Phytoestrogens Formononetin

The phytoestrogens (isoflavones) contain a flavone nucleus. Examples of isoflavones are genistein, formononetin and coumestrol, all with potent estrogenic activity. Soybean isoflavones are a concern in human nutrition because of their estrogenic benefits. 

In 1987, Ken Setchell first described the method for the isolation of phytoestrogen in soy (Setchell et al., 1987). The phytoestrogens daidzein, genistein, coumestrol, formononetin, and biochanin-A were separated on a Cl8 reversed-phase column (Hypersil ODS) with methanol-0.1 M ammonium acetate buffer, pH 4.6 (60 40 v/v), as eluent. The retention and resolution were affected by buffer concentrations, pH type, and proportion of organic solvent in the mobile phase. Detection in the low picograms range was achieved with an electrochemical detector, and the compounds were positively identified by HPLC-thermospray mass spectrometry. 

Trifolium pratense L. T. repens L. Che Zhou Cao (Red clover) (whole plant) Phytoestrogens, genisteine, iodine, daidzein, formononetin.33-48-221 Stimulating effect on female reproductive organs. 

Trifolium pratense L. China Phytoestrogens, genistein, daidzein, formononetin.33-48 Stimulating effect on female reproductive organs. 

Reinli and Block (1996) developed a compendium of literature values with 36 references for phytoestrogens (coumestrol, daidzein, genistein, biochanin A and formononetin) in foods. They also reported the relative potency of these phytoestrogen and equol (metabolites found in urine) in vitro and in vivo. Similar to the USDA-ISU database, this database reported total daidzein and genistein, which were estimated by the hydrolysis method or by normalizing the molecular weight differences of... 

Fluorescence and ED can provide better sensitivity compared to UV detection, but only some phytoestrogens like daidzein, formononetin, and coumestrol have fluorescence response whUe using ED at an operating potential above 1.2 V creates baseline instability." The weaknesses of these detection methods are their low sensitivity and nonspecihcity leading to the possibility of sample matrix interference." ... 

FIGURE 25.1 Structures of nonsteroidal phytoestrogens. The most prevalent classes of phytoestrogens are (1) flavones apigenin (2) kaempferol (3) isoflavones daidzein (4) genistein (5) formononetin (6) biochanin A (7) lignans enterolactone (8) coumestans coumestrol (9) flavanones 8-prenylnaringenin. 

A recent study found that mycorrhizal red clover showed impaired levels of isoflavones with estrogenic activity, such as biochanin A, formononetin, genistein, or daidzein [150], and natural plant metabolites called phytoestrogens, which are believed to play an important preventive role in osteoporosis, menopausal... 

FIGURE 1.8 High-performance hquid chromatography (HPLC) separation of urinary phytoestrogens (a) and standards (h) monitored at 260 and 280 nm (insert). Peak ideutificatioD DE, daidzein GE, genistein COM, coumestrol FOR, formononetin B-A, biochanin A flavone, internal standard. (Reprinted with pomission from Franke, A.A., Custer, L.J., Cema, C.M., and Narala, K., Proc. Soc. Exp. BioL Med., 208, 18-26, 1995.)... 

Lundh, T.J.O., Pettersson, J., and Kiessling, K.H., Liquid chromatographic determination of the phytoestrogens daidzein, formononetin, coumestrol, and equol in bovine blood plasma and urine, J. Assoc. Off. Anal. Chem., 71, 938-941, 1988. 

Brandon, 2001). The individual isoflavones may have different biological activity and certain combination of isoflavones may act synergistically or antagonistically (Rayburn et al., 1995). The presence of other phytoestrogens (biochanin A, coumesterol, and formononetin) in the soybean diet could also influence the results (Kudou et al., 1991). 

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