Antimicrobial activities of different extracts of eight plant species from four different family against some pathogenic microoorganisms

In this paper, the antimicrobial activities of aqueous, ethanolic, ethyl acetate and hexane extract of eight plant species were studied. The extracts of Rosmarintis officinalis (L.) (leaves), Melissa officinalis (L.) (leaves), Urtica dioica (L.) (seed), Laurus nobilis (L.) (leaves), Lavandula officinalis (L.) (leaves), Lavandula stoechas (L.) (leaves), Teucrium chamaechys (L.) (leaves), Equisetum arvense (L.) (leaves) were tested in vitro against two Gram positive (Bacillus cereus (CCM 99), Staphylococcus aureus ATCC (6538P)), two Gram negative (Escherichia colt O157:H7 (RSSK 232), Klebsiella pneumoniac (CCM 2318) and Candida albicans (ATTC 10239) species and by the microdilution method. The results indicated that five of the eight plant showed antibacterial activity, namely L. nobilis, R. officinalis, E. arvense, L. officinalis and L. stoechas compared to standard antibiotics. Among the tested plants only aqueous extracts of L. nobilis showed anticandidal activity. While S. aureus was the most sensitive bacterium, B. cereus was the most resistant bacterium against tested plants. Tested plants all posses antimicrobial growth activities with MIC values ranging from 0.78 to 3.12 mg/mL. The tested extracts showed comparable with MIC values with standard antibiotics which ranged from 0.78 to 6.25 mg/mL. Thus, the extracts were as potent as standard antibiotics ininhibiting the growth of microbial strains.