Composition and antimicrobial activity of the essential oil ofMicromeria cristata andMicromeria juliana

The chemical composition of the essential oil of Micromeria cristata and Micromeria juliana was determined by GC-MS analysis. Among the 36 identified compounds of the M. cristata essential oil, isoborneol (11.3%), borneol (8.5%), verbenone (8.2%), 10-epi-α-cadinol and thujan-3-ol, were found to be major components. The main constituents of the M. juliana oil were verbenol (11.8%), thymol (10.8%), caryophyllene oxide (10.5%), borneol (9.3%) and myrtenal (7.1%). The in-vitro antimicrobial activity of the ethanolic solution of the essential oils was investigated by the disk diffusion method with ampicillin as the standard antibiotic against six microorganisms (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella enteritidis and Aspergillus niger). At 1:20 dilution the activity of both oils was moderate while at 1:40 dilution the oils showed weak or no activity.