Study on quantitative and qualitative changes in essential oil compounds of Teucrium polium L. subsp. polium at different phenological stages

Teucrium polium L. belongs to the fam. Lamiaceae and grows mostly in the barren, rocky, and sandy areas of various parts of Europe, the Mediterranean, North Africa, and southwest Asia including Iran. It has various therapeutic properties such as analgesic, antipyretic, antioxidant, and antihypertensive. These healing properties are due to the presence of various chemical compounds in the essential oil. Plant harvest at the different phenological stages has a great impact on the amount of essential oil compounds of this species. This study was conducted to evaluate the quantitative and qualitative changes of T. polium essential oil (EO) during the growing season in Cheshmeh-e-Anjir rangelands of Fars province and at three phenological stages (vegetative peak, beginning of flowering, and flowering peak) in a completely randomized block design in 2017. The EOs were analyzed by GC and GC/MS. The results of this study showed that the main EO constituents were caryophyllene oxide (12.1%), α-pinene (11.8%), germacrene D (9.1%), myrcene (8.5%), limonene (7.2%), β-pinene (6.7%), bicyclogermacrene (6.6%), E-caryophyllene (4.6%), and α-bisabolol oxide B (3.4%) at the vegetative peak stage with the EO percentage of 0.9%, germacrene A (26.6%), bicyclogermacrene (18.3%), (E)-β-ocimene (8.9%), myrcene (7.8%), spathulenol (6.0%), limonene (5.3%), α-pinene (3.6%), and β-pinene (2.6%) at the begining of flowering with the EO percentage of 0.3%, and α-pinene (25.8%), myrcene (12.5%), germacrene D (11.8%), β-pinene (11.7%), limonene (8.5%), spathulenol (4.6%), and bicyclogermacrene (7.2%) at the flowering peak with the EO percentage of 0.2%.