Chemical composition of the essential oil of (Bartl.) Soják and (Velen.) Soják growing wild in Bulgaria, and PCA analysis of genus Mill.

Mill. genus, belonging to the Asteraceae family, includes more than 50 taxa, mainly growing in Central and Southern Europe, North Africa, Asia Minor, and the Caucasus. Previous investigations on taxa have shown that they are rich source of flavonoids and phenolic compounds but, differently from species of genus , almost devoid of sesquiterpene lactones. In the present study, the chemical composition of the essential oils from aerial parts of () and (), collected in Bulgaria, and not previously investigated, was evaluated by GC-MS. The main components of were -bergamotene (31.3%), ()-9,12,15-octadecatrien-1-ol (14.5%) and calarenepoxide (11.0%). Caryophyllene oxide (12.0%), together with -cadinol (10.9%) and spathulenol (8.8%), were recognized as the main constituent of EO. Furthermore, a complete review on the composition of all essential oils of the taxa studied so far has been inserted and cluster analysis (PCA) was carried out.