Essential Oil Polymorphism of Hungarian Common Thyme (Thymus Glabrescens Willd.) Populations

Abstract

The volatile oil compositions of Thymus glabrescens Willd. from eight different localities of Hungary were analyzed by GC/MS. Significant essential oil polymorphism was found: eight new chemovarieties may have been determined, representing a way of adaptation to the different habitat conditions. The main volatile compounds of chemotype 1 (Csesznek) were thymol (34.2%), γ-terpinene (26.2%) and p-cymene (16.4%). In the case of chemotype 2 (Várpalota), germacrene D (55.4%) and β-caryophyllene (14.8%) were identified as chief constituents. Chemotype 3 (Szentbékkálla) contained thymol (32.9%), β-caryophyllene (16.5%) and germacrene D (17.6%), while chemotype 4 (Várvölgy) accumulated α-cubebene (50.9%) and β-caryophyllene (22.9%) as the main volatiles. The oil of chemotype 5 (Várgesztes) can be characterized by geraniol (49.0%) and germacrene D (13.6%), while that of chemotype 6 (Tardosbánya) consisted of p-cymene (45.0%), geraniol (13.6%) and linalyl acetate (9.9%). In the oil of chemotype 7 (Salgó Hill), thymol (14.4%), germacrone (12.1%) and geraniol (10.8%) were found in higher percentages, while chemotype 8 (Pásztó) produced thymol (29.3%) and germacrene D (14.2%) as its main essential oil compounds. The existence of thymol chemotypes in the case of T. glabrescens is new for the literature.