Tea catechins

The functional benefits of fiavonoids the case of tea 139 8.4.1 Relative activity of tea catechins... 

Purified extracts contain higher contents of tea catechins obtained by further purification processes, for example solvent extraction or column chromatography techniques (Takeo, 2001). New techniques, such as membrane extraction and separation, may be beneficial in producing such extracts (Nwuha, 2000, Wang et al, 1995). 

Tea flavonoids, or tea extracts, are increasingly being added to foods. However, interactions with food and drink components remain unclear, and thus need to be carefully assessed in order that the full potential benefits from consuming tea, in whatever form, can be achieved. Meanwhile, tea catechins themselves undergo extensive O-methylation, glucuronidation, sulphation and ring fission... 

CAO G (1995) Influence of tea catechins on the synthesis of extracellular glucan and the adherence of Streptococcus mutans bacteria , JTea Sci, 15 (10), 57-60. 

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. 

KAWAMURA J and TAKEO T (1989) Anti-bacterial activity of tea catechin to Streptococcus mutans , Nippon Shokuhin Kogyo Gakkaishi, 36, 463-7. 

KHOKHAR s, VENEMA D, HOLLMAN P c, DEKKER M and JONGEN w (1997) An RP-HPLC method for the determination of tea catechins . Cancer Lett, 114, 171-2. 

LEE B L and ONG c N (2000) Comparative analysis of tea catechins and theaflavins by high-performance liquid chromatography and capillary electrophoresis , J Chromatog A, 881 (1-2), 439-47. 

MiKi u, HiDEYUKi Y and MASAKi s (1991) Effect of tea catechins in halitosis and their application in chewing gum , iVippoMYAokuAiMAbgyo Gakkaishi, 38 (12), 1098-102. 

NAASANI I, SEIMIYA H and TSURUO T (1998) Telomerase inhibition, telomere shortening, and senescence of cancer cells by tea catechins , Biochem Biophys Res Commun, 249 (2), 391-6. 

NAKAGAWA K and MIYAZAWA T (1997) Chemiluminescence-high-performance liquid chromatographic determination of tea catechin, (-)-epigallocatechm 3-gallate, at picomole levels in rat and human plasma , Anal Biochem, 248, 41-9. 

TANG s z, KERRY J p, SHEEHAN D, BUCKLY D J and MORRISSEY p A (2001) Antioxidative effect of dietary tea catechins on lipid oxidation of long-term frozen stored chicken meat , Meat Sci, 56, 285-90. 

TANG s z, KERRY J P, SHEEHAN D and BUCKLY D J (2002) Antioxidative mechanisms of tea catechins in chicken meat systems , Food Chem, 76, 45-51. 

UMEGAKi K, ESASHi T, TEZUKA M, ONO A, SANO M and TOMiTA I (1996) Determination of tea catechins in food by HPLC with an electrochemical detector , Shokuhin Eiseigaku Zasshi, 37, 77-82. 

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. 

WANG H, LYNCH p N, LEWIS J, BOND T and DAVIES A p (1998b) Molecular rearrangements of tea catechins , in Proc of Polyphenol Communications 98, XIXth Intern Conf on Polyphenols, 1-4 September, 1998, Lille, France, 181-2. 

YASUDA H (1992) Deodorant effect of tea catechins and their application , Shokuhin... 

IKEDA I, IMASATO Y, SASAKI E, NAKAYAMA M, NAGAO H, TAKEO T, YAYABE F, SUGANO M (1992) Tea catechins decrease micellar solubility and intestinal absorption of cholesterol in rats. Biochim Biophys Acta. 1127 141-6. 

SHIMIZU M, KOBAYASHi Y, SUZUKI M, SATSU H, MIYAMOTO Y (2000) Regulation of intestinal glucose transport by tea catechins. Biofactors. 13 61-5. 

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

VAN HET HOF K H, WISEMAN s A, YANG c s, TiJBURG L B M (1999) Plasma and lipoprotein levels of tea catechins following repeated tea consumption, Proceedings of the Society for Experimental Biology and Medicine, 220, 203-9. 

Nowadays, consumers would like those antioxidants present in food products not only to stabilise food lipids, but also to be absorbed through the intestinal wall and protect the lipids of blood plasma against oxidation. This effect is relatively evident in the case of tocopherols (which are liposoluble) or ascorbic acid (which is hydrophilic), but much less evidence is available on antioxidants of medium polarity, such as flavonoids, rosemary oleoresins or green or black tea catechins. 

Anthocyanins and anthocyanidins, compounds present with high structural diversity in fruits and wines, showed a pattern as antioxidants different from that of the tea catechins with respect to the effect of substituents. In a liposomal model system induced peroxidation was inhibited increasingly by anthocyanins/ anthocyanidins with an increasing number of hydroxyl groups in the B-ring (Fig. 16.6), while the opposite was seen for the catechins (Seeram and Nair, 2002). For anthocyanidins, the presence of a 3-hydroxy group is important... 

Green tea Tea catechins (300 ppm is typically required) Raw minced beef, pork, poultry and fish Cooked red meat, poultry and fish Frozen chicken meat Effect up to four times that of a-tocopherol Inhibits pro-oxidative effect of added NaCl Protection of a-tocopherol in muscles when added to chicken feed Tang et al., 2001c Tang et al., 2001b Tang et al., 2002... 

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. 

GUO Q, ZHAO B, SHEW s, Hou J, HU J and xiN w (1999) ESR study of the structure -antioxidant activity relationship of tea catechins and their epimers, Biochem Biophys Acta, 1427, 13-23. 

HUANG s w and frankel e n (1997) Antioxidant activity of tea catechins in different lipid systems, J Agric Food Chem, 45, 3033-8. 

TANG s, SHEEHAN D, BUCKLEY D J, MORRISSEY p A and KERRY J p (200 Ic) Anti-oxidaut activity of added tea catechins on lipid oxidation of raw minced red meat, poultry and fish muscle, Int J Food Sci Techn, 36, 685-92. 

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