Antibacterial Efficacy of Garcinia kola (Heckel) Seeds against Bacteria Involved in Throat Infections

Throat infections are common cause for visit to health care centres. This study is aimed at investigating the antibacterial efficacy of G. kola seeds against bacteria involved in throat infections. Twenty clinical and 4 typed bacterial isolates associated with throat infections were obtained. Extraction from G. kola seeds using ethanol, methanol, ethyl acetate, acetone, hot and cold water as extraction solvents was done. Phytochemical analyses of extracts, antibacterial efficacy, MIC and MBC of extracts on test isolates using ciprofloxacin as positive control and mechanisms of action of extract; were carried out. Ethyl acetate extract was most effective against Streptococcus pneumoniae with 29±0.58 mm zone of inhibition while hot water extract was the least with 6.00±0.58 mm against S. pyogenes. Ethyl acetate extract again showed the lowest MIC and MBC at 6.25 mg/ml and 12.5 mg/ml respectively against S. aureus. Time-kill kinetics of the extract also showed reduction in number of bacteria cells at 30 min intervals. The mechanism of action of ethyl acetate extract is attributed to cell wall disruption with highest leakages of Na+ and K+ in K. pneumoniae obtained at 350 Cmol/kg and 82 Cmol/kg respectively, while the highest leakage of proteins was obtained in S. aureus at 88.55±5.34 mg/ml. . These results conclude that the ethyl acetate extract of G. kola seeds is of best efficacy against the tested bacteria involved in throat infections.