Free radical-scavenging behaviour of some north-east Brazilian fruits in a DPPH• system

The antiradical capacity (radical-scavenging capacity, RSC) of seven tropical fruit from the Brazilian north-east (acai, acerola, cashew apple, mangaba, murici, umbu and uvaia) were studied using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH center dot ) assay. To determine their RSC, the second-order rate constants k(2)) for the oxidation of these extracts by DPPH center dot were calculated. The values of k(2) were compared to natural and synthetic antioxidants. The k(2) values (1/mol g s), in methanol at 25 degrees C, were 38.0, 29.7, 21.3. 20.1. 10.1. 9.54 and 5.47 for acerola, cashew apple, mangaba, umbu, acai, uvaia and murici, respectively. (c) 2008 Elsevier Ltd. All rights reserved.