Health Research Institute, National Institute of Advanced Industrial Science & Technology, Ikeda, Osaka 563-8577, Japan.
Free Radic Biol Med. 2011 Jun 15;50(12):1794-800. doi: 10.1016/j.freeradbiomed.2011.03.021. Epub 2011 Mar 26.
α-Tocopheryl phosphate (α-TP), a water-soluble analogue of α-tocopherol, is found in humans, animals, and plants. α-TP is resistant to both acid and alkaline hydrolysis and may exert its own function in this form in vivo. In this study, the uptake, hydrolysis, and antioxidant action of α-TP were measured using α-TP with a deuterated methyl group, CD(3), at position 5 of the chroman ring (α-TP(CD3)). The hydrolysis of α-TP(CD3) was followed by measuring α-tocopherol containing the CD(3) group, α-T(CD3), in comparison to unlabeled α-tocopherol, α-T(CH3). α-TP(CD3) was incubated with cultured cells, and the intracellular α-T(CD3) formed was measured with HPLC-ECD and GC-MS. α-TP(CD3) was also administered to mice for 4 weeks by mixing in the diet, and α-T(CD3) was measured in plasma, liver, brain, heart, and testis to compare with endogenous unlabeled α-T(CH3). It was found that α-TP(CD3) was taken in and hydrolyzed readily to α-T(CD3) in cultured cells and in mice. The hydrolysis of α-TP(CD3) in cell culture medium was not observed. α-TP protected primary cortical neuronal cells from glutamate-induced cytotoxicity, and α-TP given to mice reduced the levels of lipid peroxidation products in plasma and liver. These results suggest that α-TP is readily hydrolyzed in vivo to α-T, which acts as an antioxidant, and that α-TP may be used as a water-soluble α-T precursor in intravenous fluids, in eye drops, or as a dietary supplement.
α-生育酚磷酸酯（α-TP）是α-生育酚的水溶性类似物，存在于人类、动物和植物中。α-TP 既耐受酸水解又耐受碱水解，并且可能以这种形式在体内发挥其自身的功能。在这项研究中，采用在色满环的 5 位具有氘代甲基（CD(3)）的 α-TP（α-TP(CD3)）来测量 α-TP 的摄取、水解和抗氧化作用。通过测量含有 CD(3)基团的 α-生育酚（α-T(CD3)）与未标记的 α-生育酚（α-T(CH3)）相比，来跟踪 α-TP(CD3)的水解。将 α-TP(CD3)与培养的细胞孵育，并通过 HPLC-ECD 和 GC-MS 测量形成的细胞内 α-T(CD3)。还通过将其混入饮食中来向小鼠给药 4 周，并用α-T(CD3)测量血浆、肝脏、大脑、心脏和睾丸中的含量，与内源性未标记的α-T(CH3)进行比较。结果发现，α-TP(CD3)很容易被摄取并在培养的细胞和小鼠中迅速水解为 α-T(CD3)。在细胞培养液中未观察到 α-TP(CD3)的水解。α-TP 可保护原代皮质神经元细胞免受谷氨酸诱导的细胞毒性，并且给予小鼠的α-TP 降低了血浆和肝脏中脂质过氧化产物的水平。这些结果表明，α-TP 很容易在体内水解为α-T，后者作为抗氧化剂发挥作用，并且α-TP 可作为静脉内液体、滴眼剂或膳食补充剂中的水溶性α-T 前体使用。
