In vitro Antimicrobial activity of Rosmarinus officinalis leave extracts

A B S T R A C T A study was performed in which petroleum ether, methanol and water extracts of Rosamarinus officinalis leaves in different concentrations (5, 12.5 and 25%) were evaluated for their possible antimicrobial activity against six standard pathogenic microorganisms, Staphylococcus aureus (gram-positive bacteria), Escherichia coli, Proteus vulgaris and Pseudomonas aeruginosa (gram-negative bacteria) in addition to the fungi Candida albicans and Aspergillus niger. The aqueous extract in different concentrations exhibited antimicrobial activity against all tested organisms (except Ps. aeruginosa at 5%) and that the activity is concentration –dependent. At all concentrations, the petroleum ether extract had no activity against S. aureus, P. aeruginosa and C. albicans but the growth of E. coli and Proteus vulgaris was not inhibited by 12.5 and 25% concentrations and A. niger by 25%. Except for C. albicans which was inhibited by all methnol extract concentrations, other organisms grew at 5% concentration and inhibited by 12.5 and 25%. Findings were compared to those produced by Gentamicin and Nystatin (10 µg), reference antibiotic and antifungal respectively..