Abstract
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 terpenoid 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 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.