Effect of vitamin E on the secondary oxidation process of unsaturated lipids

脂质过氧化的次级过程形成一些有毒的醛。由于这一过程通过自由基中间体进行，维生素E（α-生育酚，TH）将抑制这种醛的形成。本文研究了在胶束和脂质体中TH对氯化血红素催化1-棕榈酰-2-亚油酰磷脂酰胆碱氢过氧化物（PLPC-OOH）分解的影响。氯化血红素催化PLPC-OOH分解产生作为二次氧化产物的己醛。虽然TH没有抑制PLPC-OOH的分解，但它抑制了己醛的形成。TH在胶束中的主要产物是TH醌和二聚体，以及PLPC-OOH衍生的自由基加合物（T-epoxyPLPC和TOO-epoxyPLPC）。脂质体中主要产物为TOO-环氧PLPC和二聚体，脂质体破坏后产生TH醌。结果表明，TH能捕获PLPC-OOH衍生的自由基，抑制次生代谢产物的形成。

The secondary process of lipid peroxidation forms some toxic aldehydes. Since this process proceeds via free radical intermediates, vitamin E (alpha-tocopherol, TH) would suppress the formation of such aldehydes. We have studied the effect of TH on the hemin-catalyzed decomposition of 1-palmitoyl-2-linoleoylphosphatidylcholine hydroperoxide (PLPC-OOH) in micelles and liposomes. The hemin-catalyzed decomposition of PLPC-OOH produced hexanal as the secondary oxidation product. Although TH did not suppress the decomposition of PLPC-OOH, it suppressed the formation of hexanal. The main products of TH in micelles were TH quinone and dimer, in addition to adducts of PLPC-OOH derived free radicals (T-epoxyPLPC and TOO-epoxyPLPC). In the liposomes, the main products were TOO-epoxyPLPC and dimer, and TH quinone was produced when the liposomes were destroyed. The results indicate that TH can trap PLPC-OOH derived free radicals and suppress the formation of secondary aldehydic products.