維生素E是否阻止或促進(jìn)癌細(xì)胞生長(zhǎng)已廣泛在科學(xué)期刊上以及新聞媒體上進(jìn)行了辯論,，新澤西癌癥研究所癌癥預(yù)防研究中心歐內(nèi)斯特·馬里奧·羅格斯大學(xué)藥學(xué)院的科學(xué)家,，相信兩種形式的維生素E-γ和油菜籽和玉米油以及堅(jiān)果、大豆中的δ-生育酚能預(yù)防結(jié)腸癌,、肺癌、乳腺癌和前列腺癌,。
Chung S. Yang說：有研究表明維生素E會(huì)增加患癌癥的風(fēng)險(xiǎn),，降低骨質(zhì)密度。但γ-生育酚的維生素E形式,，在美國飲食中,，維生素E和δ-生育酚的含量是最豐富的，其在植物油中也發(fā)現(xiàn),，實(shí)有利于預(yù)防癌癥的,，而維生素E補(bǔ)充劑的使用并沒有這樣的好處。
Yang說,，羅格斯大學(xué)的科學(xué)家進(jìn)行結(jié)腸癌,、肺癌、乳腺癌和前列腺癌的動(dòng)物實(shí)驗(yàn)研究發(fā)現(xiàn)植物油,，γ和δ-生育酚中發(fā)的維生素E,，能防止動(dòng)物模型中癌癥的形成和生長(zhǎng)。
Yang說：當(dāng)動(dòng)物暴露于致癌物質(zhì)環(huán)境下,，在他們的飲食中飼喂維生素E組腫瘤體積較少,。當(dāng)癌癥細(xì)胞注射到小鼠體內(nèi)后，再給予維生素E,，也能減慢腫瘤的發(fā)展,。
Yang和他的同事們、Nanjoo Suh和Ah-Ng Tony Kong總結(jié)他們的研究結(jié)果,，并發(fā)表于美國癌癥研究協(xié)會(huì)的Cancer Prevention Research雜志上,。（生物谷：Bioon.com）
doi:10.1158/1940-6207.CAPR-11-0521
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δ- and γ-Tocopherols, but not α-Tocopherol, Inhibit Colon Carcinogenesis in Azoxymethane-Treated F344 Rats
Fei Guan1, Guangxun Li1, Anna B. Liu1, Mao-Jung Lee1, Zhihong Yang1, Yu-Kuo Chen1, Yong Lin2,3, Weichung Shih2,3, and Chung S. Yang1,3
The cancer preventive activity of vitamin E has been extensively discussed, but the activities of specific forms of tocopherols have not received sufficient attention. Herein, we compared the activities of δ-tocopherol (δ-T), γ-T, and α-T in a colon carcinogenesis model. Male F344 rats, seven weeks old, were given two weekly subcutaneous injections of azoxymethane (AOM) each at a dose of 15 mg/kg body weight. Starting 1 week before the AOM injection, the animals were maintained on a modified AIN76A diet, or the same diet containing 0.2% of δ-T, γ-T, α-T, or a γ-T-rich mixture of tocopherols (γ-TmT), until the termination of the experiment at 8 weeks after the second AOM injection. δ-T treatment showed the strongest inhibitory effect, decreasing the numbers of aberrant crypt foci by 62%. γ-T and γ-TmT were also effective, but α-T was not. Immunohistochemical analysis showed that δ-T and γ-T treatments reduced the levels of 4-hydroxynonenal and nitrotyrosine and the expression of cyclin D1 in the colon, preserved the expression of PPAR-γ, and decreased the serum levels of prostaglandin E2 and 8-isoprostane. Supplementation with 0.2% δ-T, γ-T, or α-T increased the respective levels of tocopherols and their side-chain degradation metabolites in the serum and colon tissues. Rather high concentrations of δ-T and γ-T and their metabolites were found in colon tissues. Our study provides the first evidence for the much higher cancer preventive activity of δ-T and γ-T than α-T in a chemically induced colon carcinogenesis model. It further suggests that δ-T is more effective than γ-T.
