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.[2] 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.[3]
Coumestrol is a phytoestrogen, mimicking the biological activity of estrogens. Phytoestrogens are able to pass through cell membranes due to their low molecular weight and stable structure, and they are able to interact with the enzymes and receptors of cells.[4] Coumestrol binds to the ERα and ERβ with similar affinity to that of estradiol (94% and 185% of the relative binding affinity of estradiol at the ERα and ERβ, respectively),[5] although the estrogenic activity of coumestrol at both receptors is much less than that of estradiol.[6] In any case, coumestrol has estrogenic activity that is 30 to 100 times greater than that of isoflavones.[7]
The chemical shape of coumestrol orients its two hydroxy groups in the same position as the two hydroxy groups in estradiol, allowing it to inhibit the activity of aromatase and 3α-hydroxysteroid dehydrogenase.[8] These enzymes are involved in the biosynthesis of steroid hormones, and inhibition of these enzymes results in the interference with hormone metabolism.[9]
^Bickoff, E. M.; Livingston, A. L.; Witt, S. C.; Knuckles, B. E.; Guggolz, Jack; Spencer, R. R. (1964). "Isolation of coumestrol and other phenolics from alfalfa by countercurrent distribution". Journal of Pharmaceutical Sciences. 53 (12): 1496–9. doi:10.1002/jps.2600531213. PMID14255129.
^Ososki, Andreana L.; Kennelly, Edward J. (2003). "Phytoestrogens: a Review of the Present State of Research". Phytotherapy Research. 17 (8): 845–869. doi:10.1002/ptr.1364. PMID13680814. S2CID32550431.
^Blomquist CH, Lima PH, Hotchkiss JR (2005). "Inhibition of 3a-hydroxysteoid dehydogenase (3a-HSD) activity of human lung microsomes by genistein, daidzein, coumestrol and C18-, C19- and C21 hydroxysteroids and ketosteroids". Steroids. 70 (8): 507–514. doi:10.1016/j.steroids.2005.01.004. PMID15894034. S2CID54388469.
^Amr Amin; Michael Buratovich (2007). "The Anti-Cancer Charm of Flavonoids: A Cup-of-Tea Will Do!". Recent Patents on Anti-Cancer Drug Discovery. 2 (2): 109–117. doi:10.2174/157489207780832414. PMID18221056.