Tormentic acid, a major component of suspension cells of Eriobotrya japonica, suppresses high-fat diet-induced diabetes and hyperlipidemia by glucose transporter 4 and AMP-activated protein kinase phosphorylation

J Agric Food Chem. 2014 Nov 5;62(44):10717-26. doi: 10.1021/jf503334d. Epub 2014 Oct 27.


This study was designed to evaluate the effects and mechanism of tormentic acid (PTA) on diabetes and dyslipidemia in high-fat (HF)-fed mice. Feeding C57BL/6J mice with a HF diet for 12 weeks induced type 2 diabetes and hyperlipidemia. During the last 4 weeks, the mice were given orally PTA (at two dosages) or rosiglitazone (Rosi) or water. In this study, the HF diet increased glucose, triglyceride, insulin, and leptin levels, whereas PTA effectively prevented these phenomena and ameliorated insulin resistance. PTA reduced visceral fat mass and hepatic triacylglycerol contents; moreover, PTA significantly decreased both the area of adipocytes and ballooning degeneration of hepatocytes. PTA caused increased skeletal muscular AMP-activated protein kinase (AMPK) phosphorylation and Akt phosphorylation and glucose transporter 4 (GLUT4) proteins, but reduced the hepatic expressions of phosphenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6 Pase) genes. PTA enhanced skeletal muscular Akt phosphorylation and increased insulin sensitivity. PTA also enhanced phospho-AMPK in the liver. Therefore, it is possible that the activation of AMPK by PTA results in decreasing hepatic glucose production while increasing skeletal muscular GLUT4 contents, thus contributing to attenuating the diabetic state. Moreover, PTA exhibits an antihyperlipidemic effect by down-regulations of the hepatic sterol regulatory element binding protein-1c (SREBP-1c) and apolipoprotein C-III (apo C-III) and an increased peroxisome proliferator activated receptor (PPAR)-α expression, thus resulting in decreases in blood triglycerides. These findings demonstrated that PTA was effective for the treatment of diabetes and hyperlipidemia in HF-fed mice.

Keywords: AMP-activated protein kinase phosphorylation; antidiabetes; antihyperlipidemia; glucose transporter 4; tormentic acid.

MeSH terms

  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism*
  • Animals
  • Blood Glucose / metabolism
  • Cells, Cultured
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / enzymology
  • Diabetes Mellitus, Type 2 / genetics
  • Diabetes Mellitus, Type 2 / metabolism
  • Diet, High-Fat / adverse effects
  • Eriobotrya / chemistry*
  • Eriobotrya / growth & development
  • Glucose Transporter Type 4 / genetics
  • Glucose Transporter Type 4 / metabolism*
  • Humans
  • Hyperlipidemias / drug therapy*
  • Hyperlipidemias / enzymology
  • Hyperlipidemias / genetics
  • Hyperlipidemias / metabolism
  • Insulin / metabolism
  • Liver / enzymology
  • Liver / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / metabolism
  • Phosphorylation / drug effects
  • Plant Extracts / administration & dosage*
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism
  • Triglycerides / metabolism
  • Triterpenes / administration & dosage*


  • Blood Glucose
  • Glucose Transporter Type 4
  • Insulin
  • Plant Extracts
  • Sterol Regulatory Element Binding Protein 1
  • Triglycerides
  • Triterpenes
  • euscaphic acid
  • AMP-Activated Protein Kinases