Essential Oil Diversity among Stachys laxa Boiss. & Buhse Populations in North of Iran

Stachys laxa, a member of the Lamiaceae family, is a medicinal and aromatic that found in semi-cold and Mediterranean regions of northern Iran. The essential oil composition of Iranian populations of Stachys laxa were evaluated in this study. The 16 populations of Stachys laxa were collected from North of Iran. The essential oils were extracted by hydrodistillation using Clevenger type and were analyzed by GC and GC/MS. Based on the essential oils analysis, 37 different chemical compounds were identified in this study within the sixteen populations of S. laxa. The results revealed that distinct differences in the content of compounds depending on region of sample collection. The main constituents of the identified essential oils were β-Elemene (1.1-18.7%), trans-Caryophyllene (0-13.2%), Germacrene D (1.1-46.6%), and Caryophyllene oxide from (0.3-32.3%). According to the GC/MS results, some components such as Germacrene A, Spathulenol, Germacrene D, and α-cadinol were the effective components to separate different populations of S. laxa. In general, the lowest and highest content of germacrene D was founded from 1.1 to 46.6% in the population of Kiasar (KSR), and Chalus (CHL), respectively. The S. laxa populations had high diversity in term of essential oil components, which could be considered in future studies.