Ajwain is one of the medicinal plants, which the highest composition is thymol, as a strong antioxidant respect to the obtained chromatograms of GC/MS. The antioxidant activity of the Ajwain is measured by square wave voltammetry method and cyclic voltammetry method and 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) method in at the specific concentrations of 1%, 1.5%, 2% and 2.5% and constant pH. The results of the present study indicated that the antioxidant activity of Ajwain obtained from cyclic voltammetry and square wave is almost equal to the results of the DPPH method, which can be used to measure the antioxidant activity. Compared to DPPH method, electrochemical method involves a number of advantages such as simplicity, cheap operating costs, fastness, low amount of solvent, and no need for chemical reagents. Furthermore, based on the results obtained, the square wave method includes a higher sensitivity and accuracy than cyclic voltammetry method and DPPH method. Manuscript profile

Thymus is regarded as one of the medicinal species, which according to obtained chromatograms of floral water of Thymus; one of the main components is thymol as strong antioxidant. In this study the appropriate and physically powerful correlation was found between the anti-radical and oxidation potentials. The antioxidant activity of the Thymus was measured by using square wave and cyclic voltammetry methods and 2, 2-diphenyl-1-picrylhydrazyl hydrate (DPPH) method in the concentration range of 1% to 2.5% V/V. Electrochemical methods are used based on the relationship between oxidation power and antioxidant strength, which compared with ascorbic acid as standard. Based on the results of electrochemical methods, these methods have several advantages over the DPPH∙ method such as simplicity, cheaper operating costs, short integration time, high speed, low solvent and sample usage. Moreover, the square wave voltammetry method is more sensitive method for evaluation the antioxidant activities compared to DPPH and cyclic voltammetry methods. Manuscript profile