Abstract

2,2-diphenyl-1-picrylhydrazyl (DPPH)-based spectrophotometric detection of total antioxidant capacity (TAC) in samples is a common method. However, controversy exists for applying multiple absorption maximum wavelength and final concentration of DPPH used in the reaction mixture to measure TAC in terms of % of inhibition of DPPH (PID). Further, inconsistent spectrophotometric absorption values obtained during the incubation of sample with DPPH are also another drawback of this method. We tried to fix above issues by estimating the TAC in the tissue homogenate of Heteropneustes fossilis. Ascorbic acid was used as standard antioxidant in this study, and depending on tissues, the time of incubation of tissue extracts with DPPH (1.35 µM optimum concentration) to obtain optimal consistent result was found to be 20–30 min. The absorption maximum of DPPH was found to be 516 nm as compared to the used wavelength ranging from 515 to 546 nm. The order of TAC in tissues of the fish was muscle (76% PID, 20–60 min incubation), gill (71% PID, 30 min incubation), and liver (49.9% PID, 30 min incubation). This report suggests that the incubation time of tissue extracts with DPPH is important and needs to be determined accurately to get consistent results.

Key words: : DPPH radical oxidation, H. fossilis, radical scavenging activity, time of incubation, total antioxidant capacity