Miroestrol is a

phytoestrogen 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 ...

, a plant-derived chemical that mimics the

biological activity In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or ...

of the hormone

estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...

. 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 is converted to miroestrol.

A comparative study of the estrogenic properties of phytoestrogens found that both deoxymiroestrol and miroestrol were comparable in activity ''

in vitro ''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...

'' to other known phytoestrogens such as coumestrol as 17β-oestradiol

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

s. Because of their estrogenic activities, miroestrol, deoxymiroestrol, and other related compounds have been the targets of scientific research including

total synthesis Total synthesis, a specialized area within organic chemistry, focuses on constructing complex organic compounds, especially those found in nature, using laboratory methods. It often involves synthesizing natural products from basic, commercially ...

. Extracts of '' Pueraria mirifica'' reportedly containing miroestrol are marketed as dietary supplements intended to lead to breast enhancement in women. However, there is a lack of conclusive evidence for such claims. The

Federal Trade Commission The Federal Trade Commission (FTC) is an independent agency of the United States government whose principal mission is the enforcement of civil (non-criminal) United States antitrust law, antitrust law and the promotion of consumer protection. It ...

has taken legal action against marketers for these unproven claims.

References

{{Estrogen receptor modulators Phytoestrogens Natural phenols