A novel, rapid and cost-effective chlorpromazine hydrochloride (CPZH) decolorization assay is described for the screening of antioxidant activity. A chromogenic reaction between CPZH and potassium persulfate at low pH produces an reddish-pink radical cation with maximum absorption at 527 nm in its first-order derivative spectrum. The antioxidant capacity of standard solutions of an antioxidant was evaluated by comparing with the inhibition curve using Trolox as the standard. Comparison of antioxidant capacity determined with this newly developed CPZH assay and with the well-known 2,2'- azinobis- 3-ethylbenzthiazoline-6-sulfonic acid] (ABTS)-persulfate decolorization assay indicated the efficacy and sensitivity of the procedure.This method is applied on the apple juices of different brands and on Canola seeds of Different cultivars In this study total antioxidant capacity (TAC) of extracts of Canola seeds of different cultivars Leaves Zafar 2000 (Z1, Z2)Bulbul 98 (B1, B2) and Pakola (P1, P2) was investigated.