Phytochemical Screening and Antimicrobial Activity of Moringa oleifera Leaf Extracts Against Selected Bacterial Isolates in Kano, North West Nigeria

Moringa oleifera is widely cultivated across the dry savannah regions of North West Nigeria and has been employed in traditional medicine for the treatment of infectious diseases. This study evaluates the phytochemical composition and antimicrobial activity of aqueous and ethanolic leaf extracts of Moringa oleifera collected from Kano State. Standard phytochemical screening procedures were used to detect the presence of alkaloids, tannins, flavonoids, saponins, and terpenoids. Antimicrobial susceptibility testing was performed using the agar well diffusion method against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans isolated from clinical specimens obtained at Murtala Muhammad Specialist Hospital, Kano. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, and saponins in both extracts. The ethanolic extract demonstrated significantly higher antimicrobial activity compared to the aqueous extract, with the largest zones of inhibition recorded against S. aureus. MIC values ranged from 6.25 mg/mL to 25 mg/mL across tested organisms. These findings confirm the broad-spectrum antimicrobial potential of Moringa oleifera and support its continued use in community health management. The study recommends further isolation and characterisation of the bioactive constituents responsible for the observed activity. Keywords: Moringa oleifera, phytochemical screening, antimicrobial, Kano, minimum inhibitory concentration