Harvest Time Effecting on the Essential Oil Content and Compositions of Thymus vulgaris

AbstractThe highest essential oil content (2.41 %) was extracted from the herb, produced at beginning of flowering stage, and the lowest amount (0.67 %) at seed ripening stage. The essential oils content of herb of plants harvested before flowering, full flowering, and at fruit set stage were: 1.59, 1.51 and 0.69 % respectively. GC and GC-MS analyses of the essential oil showed that harvest time had effect on the essential oil compositions of Thymus vulgaris.Twenty-four components were found in the essential oil extracted from the herb harvested before flowering stage. But 23, 21, 23 and 23 components in the essential oil extracted from the herbs, which were collected at beginning of flowering, full flowering, fruit set and at seed ripening stages respectively. The major component of the essential oil was thymol. The highest thymol content (57.1 %) was identified in the oil of the herb, which was collected before flowering stage and the lowest amount (48.0 %) harvested at seed ripening stage. Other essential oil constituents affected by harvest time were: y-terpinene (9.5–19.7 %), p-cymene (6.8–20.0 %), linalool (1.6–2.7 %), carvacrol (2.4–3.2 %), E-caryophyllene (1.4–2.2 %), a- terpinene (1.3–2.0 %), ß- pinene (1.3–1.8 %), and borneol (0.3–1.7 %).