ANTIMICROBIAL ACTIVITY OF MICROMERIA-NERVOSA FROM THE PALESTINIAN AREA

Organic and aqueous solvent extracts and fractions of Micromeria nervo sa (Desf.) Benth. (Labiatae) were investigated for antimicrobial activ ities on several microorganisms including bacteria and yeast. The diff erent extracts differed significantly in their antimicrobial activitie s with the ethanolic extract being most active, followed by ethyl acet ate and petroleum ether extracts. The least active extract was the aqu eous. No significant difference between the different test microorgani sms in their susceptibility to different extracts, with Candida albica ns being the most susceptible to ethanolic extract giving 1.5 times th e effect of nystatin. One of the main active ingredients of M. nervosa was isolated and identified as carvacrol. No significant difference i n antimicrobial activity was found between carvacrol and its isomer th ymol. The most susceptible test microorganism was Proteus vulgaris to carvacrol, and P. vulgar is and C. albicans to thymol. The least susce ptible bacterium to both fractions was Pseudomonas aeruginosa. Minimum inhibitory concentration (MIG) and minimum bactericidal or fungicidal concentrations (MBC or MFC) were determined for both compounds. (C) 1 997 Elsevier Science Ireland Ltd.