PROBUCOL SCAVENGED 1,1-DIPHENYL-2-PICRYLHYDRAZYL RADICALS AND INHIBITED FORMATION OF THIOBARBITURIC ACID REACTIVE SUBSTANCES

Probucol is suggested to have antioxidant properties. The direct scave nging action of probucol on hydroxyl radicals, superoxide and 1,1-diph enyl-2-picrylhydrazyl (DPPH) radicals were examined using electron spi n resonance (ESR) spectrometry. Probucol scavenged DPPH radicals dose dependently but showed no effect on hydroxyl radicals and superoxide g enerated by Fenton reaction and by hypoxanthine-xanthine oxidase syste m, respectively. It inhibited the formation of thiobarbituric acid rea ctive substances (TBARS) in rat cortex homogenate induced by ascorbic acid and FeCl2 at low dose, but it increased TBARS formation at high d oses. Probucol showed no effect on the carbon centered radicals. Iron injection into the rat cortex, which is an experimental model for trau matic epilepsy, increased TBARS level in the cortex, hippocampus, stri atum, and cerebellum, but pretreatment with probucol inhibited the inc rease in these brain parts except for the hippocampus. These results s uggest that the antioxidant property of probucol is partly due to its free radical scavenging effect.