Polyphenols estrogenic activities

Kurarinone (13) of a lavandulyl flavanone was isolated from a polyphenolic extract of the roots of Sophora flavescens. First, kurarinone (13) had weak estrogenic activity both in the yeast screen and in the Ishikawa Var-I assay with EC50 values of 4.6 and 1.66 p,M, respectively. Second, kurarinone (13) had the potent cytotoxic activity (IC50) value = 22.2 jlM) against human MCF-7/6 breast cancer cells in the sulforhodamine-B assay (Fig. 19) [18]. 

An extract of the polyphenolic compounds from epimedium (E. brevicomum) exhibited estrogenic activity in estrogen-responsive bioassays, a yeast cell assay, and the Ishikawa Var-I assay (De Naeyer et al. 2005). 

Ti-awx-resveratrol is an especially important polyphenol derivative in wine from the viewpoint of anticancer effects. The chemical stracture of this compound resembles the hormone estradiol (Fig. 2.18). The substance in fact binds to estrogen receptors, it is sometimes called a phytoestrogen ( 3.24). However, resveratrol is much more important than its minor estrogen activity would make it appear. A very intensely studied— and also hotly debated—recent question is about the enhancement of the activity of an enzyme called sirtuirr Some researchers think that resveratrol increases this activity and helps preserve healthy cell functions. Some in vitro studies support this theory, but human clinical tests are still missing. Trans-... 

Natural products have been noted for their potential health benefits from time immemorial and are the basis of Ayurveda, an ancient Indian medical practice (Bushkin and Bushkin, 2002). However, the potential benefits of several natural products reside in one or two active ingredients. For example green tea stands for polyphenols, soy for soy estrogens, broccoli for isothiocyanates and grape seed for polyphenols. The beauty of rice bran is that there are more than 100 antioxidants, several categories of bioactive phytonutrients, such as IP6, polyphenols, phytosterols, tocotrienols, y-oryzanol, B vitamins, minerals and trace minerals in addition to fat, protein, fiber, polysaccharides and other nutrients. These phytonutrients and antioxidants of rice bran are believed to act at the cellular level, and their synergestic function is responsible for the positive health benefits. 

Anter E, Chen K, Shapira OM, Karas RH, Keaney JF Jr. 2005. p38 mitogen activated protein kinase activates eNOS in endothelial cells by an estrogen receptor alpha-dependent pathway in response to black tea polyphenols. Circ Res 96 1072-1078. 

Wfe have recently carried out experiments with cell-based and animal models of inflammatory diseases. The experiments have revealed that human polymorphonuclear cells once activated with phorbol esters to cause an inflammatory response produce copious amounts of chlorinated polyphenol species. Rats treated with lipopolysaccharide (LPS) in an in vivo model of inflammatory disease heavily nitrate polyphenols in tissues (e.g., lung and liver) where inflammatory cell invasion occurs. These modified polyphenols are better antioxidants than their parent compound. Using a luciferase reporter gene assay in COS cells, both chloro- and nitrogenistein were shown to have 1-2 orders lower estrogen receptor activation than genistein itself. In summary, metabolism of polyphenols is rampant, but not always inactivating. 

A previous study also shows that green tea catechins, including epicatechin gallate (ECG) and EGCG, are potential aromatase inhibitors. We have demonstrated that black tea polyphenols strongly suppress aromatase activity in vitro and in vivo. They can also act as a HER2/neu tyrosine kinase inhibitor and attenuate tamoxifen-resistant breast tumors in estrogen-independent breast cancer cells. Further evalua-... 

Penttinen P, Jaehrling J, Damdimopoulos AE, et al. Diet-derived polyphenol metabolite enterolactone is a tissue-specific estrogen receptor activator. Endocrinology. 2007 148 4875-4886. 

Chemler JA, Lim CG, Daiss JL, Koffas MAG (2010) A versatile microbial system for biosynthesis of novel polyphenols with altered estrogen receptor binding activity. Chem Biol 17 392-401... 

Isopaucifloral P, quadrangularin A, and paUidol are natural polyphenols that belong to the resvera-trol family and possess a variety of biological activities. In particular, pallidol shows estrogen-like... 

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