Variation in the essential oil composition of Eremostachys laciniata from Jordan at different flowering stages.

Fresh aerial parts of Eremostachys laciniata Bunge growing wild in Jordan (Lamiaceae) were collected at different flowering stages. The essential oil contents of the fresh and the air-dried plants at the flowering stage were analyzed using gas chromatography-mass spectrometry (GC-MS). Results obtained indicated variability in the teipenoid content at the different flowering stages. Monoterpene hydrocarbons were the main group of all terpenoids during the pre-flowering, fresh flowering and air-dried-flowering stages (12.1%, 24.3% and 16.0%, respectively) and reached a minimum value at the post-flowering stage (2.5%) with limonene being the major compound in this fraction at all stages. Sesquiterpene hydrocarbons reached a maximum level at the fresh flowering stage (10.0%) with α-copaene (3.0%) as the major component during this stage. Oxygenated monoterpenes were detected in highest concentration after air-drying (14.4%), whereas the oxygenated sesquiterpene content reached 5.5% at the post-flowering stage. Linear hydrocarbons and their derivatives were the main contributors to the essential oil of E. laciniata during the different stages reaching a maximum level of 80.5% at the post-flowering stage. [ABSTRACT FROM AUTHOR]