Abstract:
This study has been done to evaluate the synergistic effects of the methanol extracts of Jatropha curcas root and ampicillin on Staphylococcus aureus and Escherichia coli. The antimicrobial assay of the plant extracts has been reported. The interaction studies were carried out using the chequerboard dilution technique. The results of triplicate analysis demonstrate that the root extract alone showed reasonable activity against the tested organisms even at lower concentrations of 3.125 mg/ml. The inhibition zone diameters were in the range of 4.93 to 13.10 mm for Staphylococcus aureus and 3.03 to 10 mm for Escherichia coli while the minimum inhibitory concentrations (MICs) were 2.06 mg/ml and 3.40 mg/ml respectively. The chequerboard dilution technique revealed good interactions between combinations of plant extract and ampicillin against S. aureus but yielded poor results against E.coli. The extract in combination with ampicillin in the ratios of 1:1, 1:4, 2:3 and 3:7 showed synergistic effects and indicated higher zones of growth inhibition for Staphylococcus aureus with higher values of 21.25 mm, 23.00 mm, 25.20 mm and 28.00 mm respectively.
