1. The Effect of Green Tea on Weight Loss and Cardiovascular Health Ryan Albert, Allyson Angles, Ann Bui, Michael Dail, Laura Hunter Ford, Ruta Patel, William Wolanski Class of 2013, School of Pharmacy, Virginia Commonwealth University * Abstract Experimental Results and Discussion (cont) Figure 2signifies a dose-dependent effect of freshly brewed green tea on the LDL receptor binding activity. The data suggests an up-regulation of the LDL receptor was triggered by the binding of the catechins (particularly EGCG). Figure 3presents a dose-dependent correlation of EGCG and fat mass in subjects of a clinical trial. A positive relationship between the decrease of fat mass and the relative dose of EGCG is apparent. The evidence adds further proof of the beneficial aspects of green tea 1. Materials: -Fresh green tea leaves (pictured in introduction) -HepG2 cell cultures (pictured on right, stained purple) -LDL receptor protein (pictured on right with extracellular binding site colored in red) The use of green tea has been popular for many years due to its useful effects on weight loss and cardiovascular health. Inconsistent data has been presented regarding the exact mechanisms and efficacy of green tea on these two areas. It was found that catechins of green tea have cardiovascular benefits through their antioxidant properties by inhibiting LDL oxidation, cellular oxidation and superoxide production, and inhibiting smooth muscle cell proliferation. The results indicate a dose-dependent relationship regarding the benefits of green tea in lowering total and free cholesterol leading to an overall reduction of fat mass in the body. Also, an up-regulation of LDL receptors was observed relative to the dosing of the primary catechin, EGCG. Even though positive results have been observed, more studies are needed in order to form a stronger conclusion of its clinical benefits due to the controversial results that have been documented in the past. Methods: Green Tea: Fresh green tea leaves were used in each experiment. Green tea leaves were boiled in adequate volumes of water for an appropriate time and then filtered to remove particulate matter2. Study 1: HepG2 cell cultures were assayed for LDL receptor binding observations2. Study 2: Total and free cholesterol plasma levels were measured in mice after increasing stepwise dosing of green tea extract from 0-200 µL2. Study 3: Test subjects administered green tea extract were monitored for fat mass reduction1. As a general study design, subjects are randomized and one half of the subjects are to be given green tea extract and the other half a placebo (cellulose). For the studies presented, the patients were monitored over a period of time in order to document their effects1. Introduction Green tea (Camellia sinensis), native to eastern Asia, is cultivated in approximately 30 countries worldwide. The leaves are consumed traditionally as a beverage which is believed to be rivaled in popularity only by water. Although extensive clinical studies are lacking, green tea has been shown to exhibit strong antioxidant activity. It has a calming capacity and is used as a cardio-protective agent as well as an anticancer agent.3 Figure 2: A dose-dependent effect of green tea on the LDL receptor binding activity. Figure 3: A dose-dependent correlation of EGCG and fat mass. Conclusions Results and Discussion Green tea has long been consumed as a medicinal agent as well as a beverage in many countries throughout the world. Extensive research has been done to study the effects of the various catechins in green tea with EGCG as the most studied. Two effects, weight loss and cardiovascular health, were focused on in this study. It was found that green tea decreased the cell cholesterol concentration by 30% and increased the conversion of SREBP-1 from the inactive precursor form to the active transcription-factor form. This promotion increases cellular representation of the receptor and an increase in cholesterol uptake from the plasma via the hepatocytes. A decrease in fat mass was found in a direct correlation based on the relative dose of EGCG administered which could contribute to weight loss. Even though positive results were found in relation to the beneficial effects of green tea, more research on humans is encouraged for more accurate results. This recommendation is being made due to human metabolism differing from rodents. It is suggested that more research be done on diabetic and hypertensive patients as they will receive the most benefit from green tea on weight loss and promoting cardiovascular health. Because green tea is classified as a dietary supplement, the FDA does not regulate the efficacy of its claims.4In order for a claim to be made, it must be identified and assessed based on evidence. The FTC controls the advertising of green tea and the FDA monitors manufacturers drug safety reporting. Manufacturers are responsible for the safety of their products and use a voluntary system to report adverse reactions to the FDA4,5. Based on current literature, there do not appear to be any significant side effects or toxicity risks associated with regular green tea consumption. The only negative side effect reported has been trouble sleeping primarily due to the caffeine content present which is approximately 30-60 mg in 6-8 ounces of tea7. This can be avoided by the use of a caffeine-free product. Polyphenolsaccount for several of the beneficial effects of green tea due to its potent antioxidant properties. Alkaloids present in green tea, such as caffeine, theobromine, and theophylline, provide for its stimulatory effects3. The phenols present in green tea are classified as catechins. The primary, and most studied, polyphenol in green tea is (-)-epigallocatechin gallate (EGCG) with lesser amounts of catechins: epicatechin, gallocatechin, gallocatechin gallate (GCG), and epicatechin gallate (ECG).3 Ingestion of green tea results in a peak plasma concentration within 2 to 4 hours. Based on a recent study provided by Basu, EGCG shows the lowest bioavailability based on the average peak plasma concentrations after a single measured dose. EGC had the highest bioavailability followed by ECG. Studies show a difference in the bioavailability between the different green tea catechins which is also influenced by the dosing schedule. There are two major mechanisms that describe the role of green tea and the lowering of plasma cholesterol levels, both of which indicate that green tea plays a role in the metabolism and handling of cholesterol once consumed. The first mechanism highlights an intracellular approach in which green tea affects plasma cholesterol levels by decreasing cellular concentrations of cholesterol, wherein more is absorbed by the hepatocytes and metabolized versus being available to circulate in the plasma. In a study performed in hepatocytes, green tea decreased the cell cholesterol concentration by 30% and increased the conversion of the sterol-regulated element binding protein (SREBP-1) from the inactive precursor form to the active transcription-factor form. Consistent with this, the mRNA of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol synthesis, was also increased by green tea.2 Figure 1 represents a dose-dependent effect of freshly brewed green tea in intracellular total and free cholesterol concentrations.2Both the total and free cholesterol concentrations showed a marked decrease. References and Acknowledgements 1.Basu, Arpita, and Edralin A. Lucas. "Mechanisms and Effects of Green Tea on Cardiovascular Health." Nutrition Reviews 165.8 (2007): 361-75. 2.Bursill, Christina, Paul D. Roach, Cynthia D. K. Bottema, and Sebely Pal. "Green Tea Upregulates the Low-Density Lipoprotein Receptor." J. Agric. Food Chem 49 (2001): 5639-645. 3.Facts & Comparisons. Facts & Comparisons. Web. 26 Apr. 2010 <http://online.factsandcomparisons.com/>. 4."Dietary Supplements." U.S. Food and Drug Administration, 18 June 2009. Web. 23 Apr. 2010. <http://www.fda.gov/Food/DietarySupplements/default.htm>. 5."Dietary Supplements: An Advertising Guide for Industry." Federal Trade Commission. Web. 26 Apr. 2010. <http://www.ftc.gov/bcp/edu/pubs/business/adv/bus09.shtm>. 6.Lee, Mak-Soon, Chong-Tai Kim, and Yangha Kim. "Green Tea Epigallocatechin-3-Gallate Reduces Body Weight with Regulation of Multiple Genes Expression in Adipose Tissue of Diet-Induced Obese Mice." Annals of Nutrition and Metabolism 54 (2009): 151-57. 7.Sinija, V. R., and H. N. Mishra. "Green Tea: Health Benefits." Journal of Nutritional and Environmental Medicine 17.4 (2008): 232-42. 8.Kooa, Sung I., and Sang K. Kohb. "Green Tea as Inhibitor of the Intestinal Absorption of Lipids: Potential." Journal of Nutritional Biochemistry 18 (2007): 179-83. Group 2 would like to acknowledge the course coordinator of Pharmacognosy MEDC 553, Dr. Y. Zhang and all faculty members in collaboration of the course’s instruction. Also, the articles published by the authors of the above references were invaluable in this presentation. Green tea catechins provide cardiovascular benefits through their antioxidant properties by inhibiting LDL oxidation, reducing TBARS formation, cellular oxidation, superoxide production, and smooth muscle cell proliferation1.They have been shown to prolong lag time, inhibit formation of oxidized cholesterol and decrease lioleic acid and arachdonic acid concentrations. As evidenced by in vitro and in vivo studies, green tea catechins, mainly EGCG, inhibit the intestinal absorption of dietary lipids. In vitro studies indicate these catechins interfere with the emulsification, digestion, and micellarsolubilization of lipids which are critical steps involved in the intestinal absorption of dietary fat, cholesterol, and other lipids.8 The elevation of plasma cholesterol has been shown to be a major risk factor for the development of heart disease. An inverse association has been identified between the consumption of green tea and the plasma concentration of cholesterol, which is a major risk factor in the development of heart disease. Animal studies have found that green tea exhibits a hypocholesterolemic effect. The purified tea catechins, (-)-epicatechingallate and (-)-epigallocatechingallate, have been correlated with a decrease in plasma cholesterol due to dietary-induced hypercholesterolemia. This study primarily focuses on the effects of EGCG and its effect on weight loss and cardiovascular health. Figure 1:A dose-dependent effect of green tea in intracellular total and free cholesterol concentrations.