Abstract

The leaf, stem and root bark of Vernonia amygdalina were subjected to phytochemical screening for the presence of alkaloids, saponins, cardiac glycosides, flavonoids, anthraquinones, steroids, polyphenols, and phlobatannins. The root bark possessed all the phytochemical components tested. Stem bark possessed all the phytochemical components except flavonoids, while the leaf lacks anthraquinones and polyphenols. The result showed no significant difference in the presence of the phytochemical components between leaves, stems and root bark (P>0.05). The V. amygdalina parts were screened for antibacterial activities at 100 mg/ml against Shigella sp., S. aureus, S. typhi, E. coli, P. mirabilis, K. pneumoniae and P. aeruginosa. All the isolates were susceptible to ethanolic extract of leaves in varying degree. The antibacterial activity of the leaves extract was significantly higher than those of stem and root bark (P<0.05). There was no significant difference in the antibacterial activity of both stem and root bark (P>0.05). The result further revealed the effectiveness of ethanolic extract over aqueous extract (P<0.01). The MIC of the ethanolic extract of V. amygdalina parts were particularly high for all the isolates (125 to 250 mg/ml), and were significantly higher than that of ciprofloxacin (P<0.01).

Key words: Phytochemical, antibacterial activity, Vernonia amygdalina.