GCG-rich tea catechins are effective in lowering cholesterol and triglyceride concentrations in hyperlipidemic rats

Lipids. 2008 May;43(5):419-29. doi: 10.1007/s11745-008-3167-4. Epub 2008 Mar 26.

Abstract

The (-)-gallocatechin gallate (GCG) concentration in some tea beverages can account for as much as 50% of the total catechins, as a result of sterilization. The present study aims to examine the effects of GCG-rich tea catechins on hyperlipidemic rats and the mechanisms associated with regulating cholesterol metabolism in the liver. By performing heat epimerization of (-)-epigallocatechin gallate (EGCG), we manufactured a mixture of catechins that had a GCG content of approximately 50% (w/w). In sucrose-rich diet-induced hyperlipidemic rats, the GCG-rich tea catechins exhibited strong activity in reducing plasma cholesterol and triglyceride concentrations. Furthermore, the hepatic cholesterol and triglyceride concentrations that had increased as a result of the sucrose-rich diet were reduced due to GCG-rich tea catechins consumption. In order to investigate the hyperlipidemic mechanism of GCG-rich tea catechins, we examined the hepatic expressions of LDL receptor and HMG-CoA reductase in hyperlipidemic rats. We further evaluated the action of purified GCG on LDL receptor activity, which is a key contributor to the regulation of cholesterol concentrations. We found that purified GCG increased LDL receptor protein level and activity to a greater extent than EGCG. In conclusion, our study indicates that GCG-rich tea catechins in tea beverages may be effective in preventing hyperlipidemia by lowering plasma and hepatic cholesterol concentrations.

MeSH terms

  • Animals
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology
  • Cell Line
  • Cholesterol / blood*
  • Cholesterol / metabolism
  • Flow Cytometry
  • Humans
  • Hydroxymethylglutaryl CoA Reductases / metabolism
  • Hyperlipidemias / blood*
  • Liver / enzymology
  • Liver / metabolism
  • Rats
  • Receptors, LDL / metabolism
  • Spectrometry, Fluorescence
  • Tea / chemistry*
  • Triglycerides / blood*

Substances

  • Receptors, LDL
  • Tea
  • Triglycerides
  • gallocatechin gallate
  • Catechin
  • Cholesterol
  • Hydroxymethylglutaryl CoA Reductases