Study On The Hypoglycemic And Hepatoprotective Effects Of Rubia Cordifolia L. And Alpinia Oxyphylla Miq. Leave

This dissertation is composed of three chapters. In first chapter, the progress of adipocyte and the relationship between adipocyte and type 2 diabetes were summarized. In the second chapter, the hypoglycemic effect of Rubia cordifolia L. was been investigated with the hypoglycemic model in vitro and in vivo. The third chapter studied the antioxidant activity and ?-glucosidase inhibitiory activity of Alpinia oxyphylla Miq. leave in vitro, and its hepatoprotective and hypoglycemic effects in vivo.Chapter 1 Advances of adipocyte and the relationship between adipocyte and type 2 diabetesThe progress of adipocyte and the relationship between adipocyte and type 2 diabetes were summarized.Chapter 2 The Hypoglycemic effect of Rubia cordifolia L. in vitro and in vivoIn this study, the hypoglycemic model with isolated rat adipocytes and diabetic mice induced by alloxan, respectively, were established to evaluate the hypoglycemic effect of different extracts and active compounds from R. cordifolia in vitro. The results showed that alizarin?AZ? and mollugin?MU?, respectively isolated from ethyl acetate extract?RCEA? and petroleum ether extract?RCPE? of R. cordifolia, both could promote the rat epididymal fat cells to take in glucose, and at the concentration of 1.6 mg/m L, the glucose uptake rate of alizarin?AZ? and mollugin?MU? were 64.53±1.24%, 47.67±3.91% respectively. Compared with diabetic control mice, administration of RCPE?550 mg/kg?, RCEA?750 mg/kg b.w.?, alizarin?96, 48 mg/kg? and mollugin?200, 100 mg/kg? respectively were significantly decreased the level of fasting blood glucose?FSG?, postprandial blood glucose?PBG?, malondialdehyde?MDA?, triglyceride?TG? and total cholesterol?TC?, and could significantly increase the level of liver glycogen content and superoxide dismutase?SOD? in serum with statistical significance. Results indicate that the RCPE, RCEA, mollugin and alizarin had significant antihyperglycemic effect in alloxan-induced diabetic mice, and mollugin and alizarin might be the effective active ingredient in R. cordifolia.Chapter 3 The Hepatoprotective and Hypoglycemic effect of Alpinia oxyphylla Miq. leave in vitro and in vivoThis study investigated the antioxidant activity of the different extracts of A. oxyphylla Miq. leave in vitro by DPPH, ABTS, FRAP, H₂O₂-induced red blood hemolysis assays and TBA method for determining the content of MDA in liver and kidney tissue. The results showed that the extracts of ethyl acetate?AOLEA? and n-butanol?AOLBU? from A. oxyphylla Miq. Leave, both had good antioxidant activity, and showed a dose-dependent manner. In DPPH and ABTS methods, the screening clearance rates of AOLEA?90.36±0.70%, 97.95±1.49%, respectively? and AOLBU?89.31±0.12% ? 98.52±0.99%, respectively? had been close or equal to those of BHA?88.52±0.34%, 99.74±0.68%, respectively? as the positive control. In FRAP assays, the Trolox equivalent of AOLEA and AOLBU were 955.81±61.20 ?mol/g and 2212.89±230.98 ?mol/g, respectively, which were weaker than that of BHA?11106.65±667.16 ?mol/g?. In protecting red blood cell membrane method, at the concentration of 107.84 ?g/m L, the red blood cells emolytic rate of AOLEA and AOLBU were 18.21±0.71%, 28.76±2.65%, respectively, which were close to the negative control?11.65±0.45%?. In TBA method, the screening inhibition rates of the MDA content of AOLEA and AOLBU were 115.26±2.57% and 108.17±2.98% in liver tissue, respectively, as well as were 106.50±4.77% and 112.74±11.75% in kidney tissue, respectively; the above results were higher than those of the negative control?84.15±4.83% in liver tissue and 71.67±3.27% in kidney tissue?.?-Glucosidase inhibitory activity of different extracts of A. oxyphylla leave were also assayed. Results showed that ?-glucosidase inhibitory activity of AOLEA?IC50=55.00±0.23 ?g/m L?, AOLBU?IC50=345.70±2.51 ?g/m L? were better than that of acarbose?IC50=1130.00±52.94 ?g/m L? as the positive control.To investigate the hepatoprotective effect on carbon tetrachloride?CCl₄?-induced acute liver injury in mice of different extracts from A. oxyphylla leave, biochemical parameters were measured. Results showed that AOLEA could significantly reduce GOT viability?P<0.001? and MDA content?P<0.001?, and significantly increased SOD activity?P<0.001?, compared with liver damage control mice, While AOLBU could significantly reduce GPT and GOT viability?P<0.01, P<0.01? and MDA content?P<0.01, P<0.01, P<0.001?, and at the same time significantly increased SOD activity?P<0.05?. This study suggested that AOLEA and AOLBU were the effective extracts of A. oxyphylla leave for protecting acute liver injury, antioxidant might be one of the mechanism of action on protecting liver injury.This chapter, hypoglycemic effect of A. oxyphylla leave extracts was investigated. Compared with the model group, the groups of AOLEA?800 mg/kg?, AOLEA?400 mg/kg? and AOLBU?800 mg/kg? could significantly decrease the level of fasting blood sugar?P<0.01, P<0.05 and P<0.01, respectively? and the contents of TC?P<0.05, P<0.01 and P<0.01, respectively?, TG?P<0.01, P<0.05 and P<0.01, respectively? and MDA?P<0.001, P<0.001 and P<0.001, respectively?, and increase SOD activity?P<0.001, P<0.01 and P<0.001, respectively? and liver glycogen content?P<0.01, P<0.001, P<0.01, respectively?. The results indicated that AOLEA and AOLBU could reduce fasting blood glucose level, and promoted hepatic glycogen synthesis and inhibited excessive degradation, also rectified the derangement in lipide metabolism and strengthened antioxidant defense system.