The Hypoglycemic Effect Of Extracts From Different Kinds Of Pumpkin

Pumpkin was the fruit of the anannual vine herbaeeous plant, while belong to the genus ofCucurbita (Cucurbitaceae), and had rich healthy functions and medicinal values for human body. Manyparts of pumpkin, such as the pumpkin fruit, pumpkin polysaccharide, pumpkin protein and pumpkinseed and pectin, all had the hypoglycemic effects. The fruit was the most important parts of the pumpkin,the25different varieties of pumpkin fruit were used in this study to evaluate the α-glucosidase inhibitoryactivity and the antioxidant activity of different varieties of pumpkin in vitro, and then selected4kinds ofpumpkins used to the study their hypoglycemic effects in vivo. By compare the effect of different kindsof pumpkin extract and the pumpkin organic solvent and the polysaccharide on the different indexes todiscuss the mechanisms of pumpkin hypoglycemic effects.1. The study tried to evaluate and compare the effect on α-glucosidase inhibitory activity of extractsfrom25kinds of pumpkin with α-glucosidase inhibitory model in vitro. The relationship of inhibitoryratio and the concentration of extracts were studied and results showed that many varieties of pumpkinextracts had the α-glycosidase inhibitory activity. The petroleum ether extraces of “Heshun” pumpkinshowed the strongest activity (IC50=62.61±8.71μg/mL), far higher than that of the positive control (IC50=1257.34±15.36μg/mL). Most extracts from different solvent and pumpkin have the α-glucosidaseinhibitory activity, but they showed great different. And the active ingredients maybe existenced in lowerpolarity parts.2. Diphenyl bitter acyl(DPPH) free radical,[2,2’-hydrazine-(3-ethyl benzothiazole lin-6-sulfonicacid)](ABTS) ammonia salt free radicals and reduce iron ion (FRAP) were used to evaluate the antioxidant activity of26kinds of cultivated Cucurbita Linn., and butylated hydroxytoluene and Troloxas the positive control in vitro. Results showed that the scanvenging capability of DPPH free radicalability was weak. The ethyl acetate extract of “Shanmierhao” showed the strongest power to clear ABTSradical (IC50=4.41±0.23μg/mL), better than that of butylated hydroxytoluene (IC50=8.59±0.56μg/mL).The power of ethyl acetate for reduction of Fe3+ability was higher than that of other extracts, and“Gailiangmiben” ethyl acetate extract (TEAC=529.65±69.52μmol/g) was weaker than that of Trolox(TEAC=1387.51±37.9μmol/g).3. The hyperglycemic effect of “Shijiemei” and “Gailiangmiben” pumpkin on alloxan induceddiabetes mice were evaluated in vivo. Diabetes mice were established through the tail injection of alloxan.After gavaged for7days, postprandial blood glucose and fasting blood glucose, MDA content and SODactivity of serum and the liver glycogen contents were analyzed. It was found that two kindsof pumpkins all had certain therapeutic effects on alloxan diabetic mice. The extracts could decreased thecontents of fasting blood glucose and MDA, also can increased the level of SOD activity, but the effectson postprandial blood glucose levels and hepatic glycogen contents were not significant. All organicsolvent extracts of “Shijiemei” and “Gailiangmiben” pumpkin showed a stronger effect than that of the“Gailiangmiben” polysaccharide.The hyperglycemic effect of pumpkin showed close connectionwith oxidative stress in mice, but not the α-glucosidase. With the pumpkin can significantlyreduce fasting blood glucose, it could surmised that the repair of insulin was effected.4. The hyperglycemic effect of “Zhejiangqiye” and “Shanmeierhao” pumpkin on alloxan induceddiabetes mice were investugated in vivo. The postprandial blood glucose and fasting blood glucose,insulin, MDA, liver glycogen contents and the SOD activity in serum and they were analyzed. Results showed that two kinds of pumpkins all had certain therapeutic effects on alloxan diabetic mice. Theextracts could decrease the contents of fasting blood glucose and MDA contents, also could increasethe contents of insulin, hepatic glycogen, as well as the level of SOD activity in mice, but the effects onpostprandial blood glucose levels were not significant. The hypoglycemic mechanism of pumpkinsmaybe repair the injured β cells of pancreatic to get it restored to normal or through promote glycogensynthesis to improve the glucose utilization. And the regulation of glucose utilization also had certainassociated with the hypoglycemic effect.