PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL ACTIVITY OF METHANOL EXTRACTS AND FRACTIONS OF THE LEAF AND STEM BARK OF VITEX DONIANA SWEET (LAMIACEAE)

Aim: The objective of this study was to investigate the antimicrobial activity of leaves and stem bark of Vitex doniana Sweet (Lamiaceae) in vitro on clinical isolates of Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. Methods: Fresh dried leaves and stem bark of Vitex doniana were extracted by cold maceration which yielded a mucilaginous methanol extract. Fractionation of the crude extract was done with hexane, ethyl acetate, butanol and water in that order. Phytochemical analysis and lethality tests (LD50) were carried out using standard procedures. Antimicrobial activity of the extracts and fractions at 50, 100, 200 and 400 mg/ml were evaluated using the agar well diffusion method. Results: Phytochemical analysis revealed the presence of alkaloids, saponins, tannins, flavonoids, carbohydrates and steroids. Lethality was not observed in the mice even at 5000 mg/kg. Results showed significant (p < 0.05) antimicrobial activity as well as a broad spectrum activity. Conclusion: This study therefore supports claims by traditional health practitioners on the therapeutic use of Vitex doniana. Key words: Vitex doniana, antimicrobial, bacteriostatic, phytochemical, acute toxicity