GCG-rich tea catechins are effective in lowering cholesterol and triglyceride concentrations in hyperlipidemic rats.
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.
Lee
Sang Min
SM
Green Tea Research Team, Food Research Institute, R&D Center, Amorepacific Corporation, 314-1 Bora-dong, Giheung-gu, Yongin-si, Gyeonggi-do, South Korea.
Kim
Chae Wook
CW
Kim
Jung Kee
JK
Shin
Hyun Jung
HJ
Baik
Joo Hyun
JH
D000818:Animals; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D002784:Cholesterol / Q000097:blood* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D006949:Hyperlipidemias / Q000097:blood*; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D011973:Receptors, LDL / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013662:Tea / Q000737:chemistry*; D014280:Triglycerides / Q000097:blood*
D011973:Receptors, LDL; D013662:Tea; D014280:Triglycerides; C417940:gallocatechin gallate; D002392:Catechin; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases