FUSED 2-THIOHYDANTOIN DERIVATIVES - EVALUATION AS POTENTIAL ANTIOXIDANTS

A series of fused 5,5-diphenyl and 5-arylidene-2-thiohydantoin derivat ives were examined for their oxygen free radical inhibitory and radica l scavenging properties (RSC) using both an enzymic and non-enzymic bi ological generators of free radicals. Non-enzymic lipid peroxidation ( OH . radicals) was assayed as the amount of malondialdehyde (MDA) that had been formed during incubation of boiled rat liver microsomes in t he presence of ascorbic acid and ferric ions. Superoxide anions (. O-2 (-) anion radicals) were generated enzymatically in the xanthine-xanth ine oxidase system. Among the 20 investigated compounds only four fuse d arylidene 2-thiohydantoin derivatives showed weak antioxidant activi ty scavenging OH . radicals. There is a relationship between the elect rophilic OH . radical scavenging properties (RSC) of the tested molecu les and the value of their HOMO energy derived from semiempirical MO c alculations.