Abstract

Anzaku Samuel*, Ngwai Yakubu Boyi, David Ishaleku and Igbawua Isaac Nyiayem

ABSTRACT

Plants have been used in treatment of diseases from time immemorial. This study evaluated the Antibacterial Activity Profile of crude leaf extracts of Acacia nilotica used for the treatment of human diarrhea in Nasarawa West, Nasarawa State, Nigeria. Leaf of the plant were collected, air-dried and powdered. The powdered material was extracted by cold maceration with water, ethyl-acetate, methanol and n-Hexane. The in vitro antibacterial activities of the crude extracts were evaluated against diarrhea-causing bacteria Escherichia coli, Salmonella paratyphi and Shigella dysenteriae by the agar diffusion, dilution, and time-kill assay methods. The percentage yield of the methanolic extract was highest at 30.37% while n-hexane was the least at 0.49%. The methanolic, n-hexane, and ethyl-acetate extracts showed antibacterial activity comparable to the standard antibiotic (ofloxacin) with inhibition zone diameter of 28.00 ± 2.00 mm against E. coli and S. paratyphi. Ethyl-acetate extract was inactive against S. dysenteriae. The minimum inhibitory concentrations (MICs) range from 1.56 - 12.50 mg/ml; and the minimum bactericidal concentrations (MBCs) range from 0.00 - 50.00mg/ml. At 1/2 x MIC, all the test bacteria grew well without inhibition or kill. At 1 x MIC, all the test bacteria were killed to various extent, with the highest killing effect (0.987 log10 reduction) on S. dysenteriae at 8h. At 2 x MIC, all the bacteria were killed the more, with greatest killing-effect (-0.425 log10 reduction) on S. paratyphi at 8h. The results have demonstrated the phytopharmaceutical potential of the leaf extracts of Acacia nilotica as a bactericidal agent.