Genistein

Isoflavones, such as genistein and daidzein, occur in soybeans and various other plants, including lupin, fava beans, kudzu, psoralea, Flemingia vestita, and coffee. It is present in red clover. ==In soybean products==

Isoflavone intake from consuming soy products may be as high as 50 mg per day in Asian cuisines, and is increasing in western culture with the shift to vegan and vegetarian diet culture. Dietary supplements and infant formulas containing isoflavone extracts are marketed in some countries. == Biosynthesis ==

Genistein is an isoflavone, which are isomers of the large group of plant metabolites called flavones. Its biosynthesis begins in a phenylpropanoid metabolic pathway from the amino acid phenylalanine. After several steps, the intermediate flavanone, naringenin, is formed. It can undergo a rearrangement reaction which converts it first to the unstable hydroxlated isoflavanone, which loses water to give the isoflavone. The enzymes involved are isoflavonoid synthase and 2-hydroxyisoflavanone dehydratase. ==Metabolism, bioavailability, and safety==

Pharmacokinetics studies indicate that genistein blood concentrations peak about 6 hours after a meal containing isoflavones, which are hydrolized in the small intestine and colon. a GRAS determination specifically for genistein has not been reported. ==Potential for estrogenic activity==

Because soy isoflavones have similar chemical structure to 17-β-estradiol, the potential for genistein as an estrogenic (hormone-like) signaling molecule that binds to estrogen receptors within cells, mimicking the action of estrogen, has been the subject of research. Estrogenic effects by genistein may affect the risk of hormone-associated cancers in reproductive tissues, such as the breast, uterus, testis, or prostate gland, while it may also influence bone density and levels of blood lipids. ==Human research==

Although the potential for genistein to have diverse biological activity in humans has been extensively studied, there is only limited evidence of its specific effects. The panel further concluded that there was insufficient evidence that soy isoflavones could affect normal skin tone, respiratory functions, cardiovascular health, or prostate cancer. Some studies indicate that supplementation with genistein and soy isoflavones may reduce hot flashes and night sweats during menopause, while there is insufficient evidence for an effect on osteoporosis and cognitive function. ==Laboratory research==

In vitro, genistein is an agonist of the G protein-coupled estrogen receptor, and binds to and activates all three peroxisome proliferator-activated receptor isoforms, α, δ, and γ. Genistein is a tyrosine kinase inhibitor, mostly of epidermal growth factor receptors. Genistein was subsequently demonstrated to be effective against intestinal parasites, such as the poultry cestode Raillietina echinobothrida, and the sheep liver fluke Fasciola hepatica. It exerts its anthelmintic activity by inhibiting enzymes of glycolysis and glycogenolysis in the parasites. ==Related compounds==

• Genistin is the 7-O-beta-D-glucoside of genistein. • Wighteone can be described as 6-isopentenyl genistein ==See also==