Antibacterial activity of Jordanian medicinal plants

Abstract

The antibacterial activity of ethanol extracts of 15 plant species used in the traditional medicine in Jordan and other Middle East countries were tested. Extracts of certain parts of these plants were tested in vitro against 14 pathogenic bacterial species and strains using the agar diffusion method. Results evaluated as the diameter of inhibition zone of bacterial growth showed that 25 mg/well of 12 plant extracts have antibacterial activity on one or more of the tested bacteria. Three plants exhibited broad spectrum antibacterial activity: Punica granatum L., Quercus infectoria Olive., and Rhus coriaria L. The most susceptible bacteria were Pseudomonas aeruginosa, Bacillus cereus and Streptococcus pyogenes (ATCC 12351), and the most resistant species were Escherichia coli (ATCC 25922 and clinical isolates), Klebsiella pneumoniae, Shigella dysentriae (ATCC 49345), and Yersinia enterocolitica (ATCC 9610). The minimum inhibitory concentrations (MIC) of active extracts ranged from 4-32 mg/ml while the minimum bactericidal concentrations (MBC) were exerted at higher doses 8-62 mg/ml.