Antioxidant activities and effect of ph and temperature on the antibacterial efficacy of stem bark extracts of trichilia heudelotii planc (harm)

This study evaluated the antioxidant and effect of pH and temperature on the antibacterial efficacy of the stem bark extracts (acetone and ethanol) of Trichilia heudelotii on some pathogenic bacteria using standard procedures. The percentage yields were 9.62±0.01% and 10.20±0.10% while the antioxidant activity of the plant extracts was concentration dependent with IC50 of 1.31±0.15 and 1.55±0.03 for ethanol and acetone extracts as compared to reference ascorbic acid (0.40±0.15). Antibacterial activity of the extracts demonstrated zones of inhibition ranging from 10.00±0.58 to 14.33±0.33 and 11.33±0.58 to 17.00±0.58 for the acetone and ethanol extracts at 50mg/ml respectively. Significant activity (p≤0.05) was recorded in the ethanol extract on Staphylococcus aureusATCC25923 (17.00±0.58mm), Streptococcus pyogenes (15.67±0.58mm) and Pseudomonas aeruginosa (15.67±0.58mm). The least activity was recorded on Salmonella typhi ATCC6339 (10.00±0.58mm) against acetone extract. Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, Salmonella typhi, Staphylococcus epidermidis and Pseudomonas aeruginosa were more sensitive to the extracts exhibiting a minimum inhibitory concentration (MIC) of between 5mg/ml to 15mg/ml of the extracts. The activity of the extracts was stable when subjected to temperature changes while significant activity was only recorded at pH3 of the extracts on the sensitive bacteria. The results obtained provide support for the use of T. heudelotii stem bark in traditional medicine while further research is required for the isolation and characterization of its bioactive compounds that may lead to the development of new antibacterial drugs.