Scavenged Effects of Cu(II) Chelates of Imidazole and Thiazole Derivatives on the Active Oxygen Species in vitro.

Abstract

Scavenged effects of Cu (II) chelates of imidazole and thiazole derivatives on superoxide (SO), H2O2 and OH radical were studied and compared with that of cimetidine, which is well known as a superoxide scavenger, and with those of superoxide dismutase (SOD), catalase and Cu (ClO4)2. Six of imidazole and 6 of thiazole derivatives were cimetidine and famotidine analogues, respectively. Superoxide scavenged effects (IC50) of Cu (II) chelates were in the range of 0.48-5.67μM determined by the nitroblue tetrazolium method in a phenazine methosulfate-NADH system (method A) and in a xanthineoxidase-hypoxanthine system (method B), whereas the IC50 values of SOD were 4.5×10-2 and 3.4×10-2μM by the methods of A and B, respectively. No catalase activity of Cu (II) chelates were observed. In the studies of the scavenged effect of Cu (II) chelates on hydroxyl radical, IC50 values of Cu (II) chelates of N-methyl-N'-[2-(imidazol-4-yl) methylthioethyl]-thiourea (I-1) and its 5-methylimidazole derivative (I-2), which possessed methylthiourea groups, were 13.7 and 8.0μM, respectively, and the Cu chelate of I-2 had the highest scavenged activity against hydroxyl radical generated from Fenton reaction.