Chemical Composition and Antimicrobial Activity of the Volatile Oils from Leaf, Flower, Stem and Root of Thymus transcaucasicus from Iran

The volatile constituents from leaf, flower, stem and root of Thymus transcaucasicus Ronniger, growing in Iran, were obtained by hydrodistillation and analyzed by GC and GC-MS. The leaf oil was characterized by high amounts of thymol (35.83 %), alpha-terpineol (12.38 %), geraniol (10.79 %) and p-cymene (5.98 %). Thirty-six constituents representing 99.75 % of the flower oil were identified of which thymol (62.92 %), p-cymene (5.78 %), geraniol (5.58 %) and carvacrol (4.14 %) were major components. The main components of the root oil were thymol (60.61 %), p-cymene (9.32 %), carvacrol (4.61 %), pentacosane (3.17 %) and 1.8-cineole (3.08 %). Thymol (46.07 %) and geraniol (9.20 %) predominated in the stem oil. The antimicrobial effects of leaf, flower, stem and root essential oils from T. transcaucasicus were determined by measurement of the growth inhibitory zone, against seven Gram-positive and Gram-negative bacteria and two fungi using the disc diffusion method.