Fluphenazine hydrochloride radical cation assay: A new, rapid and precise method to determine in vitro total antioxidant capacity of fruit extracts

• Published in: Chinese chemical letters 2012-11, Vol.23 (11), p.1271-1274
• Main Authors: Asghar, Muhammad Nadeem, Alam, Qadeer, Augusten, Sharoon
• Format: Article
• Language: English
• Subjects: ABTS; Ascorbic acid equivalent; Fluphenazine hydrochloride; Radical cation
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2012.10.003

A new procedure based on generation and subsequent reduction of orange-colored fluphenazine hydrochloride radical (FPH+) is presented for the screening of total antioxidant capacity (TAC) of various fruit matrices. The FPH+ was obtained by mixing fluphenazine hydrochloride with persulfate (final concentration 2mmol/L and 0.05mmol/L, respectively) in 3mol/L H2SO4 with constant shaking for 5min. The solution formed showed maximum absorption as 0.8±0.02 at 500nm in first-order derivative spectrum. The percent inhibition of the solution increased linearly on addition of increasing amounts of standard antioxidants i.e., ascorbic acid etc. The TACs of sample citrus juices were calculated in terms of ascorbic acid equivalents (AAEs) by comparing their inhibition curves with that of ascorbic acid. Comparison of AAE values of different commercial orange juices using the newly developed FPH+ assay and the well-known ABTS/K2S2O8 and DMPD/FeCl3 assays indicated the precision and comparable sensitivity of the method. The proposed procedure is quick, economical, and more precise and gives results comparable to contemporary assays.