Free radical scavenging properties of sulfinpyrazone.

Sulfinpyrazone, a potent uricosuric drug, was tested in vitro for its scavenging action against oxygen free radicals. In this study, sulfinpyrazone was able to scavenge 1,1-diphenyl-2-picrylhydrazyl radical with IC50 value of 29.82 micrograms/ml compared to butylated hydroxytoluene (BHT, IC50 value = 20.15 micrograms/ml) and Trolox (IC50 value = 16.01 micrograms/ml). It was able to scavenge superoxide anion with IC50 value of 27.72 micrograms/ml compared to Trolox (IC50 value = 22.08 micrograms/ml) and ascorbic acid (IC50 value = 14.65 micrograms/ml). The hydroxyl radical scavenging activity of sulfinpyrazone is in a concentration-dependent fashion. In the range of concentrations used, sulfinpyrazone was not a scavenger toward H2O2. However, the intracellular H2O2-induced 2',7'-dichlorofluorescin diacetate (DCF-DA) fluorescence in HL-60 cells was significantly reduced by sulfinpyrazone during 30-60 min of incubation. Finally, phorbol-12-myristate-13-acetate induced-lucigenin chemiluminescence in whole blood was markedly inhibited by sulfinpyrazone. Our results suggest a new direction for the pharmacological actions of sulfinpyrazone in free radical scavenging properties.