Antibacterial and Toxicity Evaluation of Stem Bark Extract of Kigelia Africana (Lam.) Benth

Abstract

The study was to investigate antibacterial and toxicity evaluation of methanolic stem bark extracts of Kigelia africana (SBEKa). The antibacterial activities of the extracts were determined against one Gram-positive (Staphylococcus aureus) and three Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella spp). Distilled water was used as negative control and ciprofloxacin was used as a positive control. The SBEKa showed remarkable activity against various bacterial strains as compared to positive control. S. aureus and Salmonella spp were proved as highly sensitive strains while E. coli and pseudomonas were the resistant strain as the extracts formed no inhibition zone against it. These studies determine the phytochemical constituents as well as acute toxicity and sub-chronic toxicity test on plant stem bark. The acute toxicity was evaluated in rats according to the guideline of Organization for Economic and Cultural Development (OECD). The level chosen is the one for which we can expect to see mortality among treated animals. The animals were daily observed for 28 days after treatment and no mortality was observed. The animals were sacrificed. The results showed that the LD50 by oral route in rats was greater than 5000 mg/kg body weight. The extracts were found to contain alkaloids, Saponins, Flavonoids, Anthraquinones, and steroids were present in high amount while Glycosides in moderate amount. Tannins, Cardiac glycosides and Balsams were present in trace amount, while volatile oils were totally absent. At lower concentration SBEKa exhibited antimicrobial and these may justify the medicinal uses of the plants for treatment of microbial infections.