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Isoflavones are a type of often naturally occurring isoflavonoids, many of which act as phytoestrogens in mammals. Some are termed antioxidants because of their ability to trap singlet oxygen. Isoflavones are produced almost exclusively by the members of the ''Fabaceae'' (i.e., ''Leguminosae'', or bean) family. Isoflavones (and closely related phytoestrogens) have grown popular as dietary supplements, but there are few studies showing any benefits from these compounds, and their use is viewed within the scientific and medical community as pseudoscience. Some studies have also identified significant risks from isoflavones. ==Organic chemistry and biosynthesis== Isoflavones of nutritional interest are substituted derivatives of isoflavone, being related to the parent by the replacement of two or three hydrogen atoms with hydroxyl groups. The parent isoflavone is of no nutritional interest. Isoflavone differs from flavone (2-phenyl-4''H''-1-benzopyr-4-one) in location of the phenyl group. Isoflavones are produced via a branch of the general phenylpropanoid pathway that produces flavonoid compounds in higher plants. Soybeans are the most common source of isoflavones in human food; the major isoflavones in soybean are genistein and daidzein. The phenylpropanoid pathway begins from the amino acid phenylalanine, and an intermediate of the pathway, naringenin, is sequentially converted into the isoflavone genistein by two legume-specific enzymes, isoflavone synthase, and a dehydratase. Similarly, another intermediate naringenin chalcone is converted to the isoflavone daidzein by sequential action of three legume-specific enzymes: chalcone reductase, type II chalcone isomerase, and isoflavone synthase. Plants use isoflavones and their derivatives as phytoalexin compounds to ward off disease-causing pathogenic fungi and other microbes. In addition, soybean uses isoflavones to stimulate soil-microbe rhizobium to form nitrogen-fixing root nodules. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Isoflavones」の詳細全文を読む スポンサード リンク
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