Green tea catechins

CHEN z Y and chan p t (1996) Antioxidative activity of green tea catechins in canola oil , Chem and Phsics of Lipids, 82, 163-72. 

CHOI J H, CHA B K and RHEE s J (1998) Effects of green tea catechin on hepatic microsomal phospholipase A2 activities and changes of hepatic phospholipid species in streptozotocin-induced diabetic rats , JNutr Sci Vitaminol (Tokyo), 44 (5), 673-83. 

WANASUNDARA u N and SHAHiDi F (1996) Stabilization of seal blubber and menhaden oils with green tea catechins , J Am Oil Chem Soc, 73, 1183-90. 

TSUCHIYA H. (1999) Effects of green tea catechins on membrane fluidity. Pharmacology. 59 34-44. 

CHEN z-Y, WANG L Y, CHAN p T, ZHANG z, CHUNG H Y and LIANG c (1998) Antioxidative activity of green tea catechin extract compared with that of rosemary extract, JAOCS, 75 (9), 1141-5. 

ZHU Q Y, HUANG Y, TsoNG D aiid CHEN z Y (1999) Regeneration of a-tocopherol in human low density lipoprotein by green tea catechin, JAgric Food Chem, 47, 2020-25. 

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). 

Bettuzzi S, Brausi M, Rizzi F, Castagnetti G, Peracchia G and Corti A. 2006. Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia a preliminary report from a one-year proof-of-principle study. Cancer Res 66(2) 1234—1240. 

M. Bonoli, M. Pelillo, T.G. Toschi and G. Lercker, Analysis of green tea catechins comparative study between HPLC and HPCE. Food Chem. 81 (2003) 631-638. 

Gradisar H, Pristovsek P, Placer A, Jerala R. (2007) Green tea catechins inhibit bacterial DNA gyrase by interaction with its ATP binding site. 7 Med Chem 50 264-271. 

Kuzuhara T, Iwai Y, Takahashi H, Hatakeyama D, Echigo N. (2009) Green tea catechins inhibit the endonuclease activity of influenza A virus RNA polymerase. PLoS Curr Influenza RRN1052. 

Miketova, P. et al., Tandem mass spectrometry studies of green tea catechins. Identification of three minor components in the polyphenolic extract of green tea, J. Mass Spectrom., 35, 860, 2000. 

Valcic, S., Burr, J.A., Liebler, D.C., and Timmermann, B.N., Antioxidant chemistry of green tea catechins. Identification of products of the reaction of (—)-pigallocatechin gallate and (—)-epigallocatechin from their reactions with peroxyl radicals, Chem. Res. Toxicol, 13, 801, 2000. 

Many naturally occurring antioxidants are found in common foods. These include the green tea catechins,5 6 resveratrol from red wine,7 curcumin from curry powder,8 sul-foraphane from cruciferous vegetables,9 etc. Some synthetic materials are also added to foods to prevent rancidity of lipids. Examples include butylated hydroxy toluene (BHT) and butylated hydroxy anisole (BHA). 

Preparation of green tea catechins from green tea powder. 

Separation of green tea catechins fraction by high-performance/pressure liquid chromatography. 

Conversion of green tea catechins to black tea theaflavins, etc., by the action of Camellia sinensis polyphenoloxidase. 

A commercially available decaffeinated mixture of green tea catechins sold as TeGreen 97 (Pharmanex Corporation, Simi Valley, CA). The mixture was arbitrarily assigned the molecular weight of epigallocat-echin gallate as an approximation. 

Once again, the green tea catechins, particularly EGC, GCG, and EGCG, are the most powerful of this group of widely reported antioxidants. The data leading to this conclusion are not inflated by enzyme inhibition at these concentrations. The nature of the data is illustrated in Figure 10.11. 

Green tea catechins Various tissues Stimulation and Zhou et al., 2004... 

Demeule M, Michaud-Levesque J, Annabi B, Gingras D, Boivin D, Jodoin J, Lamy S, Bertrand Y, Beliveau R. 2002. Green tea catechins as novel antitumor and antiangiogenic compounds. Curr Med Chem 2 441-463. 

Green Tea Catechins Anticancer Effects and Molecular Targets... 

Figure 7.1 Chemical structures of major green tea catechins.

This chapter discusses the anticarcinogenic effects of green tea catechins, especially EGCG in different organ sites and effects on cellular signaling events. 

Mandel S, Amit T, Reznichenko L, Weinreb O, Youdim MB. 2006a. Green tea catechins as brain-permeable, natural iron chelators-antioxidants for the treatment of neurodegenerative disorders. Mol Nutr Food Res 50 229-234. 

Mandel S, Weinreb O, Reznichenko L, Kalfon L, Amit T. 2006b. Green tea catechins as brain-permeable, non toxic iron chelators to iron out iron from the brain. J Neural Transm Suppl 249-257. 

Anderson RF, Fisher LJ, Elara Y, Harris T, Mak WB, Melton LD, Packer JE (2001) Green tea catechins partially protect DNA from OEI radical-induced strand breaks and base damage through fast chemical repair of DNA radicals. Carcinogenesis 22 1189-1193 Anderson RF, ElarrisTA, Elay MP, Denny WA (2003a) Enhanced conversion of DNA radical damage to double strand breaks by 1,2,4-benzotriazine 1,4-dioxides linked to a DNA binder compared to tirapazamine. Chem Res Toxicol 16 1477-1483... 

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