Polyphenolics isoflavones

Flavonoids are a complex group of polyphenolic compounds with a basic C6-C3-C6 structure that can be divided in different groups flavonols, flavones, flavanols (or flavan-3-ols), flavanones, anthocyanidins, and isoflavones. More than 6,000 flavonoids are known the most widespread are flavonols, such as quercetin flavones, such as lu-teolin and flavanols (flavan-3-ols), such as catechin. Anthocyanidins are also bioactive flavonoids they are water-soluble vegetable pigments found especially in berries and other red-blue fruits and vegetables. 

On patients with cancer, the effects of green tea catechins, soy isoflavones and quercetin as chemoprotective/chemotherapeutic agents have also been studied. Although results have not been entirely satisfactory, a partial response has been achieved in some trials. For example, small decreases in plasma concentration of prostate-specific antigen were observed in prostate cancer patients who consumed soy isoflavones. Nevertheless, results in individuals with premalignant disease who consumed green tea polyphenols support their advancement into phase III clinical intervention trials aimed at the prevention of PIN, leukoplakia, or premalignant cervical disease (Thomasset and others 2006). 

Phytoestrogens are a diverse group of polyphenolic non-steroidal plant compounds that bind to human estrogen receptors (Cos et al., 2003). The best studied of these compounds are the isoflavones, the phytoestrogens present in soy and red clover. 

D Alessandro T, Prasain J, Benton MR et al. Polyphenols, inflammatory response, and cancer prevention chlorination of isoflavones by human neutrophils. J. Nutr. 133, 3773S-3777S, 2003. Boersma BJ, D Alessandro T, Benton MR et al. Neutrophil myeloperoxidase chlorinates and nitrates soy isoflavones and enhances their antioxidant properties. Free Radical Biol. Med. 35, 1417-1430, 2003. 

Flavonoids constitute a large class of polyphenols found in fruits and vegetables that share a common skeleton of phenylchromane. This basic structure allows a large number of substitution patterns leading to several subclasses of flavonoids, such as flavonols, flavones, flavanones, flavanols, anthocyanidins, isoflavones, dihydroflavonols, and chalcones. Among the diverse flavonoid subclasses, flavonols (especially quercetin) and flavanols (catechins) are the most abundant in our food. Flavonols are present in foods as diverse glycosides, whereas flavanols are usually found as aglycones. 

Vaclavikova et al. [216] have investigated the effect of 13 flavonoid derivatives—aurones, chalcones, flavones, flavonols, chromones, and isoflavones—on 14 C-paclitaxel transport in two human breast cancer cell lines, the doxorubicin-resistant NCI/ADR-RES and sensitive MDA-MB-435. The compounds with known binding affinity toward the NBD of P-gp were selected. The four aurones studied most effectively inhibited P-gp-related transport in the resistant fine in comparison with other groups of flavonoids. The aurones also most effectively increased the intracellular accumulation of paclitaxel and decreased its efflux. The results obtained did not always correlate with the binding of flavonoid derivatives to P-gp, so this indicated that the binding was not the only factor influencing the transport of paclitaxel. The different aspects of inhibition of P-gp by polyphenols was recently reviewed by Kitagawa [212],... 

Plant-derived products Polyphenols (derivatives of hydroxycinnamic acid, hydroxybenzoic acid, flavonols,3 flavones,3 anthocyanidins,3 flavanols,3 isoflavones,3 flavanones,3 stilbenes, lignans), glucosynolates, carotenoids (am /3-, y-, 8-carotene, lycopene, luthein, xeaxantin, canthaxantin), phytic acid, allicin... 

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