Antimicrobial activities of Moringa oleifera Lam leaf extracts

Plants have been reported to contain important preventative and curative compounds. Studies were conducted to determine the antimicrobial activities ofMoringa oleifera extracts using in vitro antimicrobial screening methods. The acetone extract of M. oleifera leaves at a concentration of 5 mg/ml showed antibacterial activities against Escherichia coli, Enterobacter cloace, Proteus vulgaris, Staphylococcus aureus and Micrococcus kristinae. M. kristinae was the most susceptible as its growth was inhibited at 0.5 mg/ml. On the other hand,M. oleifera acetone extract did not exhibit any inhibition on Streptococcus faecalis, Bacillus pumilus, Klebsiela pneumonia, Bacillus cereus andPseudomonas aeruginosa. The acetone extract was bactericidal on E. coli andM. kristinae. It was also bacteriostatic on S. aureus, E. cloace and P. vulgaris. However, the water extract showed no activity at the highest concentration (5 mg/ml) tested. Furthermore, both the acetone and aqueous extracts did not exhibit any antifungal activity against the fungal species of Candida albicans,Pennicillium notatum, Aspergillus flavus and Aspergillus niger even at the highest concentration of 10 mg/ml. The ability of acetone extract to inhibit the growth of some strains of bacteria is an indication of its antibacterial potential which may be employed in the management of microbial infections.   Key words: Antibacterial, antifungal, bacteriocidal, bacteriostatic, Gram positive.