Carbohydrate digestion and intestinal ATPases in streptozotocin-induced diabetic rats fed extract of yam (Dioscorea cayenensis) or dasheen (Colocasia esculenta)

Streptozotocin-induced diabetic rats were maintained for four weeks on extracts of yam or dasheen or commercial linamarin. The levels of blood glucose, digestive and membrane-bound enzymes of the intestine were determined. Rats fed commercial linamarin significantly lowered blood glucose level compared to the diabetic rats fed normal diet. Feeding of commercial linamarin to diabetic rats significantly decreased the activity of intestinal amylase compared to normal rats. Dasheen extract or commercial linamarin significantly increased the activities of intestinal disaccharidases compared to the diabetic rats fed normal diet. Na+ /K+ ATPase activity in the lower segment of the intestine was significantly reduced in diabetic rats compared to normal rats. In the upper segment of the intestine, yam or dasheen extract or commercial linamarin supplementation increased the activity of this enzyme above normal. These observations show that the hypoglycemic property of cyanoglucoside extract from dasheen and to a lesser extent yam, could be due to other chemical constituents of the extract and this needs further investigation.