Identification of a novel series of N-phenyl-5-[(2-phenylbenzimidazol-1-yl)methyl]-1,3,4-oxadiazol-2-amines as potent antioxidants and radical scavengers.

In this study, some novel 5-[[2-(phenyl/p-chlorophenyl)-benzimidazol-1-yl]-methyl]-N-substituted phenyl-1,3,4-oxadiazol-2-amine derivatives (28-45) with an oxadiazole ring were synthesized. The antioxidant properties and radical scavenging activities of the compounds were investigated employing various in vitro systems: hepatic microsomal NADPH-dependent inhibition of lipid peroxidation levels, scavenging of DPPH free radicals, and inhibition of microsomal ethoxyresorufin O-deethylase activity (EROD). Compounds 34 and 41 were found to be good scavengers of DPPH radicals (76% and 84%) when compared to BHT (90%). Almost all of the compounds examined were found to possess a good inhibitor effect on the microsomal EROD activity. Moreover, 32 and 41 were more active analogs (97% and 98%) on the microsomal EROD activity than caffeine (85%).