Mohammad Hadi Meshkatalsadat - Department of chemistry, faculty of basic sciences, Qom university of technology Qom, Iran

This paper is devoted to an investigation carried out on the essential oils of air-dried leaves of four species of Thymus Sp.: Thymus. Persicus, Thymus Eriocalyx Thymus daenensis subsp. Daenensis, and Thymus serpyllum L growing wild in the western part of Iran. The essential oil of species were obtained through hydro-distillation process and analyzed by using GC and GC/MS methods. The four species were compared to determine the similarities and differences among their volatile chemical compositions. Sixty-five compounds representing 98.05%, 89.70%, 96.45% and 93.08% of essential oils were identified respectively. The major constituents noted were as Thymus daenensis subsp. Daenensis: Trans Ocimene (6.62%), 1, 8 Cineole (6.17%), cis sabinene hydrate (9.2%), (13.18%), Thymol (5%), Caervacrol (12.38%), β-Carryophyllene (4.26%). Th.Eriocalyx: 1-Borneol (10.46%), Thymol (66.34%), Carvacrol (7.5%) Th.Percicus: 1,8-Cineole (5.24%), Limonene (11.62%), γ-Terpinene (5.63%), trans_Sabinene hydrate (7.78%), Thymol (10.38%), Carvacrol (25.71%) .Th.Serpyllium: α-Pinene (12.2%), Thymol (7.39%), Carvacrol (14.94%).

Thymus Essential oil; Thymol; Carvacrol, Labiatae gc/ms