Inhibition of intestinal glucose absorption by anti-diabetic medicinal plants derived from the James Bay Cree traditional pharmacopeia.
BACKGROUND
Type II diabetes and obesity are major health problems worldwide and aboriginal peoples are particularly at risk. To address this problem in Canadian native populations who find modern pharmaceuticals culturally inappropriate, our team is testing the traditional pharmacopeia of the James Bay Cree for anti-diabetic and anti-obesity activities. More specifically, the aim of the present study was to define the effects of traditional plants on intestinal glucose absorption, an under-appreciated anti-hyperglycaemic and anti-obesity activity.


METHODS
Crude ethanol extracts of 17 Boreal forest medicinal plants were tested in vitro using the Caco-2 human enterocytic cell line and in vivo using an oral glucose tolerance test.


RESULTS
Thirteen of seventeen extracts were observed to significantly inhibit uptake when administered simultaneously with (3)H-deoxyglucose. Inhibition was dose-dependent and, in a few cases, even surpassed that induced by a combination of the positive controls. To validate these effects in vivo, four plant extracts were administered by intragastric gavage at 250 mg/kg to normal rats simultaneously with a 3g/kg bolus of glucose. This resulted in a decrease in peak glycaemia by approximately 40% for two of them. Similarly, only 2 extracts reduced glucose transport after long term incubation and this could be related to reductions in the expression of SGLT-1 or GLUT-2 proteins.


CONCLUSIONS
These findings indicate that competitive inhibition of intestinal glucose uptake can be achieved by crude extracts of medicinal plants. Such extracts could be taken with meals to control postprandial glycaemia and reduce caloric intake in high risk populations that are positively inclined towards traditional medicine.
Nistor Baldea
Lidia A
LA
Natural Health Products and Metabolic Diseases Laboratory, Department of Pharmacology, Université de Montréal, Quebec, Canada.
Martineau
Louis C
LC
Benhaddou-Andaloussi
Ali
A
Arnason
John T
JT
Lévy
Émile
É
Haddad
Pierre S
PS
D000818:Animals; D018938:Caco-2 Cells; D002170:Canada; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D051273:Glucose Transporter Type 2 / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy; D007004:Hypoglycemic Agents / Q000494:pharmacology* / Q000633:toxicity; D007198:Indians, North American; D007408:Intestinal Absorption / Q000187:drug effects*; D008297:Male; D010602:Pharmacopoeias as Topic; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D010946:Plants, Medicinal; D051381:Rats; D017208:Rats, Wistar; D051269:Sodium-Glucose Transporter 1 / Q000378:metabolism
D051273:Glucose Transporter Type 2; D007004:Hypoglycemic Agents; D010936:Plant Extracts; C495680:SLC2A2 protein, human; C495674:SLC5A1 protein, human; D051269:Sodium-Glucose Transporter 1; D005947:Glucose