In vitro metabolism of red clover isoflavones in rumen fluid

Abstract

Isoflavones are plant secondary metabolites that take part in plant defence mechanisms, have functions in attraction of pollinators (Daems, Decruyenaere, et al., 2016) or establish the symbiotic relationship between the plant and rhizobial bacteria to form root nodules (Yu et al., 2000). Moreover, they also have numerous human health benefits (Adler et al., 2014). Because of their similarity to 17β-estradiol, these polyphenolic compounds are a part of a group called phyto-oestrogens (Daems, Romnee, et al., 2016).

In sacco evaluation of ruminal degradability of isoflavones from full‐fat soybean and extracted soybean meal—A pilot study

“…Similarly, rapid degradation of formononetin, daidzein, biochanin A and genistein within 4 to 6 h of incubation in rumen fluid was described in early study of Dickinson et al (1988). Further, recent studies of Trnková et al (2018) and Dadáková et al (2020) confirmed this rapid metabolism of isoflavones manifested also by the increases in equol production starting after about 3 h of incubation in rumen fluid in vitro. Degradation rate of daidzein and genistein in the rumen found in our study corresponds with the half-lives of those isoflavones in the rumen fluid determined by Dickinson et al (1988), being 9.3 h for daidzein and 5.5 h for genistein.…”

“…Production of metabolites can be observed after 3 h of incubation in the rumen fluid in vitro (Dadáková et al, 2020;Trnková et al, 2018).…”

Production of Bovine Equol-Enriched Milk: A Review

“…Therefore, milk and dairy products can be considered to be a source of equol for humans not able to produce this metabolite [ 53 , 54 ]. However, for the purposes of functional food production, the feed of dairy cattle, as well as milk processing should be considered, as these parameters substantially influence equol concentrations [ 53 , 55 , 56 ].…”

“…Dietary isoflavones are extensively metabolized in the rumen by ruminal microorganisms [ 51 ]. Their half-lives in the bovine rumen fluid are 4.3 h for formononetin, 9.3 h for daidzein, 3.9 h for biochanin A, and 5.5 h for genistein [ 84 ] and their metabolites occur after 3 h of incubation in the rumen fluid in vitro [ 55 , 56 ]. Concerning the main metabolites, formononetin is demethylated to daidzein, and then further metabolized to equol, a compound with significant estrogenic activity, while biochanin A is demethylated to genistein and further converted to p-ethyl-phenol with no estrogenic activity [ 5 ].…”

“…Concerning the main metabolites, formononetin is demethylated to daidzein, and then further metabolized to equol, a compound with significant estrogenic activity, while biochanin A is demethylated to genistein and further converted to p-ethyl-phenol with no estrogenic activity [ 5 ]. The course of metabolism in the rumen can be influenced by the type of diet and by the concentration of isoflavones in the diet [ 55 , 56 ]. Moreover, interaction between isoflavones and rumen bacteria should be also considered, as stimulatory/inhibitory effects of isoflavones on growth of some rumen bacteria were recently reported [ 85 , 86 , 87 ].…”