Antimicrobial effects of Quercus ilex L. extract.

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

Evaluation of antimicrobial activities of Satureja hortensis L.

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 31 isolates of 1 yeast and 4 fungi species were tested by using disc diffusion assay. The results showed that hexane extract of Satureja hortensis had no antifungal, but antibacterial activity against four strains of three Bacillus species whereas methanol extract of Satureja hortensis had both anticandidal and antibacterial effects. It inhibited the growth of 23 strains of 11 bacterial species and 6 isolates of Candida albicans, at the concentration of 300microg/ml. Satureja hortensis did not show antimicrobial activity against the remaining microorganisms (83%) tested including most and all of the clinic and plant pathogenic microorganisms, respectively. Methanol extract showed stronger and broader spectrum of antimicrobial activity as compared to hexane extract.

Antimicrobial activity of aqueous and methanol extracts of Juniperus oxycedrus L.

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 strains belonging to 56 bacterial species, and 31 isolates of 5 fungi species were evaluated based on the inhibition zone using the disc-diffusion assay, minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC) values. The aqueous extract of J. oxycedrus had no antimicrobial effect against the test microorganisms whereas the methanol extract had inhibitory effects on the growth of 57 strains of 24 bacterial species in the genera of Acinetobacter, Bacillus, Brevundimonas, Brucella, Enterobacter, Escherichia, Micrococcus, Pseudomonas, Staphylococcus, and Xanthomonas. In addition 11 Candida albicans isolates at a concentration of 31.25-250 micro g/ml were also inhibited.