Comparative chemical analysis of volatile compounds of Echinops ilicifolius using hydrodistillation and headspace solid-phase microextraction and the antibacterial activities of its essential oil

The volatile compounds from various parts of Echinops ilicifolius (Compositae) such as flowers, leaves and roots obtained by hydrodistillation (HD) and headspace solid-phase microextraction (HS-SPME) methods were subsequently analysed by GC and GC/MS and compared. Thirty-seven and 20 components of the flower of E. ilicifolius were characterized, representing 99.7% and 100.0% of the total compositions using the HD and HS-SPME methods, respectively. The major constituents of the hydrodistilled oil were identified as linalool (58.6%), geraniol (17.4%), n-dodecane (10.9%) and nerol (5.4%), whereas HS-SPME extract was rich in n-octane (34.0%), n-decane (25.1%), p-cymene (11.1%), γ-terpinene (5.3%) and 1,8-cineole (5.1%). n-Hexadecanoic acid (32.3%), linalool (16.4%) and geraniol (8.3%) were the main components among 43 constituents identified in hydrodistilled extract of the leaf, representing 99.5% of the total components detected, whereas 16 compounds representing 99.9% of the HS-SPME meth...