Thymus fedtschenkoi essential oils composition and their antioxidant activity; A comparative study on hydrodistillation and solvent free microwave extraction

Abstract

Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran E-mail: [email protected] Manuscript received 26 September 2018, accepted 01 November 2018 In the present project, the essential oil of Thymus fedtschenkoi, was obtained both by hydrodistillation (HD) procedure and the solvent free microwave extraction (SFME) method; and then, the extracts were analyzed by the GC-MS technic. Thymol (51.6%), geraniol (8.3%) and p-cymene (7.3%) were the main constituents among twenty-one identified components (97.6% of total oil) in SFME method; while, thirty-two compounds (98.2% of the oil) were characterized in hydrodistilled oil contain­ing: thymol (38.6%), geraniol (15.8%) and -y-terpinene (7.3%) as major compounds. Also, the antioxidant activity of each ex­tract was investigated using radical scavenging of DPPH radicals. The values of IC₅₀ were 2635.85 and 462.69 mg L-1 for HD and SFME approaches obtained oils, respectively.