Phenolic content and antibiofilm activity of propolis against clinical MSSA strains

Antibiofilm properties and the phenolic composition of propolis, collected from Bartın province of Turkey in the years of 2013 and 2012, were determined. Hexane, ethyl acetate and ethanol extracts of propolis were prepared and assessed for their antibiofilm activity (inhibition of biofilm formation and reduction of established biofilm) against the clinical methicillin sensitive Staphylococcus aureus (MSSA) strains and Staphylococcus aureus ATCC 33862. Ethyl acetate and ethanol extracts of propolis presented a greater effectiveness on biofilm inhibition of the tested bacteria compared to hexane extracts. The activity patterns showed slight variations in the two years. While 0.5 mg/mL ethyl acetate, ethanol and hexane extract solutions of the product in 2013 inhibited 92.89, 82.98 and 47.42% of biofilm formation of MSSA M20 strain, the inhibition percentage of the products of 2012 were determined to be 87.14%, 75.94% and 44.89% against the same bacterium (MSSA M20), respectively. The results of the validated liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) analyses showed a strong relation between the activity and the phenolic composition of the extracts. Phenolic contents of the ethyl acetate and ethanol extracts were relatively higher than hexane extracts. Caffeic acid composition of ethyl acetate, ethanol and hexane extracts of the product in 2013 was detected as 23521.0, 16881.0 and 3522.8 μg/g, respectively. On the other hand, the caffeic acid contents of the product of 2012 was found to be lower than those of 2013 (19100.0, 10416.0 and 2322.5 μg/g for ethyl acetate, ethanol and hexane extracts, respectively). Consequently, the findings have shown that propolis extracts possessed good antibiofilm activity against clinical staphylococci, and its phenolic composition has been affected by the year of collection. © 2016 ACG Publications. All rights reserved

Antimicrobial activity of leaf extracts of Bituminaria sp. genotypes at different growth stages

302-309Plants have secondary metabolites that play a role in defense mechanism are known to have effects on microorganisms. These metabolites and their amounts vary depending upon various factors. Here, we studied the antimicrobial effect of secondary metabolites of Bituminaria sp. genotypes and explored whether this effect changes with different growing stages of the plant. The results show that extracts obtained from 12 B. bituminosa genotypes were not significantly effective on Gram-negative bacteria but highly effective on Gram-positive bacteria and eukaryotic yeast. Of these genotypes, 9 and 12 genotype were more effective than the rest. Observations suggest that the extracts from the plants are more effective during the beginning of flowering stage than the growth and budding stages for the bacteria studied. It could be due to the differences in the nature of the metabolites and their quantity

Antimicrobial activity of leaf extracts of Bituminaria sp. genotypes at different growth stages

Plants have secondary metabolites that play a role in defense mechanism are known to have effects on microorganisms. These metabolites and their amounts vary depending upon various factors. Here, we studied the antimicrobial effect of secondary metabolites of Bituminaria sp. genotypes and explored whether this effect changes with different growing stages of the plant. The results show that extracts obtained from 12 B. bituminosa genotypes were not significantly effective on Gram-negative bacteria but highly effective on Gram-positive bacteria and eukaryotic yeast. Of these genotypes, 9 and 12 genotype were more effective than the rest. Observations suggest that the extracts from the plants are more effective during the beginning of flowering stage than the growth and budding stages for the bacteria studied. It could be due to the differences in the nature of the metabolites and their quantity

Effect of environmental factors on biological reduction of hexavalent chromium by Pseudomonas mendocina

In this study, the effects of pH, initial chromium concentrations, organic acids (alginic acid, galacturonic acid, glucuronic acid and citric acid) and their binary combinations on the bacterial chromium reduction were investigated. The results revealed that the Cr(VI) reduction for Pseudomonas mendocina was high at optimum pH value (6). The Cr(VI) reduction rate of P. mendocina decreased with the increase in initial chromium concentration. The Cr(VI) reduction ability of the bacterium increased in the presence of organic acids especially galactronic acid and glucuronic acid. Binary combinations of galactronic acid and glucuronic acid caused a dramatic increase in the rate of chromate reduction. Experiments with heat-inactivated cells indicated that biosorption onto cell material had a negligible impact for the loss of Cr(VI) from the solution. As a result of SDS-PAGE analysis, it was observed a protein band approximately 31 kDa in periplasmic extracts of P. mendocina cells

Reduction of Cr(VI) to Cr(III) by thermal Bacillus licheniformis B22 under different temperatures using binary and ternary combinations of organic acids

This study presents optimization of process variables for hexavalent chromium reduction using thermotolerant Bacillus licheniformis B22 isolated from Pamukkale (Denizli, Turkey). We examined the effects of binary and ternary combinations of different electron-donating substrates (galacturonic acid, glucuronic acid, and humic acid) at 45 and 50°C. The influence of different pH values (6.0, 7.0, 8.0, 9.0, and 10.0) and initial inoculation rates (2, 4, 6, and 8%) were also enumerated. The strongest stimulatory effect on Cr(VI) reduction was obtained with ternary combination of galacturonic acid, glucuronic acid, and humic acid. At 45 and 50°C, 8% inoculation rate, the reduction in ternary combination is relatively fast, completely reducing 100 mg/l Cr(VI) in 6 h compared with 2% inoculation rate (12 h). This bacterium exhibited a rapid Cr(VI) reduction ability under optimized conditions. Cr(VI) reduction of B. licheniformis B22 increased with an increase in initial inoculation rate, and the optimum initial pH for Cr(VI) reduction was 7.0. In addition, the results suggested that the reduced Cr(III) was not precipitated in the form of Cr(OH)3, and that organic acids significantly enhanced microbial Cr(VI) reduction rates by forming less toxic and highly soluble organo-Cr(III) complexes despite Cr(III) having very low solubility

Antimicrobial activity of extracts of some plants from Amasya (Turkey)

The study is to test in vitro the antimicrobial efficacy of chloroform extracts of 10 plant taxa from Turkey and four of them are endemic. The antimicrobial activity from the extracts of various plants was determined according to the disc diffusion method by using Escherichia coli ATCC 25213, Escherichia coli ATCC 35218, Klebsiella pneumoniae ATCC 27736, Proteus vulgaris RSKK 96026, Yersinia enterocolitica RSKK 1501, Salmonella enteritidis RSKK 171, Pseudomonas aeruginosa NRLL B-23, Proteus vulgaris RSKK 96026, Listeria monocytogenes Li6, Staphylococcus aureus ATCC 25923, S. aureus Cowan I, Bacillus cereus RSKK 863, B. subtilis ATCC 6633, Candida albicans ATCC 10231 and C. tropicalis (clinical isolate). 10 extracts showed antibacterial activity against all test bacteria. Four plants namely Phlomis pungens var. pungens, P. pungens var. hirta, P. armeniaca, Tanacetum argenteum subsp. canum var. canum, demonstrated broad spectrum anticandidal activity. It is shown that there is no anticandidal activity of Astragalus densifolius subsp. amasiensis, A. angustifolius subsp. angustifolius var. angustifolius, Achillea biebersteinii, A. setacea, A. teretifolia, A. phrygia. B. subtilis and B. cereus were the most sensitive bacteria to all plant extracts. On the contrary, P. aeruginosa were the most resistant microorganism

Characterization of extracellular polysaccharides (EPS) produced by thermal bacillus and determination of environmental conditions affecting exopolysaccharide production

In this study, the neutral monosaccharide composition of the Extracellular Polysaccharide (EPS), extracted from thermal Bacillus, was determined by Liquid Chromatography-Mass Spectrometry and High Performance Liquid Chromatography. Our analysis indicated that the EPS consisted of rhamnose, mannose, galactose, glucose, fructose, arabinose and xylose. In addition to the neutral sugars in the EPS, it also contained 230 mg protein/g EPS and 17.18 mg uronic acid /g EPS. The X-ray diffraction data indicated mainly of amorphous nature (80 %) and the presence of chitin, chitosan, protein and calcite. Thermogravimetric analysis curve showed that degradation of EPS takes place in three steps (13.38% at 500 °C) indicating moisture content and high content of carboxyl group, pyrolysis temperature and decomposition of calcite crystals, respectively. Additionally, laboratory batch experiments were performed characterize the effects of different natural organic acids, pH levels, temperatures and Cr(VI) concentrations on microbial EPS production by Bacillus licheniformis B22. Our results indicate that organic acids caused enhanced EPS release. Alginic acid was the most efficient organic acid at EPS production in B. licheniformis B22. The optimum pH level was 6.0-7.0 and the highest EPS production was observed at 50 °C for B. licheniformis B22. In addition, EPS production increased with increased chromium in the growth medium due to the toxic effect of Cr(VI) on cells. Maximum EPS production was observed when 150 mg/L Cr(VI) was added to the medium. © 2015, University of Tehran. All rights reserved

Phenolic profiles, antimicrobial and antioxidant activity of the various extracts of Crocus species in Anatolia

The phenolic profile and quantitative composition of methanol extracts of Crocus baytopiorum which was endemic species in Denizli, Turkey was detected by high performance liquid chromatography (HPLC-DAD). The HPLC analysis of phenolic compounds in methanol extract of C. baytopiorum showed that p-Coumaric acid, apigenin-glucoside, rosmarinic acid, quercetin and kampferol were present. Also, the methanol, ethyl acetate and hexane extracts from Crocus biflorus, C. baytopiorum and Crocus flavus subp. dissectus were investigated for their in vitro antimicrobial and antioxidant activities in the present study. Ethyl acetate and methanol extracts have demonstrated significant antimicrobial activities against tested micro organisms Escherichia coli ATCC 35218, Pseudomonas aeruginosa NRRL B-23, Klebsiella pneumoniae ATCC 27736, Yersinia enterecolitica RSKK 1501, Proteus vulgaris RSKK 96026, Bacillus cereus RSKK 863, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Micrococcus luteus NRRL B-4375 and Candida albicans (clinical isolate). The methanol extract of C. flavus subsp. dissectus had maximum activities on Yersinia enterocolitica RSKK 1501. Minimum inhibition concentrations of plant extracts have investigated on Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633 and Bacillus cereus RSKK 863. The Minimum inhibition concentration (MIC) of samples ranged from 0.10 to 20.48 mg/ml. In terms of radical scavenging activity and antioxidant activity, in the concentration of 2 mg/ml of methanol extract of C. flavus (92.67 and 89.32% respectively) displayed inhibition equal to in the concentration of 0.8 mg/ml butylated hydroxytoluene (BHA) used as standard antioxidant (91.45 and 89.78%, respectively). Positive correlations were found between total phenolic content in the Crocus extracts and their antioxidant activities. Thus, it is envisaged that Crocus species may have potential for acting as natural antioxidants