An-Najah Staff

The aim of the present study was to evaluate the antimi-crobial potential of aqueous and ethanol extracts of Thym-bra spicata L. (Lamiaceae), Nepeta curviflora Boiss. and Paronychia argentea Lam. (Caryophyllaceae) against six Gram negative bacteria and one Gram positive bacterium. Agar well diffusion method was adopted to examine the antimicrobial activity of all plant extracts being studied. Out of the seven bacterial isolates, a clinical isolate of Proteus mirabilis (II) was the most susceptible one for all the examined plant extracts except for N. curviflora etha-nol extract. Moreover, the ethanol extract of P. argentea exhibited the highest antimicrobial potential against most of the tested bacteria except for Klebsiella pneumoniae and Escherichia coli. On the other hand, all investigated ethanol plant extracts displayed antibacterial effect against the other clinical isolate of Proteus mirabilis (I), which showed resistance against the broad spectrum antibiotic Gentamycin. Further more, micro-broth dilution method was used to measure the minimum inhibitory concentra-tion (MIC) of the effective plant extracts. The examined ethanol plant extracts demonstrated higher MIC values than the aqueous extracts ranging from 1.56 to 50 mg/ml. Accordingly, the obtained results form the platform for further phytochemical and pharmacological studies which are invited to purify and characterize the active ingredient (s) of the studied plant species by the future focus on their extracts fractionation in hope of identifying the active components.

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