Evaluation of Antibacterial Activity and Preliminary Phytochemical Screening of Moringa oleifera on Pathogenic Bacteria

Abstract

The use of higher plants and their extracts to treat infections is an old practice in traditional African medicine. However, scientific research has shown that bioactive compounds in plants are valuable medically in the treatment of infections caused by pathogenic microorganisms. This research work is aimed to evaluate the antibacterial potential of Moringa oleifera extracts on standard microorganisms strains as well as multi-drug resistant strains of medical importance. Acetone, aqueous, ethanol and chloroform extracts of bark, leaves and seeds of Moringa oleifera were investigated for antibacterial activity against Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Methicillin resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Proteus mirabilis. The preliminary phytochemical screening and antibacterial assay were carried out using chemicals and agar well diffusion method respectively. The results of phytochemicals analysis revealed differences in the presence of alkaloids, reducing sugars, saponins and volatile oil in all the extracts. Tannins were present in the extract of leaves while terpenes were present in the extract of bark and leaves. Phlobatannins and flavonoids were absent in all the extracts. The antibacterial assay results showed that M. oleifera extracts exhibited broad spectrum activity against four to six bacteria isolates as indicated by the zone of inhibition ranging from 10 to 36mm with variation in the percentage sensitivity of 100%, = 100% and >100% depending on the plant part and solvent used. The minimum inhibitory concentration (MIC) and bactericidal concentration (MBC) ranged from 100mg/ml to 450mg/ml and 250mg/ml to 500mg/ml respectively against the isolates used. Standard antibiotic disc (Ofloxacin- 5?g) inhibited the growth of all the tested bacteria isolates except P. mirabilis . The results of this research work showed that M. oleifera has great potential as antibacterial compounds against Gram positive and Gram negative bacteria.