Antimicrobial activity of Moringa oleifera from different locations against some human pathogens

Medicinal herbs are moving from fringe to mainstream use with a greater number of people seeking for remedies and health approaches from side effects caused by synthetic chemicals. This has aggravated the search for antimicrobials from plants sources. In this study, aqueous extracts of Moringa oleifera samples from different areas of India were screened for antimicrobial activity against two yeast strains, three Gram positive and seven Gram negative bacteria by agar well diffusion assay. Optimal strategies for better antimicrobial activity was established by various methods. Comparison with standard antibiotics, minimum inhibitory concentration (MIC) and microbicidal properties for seeds coat, stem bark and pods’ husks (the best morphological parts of sample 1) were also determined. Most parts of the samples from Punjab region exhibited broad spectrum properties and were comparable with standard antibiotic. The MICs of seeds coat, stem bark and pods’ husks were organism specific and ranged from 0.5 – 1.25 mg/ml, 3.0 – 4.2 mg/ml and 4.0 5.6 mg/ml respectively. Both seeds’ coat and pods’ husks extracts exhibited microbicidal properties which were totally inhibited at 10 and 12 h respectively. Seeds’ coat extract was the most effective against E. coli at 0 hours, while some pathogens, treated with stem bark extract, exhibited regrowth again after 24 h apparently. Antimicrobial activity of seeds’ coat and pods’ husks is reported for the first time. The active constituents may be considered potential candidates for development of broad spectrum antimicrobial drugs.