Analysis of lipid-alkyl radical scavenging reactions of vitamin E

点击翻译按钮获取中文摘要

Formation of alkyl radicals of unsaturated lipids is the first step of lipid peroxidation. We have studied the lipid-alkyl radical scavenging reactions of vitamin E (α-tocopherol, α-TH). When cholesteryl linoleate (ChL) hydroperoxides were reacted with α-TH at 100℃, two addition products were obtained as 6-O-epoxyChL-α-TH and 6-O-ChL-α-TH. Iron-catalyzed reaction of phosphatidylcholine (PC) hydroperoxides with α-TH under nitrogen gave the addition products, 6-O-epoxyPC-α-TH. A sensitive method using a high-performance liquid chromatography with post-column reduction using platinum as the catalyst followed by fluorescence detection has been developed for the quantification of the addition products of α-TH during the peroxidation of an emulsion of ChL and PC. The addition products of α-TH with alkyl and peroxyl radicals were detected when the emulsion was peroxidized. The results indicate that α-TH may react with lipid-alkyl radicals under oxygen-insufficient conditions.