Properties of essential oil of Salvia syriaca L. under different phenological stages and climatic conditions in Chaharmahal and Bakhtiari province

Since the quantity and quality of the active ingredients of medicinal plants are dependent on the genetic and environmental factors, this research was carried out in 2018 to investigate the effects of climatic changes and phenological stages on the quantity and quality of essential oils in Salvia syriaca L to introduce the most suitable phenological stage and region. The experimental design was randomized complete design in a factorial layout with 2 factors of phenological stages (vegetative, beginning of flowering, and full flowering stages) and regions (Shahrekord, Kouhrang, and Lordegan) with three replications. The essential oil content was determined by distilling tissues in Clevenger type apparatus. All the essential oil samples were injected into a GC–MS apparatus to determine their components. Results showed a significant effect of phenological stages and regions on the components of essential oils. The highest levels of essential oil compounds included Cis- Thujone (23.9-31.4%), Camphor (16.4-19.7%), Trans- Thujone (8.8-11.5%), and 1, 8-Cineole (8.43-12.1%). The results showed significant effects of phenological stages and regions on essential oil content and composition. The highest contents of essential oil were obtained from Kouhrang region and at beginning of flowering stage. The highest contents of volatile components such as α/β-Pinene (monoterpene hydrocarbons) and Caryophyllene (sesquiterpene hydrocarbons) were obtained at the beginning of flowering stage. In addition, the amounts of volatile components and monoterpene hydrocarbons such as α/β-Pinene and Limonene of essential oils decreased from Kouhrang (temperate climate) to Lordegan (tropical climate) while the percentage of sesquiterpene hydrocarbons such as Caryophyllene in the oils increased. To obtain more aromatic components of this plant, it is recommended to harvest plants in temperate climate and at the beginning of flowering stage.