Hypoglycemic activity of a novel anthocyanin-rich formulation from lowbush blueberry, Vaccinium angustifolium Aiton.
Blueberry fruits are known as a rich source of anthocyanin components. In this study we demonstrate that anthocyanins from blueberry have the potency to alleviate symptoms of hyperglycemia in diabetic C57b1/6J mice. The anti-diabetic activity of different anthocyanin-related extracts was evaluated using the pharmaceutically acceptable self-microemulsifying drug delivery system: Labrasol. Treatment by gavage (500 mg/kg body wt) with a phenolic-rich extract and an anthocyanin-enriched fraction formulated with Labrasol lowered elevated blood glucose levels by 33 and 51%, respectively. The hypoglycemic activities of these formulae were comparable to that of the known anti-diabetic drug metformin (27% at 300 mg/kg). The extracts were not significantly hypoglycemic when administered without Labrasol, demonstrating its bio-enhancing effect, most likely due to increasing the bioavailability of the administered preparations. The phenolic-rich extract contained 287.0+/-9.7 mg/g anthocyanins, while the anthocyanin-enriched fraction contained 595+/-20.0 mg/g (cyanidin-3-glucoside equivalents), as measured by HPLC and pH differential analysis methods. The greater hypoglycemic activity of the anthocyanin-enriched fraction compared to the initial phenolic-rich extract suggested that the activity was due to the anthocyanin components. Treatment by gavage (300 mg/kg) with the pure anthocyanins, delphinidin-3-O-glucoside and malvidin-3-O-glucoside, formulated with Labrasol, showed that malvidin-3-O-glucoside was significantly hypoglycemic while delphinidin-3-O-glucoside was not.
Grace
Mary H
MH
University of Illinois, Department of Natural Resources and Environmental Sciences, Urbana, IL 61801, USA.
Ribnicky
David M
DM
Kuhn
Peter
P
Poulev
Alexander
A
Logendra
Sithes
S
Yousef
Gad G
GG
Raskin
Ilya
I
Lila
Mary Ann
MA
D000818:Animals; D000872:Anthocyanins / Q000032:analysis / Q000494:pharmacology*; D001786:Blood Glucose / Q000187:drug effects*; D029798:Blueberry Plants; D016503:Drug Delivery Systems; D004359:Drug Therapy, Combination; D005960:Glucosides / Q000032:analysis / Q000494:pharmacology; D005989:Glycerides; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000494:pharmacology*; D007333:Insulin Resistance; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009930:Organic Chemicals / Q000008:administration & dosage / Q000494:pharmacology; D010636:Phenols / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*
D000872:Anthocyanins; D001786:Blood Glucose; D005960:Glucosides; D005989:Glycerides; D007004:Hypoglycemic Agents; D009930:Organic Chemicals; D010636:Phenols; D010936:Plant Extracts; C440220:Labrasol; C494120:delphinidin 3-O-glucopyranoside; C458419:malvidin-3-glucoside