Essential oil compositions of subspecies of Scutellaria brevibracteata Stapf from Turkey

The essential oils obtained by hydrodistillation from the aerial parts of three subspecies of Scutellaria brevibracteata (subsp. brevibracteata, subsp. subvelutina and subsp. pannosula) collected from their natural localities in Turkey were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), simultaneously. On the basis of chromatographic analysis and data analyzed, beta-caryophyllene (22.8%) and caryophyllene oxide (16.0%) were determined as the main components in S. brevibracteata subsp. brevibracteata oil. In S. brevibracteata subsp. subvelutina oil, beta-caryophyllene (28.3%), linalool (12.4%) and hexadecanoic acid (10.8%) were found as major constituents. beta-Caryophyllene (36.4%), alpha-cadinol (9.8%), delta-cadinene (7.0%) and linalool (5.3%) were identified as major components in the oil of S. brevibracteata subsp. pannosula. To the best of our knowledge, this is the ?rst report on the chemical composition of the essential oils of three subspecies of Scutellaria brevibracteata.