Hydroxyl and superoxide radical scavenging abilities of chromonyl-thiazolidine-2,4-dione compounds

The oxygen free radical scavenging activities of 15 chromonyl-thiazolidine-2,4-dione compounds (CTDs) were examined in chemical systems producing superoxide anion radicals, O(2)radical anion (potasium superoxide-18-crown-6 ether-DMSO), and hydroxyl radicals, HO center dot (a Fenton reaction: Fe(II)-H2O2-sodium trifluoroacetate, pH 6.15). Chemiluminescence and electron spin resonance (ESR) spectroscopy using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as spin trap were applied to evaluate antioxidant behaviour of CTDs towards the oxygen radicals. The results indicated that 11 of the 15 tested compounds showed a significant inhibitory effect on the chemiluminescence generated from the O(2)radical anion-generating system, ranging from 41 to 86%, and 13 CTDs quenched the ESR signal of the DMPO-OH spin adduct by 33-86%, at a concentration of 1 mmol L-1. Our findings demonstrate that CTDs could be good free radical scavengers. Copyright (C) 2008 John Wiley & Sons, Ltd.