A nonsteroidal estrogen is an estrogen with a nonsteroidal chemical structure. The most well-known example is the stilbestrol estrogen diethylstilbestrol (DES). Although nonsteroidal estrogens formerly had an important place in medicine, they have gradually fallen out of favor following the discovery of toxicities associated with high-dose DES starting in the early 1970s, and are now almost never used. On the other hand, virtually all selective estrogen receptor modulators (SERMs) are nonsteroidal, with triphenylethylenes like tamoxifen and clomifene having been derived from DES, and these drugs remain widely used in medicine for the treatment of breast cancer among other indications. In addition to pharmaceutical drugs, many xenoestrogens, including phytoestrogens, mycoestrogens, and synthetic endocrine disruptors like bisphenol A, are nonsteroidal substances with estrogenic activity.
Pharmacology
Nonsteroidal estrogens act as agonists of the estrogen receptors, ERα and ERβ.
List of nonsteroidal estrogens
Synthetic
Pharmaceutical
Stilbestrols: benzestrol, bifluranol, dienestrol, diethylstilbestrol, dimestrol, fosfestrol, furostilbestrol, hexestrol, mestilbol, methestrol, pentafluranol, phenestrol, terfluranol, stilbestrol esters Triphenylethylenes: chlorotrianisene, desmethylchlorotrianisene, estrobin (), M2613, triphenylbromoethylene, triphenylchloroethylene, triphenyliodoethylene, triphenylmethylethylene Secosteroids (open-ring steroids): allenestrol, allenolic acid, bisdehydrodoisynolic acid, carbestrol, doisynoestrol, doisynolic acid, fenestrel, methallenestril Selective ERα or ERβ agonists: diarylpropionitrile, ERB-196, erteberel, FERb 033, GTx-758, prinaberel, propylpyrazoletriol, WAY-166818, WAY-214156 Others: , paroxypropione, quadrosilan, tetrahydrochrysene
SERMs like tamoxifen and raloxifene can also be considered to be nonsteroidal estrogens in some tissues.
Environmental
Synthetic xenoestrogens: alkylphenols, bisphenols (e.g., bisphenol A), parabens, phthalates, polyhalogenated compounds
Natural
Metalloestrogens: cadmium, others
Mycoestrogens: taleranol (β-zearalanol), α-zearalenol, β-zearalenol, zearalanone, zearalenone, zeranol (α-zearalanol) Phytoestrogens: coumestrol, daidzein, deoxymiroestrol, equol, genistein, miroestrol, many others