Essential oil composition and phytochemical survey of Phlomis herba-venti, Phlomis persica Boiss. and Phlomis olivieri Benth. from Northwestern Iran

Different species of Phlomis are important for terpenoid compounds and anti-inflammatory and antioxidant flavonoids in their essential oils. In the present study, three species of Phlomis including Ph.  olivieri Benth, Ph. persica Boiss, and Ph. herba-venti were collected from the natural habitats located in Azarshahr (elevation 1671 m), Urmia (elev. 1598 m) and Tuyserkan (elev. 1598 m) at the full-flowering stage in June 2017. Then, their essential oil constituents and some phytochemical properties the extracts were evaluated. The essential oils were extracted by the hydro-distillation method (Clevenger apparatus). CG and CG-MS were used to analyze chemical constituents. Extraction was performed using an ultrasonic device and phytochemical indices were evaluated in terms of total phenol content, total flavonoid, and antioxidant activity (%DPPH). A total of 38 compounds were identified in the essential oils of three plant species, which among them, Diisooctyl phthalate (69.71%), γ-Elemene (7.93%), and Germacrene D (7.44%) in Phlomis olivieri Benth. and Nepetalactone (45.24%), Bis (2-ethylhexyl) phthalate (32.72%), and Germacrene D (5.59%) in Phlomis herba-venti were the main compounds. Diisooctyl phthalate (49.74%), t-muurolol (16.18%) and Hexahydrofarnesyl acetone (7.82%) were identified as major compounds of Ph. persica Boiss. Comparison of identified compounds among the three species showed a higher percentage of Diisooctyl phthalate (69.71%) in Ph. Olivieri. Also, the highest amount of total phenol (136.34 GAE/g DW), total flavonoid (49.29 mg Qu. g-1 DW) and antioxidant activity (68.48%) were related to Plomis persica Boiss.