Elahe Tasallot Maraghi - Department of Microbiology, School of Biology, College of Science, University of Tehran
AR Gohari - Medicinal Plants Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences
N Kashef - Department of Microbiology, School of Biology, College of Science, University of Tehran

Background and Objectives: Staphylococcus aureus is one of the common pathogenic agents that causes a variety of infections. Resistance against many antibiotics in this pathogen is on the rise. Therefore, search for new substances with antimicrobial activity have become an urgent necessity. Medicinal plants are frequently used in popular medicine as remedies for many infectious diseases. This study aimed to determine the in vitro antimicrobial activity of ethyl acetatic , methanolic and water- methanolic extracts from different parts ( root, aerial parts including leaf and stem , fruit, seed) of different plant species against S.aureus (ATCC25923). Materials and Methods:15 extracts from all the following plants: Ferulla oopoda (aerial parts), Peganum harmala (seed), Quercus brantii (fruit), Medicago sativa (aerial parts), Satureja mutica (root), were screened for their antimicrobial activity, using agar disc- diffusion and microbroth dilution assays. Results: Results demonstrated that these extracts had inhibitory effects at different concentrations (0.05, 0.1, 0.2 and 0.4 g/ml) against S.aureus (ATCC25923). The highest inhibitory zones were shown by methanolic extract of Peganum harmala (19.3 ± 1.1mm), followed by ethyl acetatic extract of Quercus brantii (19 ± 1 mm), ethyl acetatic extract of Ferulla oopoda (19 mm) and methanolic extract of Quercus brantii (16 ± 2 mm), methanolic extract of Ferulla oopoda (15), water methanolic of Quercus brantii (14). Quercus brantii showed a good antibacterial property in all of extracts including ethyl acetatic , methanolic and water- methanolic extracts. Also, all of the extracts were active against S.aureus with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 3.125 mg/ml for methanolic extacts of Quercus brantii and (MIC= MBC= 6.25 mg/ml) for methanolic extract of Peganum harmala and ethyl acetatic extract of Quercus brantii and (MIC=25, MBC=50 mg/ml) for ethyl acetatic extract of Ferulla oopoda Conclusion:Our results revealed that the extracts of the above mentioned plants could have antibacterial effect against S.aureus (ATCC25923).