Hypoglycemic effect of ethanol extract from Gynura bicolor D.C in healthy mice

Zheng ZX, Tang XW, Xue CY, Zhang Y. 1Department of Nutrition, General Hospital of Chinese PLA, Beijing 100853, China; 2National Engineering Research Center for Vegetable, Beijing 100089, China  

AIM: To investigate the hypoglycemic effect of ethanol extract from Gynura bicolor D.C as a kind of natral extract in normal mice and its possible mechanism and provide experimental evidences for diabetic cases. METHODS: The experiment was carried out at the Experimental Animal Center and Laboratory of Department of Nutrition of General Hospital of Chinese PLA from June to September 2006. ①Forty normal healthy male Kunming species mice were divided into four groups randomly, starch group, starch plus ethanol extracted from Gynura bicolor D.C group, glucose group and glucose plus ethanol extract from Gynura bicolor D.C group. Starch and glucose were administered intragastric perfusion at dose of 3.0 g/kg and 2.0 g/kg respectively; ethanol extract was given 1.0 g/kg after mixed with starch or glucose. In starch group and starch plus ethanol extracted from Gynura bicolor D.C group, blood glucose of tail vein was measured at hours 1 and 2 after intragastric perfusion; in glucose group and glucose plus ethanol extract from Gynura bicolor D.C group, blood glucose of tail vein was measured at hours 0.5, 1 and 2 after intragastric perfusion. ②Twenty healthy male Kunming mice were divided into two groups randomly. Blood glucose of tail vein was measured 4 hours after fasting. Mice of the experimental group were given ethanol extract at dose of 1.0 g/kg and mice in the control group were given redistilled water, and blood glucose of tail vein was measured at hours 1 and 2 after intragastric perfusion. ③Twenty healthy ad lib mice were divided into two groups with 10 in each group and blood glucose of tail vein was measured. Mice of the experimental group were given ethanol extract at dose of 1.0 g/kg and mice of the control group were given redistilled water, meanwhile feed was withdrawn and mice drank freely. Blood glucose of tail vein was measured at hours 1 and 2 after intragastric perfusion. ④There were blank group, negative control group, ethanol extract from Gynura bicolor D.C group and ethanol extract from Gynura bicolor D.C control group (only ethanol extract, no substrate to subtract the extractive ground color). The inhibitive effect on α-glucosidase activity of ethanol extract from Gynura bicolor D.C was measured compared with acarbose as a positive control in vitro by measuring absorbance at 405 nm with UV-120-02 visible-ultraviolet spectrophotometer. RESULTS: All 80 mice were involved in the results analysis, no drop out. ①Blood glucose level was significantly lower in the starch plus ethanol extracted from Gynura bicolor D.C group than the starch group at hour 1 [(12.33±1.82),(10.32±1.14) mmol/L,P 0.01]. Blood glucose level was obviously lower in the glucose plus ethanol extract from Gynura bicolor D.C group than the glucose group at hours 0.5 and 1 [(12.01±1.61),(10.15±1.23) mmol/L;(11.70±0.94),(9.62±0.74) mmol/L,P 0.01]. ②The blood glucose level in fasting mice was remarkably lower 1 hour after administered extract compared with the control group [(8.07±1.02),( 6.93±0.76) mmol/L,P 0.05]. ③After administered extract in ad lib mice, the blood glucose level was markedly lower than that of control group at hour 1 [(9.36±0.89),(7.82±1.07) mmol/L,P 0.05]. ④At the dose of 25-800 mg/L, ethanol extract of Gynura could inhibit the α-glucosidase activity, its half inhibition rate was 320 mg/L,while acarbose's IR50 was 258 mg/L。 CONCLUSION: ①Ethanol extract from Gynura bicolor D.C can improve glucose tolerance in normal mice, and can decrease fasting glucose and postprandial blood glucose significantly. ②Ethanol extract from Gynura bicolor D.C can inhibit the α-glucosidase activity, which may be the possible mechanism of hypoglycemic effect.

【Key Words】：
【CateGory Index】： R285.5
【DOI】： CNKI:SUN:XDKF.0.2007-47-023

Download(CAJ format) Download(PDF format)

CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.