| Black raspberry(BRB)belongs to RubuscorchorifoliusL.f.and has been proved with abundant active substances like,phenolic acids,flavonoids,procyanidins,tannic acid,styrene,wooden fat element,terpene and sterol,etc.Procyanidins and ellagic acid contained in BRB shows impressive positive effect on cancer prevention,especially for colon cancer,and esophagus cancer.As the positive substances,most are polyphenols,found in BRB all had been reported for the contribution to the metabolic diseases.So this study was aimed to investigate the effect of polyphenols from BRB on the prevention of diabetes mellitus.The results we found were showed as below:(1)BRB polyphenols reduced the blood glucose level and improved the diabetic glucose toleranceWe found that BRB reduced the blood glucose levels of both alloxan-reduced and STZ-reduced diabetic mice since the first week treatment.After administrated injected respectively(i.p.)with alloxan 100mg/kg twice(once the other day)after the fasting,the mice suffered from diabetes.The blood glucose concentration had been kept in high level among 20–30mM in ALX group throughout whole experiment periods.But the blood glucose in the A-BRB groups lowered significantly.With the dose of 10% BRB feeding,the blood glucose of alloxan-reduced diabetic mice decreased by degrees comparing to the ALX group.STZ showed much mild hyperglycemia reduction,the blood glucose concentration kept around 10 mM.The hypoglycemic effects of S-BRB at 5% and 10% is less than the S-Control group.The results showed that BRB possesses remarkable hypoglycemic effect on hyperglycemia in diabetic mice induced by alloxan or STZ.(2)BRB polyphenols increased the expression of insulin receptor signaling path wayDiabetes mellitus could be characterized by the disorder of the expression of a series of glucose metabolic genes expression.Here we chose the glucose metabolic genes,IR,p-IR,p-IRS,GSK3?,AKT,AMPK and GLUT4 to evaluate the effect of BRB on glucose metabolism.The expressions of GLUT4 are increased in the BRB treatment groups.The expressions of IR,P-IR,P-IRS and AMPK were also up regulated significantly in the BRB treatment mice groups comparing to the diabetic groups both in alx-reduced mice and stz-reduced mice.(3)Effects of BRB polyphenols on diabetic complicationsThe kidney mess(per body weight)in 10%BRB group was significantly lower than the A-ALX group.The fasting-state plasma cholesterol(CHO)and triglycerides(TG)levels of mice are tested at the end of the experiment period(4wk).Both CHO and TG levels of A-ALX group were significantly higher than the normal mice group,while the 10%BRB group showed a significant decrease comparing to the A-ALX group.To further investigate the effect of BRB treatment on hepatic injury in alloxan reduced diabetic mice,the levels of inflammatory markers,IL-1,IL-6,COX2,and TNF-? were measured.Compared with ALX group,the levels of IL-1,IL-6,COX2 and TNF-? in the 10%S-BRB treated group were significantly decreased(p<0.01).The data suggested that BRB treatment significantly decreased the elevation in hepatic inflammatory markers to protect the liver from detection.All the datas proved that BRB could reduced the complications caused by continuous hyperglycemia with normal trends organ index,lower TG and CHO levels in blood and a significant reduction on hepatic inflammatory in alloxan reduced diabetic mice.In this study,we investigate the potential function of polyphenols from black raspberry on diabete mellitus in chemical diabetic mice models.The results show that black raspberry can reduce the blood glucose levels of diabetic mice through the activation of key proteins on insulin signaling pathway. |
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