Chemical Characterization and Chemotaxonomic Significance of Essential Oil Constituents of Grown in Two Different Agro-Climatic Conditions.

A comprehensive study on chemical characterization of essential oil (EO) constituents of a rarely explored plant species () of the Asteraceae family grown in Saudi Arabia and Jordan was carried out. Analyses were conducted employing gas chromatographic approaches such as GC-MS, GC-FID, and Co-GC, as well as RT, LRI determination, and database and literature comparisons, on two diverse stationary phase columns, which led to the identification of a total of 135 constituents from both EOs. Oxygenated sesquiterpenes were found to be the most predominant chemical class of Saudi EOs, in which -bisabolol (27.8%), -gurjunenepoxide (21.7%), (, )--farnesene (16.3%), and -spiroether (7.5%) were present as major components. In contrast, the most dominant chemical class of Jordanian oil was found to be sesquiterpene hydrocarbons, where (, )--farnesene (50.2%), -gurjunenepoxide (8.5%), ()--farnesene (8.1%), and (, )--farnesene (4.4%) were detected as chief constituents. It is interesting to mention here that Saudi and Jordanian EOs showed quite interesting chemical compositions and were found to have different chemotypes when compared to previously reported EO compositions.