Dietary anthocyanin-rich bilberry extract ameliorates hyperglycemia and insulin sensitivity via activation of AMP-activated protein kinase in diabetic mice.
Blueberries or bilberries contain large amounts of anthocyanins, making them one of the richest sources of dietary anthocyanin. These berries are widely consumed as fresh and dried fruits, jams, or juices. Considerable attention has been focused on the health benefits of bilberry fruits beyond their antioxidant content or their ability to improve vision. In this study, we tested the effect of dietary bilberry extract (BBE) on hyperglycemia and insulin sensitivity in type 2 diabetic mice. We found that dietary BBE ameliorates hyperglycemia and insulin sensitivity via activation of AMP-activated protein kinase (AMPK). Dietary BBE significantly reduced the blood glucose concentration and enhanced insulin sensitivity. AMPK was activated in white adipose tissue (WAT), skeletal muscle, and the liver of diabetic mice fed BBE. This activation was accompanied by upregulation of glucose transporter 4 in WAT and skeletal muscle and suppression of glucose production and lipid content in the liver. At the same time, acetyl-CoA carboxylase was inactivated and PPARalpha, acyl-CoA oxidase, and carnitine palmitoyltransferase-1A were upregulated in the liver. These changes resulted in improved hyperglycemia and insulin sensitivity in type 2 diabetes. These findings provide a biochemical basis for the use of bilberry fruits and have important implications for the prevention and treatment of type 2 diabetes via activation of AMPK.
Takikawa
Masahito
M
College of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi 487-8501, Japan.
Inoue
Seiya
S
Horio
Fumihiko
F
Tsuda
Takanori
T
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D052242:Adiponectin / Q000235:genetics / Q000378:metabolism; D052436:Adipose Tissue, White / Q000378:metabolism; D000818:Animals; D000872:Anthocyanins / Q000737:chemistry* / Q000494:pharmacology; D001786:Blood Glucose; D001835:Body Weight; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004032:Diet; D004435:Eating; D004734:Energy Metabolism; D015971:Gene Expression Regulation, Enzymologic; D005943:Gluconeogenesis; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D006943:Hyperglycemia / Q000188:drug therapy*; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics / Q000378:metabolism; D007333:Insulin Resistance; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D018482:Muscle, Skeletal / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D054419:Receptors, Adiponectin / Q000235:genetics / Q000378:metabolism; D054839:Retinol-Binding Proteins, Plasma / Q000235:genetics / Q000378:metabolism; D029800:Vaccinium myrtillus / Q000737:chemistry*
D052242:Adiponectin; D000872:Anthocyanins; D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D010936:Plant Extracts; C502487:Rbp4 protein, mouse; D054419:Receptors, Adiponectin; D054839:Retinol-Binding Proteins, Plasma; C495693:Slc2a4 protein, mouse; D055372:AMP-Activated Protein Kinases