Antibacterial Activity of Three Medical Plant Extracts of Saudi Arabia on Isolated Bacteria

This study focuses the significant antibacterial activity of three medical plants ( Salvadora persica, Alluim sativum and Tamarix aphylla ) used in folk medicine in Saudi Arabia. The antibacterial activity of their ethanolic extracts were determined using the agar well diffusion technique. Two microorganisms were used, Gram positive Staphylococcus areus and Gram negative Escherichia coli , distilled water was used as the negative control. The result indicated that the ethanolic extracts of all tree plants exhibited antibacterial activity. The aqueous extract was not effective when compared to the ethanolic extract. The inhibition zone was higher against the Gram-negative bacteria than the Gram-positive bacteria. The antibacterial activity of the leaf extract of Salvadora persica demonstrated the highest activity (14 – 17 mm) compared to the other plant extracts. Minimum inhibitory concentration (MIC) values were also evaluated in this study. The MIC values obtained using the agar-dilution test ranged from 3.45 to 6.25 mg.ml -1 . Further research aimed at elucidating the chemical constituents of these species will likely open new avenues, including the development of drugs.