飯塚　讓    Department   School of Medicine, School of Medicine    Position   Assistant Professor
Article types	Original article
Language	English
Peer review	Peer reviewed
Title	Blackcurrant Extract Ameliorates Hyperglycemia in Type 2 Diabetic Mice in Association with Increased Basal Secretion of Glucagon-Like Peptide-1 and Activation of AMP-Activated Protein Kinase.
Journal	Formal name：Journal of nutritional science and vitaminology Abbreviation：J Nutr Sci Vitaminol (Tokyo) ISSN code：18817742/03014800
Domestic / Foregin	Foregin
Volume, Issue, Page	64(4),pp.258-264
Author and coauthor	Iizuka Yuzuru, Ozeki Aoi, Tani Tsubasa, Tsuda Takanori
Authorship	Lead author
Publication date	2018/03
Summary	Blackcurrants are berries that contain high levels of anthocyanins, particularly delphinidin 3-rutinoside (D3R). Several studies have reported that the consumption of blackcurrant extract (BCE) lowers blood glucose levels and ameliorates glucose tolerance, but the mechanism underlying this effect remains unclear. Glucagon-like peptide-1 (GLP-1) and AMP-activated protein kinase (AMPK) are considered one of the most significant molecular targets for the prevention and treatment of type 2 diabetes. In this study, we showed that dietary BCE significantly reduced blood glucose concentration and improved glucose tolerance in type 2 diabetic mice (KK-Ay). The basal GLP-1 concentration in plasma was significantly increased in the BCE group accompanied by upregulation of prohormone convertase 1/3 (PC1/3), the enzyme that processes intestinal proglucagon. Moreover, the level of phospho-AMPKα protein in skeletal muscle was significantly increased in the BCE group, and this was increase accompanied by significant upregulation of glucose transporter 4 (Glut4) proteins in the plasma membrane of BCE group. In conclusion, dietary BCE significantly reduced blood glucose concentration and improved glucose tolerance in association with increased basal GLP-1 concentration in plasma, upregulation of PC1/3 expression, and translocation of Glut4 to the plasma membrane of skeletal muscle in type 2 diabetic mice; furthermore, these effects were accompanied by activation of AMPK. Our findings demonstrated that D3R-rich BCE may help prevent diabetes and allow the dosages of diabetes drugs to be reduced.
DOI	10.3177/jnsv.64.258
PMID	30175788