Brigelius-Flohé Regina
Department of Biochemistry of Micronutrients, German Institute of Human Nutrition Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany.
Nutr Res Rev. 2006 Dec;19(2):174-86. doi: 10.1017/S0954422407202938.
More than 80 years after the discovery of the essentiality of vitamin E for mammals, the molecular basis of its action is still an enigma. From the eight different forms of vitamin E, only alpha-tocopherol is retained in the body. This is in part due to the specific selection of RRR-alpha-tocopherol by the alpha-tocopherol transfer protein and in part by its low rate of degradation and elimination compared with the other vitamers. Since the tocopherols have comparable antioxidant properties and some tocotrienols are even more effective in scavenging radicals, the antioxidant capacity cannot be the explanation for its essentiality, at least not the only one. In the last decade, a high number of so-called novel functions of almost all forms of vitamin E have been described, including regulation of cellular signalling and gene expression. alpha-Tocopherol appears to be most involved in gene regulation, whereas gamma-tocopherol appears to be highly effective in preventing cancer-related processes. Tocotrienols appear to be effective in amelioration of neurodegeneration. Most of the novel functions of individual forms of vitamin E have been demonstrated in vitro only and require in vivo confirmation. The distinct bioactivities of the various vitamers are discussed, considering their metabolism and the potential functions of metabolites.
在发现维生素E对哺乳动物的必要性80多年后，其作用的分子基础仍然是个谜。在维生素E的八种不同形式中，只有α-生育酚能在体内留存。这部分归因于α-生育酚转运蛋白对RRR-α-生育酚的特异性选择，部分归因于与其他维生素异构体相比，它的降解和消除速率较低。由于生育酚具有相当的抗氧化特性，一些生育三烯酚在清除自由基方面甚至更有效，因此抗氧化能力不能解释其必要性，至少不是唯一的原因。在过去十年中，几乎所有形式的维生素E都被描述了大量所谓的新功能，包括细胞信号传导和基因表达的调节。α-生育酚似乎最参与基因调控，而γ-生育酚似乎在预防癌症相关过程中最为有效。生育三烯酚似乎对改善神经退行性变有效。各种维生素异构体的大多数新功能仅在体外得到证实，需要体内验证。考虑到它们的代谢和代谢产物的潜在功能，讨论了各种维生素异构体的独特生物活性。
