keywords: Aqueous extract, Garcinia kola, methanol extract, MIC, MBC, sensitivity
Garcinia kola is a plant of Western and Central African origin and has been found to be medicinally important. Antibacterial activity of aqueous and methanol extracts of the plant was conducted against Isolates of Klebsiella pneumoniae, Shigella species and Salmonella typhi. The seed extracts were prepared by soaking 35 g of powdered seeds in 135 ml of methanol and 21 g in 100 ml of sterile distilled water and processing to produce 1.40, 0.70 and 0.35 mg/ml for aqueous and 2.50, 1.25 and 0.625 mg/ml for methanolic extract. Well diffusion method was used to test extracts against organisms and minimum inhibitory concentration (MIC) was obtained from turbidimetry. The test organisms were found to be more susceptible to methanol extract than the aqueous extract; methanol extract showed antibacterial activity only against K. pneumoniae and Shigella species but was ineffective against S. typhi. The MIC of aqueous extract of G. kola seeds onall the test organisms was 1.40 mg/ml. The MIC of methanol extract was found to be at 1.25 mg/ml for K. pneumoniae and Shigella species. The minimum bactericidal concentrations (MBC) of both aqueous and methanol seed extracts in the test organisms were also examined. Methanol extract showed bactericidal effects on K. pneumoniae and Shigella species at the same concentration of 2.5 mg/ml. Therefore, the extracts found to be effective to the test organisms should be considered by pharmaceutical industry for the production of antibacterial agents for the treatment of diseases caused by the test organisms and other enteric species.