Isoflavone Isoflavone Electromagnetic telegraph Category="Flavonoids"This article needs to be cleaned up to conform to a higher standard of quality

Isoflavones are flavonoids acting as phytoestrogens that are thought of by many as useful in treating Cancer.

Isoflavones are polyphenolic compounds produced almost exclusively by the members of the Leguminosae family (bean-family). They are long known for their Estrogen-like effect on mammals. Because of this nature, they are used as plant derived estrogen supplements by post-menopausal women. While they alleviate most symptoms associated with Menopause such as Osteoporosis, they do not have the unwanted side-effects of estrogen such as Breast cancer. In addition, they also are potent antioxidants and thought to provide protection against several types of cancers. Other health benefits of isoflavones have been documented as well.

History

Early evidence that plants produced estrogen-like compounds occurred from the observation of Infertility among Sheep that ate large amounts of Clover in Australia. Similarly, Californian Quails were thought to feed on high isoflavone legume seeds during periods of food shortage to reduce their fertility.

Biosynthesis

Isoflavones are produced from a branch of the general phenylpropanoid pathway that produces all Flavonoid compounds in higher plants. Soybeans are the most common source of isoflavones and 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 in to 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.

Occurrence

Soybeans contain the most abundant levels of isoflavones (primarily dadizein and genistein) among all plants. While tofu retains a significant amount of isoflavones, highly processed soy based foods such as Soy sauce or infant formula contain only negligible amounts of these compounds. Kudzu vine (Pueraria lobata) roots also have abundant levels of isoflavones (mostly puerarin). Other dietary sources of isoflavones include chick pea (biochanin A), Alfalfa sprouts (formononetin and coumestrol) and Peanuts (genistein).