Phytochemical Screening and Antibacterial Activity of Bitter Leaf (Vernonia amygdalina)

Herbal medicine is the oldest form of healthcare known to mankind. The study was aimed to determine the phytochemical constituents and antibacterial activity of Vernonia amygdalina leaf extracts against some bacteria associated with gastroenteritis. Five (5) different bacterial isolates associated with gastroenteritis namely; Klebsiella pneumoniae, Salmonella typhi, Shigella sp, Escherichia coli, and Staphylococcus aureus were obtained from Pathology Laboratory of Murtala Muhammad Hospital Kano. Phytochemical screening of the leaf extract was conducted to ascertain the presence and amount of bioactive components present in the leaves. The antimicrobial assay of the leaves extracts was performed by disc diffusion method. The qualitative and quantitative phytochemical screening of the extract indicated the presence of Alkaloid, terpenoid, flavonoids, steroid, phenol, saponin and tannin, with flavonoid being the most abundant constituent making about 12.2% followed by steroid, alkaloid and phenol constituting 4.8, 4.6 and 3.6% respectively. The result shows that the extracts were active against the microorganisms. The Methanol extract showed higher activity (12.2 mm) against the bacterial isolates than aqueous extracts (10.2 mm). Statistical analysis of the result shows no significant different on the activity of the extract against the test isolates at p<0.05. It is concluded that the application of V. amygdalina leaf in ethno medicine is justified.

Keywords: Antibacterial activity, bacteria, gastroenteritis, phytochemical, Vernonia amygdalina