Experimental Study Of Shizidaiping Formula And Its Active Ingredients On Dipeptidyl Peptidase ?

Objectives To observe the hypoglycemic effect and mechanism of inhibitory effect of DPP-4 through animal experiment of Shizidaiping Formula to improve spontaneously T2 DM GK rat glucose metabolism and the in vitro selection experiment of Shizidaiping Formula, its component Chinese medicine, their main ingredients on the inhibit activity effect of DPP-4,Clear of the hypoglycemic effect and DPP-4 inhibitory effect.Confirm the main Chinese herb and their main ingredients on DPP-4.To provide experiment basis for clinical application and active ingredients compatibility.Methods 1 Selected 45 SPF male GK rats,T2 DM model was established by feeding high fat feed for 4 weeks, detected 2h plasma glucose(PG2h), PG2h>11.1 mmol/L was considered succeed T2 DM model. And the T2 DM rats were randomly divided into model group, metformin group, Shizijiangtang Formula groups with high, medium and low dose respectively. The normal group were wistar rats. Other groups were administered intragastrically with corresponding drugs for 8 weeks. The levels of PG2 h and FBG were detected at the beginning of treatment, and at the end of the 8th week. Hb Alc was detected at the end of 8th week. The rats were sacrificed after 8 week, and the level of GSP, TG,CHO,HDL-C,LDL-C,GLP-1 content, DPP-4 activity were detected.Took GK rat pancreas, detected GLP-1 protein expression with Western blot method; The second part, established vitro screening model of DPP-4 inhibitor with DPP-4 enzyme, Tris-hcl buffer and Gly-Pro-p NA substrate, and screened Shizidaiping Formula and its component meidicine, which including Tusizi, Laifuzi, Cheqianzi, Chongyuzi, Gouqizi, Juemingz,i Nvzhenzi, Zhizi, Suziand, Wuweizi. Their main ingredients Geniposidic acid, Chrysophanol, Stachydrine Chloride, Betaines, Sinapine Thiocyanate, Nvzhenoside, Hyperoside, Geniposidic, Rosmarinic Acid, Chizandrol A, Select the Sitagliptin Phosphate Tablets as positive control drug. Then determine the absorbance(OD).Results Compared with model group, Shizidaiping Formula can reduce the levels of FBG, each does group has significant different(P<0.01,P<0.05); PG2 h levels of Shizidaiping Formula each group significantly lower than the model group(P<0.05, P< 0.01), but higher than metformin group. Compared with the model group the levels of Hb Alc and GSP of Shizidaiping Formula high, medium and low dose groups had significant difference(P<0.05,P<0.01). Shizidaiping Formula high, medium and low dose group can reduce the levels of TG and CHO, and significant differences compared with model group(P<0.05, P<0.01), Shizidaiping Formula high dose group compared with model group can reduce the level of LDL-C(P<0.05), and HDL-C result,each dose group has no statistical difference(P>0.05)compared with model group, but has a trend to improve HDL-C. Shizidaiping Formula high,medium and low dose group can effectively inhibit DPP-4 activity,compared with model group has significant differences(P<0.01), and compared with the normal group has significant differences(P<0.01).GLP-1 content comparison,each Shizidaiping Formulagroup were higher than model group(P< 0.01), Shizidaiping Formula high and medium does group can increase pancreas GLP-1 protein expression, significant differences compared with model group(P<0.01);In vitro screening experiment show that IC50 of Shizidaiping Formula is(5611.651±905.286)mg/L, IC50 of Laifuzi is(382.554±7.7496)mg/L, Inhibition of DPP-4,IC50 of Tusizi is(843.391±135.23)mg/L. IC50 of Zhizi is(1027.921±104.316)mg/L. Geniposidic is(0.075±0.004)mmol/L, Stachydrine Chloride is(2.638±0.715)mmol/L, Hyperoside is(3.135±0.656)mmol/L. Sinapine Thiocyanate is(6.975±1.099)mmol/L, Betaines is(60.265±29.117)mmol/L.Sinapine Thiocyanate is(6.975±1.099)mmol/L.Conclusions Shizidaiping Formula can improve glucose and lipid metabolism, the inhibitory effect on DPP-4 and the increasing effect on GLP-1 content is the possible mechanism and Laifuzi, Tusizi and Zhizi are probably the main composition medicine which play an important role in the inhibition of DPP-4. Geniposidic, Stachydrine Chloride, Hyperoside, Sinapine Thiocyanate, Betaines has a certain DPP-4 inhibitory effect, Geniposidic has the significant effect. The DPP-4 inhibitory effect of active ingredients and single herb has relevance and the inhibitory effect of DPP-4 is superior to single herb,single herb is superior to compound. Thus,the above monomers may be probably the main active ingredients, play an important role in the reducing blood glucose on inhibition of DPP-4.This study provides experimental basis for clinical application and active ingredients compatibility.