Monomeric polyphenols

The appeal of chocolate is universal, but the pleasures of eating chocolate products may perhaps be tempered by their fat and sugar content. However, in a series of human feeding studies it has been shown that the high proportion of stearic acid in the cocoa butter of chocolate does not adversely affect plasma lipids. Two recent reports of antioxidant activity have increased interest in the health aspects of chocolate an in vitro low-density liposprotein (LDL) oxidation study and a short-term in vivo study. Epicatechin, the major monomeric polyphenol antioxidant in chocolate, and an extract of chocolate liquor were both found to stimulate cellular immune response in vitro. 

Chemical processing of bark is limited and the principal chemical products produced commercially from barks are based on the barks phenolic content (1,12). Barks generally are richer than wood in quantity and complexity of extractive components, the most important being a) the monomeric polyphenols or flavonoid compounds, and b) the polymeric phenolics, such as tannin, phloba-phenes and phenolic acids. 

Plant polyphenols can be separated into polymeric or oligomeric tannins and monomeric polyphenols. In general, it is accepted that monomeric polyphenols and some oligomeric tannins with relatively low molecular weight are selectively absorbed into the body by... 

Angeletti, M. and Sparapani, L., Process for producing a grape seed extract having a low content of monomeric polyphenols, PCT Int. AppL, 2005. 

Polyphenols (PP) represent a very wide variety of about 6000 compounds divided into I I different classes represented by hydroxybenzoic acids, hydroxycinnamic acid, anthocyanidins, flavonols, flavanones, flavanols (divided into monomeric cathechins and polymeric proanthocyanidins3), flavones, isoflavones, stilbenes, and lignans (16). 

Polyphenol thin films were obtained using Langmuir—Blodgett technique.21b-24 A monomeric mono-layer was formed from p-tetradecyloxyphenol and phenol at the air—water interface in a Langmuir trough, which was polymerized by HRP catalyst in the subphase. The polymerized film could be deposited on silicon wafer with a transfer ratio of 100% for the Y-type film with a thickness of 27.8 A. 

It is well known that tea contains catechins besides caffeine. Although catechins are widely distributed in the plant kingdom, the catechin monomers in many plants coexist with larger amounts of dimeric to polymeric proanthocyanidins, which are comprised of catechin units connected by C-C bonds. However, the polyphenol composition of C. sinensis is unique, and mainly comprised of four monomeric catechins—(-)-epicatechin (1), (-)-epigallocatechin (2) and their galloyl esters. 

The majority of the biological functions of teas may be attributed to their poly-phenolic components (see figures 9.1 and 9.2) the chemical structures of the main polyphenols isolated from green, black, oolong, and pu-erh teas are structurally related but not identical. The monomeric catechins from green tea may be considered the precursors of the more complex polyphenols found in other teas as a result of fermentation. 

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