The study of essential oil composition and antioxidant activity of Oliveria decumbens vent. were collected from different regions of Khuzestan province ر

Aromatic herbs are considered the most valuable antioxidant source in nature. In this research, 3 different ecotypes of Oliveria decumbens vent. were collected from three important regions in Khuzestan province, including Behbahan, Shushtar and Masjed Soleyman in flowering stage. Essential oils were extracted by hydrodistillation method (Clevenger apparatus) and d were analyzed by GC /Mass and the antioxidant activities were specified by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Results were showed that the highest thymol (29.67) and carvacrol (27.88%) were dominanted in Behbahan region oil. The percentage of degradation of DPPH free radicals in different concentrations of essential oil including 50, 100, 200, 300, and 400 μl were calculated to determine the antioxidant activity of the essential oil. The IC50 values were calculated 34.21, 26.85 and 21.23, respectively from Shushtar, Masjed Soleyman and Behbahan regions. Finally, Behbahan ecotype with the highest source of thymol, carvacrol and antioxidant properties can be considered as a new best natural source of antioxidant supply.