Sen Chandan K, Khanna Savita, Roy Sashwati
Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio 43210, USA.
Life Sci. 2006 Mar 27;78(18):2088-98. doi: 10.1016/j.lfs.2005.12.001. Epub 2006 Feb 3.
In nature, eight substances have been found to have vitamin E activity: alpha-, beta-, gamma- and delta-tocopherol; and alpha-, beta-, gamma- and delta-tocotrienol. Yet, of all papers on vitamin E listed in PubMed less than 1% relate to tocotrienols. The abundance of alpha-tocopherol in the human body and the comparable efficiency of all vitamin E molecules as antioxidants, led biologists to neglect the non-tocopherol vitamin E molecules as topics for basic and clinical research. Recent developments warrant a serious reconsideration of this conventional wisdom. Tocotrienols possess powerful neuroprotective, anti-cancer and cholesterol lowering properties that are often not exhibited by tocopherols. Current developments in vitamin E research clearly indicate that members of the vitamin E family are not redundant with respect to their biological functions. alpha-Tocotrienol, gamma-tocopherol, and delta-tocotrienol have emerged as vitamin E molecules with functions in health and disease that are clearly distinct from that of alpha-tocopherol. At nanomolar concentration, alpha-tocotrienol, not alpha-tocopherol, prevents neurodegeneration. On a concentration basis, this finding represents the most potent of all biological functions exhibited by any natural vitamin E molecule. An expanding body of evidence support that members of the vitamin E family are functionally unique. In recognition of this fact, title claims in manuscripts should be limited to the specific form of vitamin E studied. For example, evidence for toxicity of a specific form of tocopherol in excess may not be used to conclude that high-dosage "vitamin E" supplementation may increase all-cause mortality. Such conclusion incorrectly implies that tocotrienols are toxic as well under conditions where tocotrienols were not even considered. The current state of knowledge warrants strategic investment into the lesser known forms of vitamin E. This will enable prudent selection of the appropriate vitamin E molecule for studies addressing a specific need.
在自然界中，已发现有八种物质具有维生素E活性：α-、β-、γ-和δ-生育酚；以及α-、β-、γ-和δ-生育三烯酚。然而，在PubMed上列出的所有关于维生素E的论文中，涉及生育三烯酚的不到1%。人体内α-生育酚含量丰富，且所有维生素E分子作为抗氧化剂的效率相当，这导致生物学家忽视了非生育酚维生素E分子，不将其作为基础和临床研究的课题。最近的进展值得对这种传统观念进行认真反思。生育三烯酚具有强大的神经保护、抗癌和降低胆固醇的特性，而生育酚通常不具备这些特性。维生素E研究的当前进展清楚地表明，维生素E家族成员在生物学功能方面并非多余。α-生育三烯酚、γ-生育酚和δ-生育三烯酚已成为具有与α-生育酚明显不同的健康和疾病相关功能的维生素E分子。在纳摩尔浓度下，是α-生育三烯酚而非α-生育酚可预防神经退行性变。基于浓度而言，这一发现代表了任何天然维生素E分子所展现的所有生物学功能中最强大的功能。越来越多的证据支持维生素E家族成员在功能上是独特的。认识到这一事实，稿件中的标题声明应限于所研究的维生素E的特定形式。例如，某种特定形式的生育酚过量时的毒性证据，不能用于得出高剂量“维生素E”补充剂可能增加全因死亡率的结论。这样的结论错误地暗示在甚至未考虑生育三烯酚的情况下，生育三烯酚也是有毒的。当前的知识状况需要对鲜为人知的维生素E形式进行战略投资。这将有助于为满足特定需求的研究谨慎选择合适的维生素E分子。
