Abstract

In vitro antibacterial activities of stem bark extract and fractions of Lannea barteri was investigated against four (4) reference bacterial strains including gram-positive and gram-negative bacteria. Powdered stem bark of L. barteri was extracted with methanol using cold maceration technique. A weight of 300 g of methanolic extract was obtained after extraction. Partitioning of the crude extract with hexane, ethyl acetate and n-butanol solvents gave three successive fractions, Hexane (0.1 g), ethyl acetate (4.46 g), n-butanol (4.83 g), respectively. Antibacterial activity of the extract and resultant fractions was performed by disk diffusion and broth microdilution with varying concentrations of 100, 50, 25 and 12.5 mg/ml. The crude extract, ethyl acetate and n-butanol fractions exhibited inhibitory action against the Gram-positive organisms at concentrations of 100, 50, 25 and 12.5 mg/ml with the exception of crude extract with no activity recorded against B. subtilis at concentration of 12 mg/ml, while hexane fraction exhibited inhibitory action against E coli at concentrations of 100 and 50 mg/ml with no activity recorded at 25 and 12.5 mg/ml for both gram-negative organisms tested, the crude extract possess activity on the gram positive only with highest zone of inhibition of 20 mm. The highest zone of inhibition recorded was 22 mm for the fractions and 40 mm for the standard drug used (ciprofloxacin). The results obtained from this research further justify the traditional claim on the wound healing activity of the stem-bark of L. barteri.