ABSTRACT

Antibacterial activities of aqueous and ethanolic extracts of different parts of Moringa oleifera plant were evaluated against some human bacteria pathogens. Plant parts were seed, leaf, leafstalk, stem and root while the bacteria pathogens were Escherichia coli. Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella species. Results obtained showed that the different phytochemical substances: alkaloid, saponin, tannin, flavanoid, phenol and others were present in all parts of the plant studied, although to varying levels. It was also found that the activity of the extracts varied with extracting solvents as well as with the test bacteria species. Statistically, the activities of the extracts were significantly different and their effects on the test organisms also significantly different, (P <0.05). The aqueous extract of the seed inhibited the growth of pathogens with inhibition zone diameters ranging from 6.33 ± 0.88mm (Escherichia coli) to 8.67 + 0.58mm (Salmonella). The ethanol extracts of seed had corresponding inhibition zone range of 7.00 ± 1.00mm (Pseudomonas aeruginosa) to 14.33 ±0.58mm (Staphylococcus aureus) .The aqueous extracts of the leaf caused inhibition zones with diameter range of 11.67 + 1.15mm (Pseudomonas aeruginosa) to 16.33± 1.53mm (Salmonella). However, the leaf extracts were found to be more potent against the pathogens showing inhibition zone diameters of 13.0mm to16.3mm in aqueous and 13.3mm to 18.0mm in ethanol extract, while leafstalk was the least, 5.7mm to 7.7mm (aq) and 7.3mm to 9.3mm (eth). Furthermore, the standard antibiotics were found to be significantly different, (P < 0.05) more active on the organisms than the extracts having caused inhibition zones range of 18.67 ± 0.58mm (Pseudomonas aeruginosa) to 21.67 ± 0.58mm (Salmonella). The potency of the extracts against the pathogens was attributed to the different phytochemical substances present in the plant parts