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Green Tea

Green Tea. Rob Glotfelty & Selen Tolu. http://en.wikipedia.org/wiki/Green_tea. Taxonomy. Kingdom: Plantae Phylum: Magnoliophyta Class: Magnoliopsida Order: Ericales Family: Theaceae Genus: Camellia Species: C. sinensis (L.) Kuntze. History.

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Green Tea

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  1. GreenTea Rob Glotfelty & SelenTolu http://en.wikipedia.org/wiki/Green_tea

  2. Taxonomy Kingdom: PlantaePhylum: Magnoliophyta Class: Magnoliopsida Order: Ericales Family: TheaceaeGenus: Camellia Species: C. sinensis(L.) Kuntze

  3. History • Green tea is made from the dried leaves of Camellia sinensis , a perennial evergreen shrub. Green tea has a long history of use, dating back to China approximately 5,000 years ago. • Green tea has been used as traditional medicine in areas such as India, China, Japan and Thailand to help • everything from controlling bleeding and helping heal wounds to regulating body temperature, blood • sugar and promoting digestion.

  4. Green or Black? • Green tea and black tea are derived from the same leaf. The difference lies in how they are processed. • When making green tea the leaves are plucked processed immediately to prevent them from fermenting. • Unfermented leaves contain large amounts of catechins, which are powerful disease fighters and potent antioxidants. • When making black tea, the leaves are picked and are left to ferment. This changes the chemical structure of the • catechins into substances called thearubigens and • theaflavins, which have some health benefits but not • nearly as many as the catechins.

  5. Brewing and Dosage • Generally, 2.25 grams of tea per 6 ounces of water, or about one teaspoon of green tea per cup, should be used. • The average 6-ounce cup of green tea contains between 50 and 100 mg catechins. • Most studies have concluded that you need 3-10 • cups of green tea per day, or up to 1,000 mg. of • catechins in order to get the healthy benefits of • green tea

  6. What Can Green Tea Prevent? • Alzheimer’s disease • Parkinson’s disease • Cancer • HIV • multiple sclerosis • LDL cholesterol • Cardiovascular disease • Raise metabolism • insulin sensitivity • hypertension • tooth decay • cholera • And anything else you can think of….

  7. Active Constituents[25]

  8. Catechins [25] • family of flavan-3-ols • Sub group of flavanoids –technically not a flavanoid due to lack of carbonyl group • Are polyphenyl groups which have been shown to have anti-oxidant and anti-carcinogenic properties • Catechins make up slightly less than 30% of dry weight

  9. Catechins • Epicatechin and epogallocatechin most commonly found in nature • Epigallocatechin gallate most frequent catechin found in Green Tea • Thought to hold most antioxidant activity • Gallic acid attached to catechin • Gallic acid found freely and within tannins in many other plants

  10. Other Active Components • Vitamin C • antioxidant • B Vitamins • Metabolize carbohydrates • Manufacture fatty acids and amino acids • Vitamin E • Antioxidant • Fluoride • Protection of tooth decay and gum disease • Caffeine (3-4%) • About a quarter of that of coffee

  11. The Asian Paradox[1] • Next to Green Tea, cigarettes are mostly widely consumed product in Asia • Asians have some of the lowest cardio-related death rates in the world • Clinical studies have been performed to view different aspects and health benefits of green tea that lead to this paradox

  12. Pharmacokinetics[2] • Changes in blood count and blood chemistry profiles not significant in individuals given EGCG dosages • Non-significant difference in amount of tea catechins found after initial dosage and 4 weeks later after daily regimen of EGCG at 800 mg/day and 400 mg/ day • >60% increase in the systemic availability of free EGCG after chronic green tea polyphenol administration at 800 mg/day

  13. Pharmacokinetics[2] • Side Effects found in this study: • Excess gas • Upset stomach • Heartburn • Abdominal pain • Dizziness • Headache • Muscle pain • All reported as mild events

  14. Pharmacokinetics[3] • Found that EGCG levels rose significantly at about 3 hours and peaked between 8-15 hours after a single dosage • 90% of EGC and EC excreted in urine between 0-8 hours • Supports other study with similar results

  15. Clinical Trials; Heart Disease • In a double-blinded, randomized, placebo-controlled trial ,240 adults were given either theaflavin-enriched green tea extract in form of 375mg capsule daily or a placebo. After 12 weeks, patients in the tea extract group had significantly LDL cholesterol and total cholesterol (16.4% and 11.3% lower than baseline, p<0.01) than the placebo group [4] • A meta-analysis examining the effect of green tea on cardiovascular heart health found a decrease in the rate of heart disease outcomes with increasing tea consumption. [5] However, two studies from the UnitedKingdom [6][7] and two studies from the United States [8][9] indicated an increased risk with increasing tea consumption,whereas the other studies indicated a decrease in risk.

  16. Clinical Trials; Cancer • EGCG and other tea polyphenols inhibited growth of human lung cancer cell line, PC-9 cells with G2/M arrest. [10] • Many studies have studied the inhibitory effects of EGCG and green tea extract on carcinogenesis in various organs of rodents [11][12][13]

  17. Skin Cancer[14] • 2 groups of lab mice (30 each) subjected to equal amounts of UVB radiation • One group treated with 1.25% green tea drinking water and other with 2.5% green tea drinking water, control with distilled water • Decreased number of skin tumors and substantially reduced size of tumors

  18. Skin Cancer[14]

  19. Breast Cancer [15] • In vitro • green tea catechins inhibits proliferation of ER-positive MCF-7 breast cancer cells • In vivo • Mice studied had increased levels of catechins in mammary fat pads and levels were relative to how much tea was administered to each group • In both aspects of the study catechins used with tamoxifen, a orally active selective estrogen receptor modulator, showed the best results in comparison to catechins or tamoxifen alone

  20. Clinical Trials; Obesity • Mice that were fed high fat diets supplemented with tea catechins for 11 months resulted in a significant reduction of diet-induced weight gain [16] • Ingestion of tea catechins stimulated O2 consumption and energy expenditure and decreased the respiratory quotient in humans. [17] • Injection of EGCG modulates appetite and reduces food intake through the leptin receptor-independent pathway in rats.[18]

  21. Clinical Trials; Diabetes • Green tea supplementation ameliorates insulin resistance and increases glucose transporter IV content in a fructose-fed rat models of diabetes [21] • Some studies have shown that plasma glucose levels in diabetic rats are lowered when the rats are given (-) epicatechin [19] [20]

  22. Gastrointestinal [22] • Test of each catechin found in green tea to find which best treats GI infection by Helicobacter pylori • chronic gastritis, peptic ulceration, and gastric cancer • In vivo study • Mongolian gerbils inoculated with equal levels of H. pylori • fed different diet containing (0, .5, 1, or 2%) catechins for 2 weeks • H. pylori was eradicated in about 10% of the gerbils • In ones not eradicated, 10-36% decrease of H. pylori • Similar to success rate in human cell in vitro studies with antibiotics • More studies need on impacts of catechins on H. pylori other than eradication

  23. Epidemiological Studies[23] • Few have been done and ones completed take place in Asia • So many variables to account for, e.g. smoking, alcohol consumption, diet, exercise it is hard to derive results • One study looked at over 18000 men from Shanghai and said there was a slight decrease in cancer rates, but results seem to be unverifiable due to high variability of subjects

  24. Contraindications[24] • Caffeine only substance that has potential to do harm • Pregnant/nursing women should limit caffeine intake • Should not be taken if used with Warfarin • Vitamin K interacts with anticoagulation

  25. References • Sumpio, Bauer E. et al. “Green tea, the “Asian paradox,” and cardiovascular disease.” Journal of American College of Surgeons. 2006. 202:5, pp. 813- 825. • Chow, Sherry, et al. “Pharmacokinetics and safety of green tea polyphenols after multiple-dose administration of epigallocatechin gallate and polyphenon E in healthy individuals.” Clinical Cancer Research. 2003. 9, pp. 3312-3319. • Lee, M.J., et al. “Pharmacokinetics of tea catechins after ingestion of green tea and epigallocatechin-3-gallate by humans: formation of different metabolites and individual variability.” Cancer Epidemiol Biomarkers Prev. 2002. 10:1, pp.1025- 1032. • David J. Baron et al. “Cholesterol-Lowering Effect of a Theaflavin-Enriched Green Tea Extract.” Arch Intern Med. 2003.163:1448-1453. • Ulrike Peters et al. “Does Tea Affect Cardiovascular Disease? A Meta-Analysis.” American Journal of Epidemiology. 2001. 154:6 pp. 495-503. • Woodward M, Tunstall-Pedoe H. “Coffee and tea consumption in the Scottish Heart Health Study follow up: conflicting relations with coronary risk factors, coronary disease, and all cause mortality.” J Epidemiol Community Health. 1999. 53: 481-487.

  26. Hertog MG, Sweetnam PM, Fehily AM, et al. “Antioxidant flavonols and ischemic heart disease in a Welsh population of men: the Caerphilly Study.” Am J Clin Nutr. 1997. 65: pp. 1489–94. • Rosenberg L, Palmer JR, Kelly JP, et al. “Coffee drinking and nonfatal myocardial infarction in men under 55 years of age.” Am J Epidemiol. 1988. 128: pp. 570– 578. • Rimm EB, Katan MB, Ascherio A, et al. “Relation between intake of flavonoids and risk for coronary heart disease in male health professionals.” Ann Intern Med. • S. Okabe, M. Suganuma, M. Hayashi, E. Sueoka, A. Komori, H. Fujiki. “Mechanisms of growth inhibition by tea polyphenols on human lung cancer cell line, PC-9” Japan J. Cancer Res. 1997. 88: pp.639–643. • M. Suganuma, Chemoprevention of cancer, in: T. Bowden, S. Fischer Eds.. “Comprehensive Toxicology.” Elsevier, UK.1997. pp. 453–471. • Bushman JL. “Green tea and cancer in humans: a review of the literature.” Nutr Cancer. 1998. 31:3 pp.151-159. • Fujiki H, Suganuma M, Okabe S, et al. “Cancer inhibition by green tea.” Mutation Research. 1998. pp. 307-310. • Wang, Zhi-Yuan, et al. “Inhibitory effect of green tea in the drinking water on tumorigenesis by ultraviolet light and 12-O-tTetradecanoylphorbol-13- acetate in the skin of SKH-1 mice.” Cancer Research. 1992. 52, pp. 1162-1170. • Sartippour, Maryam R. et al. “The combination of green tea and tamoxifen is effective against breast cancer.” Carcinogenesis. 2006. 27:12, pp. 2424-2433. • T. Murase et al. “Beneficial effects of tea catechins on diet-induced obesity: stimulation of lipid catabolism in the liver.” International Journal of Obesity. 2002. 26:11, pp. 1459-1464.

  27. Dulloo AG, Duret C, Rohrer D, et al. “Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humnas.” Am J Clin Nutr . 1999. 70, pp.1040-1045. • Kao YH, Hiipakka RA, Liao S. “Modulation of obesity by a green tea catechin.“ Am J Clin Nutr. 2000. 72, pp. 1232 – 1234. • Sheehan EW,Zematis MA . “A constituent of Pterocarpus Marsupium, (-)epicatechin, as a potential antidiabetic agent.” J Nat Prod. 1988. 46, pp. 232–234. • Chakravarthy BK, Gupta S, Gode KD. “Functional beta cell regeneration in the islets of pancreas in alloxan induced diabetic rats by (-)-epicatechin.” Life Sci. 1982. 31, pp. 2693–2697. • Lucy Sun Hwang et al. “Green tea supplementation ameliorates insulin resistance and increases glucose transporter IV content in a fructose-fed rat model.” European Journal of Nutrition. 2004. 43:2, pp.116-124. • Mabe, Katsuhiro, et al. “In Vitro and In Vivo Activities of Tea Catechins against Helicobacter pylori.” Antimicrobial Agents and Chemotherapy. 1999. 43:7, pp. 1788–1791. • Sun, Can-Lan, et al. “Urinary tea polyphenols in relation to gastric and esophageal cancers: a prospective study of men in Shanghai, China.” Carcinogenesis. 2002. 23:9, pp. 1497 -1503. • Wolters Kluwer Health. “Green Tea.” 2006. Green Tea Information. Accessed on 6, April, 2008. < http://www.drugs.com/npc/green-tea.html>. • Zaveri, Nurulain T. “Green tea and its polyphenolic catechins: Medicinal uses in cancer and noncancer applications.” Life Sciences. 2006. 78:18, pp. 2073- 2080.

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