Equol: Pharmacokinetics and Biological Actions ,

Abstract

Equol [7-hydroxy-3-(4'-hydroxyphenyl)-chroman], an isoflavan produced by intestinal bacteria in response to soy isoflavone intake in some but not all humans, exhibits a wide range of biological properties. It exists as the diastereoisomers S-(-)equol and R-(+)equol. Intestinal bacteria produce exclusively S-(-)equol, which has selective affinity for estrogen receptor (ER)-beta. The evidence is conflicting on whether there is an advantage to producing S-(-)equol in response to soy isoflavone intakes, but the ability to now synthesize these diastereoisomers opens the way for future clinical trials to directly examine their potential in a number of hormone-dependent conditions. In this review, the plasma and urinary pharmacokinetics of S-(-)equol and R-(+)equol are reviewed and summarized, and some of the more recent evidence supporting potential biological effects of S-(-)equol is considered.

Epidemiological profiles between equol producers and nonproducers: a genomewide association study of the equol-producing phenotype

“…Equol has a similar structure to estradiol and has high affinity for ER, acting as its ligand (Setchell and Clerici 2010). Based on these data, we speculate that HACE1 expression in individuals with the major allele (harboring AP-1 sites) is altered by the equol-ER complex that is bound to AP-1 sites.…”

The Soy Isoflavone Equol May Increase Cancer Malignancy via Up-regulation of Eukaryotic Protein Synthesis Initiation Factor eIF4G

“…Equol is a chiral molecule capable of existing in two enantiomeric forms: R-(ϩ) equol and S-(Ϫ) equol; the latter is the natural diasteromer produced by intestinal bacteria (6,11). Both equol enantiomers show better uptake and have higher bioavailability (65-83%) than the isoflavones daidzein (30 -40%) or genistein (7-15%) (57).…”

“…1). In rodents, equol is the major circulating metabolite, and all rodents are equol producers (6,11). Therefore, we reasoned that the daidzein effects on MDA-MB-435 metastatic cell lines in vivo may be due to the metabolite equol.…”

“…Unlike the metabolite O-desmethylangolensin, which has low biological activity (6,11), equol is structurally similar to estrogen with 80 times more estrogen receptor-␤ (ER␤) 2 affinity than its precursor daidzein (11)(12)(13). Equol has been implicated with decreased prostate cancer cell proliferation and prostate cancer risk by acting as an antagonist for dihydrotest-erone (14,15).…”

Isoflavonas de soya y salud humana: cáncer de mama y sincronización de la pubertad

“…Las ISO glicosiladas no se pueden absorber como tal, pero en el intestino son hidrolizadas por enzimas de la microfl ora a las respectivas formas agliconas activas 2 . Cabe mencionar además que el equol, un metabolito de la daidzeina producido en el intestino de solamente 30% de la población humana occidental, es un potente compuesto bioactivo 3 .…”