Anti-obesity action of oolong tea

Abstract

OBJECTIVE: Oolong tea is traditionally reported to have anti-obesity and hypolipidaemic effects. The present study was performed to clarify whether oolong tea prevented obesity induced in mice by the oral administration of a highfat diet for 10 weeks. DESIGN: High-fat diet-induced obese mice were treated with oolong tea for 10 weeks. The effects of various active fractions isolated from oolong tea on noradrenaline-induced lipolysis were examined with isolated fat cells and a cellfree system consisting of lipid droplets and hormone-sensitive lipase (HSL). RESULTS: The mean food consumption was not signi®cantly different between high-fat diet-treated mice and high-fat plus oolong tea diet-treated mice. Oolong tea prevented the obesity and fatty liver induced by a high-fat diet. A water extract of oolong tea enhanced noradrenaline-induced lipolysis, and the active substance was identi®ed as caffeine. Caffeine enhanced noradrenaline-induced lipolysis in fat cells without a concomitant increase in HSL activity and also accelerated the hormone-induced lipolysis in a cell-free system consisting of lipid droplets and HSL, but not in the cellfree system with sonicated lipid droplets and HSL. Oolong tea extract inhibited pancreatic lipase activity. CONCLUSION: It was demonstrated that the anti-obesity effects of oolong tea in high-fat diet-treated mice might be due partly to the enhancing effect of caffeine isolated from oolong tea on noradrenaline-induced lipolysis in adipose tissue, and to the inhibitory action of some other substance in oolong tea on pancreatic lipase activity. Caffeine was found to enhance lipolysis through acting on lipid droplets but not on HSL. The results suggest that oolong tea may be an effective crude drug for the treatment of obesity and fatty liver caused by a high-fat diet.

Anti-obesity effects in rodents of dietary teasaponin, a lipase inhibitor

“…3 Furthermore, we found that caffein was isolated from oolong tea as an accelerating substance of norepinephrine-induced lipolysis. 3 Therefore, we suggest that saponins of tea may have anti-obesity action through inhibiting pancreatic lipase activity in high-fat diettreated obesity mice. In this experiment, we found that teasaponin (a mixture of theasaponins E 1 and E 2 ) isolated from oolong tea inhibited pancreatic lipase in vitro.…”

“…2 In the previous paper, we found that oolong tea prevented obesity induced by feeding a high-fat diet through inhibiting pancreatic lipase activity and accelerating catecholamineinduced fat mobilization. 3 We reported that epicatechin gallate and epigallocatechin gallate had no effect on pancreatic lipase activity, but that saponin fraction inhibited pancreatic lipase activity. 3 Furthermore, we found that caffein was isolated from oolong tea as an accelerating substance of norepinephrine-induced lipolysis.…”

“…3 We reported that epicatechin gallate and epigallocatechin gallate had no effect on pancreatic lipase activity, but that saponin fraction inhibited pancreatic lipase activity. 3 Furthermore, we found that caffein was isolated from oolong tea as an accelerating substance of norepinephrine-induced lipolysis. 3 Therefore, we suggest that saponins of tea may have anti-obesity action through inhibiting pancreatic lipase activity in high-fat diettreated obesity mice.…”

Anti-Obesity and Hypotriglyceridemic Properties of Coffee Bean Extract in SD Rats

“…Han et al (1999Han et al ( , 2001) have pointed out that slower absorption of dietary fat decreased the deposition of visceral fat. Shimoda et al (2006) have shown that CBE and caffeine, but not chlorogenic acid, suppress the elevation of the serum triglyceride level after oral oil administration to mice.…”

Diabetes, Oxidative Stress and Tea

“…Improved glucose tolerance and increased plasma insulin concentrations by tea, have been found in some studies which may be, in part, explained by the effect of tea antioxidants on insulin resistance and -cell function. EGCG has also been shown to suppress cytokine-inducedcell damage; this may also contribute to glucose lowering effect of tea (Gomes et al, 1995;Han et al, 1999;Kao et al, 2000;Sabu et al, 2002;Wu et al, 2004;Tsuneki et al, 2004;Wolfram et al, 2006;Igarashi et al, 2007;Badawoud et al, 2007;Ostad Rahimi et al, 2007;Potenza et al, 2007).…”