Tenovus Cancer Research Centre, Cardiff CF4 4XN, UK.
Environ Toxicol Pharmacol. 1999 Jul;7(3):221-5. doi: 10.1016/s1382-6689(99)00018-6.
The metabolites of oestrogenic substances of plant origin, phyto-oestrogens, have been proposed as cancer-protective agents in Asian and vegetarian populations. The two principle classes of these weak oestrogens are isoflavonoids and mammalian lignans. The former is derived from soya-based foods and the latter from oilseeds, cereals and whole grains. Asian populations such as the Japanese have high plasma concentrations of the isoflavones, daidzein and genistein, whereas vegetarians excrete large quantities of the lignan enterolactone, in their urine. The concentrations of these compounds in biological samples and foods are usually determined by GC-MS, although other techniques such as HPLC and LC-MS have also been used. A simple, robust method employing isotope dilution GC-MS will be described which could be applied to the determination of phyto-oestrogens in biological samples and food matrices. Briefly, samples are hydrolysed with β-glucuronidase, the aglycones extracted and the phyto-oestrogen fraction isolated by chromatography on Sephadex LH20. This fraction is then derivatised for GC-MS by reaction with N,O-bistrimethylsilyl-triflouroacetatamide to form trimethylsilyl derivatives. Using this technique we have determined the concentrations of the lignans, enterodiol and enterolactone, and the isoflavonoids, equol, daidzein and genistein, in the serum of men from Japan (n=42). The mean levels of daidzein and genistein in these men were 82.5 ng/ml (range 1.9-577) and 158.6 ng/ml (range 5.3-852), respectively. The majority of these men (57%) produced equol concentrations of >5 ng/ml, with a mean value of 26.7 ng/ml. Mean Levels of enterodiol and enterolactone were 0.6 and 9.4 ng/ml, respectively. The levels of daidzein and genistein produced from the hydrolysis of soya bean hulls, soya bean hypocotyl, dehulled soya beans, soya flour, soya grit and soya concentrates have also been determined by this method. Soya bean hypocotyl, for example, produces 2.1 mg/g of daidzein and 1.2 mg/g genistein, whereas some concentrates yield as much as 40% isoflavones.
植物雌激素代谢物，植物雌激素，已被提议作为亚洲和素食人群的抗癌保护剂。这些弱雌激素的两个主要类别是异黄酮和哺乳动物木酚素。前者来源于大豆类食品，后者来源于油籽、谷物和全谷物。日本人等亚洲人血浆中异黄酮大豆苷元和染料木黄酮的浓度较高，而素食者尿液中则大量排泄木酚素肠内酯。这些化合物在生物样本和食物中的浓度通常通过 GC-MS 来确定，尽管也使用了其他技术，如 HPLC 和 LC-MS。将描述一种简单、强大的方法，该方法采用同位素稀释 GC-MS，可以应用于生物样本和食物基质中植物雌激素的测定。简而言之，样品用β-葡萄糖醛酸酶水解，苷元提取，植物雌激素通过 Sephadex LH20 色谱分离。然后通过与 N,O-双三甲基硅基三氟乙酰胺反应将该馏分衍生化，形成三甲基硅烷基衍生物。使用该技术，我们已经确定了来自日本的男性（n=42）血清中木酚素、肠二醇和肠内酯以及异黄酮、结合物、大豆苷元和染料木黄酮的浓度。这些男性的大豆苷元和染料木黄酮的平均水平分别为 82.5ng/ml（范围 1.9-577）和 158.6ng/ml（范围 5.3-852）。这些男性中的大多数（57%）产生的结合物浓度>5ng/ml，平均值为 26.7ng/ml。肠二醇和肠内酯的平均水平分别为 0.6 和 9.4ng/ml。通过该方法还确定了大豆豆皮、大豆胚轴、去壳大豆、大豆粉、大豆粗粉和大豆浓缩物水解产生的大豆苷元和染料木黄酮的水平。例如，大豆胚轴产生 2.1mg/g 的大豆苷元和 1.2mg/g 的染料木黄酮，而一些浓缩物的异黄酮含量高达 40%。
