Essential oil composition of two Scutellaria species from Iran

Objective: Medicinal plants Scutellaria multicaulis and Scutellaria bornmuelleri belong to the Scutellaria genus and Lamiaceae family, and are widely used in traditional Iranian medicine. This study aims to characterize promising bioactive phytochemicals found in the aerial parts of S. multicaulis and S. bornmuelleri.Methods: Accordingly, volatile oils were obtained by hydrodistillation of S. multicaulis and S.bornmuelleri leaves and stems, and then analyzed by gas chromatographyemass spectrometry(GC/MS).Results: A total of 88 components, representing 92.4% of the oil(oil yield determined to be0.53%, v/w), were identified in the essential oils of S. multicaulis. The main group was sesquiterpene hydrocarbons(24%), with a-himachalene(7.2%), a-longipinene(6.8%), and a-copaene(3.2%) as the main components. A total of 89 chemicals, representing 83.2% of the essential oil(oil yield determined to be 0.31%, v/w), were detected in the essential oil of S. bornmuelleri.The main components were steroids, such as 14-b-H-pregna(32.9%), hydrocarbons(22.5%),sesquiterpenes(11.4%), and monoterpenes(4.6%), which were considered minor constituents.The contents of sesquiterpene and monoterpene hydrocarbons present in S. multicaulis and S.bornmuelleri were 24% and 7.1%, respectively. However, the contribution of oxygenated monoterpenes(4%) and sesquiterpenes(4.3%) in both species was less than 5%.Conclusion: As the first report on the chemical composition of S. multicaulis and S. bornmuelleri, this study showed that the major compounds were steroids and sesquiterpenes.