are known as phytoestrogens (natural estrogen) and have similar but lower
effects including hormonal and nonhormonal actions because of broadly
similarity to the main female hormone, estradiol. Isoflavones act at the level
of hypothalamus and pituitary to alter gonadotropin secretion and serves as
both agonist and antagonist and it is dose-dependent effect.
show a competitive binding for mammary tissue estrogen receptors, raising the
possibility of stimulation of estrogen- dependent neoplasm. In large doses, the
phytoestrogens inhibit breast cancer development and suppress tumor growth.
protective effect against cancer may be due to its inhibition of growth-promoting
steroid hormone metabolism by inhibiting 5α- reductase and 17β- hydroxyl
steroid dehydrogenase. Genistein is a potent inhibitor of protein tyrosin
kinase (PTK), which plays an important role in cell growth and smooth muscle
contraction. Because of this inhibitory effect, genistein can cause an
apoptosis of cancer cells and reduce the proliferation of human malignant