Bacterial susceptibility to and chemical composition of essential oils from Thymus kotschyanus and Thymus persicus.
Susceptibility of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia, and Pseudomonas aeroginosa to the essential oils extracted from two varieties of Thyme, i.e., Thymus kotschyanus Boiss. and Hohen. and Thymus persicus L. at preflowering and flowering stages were studied. The disk diffusion method was used to evaluate the zone of microbial growth inhibition at various concentrations of the oils. Minimal inhibitory concentration and minimal bactericidal concentration of the oils were determined and compared with each other. The oils from the above plants were found to be strongly bactericidal with that of T. kotschyanus being more effective. T. kotschyanusand T. persicus oils analyzed by gas chromatography (GC) and GC/mass spectrometry (MS) lead to identification of 33 and 26 components, respectively. The profile of the oil components from T. persicuswas similar to that of T. kotschyanus in almost all of the compounds but at different concentrations. The major components of T. kotschyanus oil before and at the flowering stages were carvacrol (35.06, 22.75%), thymol (26.60, 16.52%), gamma-terpinene (7.81, 0.34%), gamma-terpinene (4.34, 0%), borneol (2.29, 4.52%), myrcene (0.26, 12.65%), thymolquinone (0, 11.39%), nerol (0, 6.10%), and beta-caryophyllene (0, 5.54%), respectively, and those of T. persicus at the same stages were carvacrol (38.96, 27.07%), thymol (6.48, 11.86%), P-cymene (7.51, 10.16%), gamma-terpineol (0, 9.51%), nerol (15.66, 9.41%), gamma-terpinene (6.11, 6.51%), and thymol acetate (5.29, 5.30%), respectively. The contribution of oil components to its antibacterial property is discussed. High aromatic compound content of the phenol-rich oils seems to account for strong antibacterial activity.
Rasooli
Iraj
I
Department of Biology, College of Basic Sciences, Shahed University, Vali Asr-Taleqani Cross, Tehran-15987, I.R. Iran. irasooli@yahoo.com
Mirmostafa
Seyed Akbar
SA
D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects; D007711:Klebsiella pneumoniae / Q000187:drug effects; D019686:Lamiaceae / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D009822:Oils, Volatile; D010938:Plant Oils