Analysis of the free radical scavenging products of vitamin E in biological systems using a high-sensitive HPLC method

高效液相色谱电化学检测法采用高效液相色谱法（ECD-HPLC）对维生素E的氧化产物进行了分析（α-生育酚，α-TH），包括8α-（磷脂酰胆碱二氧）-α-生育酚（TOO-PC）、α-生育酚醌（α-TQ）和环氧-α-生育酚醌（环氧-α-TQ）在大鼠组织匀浆（肝、心、肺和肾）过氧化过程中的作用。在37℃加入自由基引发剂使各组织匀浆过氧化时，内源性α-TH可清除磷脂酰胆碱（PC）的过氧自由基，抑制PC过氧化氢（PC-OOH）的形成。各组织中α-TH的主要产物为α-TQ和α-TH与PC-过氧自由基的加成产物（TOO-PC）。经LC-ESIMS分析，TOO-PC的结构为1-棕榈酰-2-[（8α-二氧-α-生育酮）-环氧十八烯酰]-3-sn-磷脂酰胆碱。结果表明，大鼠组织中内源性α-TH的含量明显高于对照组， ...更多信息 氧化应激参与了糖尿病的发病过程，α-TH可能通过减少脂质过氧化和氧化损伤而预防糖尿病并发症的发生。因此，本研究采用高灵敏度的ECD-HPLC法，对STZ诱导的糖尿病大鼠血清、心、肝、肾、肺组织中α-TH的氧化产物进行了研究。在STZ注射后的不同时间点，除了测量氧化应激的标志物PC-OOH之外，还测量了这些组织中内源性α-TH及其氧化产物的量。糖尿病大鼠注射STZ 4周后，血浆、肝脏和肾脏中的PC-OOH增加。因此，氧化应激发生在这些组织中。糖尿病大鼠各组织中α-TH含量与对照组相同，但血浆、心、肝、肺中氧化产物α-TQ含量均高于对照组。此外，采用ECD-HPLC法在糖尿病大鼠的某些组织中检测到TOO-PC。结果提示，糖尿病大鼠组织中α-TH可能与脂质过氧化自由基反应生成α-TQ作为氧化产物。总之，在体外和体内系统中均检测到α-TH的氧化产物。少

The high-sensitive method using a high-performance liquid chromatography with electrochemical detection (ECD-HPLC) has been applied for the analysis of the oxidation products of vitamin E (α-tocopherol, α-TH), including 8α-(phosphatidylcholine-dioxy)-α-tocopherones (TOO-PC), α-tocopherylquinone (α-TQ), and epoxy-α-tocopherylquinones (epoxy-α-TQ) during the peroxidation of rat tissue homogenates (liver, heart, lung, and kidney). When each tissue homogenate was peroxidized by the addition of a free radical initiator at 37℃, the endogenous α-TH could scavenge peroxyl radicals of phosphatidylcholines (PC) to suppress the formation of PC hydroperoxides (PC-OOH). The main products of α-TH in each tissue were α-TQ and the addition products of α-TH with PC-peroxyl radicals (TOO-PC). The structure of TOO-PC was characterized as 1-palmitoyl-2-[(8α-dioxy-α-tocopherone)-epoxyoctadecenoyl]-3-sn-phosphatidylcholine by the LC-ESIMS analysis. The results indicate that endogenous α-TH in rat tissue hom … More ogenates can react with lipid-peroxyl radicals to form α-TQ and TOO-PC as the reaction products.Oxidative stress has been implicated in the pathogenesis of diabetes mellitus, and α-TH might prevent the development of diabetic complications in some tissues by reducing lipid peroxidation and oxidative damage. Therefore, the oxidation products of α-TH in the tissues, serum, heart, liver, kidney, and lung, of storeptozotocin (STZ)-induced diabetic rats have been studied using the high-sensitive ECD-HPLC method. The amounts of endogenous α-TH and its oxidation products were measured in these tissues at different time points after STZ injection, in addition to the measurement of PC-OOH, a marker of oxidative stress. The PC-OOH was increased in plasma, liver, and kidney of diabetic rats 4 weeks after STZ injection. Therefore, oxidative stress occurred in these tissues. Although the level of α-TH in the tissues of diabetic rats was the same, the oxidation product α-TQ in the plasma, heart, liver, and lung was high compared with the control rats. Furthermore, TOO-PC has been detected in some tissues of diabetic rats using the ECD-HPLC method. The results suggest that α-TH in the tissues of diabetic rats may scavenge lipid-peroxyl radicals to form α-TQ as the oxidation product. In conclusion, the oxidation products of α-TH have been detected ex vivo and in vivo systems. Less