Genistein estrogenic activity

Hirsch, K, A Atzmon, M Danilenko, J Levy, and Y Sharoni. 2007. Lycopene and other carotenoids inhibit estrogenic activity of 17 beta-estradiol and genistein in cancer cells. Breast Cancer Res Treat 104 221-230. 

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. 

Isofavonoids have a substituent at C-3. Examples are genistein and for-mononetin (see Fig. 11.11, below). Isoflavones exert estrogenic activity in mammals, interfere with reproduction in birds, and may render farm animals infertile. For example, sheep feeding on isoflavonoid-containing Trifolium suh-terraneum suffer reduced lambing (Harborne, 1993). 

Isoflavonoids are of limited distribution (Fabaceae, bean family) and are probably formed through the epoxidation and rearrangement of the enol form of a flavone (e.g., the conversion of naringenin to genistein Fig. 16). Several isoflavonoids are associated with strong estrogenic activity, and there is interest in their potential in the prevention of hormone-dependent... 

A number of foodstuffs and plant-derived products, largely from soy, are available as nonprescription items and often are touted as providing benefits similar to those from compounds with established estrogenic activity. These products may contain flavonoids such as genistein, which display estrogenic activity in laboratory tests, albeit generally much less than that of estradiol. In theory, these preparations could produce appreciable estrogenic effects, but their efficacy at relevant doses has not been established in human trials. 

Besides the affinity of genistein, daidzein, biochanin A, formononetin, coumestrol and some other flavonoids, there is little information regarding other isoflavones, of which more than 300 have been reported to exist [6], One such example is glycitein, whose estrogenic activity has been reported in one study. The data indicated that glycitein, when fed to female mice at 3 mg/day for 4 days, produced weak estrogenic activity comparable to that of other isoflavones, but much lower than that produced by diethylstilbestrol and 17[3-estradiol [54],... 

Isoflavones Genistein, daidzein, formononetin (D 22.3.3) Estrogenic activity in mammals and birds... 

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... 

Isoflavonoids show fungicidal and bactericidal effects. They play an important role as constitutive constituents and also as phytoalexins. From the pharmacological point of view estrogenic activity of isoflavones such as genistein and daidzein is of increasing relevance (Harbome and Williams 2000). Rotenoids, especially rotenone, are potent insecticides. 

Coumestrol, genistein, biochanin A, and daidzein have estrogenic activities on ruminants. Stndies have also demonstrated that coumestrol when fed to pullets increases the age of matnrity and depresses egg... 

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