Antibacterial Activity of Tribulus Terrestris L. Against Escherichia Coli and Staphylococcus Aureus

Abstract

The experiment was performed on the plant Tribulus terrestris L. which was collected from Khobar region in Al Dhale’ Governorate, Republic of Yemen on March. The extracts used (aqueous and methanol) were prepared in Lab of Pharmacognosy, Faculty of Pharmacy – Aden University. The experiment was done on two types of bacteria, one Gram negative (Escherichia coli) and one Gram positive (Staphylococcus aureus). The antimicrobial part of the experiment was carried out in the Microbiology Lab - University of Science and Technology, Aden, Yemen. The experiment was performed in triplicates, and using three factors (Type of solvent, Time and Concentrations). The results obtained were the following: The best solvent for extracting antibacterial substances was methanol in both bacteria (E. coli and S. aureus). The concentrations that produced the highest inhibition zones in E. coli were 600 and 800 mg/ml using well method, while in S. aureus the best concentrations were 400 and 600 mg /ml. The best result was obtained after 72 h using disk method on S. aureus, and using well method on E. coli. Interaction between concentrations and type of solvent showed that the best result was obtained by methanol extract using disk method at 200 mg/ml against E. coli, while the best result against S. aureus was obtained by methanol extract using disk method at 800 mg/ml. Interaction between different times and type of solvent indicated that the best result against E. coli was observed after 72h by aqueous extract using well method, while the best result against S. aureus was observed after 72h by methanol extract using disk method. Interaction between concentrations and different times showed that the best result was obtained after 72h at concentration 800mg/ml using well method against E. coli, while the best result against S. aureus was after 72h at concentration 400mg/ml using disk method. Interaction between type of solvent, concentrations and different times indicated that the best result in E. coli was observed after 72h by methanol extract at 200mg/ml using disk method, while the best result in S. aureus was observed after 72h by aqueous extract at 600mg/ml using disk method.