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.

Variability of Phenolic Compounds of Four Aromatic Lamiaceae Species in Consequence of Different Water Supply

“…Unfortunately, the experimental conditions of these studies are hardly comparable with the present ones. Nevertheless, to some extent, our mentioned results do not seem to be in full harmony with the fact that in the practice peppermint is considered as specifically water demanding species not advised to cultivate without irrigation [Hoppe 2013] and thyme, on the contrary, is a well-known xerophyte [Pluhár et al 2008]. It may reflect a largely different adaptability potential of the target species.…”

“…Beside the main constituents of the essential oil, thymol and carvacrol, the plant accumulates flavonoids and phenolic acid derivatives like rosmarinic acid [Fecka andTurek 2008, Roby et al 2013], as well. Accumulation of volatile phenolic compoundsprimarily thymolseems to be accelerated by warm and dry climatic conditions [Aziz et al 2008, Pluhár et al 2008] which characterize the indigenous habitats of thyme species. Nevertheless, changes in the level of non-volatile phenolics are less studied and findings are contradictory [Khosh-Khoi et al 2012, Alavi-Samani et al 2013.…”

Factors Affecting Chemical Variability of Essential Oils: A Review of Recent Developments

“…Interestingly, the plants were collected according to their odor: ester-like, phenol-like and lemon-like, and, after chemical analysis, three corresponding chemotypes were identified: α-terpenyl acetate, carvacrol, and citral-geraniol. Pluharand and coworkers [43] reported the existence of eight chemovarieties of Hungarian T. glaborescens Willd. sampled from eight corresponding different localities.…”

Volatile Constituents of Two Rare Subspecies of Thymus praecox

“…It is believed that part of these activities is due to the volatile constituents. In recent years, the essential oil chemistry and polymorphism of various Thymus species have been extensively investigated [3][4][5][6][7]. These studies have emphasized the existence of marked chemical differences among oils extracted from different species or varieties.…”