Abstract
To elucidate the differences in the antioxidant potency of troglitazone and α-tocopherol in the oxidation of low density lipoprotein (LDL), the structure of the phenoxyl radical of troglitazone and the antioxidant activity of troglitazone in homogeneous solution and liposomal membranes were investigated. The antioxidant activity of troglitazone in homogenous solution based on the cis-parinaric acid fluorescence method was not substantially different from that of α-tocopherol. The ESR study using a spin label technique showed that troglitazone more effectively scavenged the radicals generated in the water phase outside of the liposomal membranes than those generated from the interior of the membranes than did α-tocophenol. These results suggest that the difference in the antioxidant potency of troglitazone and α-tocopherol in the oxidation of LDL is partly due to the mobility and the position of these compounds in the liposomal membrane.
