Antibacterial activity of fruit and bark extracts of <i>Tamarindus indica</i> against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>

Abstract

The preliminary antibacterial activity of fruit and bark extracts of Tamarindus indica was evaluated against Escherichia coli and Staphylococcus aureus using agar well diffusion method. The bioactive components of the dried powdered plant parts were extracted using aqueous, ethanol and acetone solvents. The ethanol fruit extract of T. indica was found to be effective at different concentrations of 6.25mg/ml-100mg/ml, with mean zone of inhibition ranging between 6.0±2.5mm-20.0±4.5mm for S. aureus and 5.0±2.2mm-19.0±4.5mm for E. coli. Aqueous extract at 6.25mg/ml-100mg/ml concentrations, had mean zone of inhibition of 10.0±3.2mm-23.0±4.8mm for S. aureus and 9.0±3.0-20.0±4.5mm for E. coli. Acetone extract at 6.25mg/ml-100mg/ml concentrations, had mean zone of inhibition of 3.0±1.7-18.0±4.5mm for S. aureus and 3.0±1.7-9.0±3.0mm for E. coli. For the bark extract of T. indica, ethanol extract at 6,25mg/ml-100mg/ml concentrations, had a mean zone of inhibition ranging between 4.0±2.0-16±4.0mm for S. aureus and 1.0±1.0-9.0±3.0mm for E. coli. Aqueous extract at 6.25mg/ml-100mg/ml had mean zone of inhibition of 5.0±2.2-20±4.5mm for S. aureus and 2.0±1.4-6.0±2.4mm for E. coli. For the fruit, aqueous extract had MIC value of 12.5mg/ml and MBC value of 25mg/ml for both E. coli and S.aureus, ethanol extract had MIC value of 6.25mg/ml and MBC value of 12.5mg/ml for both E. coli and S. aureus, while acetone extract had MIC value of 6.25mg/ml and MBC value of 12.5mg/ml for E. coli and MIC value of 12.5mg/ml and MBC value of 25mg/ml for S. aureus. For the bark, aqueous extract had MIC value of 12.5mg/ml and MBC value of 25mg/ml for both E.coli and S. aureus. Ethanol extract had MIC value of 6.25mg/ml and MBC value of 12.5mg/ml for both E. coli and S. aureus. Acetone extract had MIC value of 12.5mg/ml and MBC value of 25mg/ml for both E. coli and S. aureus. The results support the use of the plant parts as therapeutic agents against diseases caused by E. coli and S. aureus.

Key words: Antibacterial Activity, Tamarindus indica, Escherichia coli, Staphylococcus aurues