Antibacterial activity of Moringa oleifera methanolic leaves extracts against some Gram-positive and Gram-negative bacterial isolates

Abstract

Background: Moringa oleifera Lam. (Moringaceae) found to be very useful tree in tropical countries. In folklore and Ayurvedic all parts of the tree are used in different healing procedures for different diseases. The plant leaves are very good nutrient supplement for malnutrition and also used as an antibiotic. Methods: Phytochemical analysis of the leaf in solvents of varying polarity; viz., aqueous and methanol were also carried out. Results: The phytochemical screening indicated the presence of phenolics, flavonoids, tannins, glycosides etc. The antibacterial activity of Moringa oleifera leaf extracts against four microorganisms, viz. Escherichia coli, Shigella, Staphylococcus aureus and Streptococcus; the methanolic extract was active against E.coli, Shigella, Staphylococcus aureus whereas the aqueous extract exhibited an inhibitory effect on E. coli and Shigella only at different zone of inhibition levels of extracts. Well diffusion method was used to assess the antibacterial effect of the extracts on both Gram positive and Gram negative micro-organisms. Moreover, statically, the results were not significant at both 1% and 5% level of significances. It became obvious that, the higher reducing power of the aqueous extract could be due to the better solubility of the antioxidant components in water whereas the predominant antibacterial activity in organic solvent extracts as compared to aqueous extracts, indicated that the active components responsible for the bactericidal activity are more soluble in organic solvents. Conclusion: This study provided an evidence to support traditional medicinal uses of the plant.