Essential Oil Composition of Thymus × citriodorus (Pers.) Schreb. at Different Harvest Stages

Abstract

Thymus is represented by 39 species (60 taxa) in Turkey and the rate of its endemism is 45% in Turkey. The herb is widely used for several purposes. Its essential oil compositions and biologically active substances are affected by the phenological stages. Therefore, the aim of this study is to evaluate the variations in the essential oil composition of Thymus × citriodorus (Pers.) Schreb. growing in Southeastern Anatolia Region of Turkey at different phenological stages (pre-flowering, full flowering, post flowering). The oils were obtained by hydrodistillation of air-dried samples. The yields of oils (w/w %) at different phenological stages was respectively 2.0% at pre-flowering state, 1.9% at flowering stage, and 1.3% at post-flowering stage. T. × citriodorus was determined mainly by using GC/MS. A total of 21 compounds, representing 93.9% in the pre-flowering stage, 98.8% in the flowering stage and 98.91% in post-flowering of the total oil, were identified. Monoterpene hydrocarbons (terpinolene) and oxygenated monoterpenes (α-terpineol) were observed to have the highest percentage in T. × citriodorus oil. The major compounds of the oil were terpinolene, α- terpineol, linalool, bornyl acetate and borneol. The highest percentage of terpinolene was determined to be 71% in flowering stages.