Phytoestrogens

Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a stilbenoid, a type of natural phenol or polyphenol and a phytoalexin produced by several plants in response to injury or when the plant is under attack by pathogens, such as bacteria or fungi. Sources of resveratrol in food include the skin of grapes, blueberries, raspberries, mulberries, and peanuts.

thumb|right|class=skin-invert-image|UV visible spectrum of quercetin, with lambda max at 369 nm

A phytoestrogen is a plant-derived xenoestrogen (a type of estrogen produced by organisms other than humans) not generated within the endocrine system, but consumed by eating plants or manufactured foods. Also called a "dietary estrogen", it is a diverse group of naturally occurring nonsteroidal plant compounds that, because of its structural similarity to estradiol (17-β-estradiol), have the ability to cause both estrogenic or antiestrogenic effects.

Genistein (C15H10O5) is a plant-derived, aglycone isoflavone. Genistein has the highest content of all isoflavones in soybeans and soy products, such as tempeh. As a type of phytoestrogen, genistein is classed as an endocrine disrupting chemical due to its estrogenic activity in vitro and in vivo. Consequently, excessive consumption of soy products has been linked to disruption of the reproductive organs, such as the uterus, breast, and testis.

Apigenin (4′,5,7-trihydroxyflavone), found in many plants, is a flavone compound that is the aglycone of several naturally occurring glycosides. It is a yellow crystalline solid that has been used to dye wool.

Hydroxytyrosol is an organic compound with the formula . It is a phenylethanoid, i.e. a relative of phenethyl alcohol. Its derivatives are found in a variety of natural sources, notably olive oils and wines. Hydroxytyrosol is a colorless solid, although samples often turn beige during storage. It is a derivative, formally speaking, of catechol.

Oleuropein is a glycosylated seco-iridoid, a bitter phenolic compound found in green olive skin, flesh, seeds, and leaves. The term oleuropein is derived from the botanical name of the olive tree, Olea europaea.

Isoflavones are a type of naturally occurring isoflavonoids, many of which act as phytoestrogens in mammals. Isoflavones occur in many plant species, but are especially high in soybeans.

Naringenin is a flavanone from the flavonoid group of polyphenols. It is commonly found in citrus fruits, especially as the predominant flavonone in grapefruit.

Kaempferol (3,4′,5,7-tetrahydroxyflavone) is a natural flavonol, a type of flavonoid, found in a variety of plants and plant-derived foods, including kale, beans, tea, spinach, and broccoli. It is also found in propolis extracts. Kaempferol is a yellow crystalline solid with a melting point of . It is slightly soluble in water and highly soluble in hot ethanol, ethers, and DMSO. Kaempferol is named for 17th-century German naturalist Engelbert Kaempfer.

β-Sitosterol (beta-sitosterol) is one of several phytosterols (plant sterols) with chemical structures similar to that of cholesterol. It is a white, waxy powder with a characteristic odor, and is one of the components of the food additive E499. Phytosterols are hydrophobic and soluble in alcohols.

Daidzein (7-hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one) is a naturally occurring compound found exclusively in soybeans and other legumes, and structurally belongs to a class of compounds known as isoflavones. Daidzein and other isoflavones are produced in plants through the phenylpropanoid pathway of secondary metabolism and are used as signal carriers, and defense responses to pathogenic attacks. Upon consumption of isoflavone-rich foods, daidzein has poor bioavailability and low water solubility.

Coumestrol is a natural organic compound in the class of phytochemicals known as coumestans. Coumestrol was first identified as a compound with estrogenic properties by E. M. Bickoff in ladino clover and alfalfa in 1957. It has garnered research interest because of its estrogenic activity and prevalence in some foods, including soybeans, brussels sprouts, spinach and a variety of legumes. The highest concentrations of coumestrol are found in clover, Kala Chana (a type of chick pea), and Alfalfa sprouts.

Equol (4',7-isoflavandiol) is an isoflavandiol estrogen metabolized from daidzein, a type of isoflavone found in soybeans and other plant sources, by bacterial flora in the intestines. While endogenous estrogenic hormones such as estradiol are steroids, equol is a nonsteroidal estrogen. Only about 30–50% of people have intestinal bacteria that make equol.

chemical compound

Miroestrol is a phytoestrogen, a plant-derived chemical that mimics the biological activity of the hormone estrogen. Miroestrol was first reportedly isolated from the Thai herb Pueraria mirifica in 1960 and thought to be responsible for the supposed rejuvenating properties of the plant. However, more recent studies have suggested that the active ingredient may actually be the closely related chemical compound deoxymiroestrol (shown below), and the reported presence of miroestrol may only have been an artifact of the isolation procedure. When deoxymiroestrol is exposed to the oxygen in air, it

Enterolactone is an organic compound classified as an enterolignan. It is formed by the action of intestinal bacteria on plant lignan precursors present in the diet.

alt=Flaxseed is poured from a jar into the hand.|thumb|One of the ingredients in Femarelle is flaxseed.

8-Prenylnaringenin (8-PN; also known as flavaprenin, '(S)-8-dimethylallylnaringenin, hopein, or sophoraflavanone B') is a prenylflavonoid phytoestrogen. It is reported to be the most estrogenic phytoestrogen known. The compound is equipotent at the two forms of estrogen receptors, ERα and ERβ, and it acts as a full agonist of ERα. Its effects are similar to those of estradiol, but it is considerably less potent in comparison.

Coronaridine, also known as 18-carbomethoxyibogamine, is an alkaloid found in Tabernanthe iboga and related species, including Tabernaemontana divaricata for which (under the now obsolete synonym Ervatamia coronaria) it was named.

Liquiritigenin is a flavanone that was isolated from Glycyrrhiza uralensis, and is found in a variety of plants of the Glycyrrhiza genus, including Glycyrrhiza glabra (licorice). It is an estrogenic compound which acts as a selective agonist of the ERβ subtype of the estrogen receptor (ER), though it is also reported to act as an ERα partial agonist at sufficient concentrations. It also has a choleretic effect.