Chemotaxonomic importance of the essential-oil composition in two subspecies of Teucrium stocksianum Boiss. from Iran.

The hydrodistilled essential oils obtained from aerial flowering parts of Teucrium stocksianum ssp. stocksianum (TSS) and T. stocksianum ssp. gabrielae (TSG) from Iran were analyzed by capillary GC and GC/MS. The oil analysis of two subspecies led to the identification of 65 compounds that accounted for 93.3 and 95.1% of the total oil compositions, respectively. Sesquiterpenoids (52.9%) constituted the main compounds in the essential oil of TSS represented mainly by cis-sesquisabinene hydrate (12.0%), followed by epi-β-bisabolol (6.6%), guaiol (5.4%), and β-eudesmol (4.4%), whilst monoterpenoids (61.2%) were found to be the major components of the oil of TSG, represented by α-pinene (23.0%), β-pinene (13.0%), myrcene (6.3%), and sabinene (6.3%). The principal component in both subspecies, TSS and TSG, was α-pinene (22.0 and 23.0%, resp.) and β-pinene (6.5 and 13.0%, resp.). epi-α-Cadinol, myrcene, and sabinene, which were detected as principal compounds of TSG, were characterized in lower amounts (<1.5%) in the oil of TSS. Seven components were identified in the oil of TSS corresponding to 25.9% of total oil, which were totally absent in the oil of TSG, of which cis-sesquisabinene hydrate (12.0%), guaiol (5.4%), and β-eudesmol (4.4%) were in considerable amounts. Taxonomic position of the subspecies is discussed on the basis of phytochemical data.
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