Exploitation of Phytochemical Extracts of Moringa oleifera as Antimicrobial Agent against Human Pathogenic Bacteria

The rapid rise of antimicrobial resistance to commercially available antibiotics has led researchers to search for an alternative drug source. Medicinal plants pose as a potential source of natural antimicrobial drugs that compact drug resistant microorganisms. The qualitative phytochemical analysis of M. oleifera leaves and flowers extracts led to the identification of an important pharmacological bioactive natural compounds. The antibacterial activity of leaves and flowers extract were determined using agar disc diffusion method and MIC assay against selected human pathogens. The ethanolic and methanolic leaves and flowers extracts yielded 19.5%, 24.38%, 15.62% and 18.02% respectively. Leaves and flowers extracts were active against bacterial strains in a dose dependent manner. The ethanolic leaves extract (100 mg/mL) possessed potential antibacterial activity against the two tested Gram-negative bacteria: E. coli, A. baumannii and three Gram-positive bacteria: Staphylococcus aureus, S. saprophyticus and E. Faecalis by producing 20.00±0.50, 20.67±0.84, 15.33±1.04, 20.43±0.63, 25.83±0.76 mm zone of growth inhibition respectively compared to the control. However, methanolic leaves extract exhibited considerable inhibitory efficacy against two bacterial strains A. baumannii and S. saprophyticus with 17.17±0.59 and 15.81±0.62 respectively. The tested strains were highly sensitive to 200 mg/mL where the highest zone of inhibition was 30.29±0.92 mm observed against E. faecalis, and the lowest zone of inhibition was against Staphylococcus aureus with 20.33±1.04 mm. Both ethanolic and methanolic extracts showed antimicrobial efficacy more than that exhibited by ethanolic and methanolic flowers extracts. Ethanolic and methanolic leaves extracts had MIC of 200 mg/mL against all tested strains where ethanolic leaves extract showed MIC of 100 mg/mL against three strains, E. coli, A. baumannii and S. saprophyticus. This study suggests that the extracts of M. oleifera can be used to discover antibacterial agent for developing new pharmaceuticals against human pathogens.