Investigation of seven species of essential oils of thyme and comparison their antioxidant properties

Abstract

Introduction: Thyme is one of the mint family geniuses that belongs to Nepetoideae subfamily. This plant has been known as an antiseptic, antispasmodic and antitussive. Thyme essential oil has many properties that one of which is antioxidant activity. Objective: The aim of this study was the investigation of seven thyme oils and the comparison of their antioxidant activities. In this paper, seven species of essential oils of thyme from different regions have been collected and dried. Methods: The essential oil was extracted by using a Clevenger-type apparatus as British pharmaceutical for four hours. Obtained essential oils were analyzed by gas chromatography–mass spectroscopy (GC-MS) technique. Results: Different compounds were identified in the essential oils with different percentages. The main compound in Thymus daenensis and Thymus vulgaris was thymol with percentage of 43.8 for the former and 45.1 for the latter. While the dominate compound in Thymus migricus, Thymus eriocalyx, Thymus serpylum, Zataria multiflora and Thymus kotschyanus are linalool (41.8%), geraniol (61.8%), para cymene (23.8%), carvacrol (57.7%), and Pulegone (37.2%), respectively. Antioxidant activity of essential oils was measured by 2,2-diphenyl-1-picrylhydrazyl )DPPH) radical scavenging test. Conclusions: Antioxidant activities of Thymus vulgaris, Thymus daenensis, and Zataria multiflora were higher than other essential oils.

Keywords

• thyme essential oil
• antioxidant activity
• gas chromatography–mass spectroscopy