title: Theaflavins attenuate hepatic lipid accumulation through activating AMPK in human HepG2 cells.
abstract: Black tea is one of the world's most popular beverages, and its health-promoting effects have been intensively investigated. The antiobesity and hypolipidemic effects of black tea have attracted increasing interest, but the mechanisms underlying these phenomena remain unclear. In the present study, the black tea major component theaflavins were assessed for their hepatic lipid-lowering potential when administered in fatty acid overload conditions both in cell culture and in an animal experimental model. We found that theaflavins significantly reduced lipid accumulation, suppressed fatty acid synthesis, and stimulated fatty acid oxidation. Furthermore, theaflavins also inhibited acetyl-coenzyme A carboxylase activities by stimulating AMP-activated protein kinase (AMPK) through the LKB1 and reactive oxygen species pathways. These observations support the idea that AMPK is a critical component of decreased hepatic lipid accumulation by theaflavin treatments. Our results show that theaflavins are bioavailable both in vitro and in vivo and may be active in the prevention of fatty liver and obesity.
authors.affiliation: Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Chih-Li
authors.initials: CL
authors.lastname: Lin
authors.forename: Hsiu-Chen
authors.initials: HC
authors.lastname: Huang
authors.forename: Jen-Kun
authors.initials: JK
authors.lastname: Lin
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase / Q000037:antagonists & inhibitors; D000818:Animals; D044946:Biflavonoids / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology*; D004041:Dietary Fats / Q000008:administration & dosage; D004789:Enzyme Activation; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects*; D008099:Liver / Q000378:metabolism*; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D044946:Biflavonoids; D004041:Dietary Fats; D009097:Multienzyme Complexes; C056068:theaflavin; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; D017346:Protein Serine-Threonine Kinases; C109790:STK11 protein, human; D000091162:AMP-Activated Protein Kinase Kinases; D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase; C057580:gallocatechol