GC–MS analysis and antibacterial activities of Moringa oleifera leaf extracts on selected clinical bacterial isolates

Abstract Background Man has a long history of utilizing herbal preparations to treat infections. Therefore, this study aimed to investigate the quantitative phytochemical components, gas chromatography–mass spectrometry analysis, and the antibacterial properties of the aqueous and ethanol leaf extracts of Moringa oleifera on some clinical bacterial isolates. Results Aqueous and ethanol extractions from Moringa oleifera yielded 40.75% and 62.87%, respectively. Flavonoid (20.76 mg/100 g) was the highest, while saponin (2.00 mg/100 g) was the least of all phytochemicals detected. The proximate nutrient composition revealed that carbohydrate (46.59%) had the highest, while lipid (7.37%) was the least. Eleven compounds were detected in both extracts by gas chromatography–mass spectrometry. The eleven compounds identified had higher concentrations in the ethanol extract except 2-octenoic (26.09 mg/kg) acid and 1, 2-epoxyhexadecane (8.84 mg/kg) in aqueous extract which were considerably higher than 0.62 mg/kg and < 0.01 mg/kg in ethanol extract. The minimum inhibitory concentration and minimum bactericidal concentration were 6.25 mg/ml against the test organisms for ethanol extract. Conclusion The antibacterial activity of the ethanol extract was more active against the bacterial isolates than the aqueous, which increased as the extract concentration increases. The reports revealed that Moringa oleifera is an all-important herb that can inhibit infections from the studied pathogenic bacteria isolates.