Rowland Ian, Faughnan Marian, Hoey Leane, Wähälä Kristiina, Williamson Gary, Cassidy Aedin
Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, UK.
Br J Nutr. 2003 Jun;89 Suppl 1:S45-58. doi: 10.1079/BJN2002796.
The term phyto-oestrogen encompasses isoflavone compounds, such as genistein and daidzein, found predominantly in soya products and the lignans, such as matairesinol and secoisolariciresinol, found in many fruits, cereals and in flaxseed. There is evidence that they have potential health benefits in man particularly against hormone-dependent diseases such as breast and prostate cancers and osteoporosis. This has led to intense interest in their absorption and biotransformation in man. The metabolism of isoflavones and lignans in animals and man is complex and involves both mammalian and gut microbial processes. Isoflavones are present predominantly as glucosides in most commercially available soya products; there is evidence that they are not absorbed in this form and that their bioavailability requires initial hydrolysis of the sugar moiety by intestinal beta-glucosidases. After absorption, phyto-oestrogens are reconjugated predominantly to glucuronic acid and to a lesser degree to sulphuric acid. Only a small portion of the free aglycone has been detected in blood, demonstrating that the rate of conjugation is high. There is extensive further metabolism of isoflavones (to equol and O-desmethylangolensin) and lignans (to enterodiol and enterolactone) by gut bacteria. In human subjects, even those on controlled diets, there is large interindividual variation in the metabolism of isoflavones and lignans, particularly in the production of the gut bacterial metabolite equol (from daidzein). Factors influencing absorption and metabolism of phyto-oestrogens include diet and gut microflora.
植物雌激素一词涵盖异黄酮化合物，如主要存在于豆制品中的染料木黄酮和大豆苷元，以及木脂素，如存在于许多水果、谷物和亚麻籽中的开环异落叶松脂素和落叶松脂醇。有证据表明，它们对人类具有潜在的健康益处，尤其是对激素依赖性疾病，如乳腺癌、前列腺癌和骨质疏松症。这引发了人们对其在人体中的吸收和生物转化的浓厚兴趣。异黄酮和木脂素在动物和人体中的代谢很复杂，涉及哺乳动物和肠道微生物过程。在大多数市售豆制品中，异黄酮主要以糖苷形式存在；有证据表明，它们不以这种形式被吸收，其生物利用度需要肠道β-葡萄糖苷酶先将糖部分水解。吸收后，植物雌激素主要与葡萄糖醛酸重新结合，较少程度上与硫酸结合。在血液中仅检测到一小部分游离苷元，这表明结合率很高。异黄酮（转化为雌马酚和O-去甲基安哥拉紫檀素）和木脂素（转化为肠二醇和肠内酯）会被肠道细菌进一步广泛代谢。在人类受试者中，即使是饮食受到控制的人，异黄酮和木脂素的代谢也存在很大的个体差异，尤其是肠道细菌代谢产物雌马酚（由大豆苷元产生）的生成。影响植物雌激素吸收和代谢的因素包括饮食和肠道微生物群。
