Antibacterial activity and brine shrimp lethality of Vitex doniana sweet, stem bark extracts
The stem bark of Vitex doniana was extracted with n-hexane, chloroform, ethylacetate, acetone, ethanol and water sequentially using cold extraction method. The fractions were tested for antibacterial activity using disc agar diffusion technique and brine shrimp lethality followed by screening for secondary metabolites. All the fractions showed a remarkable activity against some respiratory tract pathogenic bacteria particularly the n-hexane and ethanol soluble fractions at 100 μg/disc, 300 μg/disc and 500 μg/disc concentrations. The Brine shrimp test showed highest toxicity in n-hexane and ethanol soluble fractions with LC50 values of 6.7674μg/ml and 5.3421μg/ml respectively. Phytochemical analysis of the fractions revealed the presence of alkaloids, steroids, cardiac glycosides, tannins, reducing sugars and flavonoids.