Composition of essential oil compounds from different populations of Thymus caramanicus Jalas

Thymus caramanicus Jalas. (Lamiaceae) is an endemic herb growing wild in Iran. Essential oils from the aerial parts of T. caramanicus, at full flowering stage of seven locations in three provinces in Iran were obtained by hydrodistillation. The essential oils yield was 0.41-2.9% (w/w). About 97.9-99.9% of the total constituents were detected by gas chromatography and gas chromatography-mass spectroscopy analyses, of which oxygenated monoterpenes (87.5-97.5%) were the main group of the constituents in all populations. The main components of the essential oils were carvacrol (19.8-96.2%), thymol (0.6-61.8%), and p-cymene (0.2-8.2%). Therefore, the phenolic compounds, including carvacrol and thymol, were the most abundant constituents in the oils of all populations, which seem to play a significant role in the adaptation of this species to its environment that is characterized by dry hot climate and calcareous, stony soils.