Phenols/polyphenols structures

Fukuoka T, Uyama H, Kobayashi S (2004) Effect of phenolic monomer structure of precursor polymers in oxidative coupling of enzymatically synthesized polyphenols. Macromolecules 37 5911-5915... 

Coche-Guerente, L., Labbe, P., Mengeaud, V. (2001). Amplification of amperometric biosensor responses by electrochemical substrate recycling. 3. Theoretical and experimental study of the phenol-polyphenol oxidase system immobilized in Laponite hydrogels and layer-by-layer self-assembled structures. Anal. Chem. 73 3206-18. 

Polyphenols. Also called phenolic acids or phenolics, polyphenols are the parent class of several thousand compounds having similar chemical structure. Here is a list of the principal polyphenols to keep in mind for superfruits ... 

It is now well-established that some enzyme families, including various peroxidases and laccases, catalyze the polymerization of vinyl monomers and other redox active species such as phenol-type structures. Vinyl polymerization by these redox catalysts has recently been reviewed 93). These catalysts have been used to prepare polyanilines 94) and polyphenols 95,96). A few examples of related research are included in this book. For example. Smith et al (57) described a novel reaction catalyzed by horseradish peroxidase (HRP). In the presence of HRP and oxygen, D-glucuronic acid was polymerized to a high molecular weight (60,000) polyether. However, the authors have not yet illucidated the polyether structure. Two other oxidative biotransformations were discussed above i) the sono-enzymatic polymerization of catechol via laccase 31), and ii) the oxidation of aryl silanes via aromatic dioxygenases 30). 

Crozier, A., Jaganath, I.B., and M.N.C. 2006. Phenols, polyphenols and tannins an overview. In Plant secondary metabolites occurrence, structure and role in the human diet. Wiley-Black-well, Oxford U.K., 1-24. 

Dietary Phenolics, Polyphenolics, Tannins Structure and Human Metaboiism... 

Fig. 22 Modelling ability of the optimized ANN for the multicomponent determination of phenolic compounds present in wine. Training filled circles), external test empty circles) and spiked wine samples empty diamonds) set adjustments of the expected concentration vs. obtained concentrations for top) catechol, middle) caffeic acid and bottom) ( )-catechin. Dashed lines correspond to theoretical diagonal line. Error bars correspond to five different retrainings with random reinitialization of weights for the final architecture. Polyphenolic structures attached to the graphs and fitted regression lines for the three subsets stated on top of each plot. Adapted from [63], with permission from the Royal Society...

Polyphenols are the most abundant antioxidants in human diets. They are secondary metabolites of plants. These compounds are designed with an aromatic ring carrying one or more hydroxyl moieties. Several classes can be considered according to the number of phenol rings and to the structural elements that bind these rings. 

Polyphenoloxidase (PPO, EC 1.14.18.1) is one of the most studied oxidative enzymes because it is involved in the biosynthesis of melanins in animals and in the browning of plants. The enzyme seems to be almost universally distributed in animals, plants, fungi, and bacteria (Sanchez-Ferrer and others 1995) and catalyzes two different reactions in which molecular oxygen is involved the o-hydroxylation of monophenols to o-diphenols (monophenolase activity) and the subsequent oxidation of 0-diphenols to o-quinones (diphenolase activity). Several studies have reported that this enzyme is involved in the degradation of natural phenols with complex structures, such as anthocyanins in strawberries and flavanols present in tea leaves. Several polyphenols... 

OH groups attached to benzene rings are termed phenols (Chapter 7). Since there are three such structures in this molecule, resveratrol is a polyphenol. 

Fukai, T. and Nomura, T., New NMR structure determination methods for prenylated phenols, Basic Life Sciences, 66 (Plant Polyphenols 2), 259, 1999. 

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