Dmitriev L F, Ivanova M V, Lankin V Z
Group of Lipid Biochemistry, Cardiology Research Centre, Moscow, Russia.
Chem Phys Lipids. 1994 Jan;69(1):35-9. doi: 10.1016/0009-3084(94)90025-6.
alpha-Tocopherol (alpha-TOH) is thought to act as a lipid-soluble antioxidant by scavenging the chain-carrying lipid peroxyl radical (LOO.), giving rise to alpha-TO. and LOOH. The aim of the present work is to test the possibility that alpha-TOH may also exert a protective action by converting LOO. into the parent, unoxidized lipid molecule (LH) with concomitant formation of O2- and T+O. To assess the relative contribution of the two pathways, the amounts of products accumulating were measured, i.e. LOOH and O2-, under conditions where lipid peroxidation was initiated at linear rates by the UV light-induced decomposition of AIBN. The overall conclusion of the study is based on the observation that significant amounts of O2- were produced, whereas the delta LOOH/delta alpha-TOH was considerably smaller than 1.0. A mechanism of one or two-electron oxidation of TOH is considered; according to it the phospholipid primary structure is restored (LOO.-->LH, breaking of the C-->O bond). This leads to the oxygen or superoxide anion-radical release accordingly.
α-生育酚（α-TOH）被认为通过清除携带链的脂质过氧自由基（LOO·）发挥脂溶性抗氧化剂的作用，生成α-生育酚自由基（α-TO·）和氢过氧化物（LOOH）。本研究的目的是测试α-TOH是否也可能通过将LOO·转化为母体未氧化脂质分子（LH）并伴随生成超氧阴离子（O2-）和生育酚阳离子自由基（T+O·）来发挥保护作用。为了评估这两条途径的相对贡献，在通过紫外线诱导偶氮二异丁腈（AIBN）分解以线性速率引发脂质过氧化的条件下，测量了积累的产物量，即LOOH和O2-。该研究的总体结论基于以下观察结果：产生了大量的O2-，而ΔLOOH/Δα-TOH远小于1.0。考虑了生育酚的单电子或双电子氧化机制；据此，磷脂的一级结构得以恢复（LOO·→LH，C→O键断裂）。这相应地导致了氧气或超氧阴离子自由基的释放。
