samples harvested in winter had moderate antifungal activity: L1, L2, L3, L4, L5, L6, LP1, LP2, and LP3 had moderate activity against C. albicans (ATCC strains) with MIC of 0.63mg/ml in all cases while L2, L3 and L4 as well as L6, LP1, LP2, LP3, LP5 and LP6 against A. fumigatus (MICs 0.63mg/ml) and C. neoformans (MICs 0.63mg/ml), respectively. Apart from L1 (MIC 0.31mg/ml), L2, L3 and LP6 (MICs 0.63mg/ml in all cases) with moderate activity, all the samples collected during summer had weak activity against A. fumigatus (MICs 1.25–2.50mg/ml). All the extracts had a low radical scavenging activity with the IC50 values ranging from 34.72 to 109.62μg/ml, compared to the reference standard l-ascorbic acid (IC50 2.41μg/ml). This may be related to the extractant used. ConclusionThe large variation in antimicrobial activity and antioxidant activities of 24 acetone leaf extracts of 12 M. oleifera trees may lead to the selection of clonal material to serve as a source of propagation materials. Successful propagation and growth of tree LP with very good activity against E. coli and a high total activity could provide an additional use of this valuable plant species to rural people.

English

The aim of the current study was to evaluate the antioxidant, antimicrobial and thrombolytic potentials of the exocarp of Spondias pinnata fruits. The crude ethanolic extract of the exocarp of S. pinnata fruit was partitioned successively by solvents of different polarity. All fractions were then investigated for qualitative preliminary phytochemical screening by specific standard procedure. The antioxidant potential of all fractions were then evaluated in terms of total phenolic content, total flavonoid content, DPPH free radical scavenging potential, reducing potential and total antioxidant capacity by specific standard procedure. The disc diffusion method was incorporated to evaluate the in vitro antimicrobial activity on nutrient agar medium. The highest total phenolic content was found in aqueous fraction (570.20±0.48 mg GAE/g of dried extract) while the lowest in the n-Hexane fraction (337.51±0.21 mg GAE/g of dried extract). However, ethyl acetate fraction exhibited the highest flavonoid content which amounted to 132.27±0.25 mg quercetin equivalents/g of dried extract. Likewise, ethyl acetate fraction showed the highest antioxidant capacity (21.61±0.11 g of L-ascorbic acid equivalents/g of dried extract) along with the lowest IC50 (1.72±0.39 µg/ml) & EC50 (2.25±0.75 µg/ml) value. However, DPPH free radical scavenging activity and reducing power of all fractions were found to be concentration dependent. Nonetheless, comparatively more polar fractions (ethyl acetate and aqueous fraction) were found to be ineffective against all the microbial strains except S. dysentery and P. aeruginosa while non- polar fractions (n-hexane and dichloromethane fraction) showed variable antimicrobial activity. In addition, all fractions produced statistically significant (P<0.05 for ethyl acetate and aqueous fraction, P<0.001 for others) thrombolytic activity. To conclude, our present study suggested that exocarp of S. pinnata fruit exhibits antimicrobial activity against a wide variety of strains while it produces noteworthy

Functional Properties of Lactic Acid Bacteria Isolated from Romanian Fermented Vegetables

A total of 139 lactic acid bacterium (LAB) strains isolated from Romanian traditionally fermented vegetables were screened for the ability to produce exopolysaccharides and for their antagonistic activity against a set of nine LAB strains, three Bacillus strains, and four Gram-negative bacteria. Eighty-five of the tested strains showed a variable antimicrobial activity against Listeria monocytogenes ATCC 1911, 35 of the strains showed a limited inhibition zone against Escherichia coli ATCC25922, and 26 strains against Salmonella enterica ATCC 14024, while 19 strains showed inhibition against one or all three Bacillus strains used as indicators. None of the tested strains showed an antimicrobial activity against Staphylococcus aureus ATCC 25923. Several strains showed antibacterial activity against more than one indicator strain. For instance, Lactobacillus plantarum 307, Lactobacillus brevis 308, and Lactobacillus plantarum/pentosus 358 were active against five of the indicator strains used, while other 23 LAB were active against three indicator strains. In the case of two strains, namely Leuconostoc citreum 344 and Lactobacillus brevis 183, the activity was maintained after neutralizing the pH of the cell-free supernatant likely due to the production of bacteriocins. The gel permeation chromatography-based screening revealed seven EPS-producing LAB strains. Two of the positive strains, namely Leuconostoc citreum 177 and Leuconostoc citreum 52, have been shown to produce large amounts of EPS, of about 20 g/L. All isolated EPS have a high molecular mass, of above 1400 KDa, and a monomer composition dominated by the presence of glucose.

Antimicrobial and free radical scavenging activities of five palestinian medicinal plants

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

Potential effluent oil mills and antibacterial activity polyphenols against some pathogenic strains

The recovery of polyphenols from olive mill wastewaters (OMWs) provides the double opportunity to obtain high-added value biomolecules and to reduce the phytotoxicity of the effluent. The purpose of this study is to gain information about the hygienic quality of the raw material by performing a microbiological analysis of olive mill wastewater, from an extraction system of three phases. The determination of total coliforms,fecal coliforms,aecal streptococci, and another group of microorganisms have been explored, namely yeasts, molds and total aerobic mesophilic flora. We examined the results of the confrontation of olive mill wastewater polyphenols with certain strains known for their pathogenicity, and the minimum concentrations inhibiting bacteria and the minimal bactericidal concentration (MBC) were determined by the dilution method. Polyphenols are particularly the delipidated fraction of OMW extracts according to liquid–liquid phase. The overall yield is 1.367 ± 0.108 %. The quantitative estimation of total polyphenols was assessed by the colorimetric reagent Folin–Ciocalteu, gallic acid and tyrosol, tannic acid and total flavonoids catechin (the method using aluminum trichloride). The results of microbiological analysis confirmed that there is no fecal contamination. For the in vitro bioassay, polyphenols showed a variable antimicrobial activity against six bacteria: Escherichia coli, Proteus sp., Pseudomonas aeruginosa, Enterroccus feculis, Staphylococcus aureus, and Klebsiella pneumoniae. This variability depends essentially on the microorganism tested and the nature of the product tested. Indeed, we found complete inhibition of the growth of Proteus sp. and E. fecalis by the sinks method. Some microorganisms were sensitive to phenols with MBC values between 1/50 and 1/25.

Synthesis, characterization, and antimicrobial activities of barbital-based alkaline earth metal complexes: the X-ray crystal structure of [Ba2H(Barb)5] (Barb = 5,5-diethyl barbiturate)

Three barbital-based alkaline earth metal complexes, [Ca(Barb)2] · 3H2O (1), [Ba2H(Barb)5] (2) and [Mg(Barb)2] · 2H2O (3) (Barb = 5,5-diethyl barbiturate sodium salt), were synthesized and characterized with elemental analysis, thermal analysis, and infrared, Raman, ultraviolet, and NMR (1H and 13C) spectroscopies. Single-crystal X-ray diffraction studies reveal that 2 is a dimer. Each barium(II) is surrounded by an O7N2 donor set in an approximate monocapped square antiprism with Ba–O distances ranging from 2.6512(14) to 2.9168(15) Å and Ba–N distances of 2.7601(15) and 3.2558(17) Å. The complex forms polymeric networks in the solid state with different coordinating abilities of O and N donors and N–H···O hydrogen bonds. The antimicrobial activities of 1–3 were observed against different gram-positive and gram-negative bacteria, yeast, and molds. Variable antimicrobial activity against the different bacteria strains was observed and compared with that of standard antibiotics; minimum inhibitory concentration values ranged from 22 to 170 µg mL−1 for bacteria.

Reduction of Listeria monocytogenes biofilms on stainless steel and polystyrene surfaces by essential oils.

Plant-derived essential oils were tested for their ability to eliminate biofilms of Listeria monocytogenes on polystyrene and stainless steel surfaces. Various concentrations of essential oils were tested with different contact times on biofilms of various ages. Preliminarily screening of nine essential oils and related phenolic compounds in a disk diffusion assay revealed that thyme oil, oregano oil, and carvacrol had the highest antimicrobial activity. Further screening of these three compounds against 21 L. monocytogenes strains representing all 13 serotypes indicated some strain-specific variations in antimicrobial activity. For 1-day-old biofilms of mixed L. monocytogenes strains produced at 22°C on polystyrene microtiter plates, only 0.1% concentrations of thyme oil, oregano oil, and carvacrol were needed to eliminate 7 log CFU per well. On the stainless steel coupons, a 0.5% concentration of these compounds was adequate to completely eliminate 4-day-old biofilms at 7 log CFU per coupon. Our findings indicate that these compounds are potential candidates for elimination of L. monocytogenes biofilms on stainless steel and polystyrene surfaces.