(Article)
a Natural Health Products and Metabolic Diseases Laboratory, Department of Pharmacology, Université de Montréal, P.O. Box 6128, Station Centre-Ville, Montréal, QC, Canada
b Centre for Research in Biotechnology and Biopharmaceuticals, Department of Biology, University of Ottawa, Ottawa, ON,
b Centre for Research in Biotechnology and Biopharmaceuticals, Department of Biology, University of Ottawa, Ottawa, ON,
Abstract
Purpose: Using a diet-induced obesity (DIO) mouse model, we investigated the antidiabetic effect of Labrador tea [Rhododendron groenlandicum (Oeder) Kron and Judd], a beverage and medicinal tea used by the Cree Nations of northern Quebec. Methods: C57BL6 mice were divided into five groups and given standard chow (~4 % of lipids) or high-fat diet (~35 % of lipids) for 8 weeks until they became obese and insulin resistant. Treatment began by adding the plant extract at three doses (125, 250 and 500 mg/kg) to the high-fat diet for another 8 weeks. At the end of the study, insulin-sensitive tissues (liver, skeletal muscle, adipose tissue) were collected to investigate the plant’s molecular mechanisms. Results: Labrador tea significantly reduced blood glucose (13 %), the response to an oral glucose tolerance test (18.2 %) and plasma insulin (65 %) while preventing hepatic steatosis (42 % reduction in hepatic triglyceride levels) in DIO mice. It stimulated insulin-dependent Akt pathway (55 %) and increased the expression of GLUT4 (53 %) in skeletal muscle. In the liver, Labrador tea stimulated the insulin-dependent Akt and the insulin-independent AMP-activated protein kinase pathways. The improvement in hepatic steatosis observed in DIO-treated mice was associated with a reduction in inflammation (through the IKK α/β) and a decrease in the hepatic content of SREBP-1 (39 %). Conclusions: Labrador tea exerts potential antidiabetic action by improving insulin sensitivity and mitigating high-fat diet-induced obesity and hyperglycemia. They validate the safety and efficacy of this plant, a promising candidate for culturally relevant complementary treatment in Cree diabetics. © 2015, Springer-Verlag Berlin Heidelberg.
Author keywords
AMPK; Diabetes; GLUT4; Labrador tea; Natural health products; SREBP-1
Indexed keywords
EMTREE drug terms: adiponectin; alanine aminotransferase; antidiabetic agent; aspartate aminotransferase; cholesterol; glucose; glucose transporter 4; high density lipoprotein; hydroxymethylglutaryl coenzyme A reductase kinase; insulin; leptin; low density lipoprotein; plantextract; Rhododendron groenlandicum extract; sterol regulatory element binding protein 1; triacylglycerol; unclassified drug
EMTREE medical terms: alanine aminotransferase blood level; animal experiment; animal model; antidiabetic activity; Article; aspartate aminotransferase blood level; brown adipose tissue; cholesterol blood level; controlled study; diet induced obesity; fatty liver; glucose blood level; insulin blood level; insulin resistance; insulin sensitivity; lipid diet; male; mouse; non insulin dependent diabetes mellitus; nonhuman; oral glucose tolerance test; protein phosphorylation; Rhododendron groenlandicum; treatment duration; triacylglycerol blood level; white adipose tissue
Chemicals and CAS Registry Numbers: adiponectin, 283182-39-8; alanine aminotransferase, 9000-86-6, 9014-30-6; aspartate aminotransferase, 9000-97-9; cholesterol, 57-88-5; glucose, 50-99-7, 84778-64-3; glucose transporter 4, 188071-24-1; hydroxymethylglutaryl coenzyme A reductase kinase, 172522-01-9, 72060-32-3; insulin, 9004-10-8
ISSN: 14366207 CODEN: EJNUFSource Type: Journal Original language: English
DOI: 10.1007/s00394-015-0908-zDocument Type: Article
Publisher: Dr. Dietrich Steinkopff Verlag GmbH and Co. KG
Haddad, P.S.; Natural Health Products and Metabolic Diseases Laboratory, Department of Pharmacology, Université de Montréal, P.O. Box 6128, Station Centre-Ville, Canada; email:pierre.haddad@umontreal.ca
© Copyright 2016 Elsevier B.V., All rights reserved.
© Copyright 2016 Elsevier B.V., All rights reserved.
