Catechin from

ADCOCKS c, COLLIN P and BUTTLE D J (2002) Catechins from green tea Camellia sinensis) inhibit bovine and human cartilage proteoglycan and type 11 collagen degradation in vitro , JNutr, 132 (3), 341-6. 

DU Q z, LI M J, CHENG Q K, CHENG Q and LU c Y (1997) The study on separation catechins from tea leaves and transforming gallate-catechins into nongallate-catechins . Res Develop Basic Agric and High Technol, 1, 40-47. 

Catechins and proanthocyanidins have a documented antiviral activity. Catechins from an extract of Cocos nucifera husk fibre exhibited a strong inhibitory activity against acyclovir-resistant herpes simplex virus type 1 (HSV-l-ACVr) [62]. The use of 10 to 20ngml of ECG and EGCG has been reported to cause 50% inhibition of human immunodeficiency virus reverse transcriptase [89], while Kara and Nakayama [90] reported that a patented chewing gum containing tea catechins is claimed to prevent viral infections against influenza and to inhibit dissemination of this virus. 

LAR removes the 4-hydroxyl from leucoanthocyanidins to produce the corresponding 2,3-tran5-flavan-3-ols, e.g., catechin from leucocyanidin. Despite early biochemical characterization, it is only recently that a LAR cDNA was isolated and the encoded activity characterized in detail. Tanner et al. purified LAR to homogeneity from Desmodium uncinatum (silverleaf desmodium), and used a partial amino acid sequence to isolate a LAR cDNA. The cDNA was expressed in E. coli, N. tabacum, and Trifolium repens (white clover), with the transgenic plants showing significantly higher levels of LAR activity than nontransformed plants. 

Nay, B. et al.. Total synthesis of labeled flavonoids. 2. C-labeled ( )-catechin from potas-sium[ C]cyanide, Eur. J. Org. Chem., 1279, 2000. 

Amarowicz R, Shahidi F. A rapid chromatographic method for separation of individual catechins from green tea. Food Research International 1996 29 71-76. 

Preparation of green tea catechins from green tea powder. 

Yang, X., G. Wang, and X. Zhang. 2004. Release kinetics of catechins from chewing gum. J Pharm Sci 93 293. 

Kivits, G.A.A. van der Sman, F.J.P. Tijburg, L.B.M. 1997. Analysis of catechins from green and black tea in humans a specific and sensitive colorimetric assay of total catechins inbiological fluids. Int. J. Food Sci. Nutr. 48 387-392. 

Precursors. The precursors for this reaction are anthocyanins, flavanols or flavanols containing a vinyl residue at C-8 (i.e., 8-vinylflavanols). 8-Vinylflavanols could arise from the cleavage of flavanol-ethyl-flavanol oligomers or from the dehydration of the flavanol-ethanol adduct formed after the attack of aldehyde cation to the flavanol (Chapter 9B). Saucier et al. (1997) have supported evidence for this precursor when detecting an ion corresponding to vinyl-catechin from the fragmentation of ethyl-linked catechin dimers under ESI-MS in positive or negative mode. 

S. B. Lotito and C. G. Fraga. Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma. Biological Research 33 (2(KX)) 151-157. 

Yoshida, Y, Kiso, M., and Goto, T. 1999. Efficiency of the extraction of catechins from green tea. Food Chem. 67 429-33. 

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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