Quantification of Antioxidants by Using Chlorpromazine Hydrochloride: Application of the Method to Food and Medicinal Plant Samples

Abstract

Chlorpromazine hydrochloride (CPH) (3-(2-chloro-phenothiazine-10-yl)-propyl] dimethylamine hydrochloride) has been the subject of a large number of studies employing a broad spectrum of oxidants, and chosen to examine the course of electron transfer reactions. We report on a method to determine the antioxidant activity of some food and medicinal plants using the oxidation of CPH by chromium(VI) to form a stable CPH radical in the 1:1 orthophosphoric acid–ethyl alcohol (OPA-EtOH) medium. The pink color of the control solution was measured at λ_max of 530 nm. Nine standard antioxidants have been studied by this method, along with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The EC₅₀, TEC₅₀, antioxidant efficacy and the stoichiometric values for antioxidants have been evaluated. The radical scavenging activity expressed as EC₅₀ ranged from 9.2 μg/mL in Camellia sinensis to 448.18 μg/mL in Cuminum cyminum. The application of a simple and versatile antioxidant capacity assay for dietary polyphenols and medicinal plant extracts, which are commonly used in Ayurveda opens its relevance in the field of antioxidant analysis.