Catechins Chemical

Catechins are water-soluble however, they can be rendered insoluble by chemical reaction (Yayabe, 2001). Insoluble catechins do not lose their phenol hydroxyl groups, and their anti-bacterial and deodorising actions remain almost unaffected. In this form they are useful as natural anti-bacterial and deodorising materials for application to fibres and plastics. 

ZEEB D J, NELSON B c, ALBERT K and DALLUGE J J (2000) Separation and identification of twelve catechins in tea using liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry , Chem, 72, 5020-26. 

NICOLI M c, CALLIGARIS s and MANZOCCO L (2000) Effect of enzymatic and chemical oxidation on the antioxidant capacity of catechin model systems and apple derivatives , JAgric Food Chem, 48 (10) 4576-80. 

The chemical formulae for a variety of plant phenols are given in Fig. 16.2, including examples of simpler phenols, such as cinnamic acid derivative, and of tocopherols, flavonoids, flavonoid glycosides and anthocyanidins. The flavonoids include the following subclasses flavanones (taxifolin), flavones (luteolin), flavonols (quercetin) and flavanols (catechin/epicatechin). The... 

The chemical characteristics of the proanthocyanidins were elucidated by total oxidation and partial degradation in the presence of phloroglucinol followed by HPLC analysis. The native extract of proanthocyanidins contained (+) gallocatechin, (-) epigallocatechin, (h-) catechin, and (-) epicatechin units. ... 

A complete NMR approach has been employed to evaluate the complexation process of catechin A with p-CD and synthetic analogues.125 The analysis of the variation of the proton chemical shifts indicated the formation of a 1 1 stoichiometric complex. 2D-ROESY provided detailed spatial information of the complex while the binding constants were obtained by using diffusion-order spectroscopy (DOSY) techniques. 

The sugars attached to the anthocyanin molecule are in order of relative abundance glucose, rhamnose, galactose, xylose, arabinose, and glucuronic acid. The molecule may also contain one or more of the acyl acids p-coumaric, caffeic, and ferulic or the aliphatic acids malonic and acetic esterified to the sugar molecules. Extracts of anthocyanins invariably contain flavonoids, phenolic acids, catechins and polyphenols. The net result is that it is impossible to express the chemical composition accurately. Specifications usually present tinctorial power, acidity, per cent solids, per cent ash and other physical properties. 

Treutter D (1989) Chemical reaction detection of catechins and proanthocyanidins with 4-dimethylaminocinnamaldehyde. J Chromatogr 467 185-193... 

Suzuki, M., Sano, M., Yoshida, R., Degawa, M., Miyase, T., and Maeda-Yamamoto, M., Epimerization of tea catechins and 0-methylated derivatives of (—)-epigallocatechin-3-0-gallate relationship between epimerization and chemical structure, J. Agric. Food Chem., 51, 510, 2003. 

Tomita, I., Sano, M., Sasaki, K., and Miyase, T., Tea catechin (EGCG) and its metabolites as antioxidants, in Functional Foods for Disease Prevention, 213th Meeting of the American Chemical Society, Shibamoto, T., Terao, T., and Osawa, T., Eds., American Chemical Society, Washington, DC, 1998, p. 21. 

Sang, S., Tian, S., Wang, H., Stark, R.E., Rosen, R.T., Yang, C.S., and Ho, C.T., Chemical studies of the antioxidant mechanism of tea catechins radical reaction products of epicatechin with peroxyl radicals, Bioorg. Med. Chem., 11, 3371, 2003. 

Chemical analyses and fractionations. Freeze-dehydrated cotton tissue was analyzed for condensed tannin (heated n-BuOH-HCl), gossypol (phlorogluclnol-HCl), and anthocyanlns-anthocyanldlns (ale. HCl at 540 nm). Other analyses performed but not reported here were for catechin, total phenols, (tannin), and aniline reactive terpenes (gossypol). 

From a chemical standpoint tannins are formed by the polymerization of elementary phenolic molecules according to the nature of these molecules, one can distinguish hydrolyzable tannins (gallics) and condensed tannins (catechins). 

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