title: Anti-diabetic properties of the Canadian lowbush blueberry Vaccinium angustifolium Ait.
abstract: Incidence of type II diabetes is rapidly increasing worldwide. In order to identify complementary or alternative approaches to existing medications, we studied anti-diabetic properties of Vaccinium angustifolium Ait., a natural health product recommended for diabetes treatment in Canada. Ethanol extracts of root, stem, leaf, and fruit were tested at 12.5 microg/ml for anti-diabetic activity in peripheral tissues and pancreatic beta cells using a variety of cell-based bioassays. Specifically, we assessed: (1) deoxyglucose uptake in differentiated C2C12 muscle cells and 3T3-L1 adipocytes; (2) glucose-stimulated insulin secretion (GSIS) in beta TC-tet pancreatic beta cells; (3) beta cell proliferation in beta TC-tet cells; (4) lipid accumulation in differentiating 3T3-L1 cells; (5) protection against glucose toxicity in PC12 cells. Root, stem, and leaf extracts significantly enhanced glucose transport in C2C12 cells by 15-25% in presence and absence of insulin after 20 h of incubation; no enhancement resulted from a 1 h exposure. In 3T3 cells, only the root and stem extracts enhanced uptake, and this effect was greater after 1 h than after 20 h; uptake was increased by up to 75% in absence of insulin. GSIS was potentiated by a small amount in growth-arrested beta TC-tet cells incubated overnight with leaf or stem extract. However, fruit extracts were found to increase 3H-thymidine incorporation in replicating beta TC-tet cells by 2.8-fold. Lipid accumulation in differentiating 3T3-L1 cells was accelerated by root, stem, and leaf extracts by as much as 6.5-fold by the end of a 6-day period. Stem, leaf, and fruit extracts reduced apoptosis by 20-33% in PC12 cells exposed to elevated glucose for 96 h. These results demonstrate that V. angustifolium contains active principles with insulin-like and glitazone-like properties, while conferring protection against glucose toxicity. Enhancement of proliferation in beta cells may represent another potential anti-diabetic property. Extracts of the Canadian blueberry thus show promise for use as a complementary anti-diabetic therapy.
authors.affiliation: Department of Pharmacology and Membrane Protein Study Group, Université de Montréal, and Montreal Diabetes Research Center, Centre de recherche du Centre Hospitalier de l'Université de Montréal, QC, Canada.
authors.forename: Louis C
authors.initials: LC
authors.lastname: Martineau
authors.forename: Audrey
authors.initials: A
authors.lastname: Couture
authors.forename: Danielle
authors.initials: D
authors.lastname: Spoor
authors.forename: Ali
authors.initials: A
authors.lastname: Benhaddou-Andaloussi
authors.forename: Cory
authors.initials: C
authors.lastname: Harris
authors.forename: Bouchra
authors.initials: B
authors.lastname: Meddah
authors.forename: Charles
authors.initials: C
authors.lastname: Leduc
authors.forename: Andrew
authors.initials: A
authors.lastname: Burt
authors.forename: Tri
authors.initials: T
authors.lastname: Vuong
authors.forename: Phuong
authors.initials: P
authors.lastname: Mai Le
authors.forename: Marc
authors.initials: M
authors.lastname: Prentki
authors.forename: Steffany A
authors.initials: SA
authors.lastname: Bennett
authors.forename: John T
authors.initials: JT
authors.lastname: Arnason
authors.forename: Pierre S
authors.initials: PS
authors.lastname: Haddad
mesh_terms: D016475:3T3 Cells; D000818:Animals; D029798:Blueberry Plants / Q000737:chemistry*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects; D003847:Deoxyglucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism / Q000633:toxicity; D007004:Hypoglycemic Agents / Q000032:analysis / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects; D051379:Mice; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D010936:Plant Extracts; D003847:Deoxyglucose; D005947:Glucose