Red Clover,
It can go either way, I wouldn't take RC with a history of blood clots, although it's an anti-inflammatory. Here again you'll find contradictory evidence, some obvious ones are on ER-a & ER-b. My opinion?, it's a pro ER-a.......and an aromatase. You'll notice this quote " low dose affects vs. high dose affects" repeat itself.
Genistein, daidzein (Dixon-Shanies & Shaikh 1999), and
biochanin A, a precursor of genistein (Dixon-Shanies & Shaikh 1999; Hsu et al. 2000), all inhibit the growth of the human ER positive breast cancer cells MCF-7. However, genistein (Twaddle et al. 1999), enterolactone and equol (Welshons et al. 1987), a derivative of daidzein, have also been shown to stimulate the growth of MCF-7 cells. The effect of many plant-derived estrogens on the DNA synthesis of MCF-7 cells is biphasic; at low concentrations (0.1-10 μM), genistein, biochanin A and enterolactone stimulate the DNA synthesis, whereas at high concentrations (20-80 μM) their effects are inhibitory (Wang & Kurzer 1997).
This suggests that the low concentrations of plant-derived estrogens cause an estrogenic effect on MCF- 7 cells, but at high concentrations other mechanisms begin to have an influence. For more references see review by Tham et al. (1998).
biochanin A, shown to stimulate the growth of MCF-7 cells. The effect of many plant-derived estrogens on the DNA synthesis of MCF-7 cells is biphasic; at low concentrations (0.1-10 μM), genistein, biochanin A and enterolactone stimulate the DNA synthesis, whereas at high concentrations (20-80 μM) their effects are inhibitory (Wang & Kurzer 1997)
http://www.sciencedirect.com/science/art...0327100529
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Biochanin A (5, 7-dihydroxy-4’-methoxyisoflavone) is an isoflavone extracted from red clover (Trifolium pretense) by Pope et al. [92]. The first evidence that red clover has estrogenic activity were reported by Bennets et al. [93] after observing breeding problems of sheep grazing on red clover pastures which have been attributed to the isoflavone and coumestrol content of red clover. Serious fertility disturbances indicating estrogenic stimulation of cattle fed with red clover silage were reported [94-96]. Although biochanin A was moderately active in inhibiting microsomal aromatase activity (IC50: 5-10 μM) but was
strongly active when tested in JEG-3 cells (human placental choriocarci- noma cell line).
However, it did not inhibit aromatase activity in granulosa-luteal cells, and human preadipocyte cells and was also inactive in trout ovarian aromatase assay [61]. Interestingly, in MCF-7 cells (ER-positive breast cancer cells)
biochanin A exhibited a dual action. It inhibited aromatase activity at low concentrations, but was estrogenic at high concentrations [97]. Furthermore, in SK-BR3 cells (ER-negative breast cancer cells) biochanin A was reported to inhibit aromatase enzyme activity and reduce mRNA expression. By using a luciferase reporter.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3142499/