Extraction and purification of pumpkin polysaccharides and their hypoglycemic effect

The anti-diabetic activity of the polysaccharides (PPs) obtained from the dried pumpkin pulp was studied in this paper. The PPs were administered by intraperitoneal injection to the alloxan-induced diabetic male ICR mice. The PPs hypoglycemic effect was evaluated by testing the fast blood glucose level, fasting serum insulin and hepatic glycogen. After 7 h administration, the PPs showed a significantly hypoglycemic effect (p < 0.01) and could significantly increase hepatic glycogen and insulin level (p < 0.05). PPs-e with potential to enhance the islet cells proliferation activity by MTT assays in vitro was obtained from the PPs through alcohol fractional precipitation and gel chromatography. PPs-e composed of rhamnose, arabinose, glucose, galactose, and little amount of inositol could maintain the blood glucose at a low level in diabetic mice and could even last for more than 24 h. These results suggest the potential hypoglycemic effect of the pumpkin polysaccharides in alloxan-induced diabetic mice and for the treatment of diabetic mellitus.