Phytochemical and antibacterial investigations of moringa (Moringa oleifera) leaf extract on selected bacterial pathogens

This study aimed at evaluating the health benefits of popular Moringa oleifera leaf. The aqueous and methanolic extracts of the leaf at two different concentrations (1:1 and 1:2) was used to determine the phytochemical screening and its antibacterial activity. Escherichia coli, Streptococcus pneumonia and Staphlococcus aureus were used in this study, applying agar diffusion methods. The phytochemical screening indicated presence of secondary metabolites such as alkaloid, flavonoids, anthraquinoines, tannins and phenol in both extracts making it to have antibacterial potentials. Both extract showed remarkable activity against the growth of the selected bacteria; nevertheless, the methanol extract had more antibacterial activity than the water extract, more so the extracts were discovered to be more active at higher concentration. The water extract was not active at low concentration, that is 1:1 but had diameter zone of inhibition of 10 mm each for 1:2 concentration. The minimum inhibition concentration (MIC) that inhibits these bacterial ranged between 1:4 and 1:16 and the minimum bactericidal concentration (MBC) that kills the growth of the bacterial isolates completely was 1:16. The result of this study showed that M. oleifera could be a valuable antibacterial drug in the treatment of infections caused by the test organisms. Key words: Agar diffusion method, aqueous and methanol extracts, secondary metabolites, zone of inhibition, minimum inhibition concentration (MIC), minimum bactericidal concentration (MBC).