Essential oil composition of Turkish mountain tea (Sideritis spp.)

The essential oil components of aerial parts from Sideritis bilgerana, Sideritis tmolea and Sideritis congesta were investigated by GC and GC–MS. The oil yields of dried plants obtained by hydro-distillation were 0.26, 0.33 and 0.83 (v/w), respectively. Fifty compounds representing 94.6% of the S. bilgerana oil were identified. The main ones were β-pinene (51.2%) and α-pinene (30.2%). Thirty-six components, representing 79.7% of the S. congesta oil were determined with high contents of muurol-5-en-4-a-ol (11.7%) and muurol-5-en-4-b-ol (33.0%). Fourty-four components were identified accounting for 89.6% of the S. tmolea oil. Major constituents were α-cadinol (21.9%), β-caryophylene (10.6%), calamenene (7.05%), muurrol-5-en-4-b-ol (7.05%) and α-pinene (5.1%). All oils consist of monoterpenic hydrocarbons, oxygenated monoterpenes and sesquiterpenes. Muurol-5-en-4a-ol and muurol-5-en-4b-ol, at high percentages, were distinct components of S. congesta.