Equilenin

Equilenin is a steroidal estrogen that is naturally produced by horses, particularly in the urine of pregnant mares[1][2]. It has a total of five double bonds in the A- and B-ring and is classified as a small molecule[1]. Equilenin is known for being the first complex natural product to be fully synthesized in a laboratory, a feat accomplished in 1939 by W. E. Bachmann, Wayne Cole, and A. L. Wilds at the University of Michigan[2]. It is used as a component in conjugated estrogens, such as Premarin, which is a hormone therapy primarily used to treat hot flashes, vaginal burning, and dryness experienced by postmenopausal women who have undergone hysterectomies[2]. However, Premarin has been associated with many adverse side effects and has been replaced by estradiol in some parts of the world[2]. Equilenin and other conjugated equine estrogens are also used to treat certain cancers, although they are suspected of causing cancer as well[2].

Citations:

[1] https://go.drugbank.com/drugs/DB03515

[2] https://www.acs.org/molecule-of-the-week/archive/e/equilenin.html

[3] https://en.wikipedia.org/wiki/Equilenin

[4] https://pubmed.ncbi.nlm.nih.gov/6891343/

[5] https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI%3A34739