Effects of Phenological Stage and Elevation on Phytochemical Characteristics of Essential Oil of Teucrium polium L. and Teucrium orientale L.

This study aimed to evaluate effects of elevation and phenological stage on essential oil components of Teucrium polium L. and Teucrium orientale L. belonging to the Lamiaceae family. The aerial parts of the grown plants in two ranges of elevation including 2000-2500 and 2500-3000 m above sea level were harvested at three time-points, including end of vegetative, flowering, and seed filling stages. The main components in the T. polium oil were α-pinene (40.52 to 54.05%), β-pinene (17.36 to 23.3%), and limonene (10.10 to 15.19%) and the major constituents in the essential oil of T. orientale were α-pinene (0.00 to 25.10%), and β-caryophyllene (18.18 to 56.01%). Analysis of results confirmed the significant effects of phenological stage and elevation on the percentages of essential oil components. High elevation above sea level caused increase in aromatic compounds such as α-pinene and limonene from monoterpene hydrocarbons but decrease in sesquiterpene compounds such as β-caryophyllene contents. There was significant correlation between essential oil constituents under different elevations and phenological stages. In addition, harvesting time at different phenological stages affected the chemical compositions in the essential oils, in a way that the highest concentrations of α-pinene and β-pinene as volatile components (monoterpene hydrocarbons) and β-caryophyllene (sesquiterpene hydrocarbons) as important constitutes in pharmaceutical industry were obtained from flowering stage.