The Inhibition On Postprandial Blood Glucose And Metabolic Effect Of Chalcone-1-Deoxynojirimycin Heterocomplex In Rats

Alpha-glucosidase inhibitors can delay the digestion and absorption of carbohydrates such as starches in vivo,and therefore can effectively suppress to the sharp increase of postprandial hyperglycemia.At present,α-glucosidase inhibitors have been more and more widely used as one of the preferred methods for the treatment of type II diabetes.In the previous studies of our laboratory,a novelα-glucosidase inhibitor was successfully developed,which was named as chalcone-1-deoxynojirimycin heterozygote（DC-5）and has been proved by in vitro experiments to be an potentα-glucosidase inhibitor.In this paper,the in vivo inhibition activity of DC-5 on the PBG（postprandial blood glucose）was further evaluated by single and long-term feeding experiments using normal and diabetic rats as experimental animals.The in vivo metabolism of DC-5 in rats was studied,and its absorption,tissue distribution and excretion as well.Meanwhile,the effects of long-term intragastric administration of DC-5 on daily activities,related biochemical indexes,and organ tissues were also determined.Furthermore,16S r DNA determination was performed to investigate the effect of long-term intragastric administration of DC-5 on intestinal flora of rats.The main results and conclusions were as follows.（1）Evaluation on the inhibitory effect of DC-5 on PBG of rats:the inhibitory effect of DC-5 on PBG of rats was evaluated by single and long-term feeding experiments using normal and diabetic rats as experimental animals.Results showed that DC-5 had a good inhibitory effect on PBG of both normal and model rats.The peak PGB concentration of normal rats was 9.5 mmol/L after a single intragastric administration of starch,while that of the high dosage of DC-5,1-DNJ（1-deoxynojirimycin）and acarbose treated group were5.67 mmol/L,8.36 mmol/L and 5.94 mmol/L respectively,which was significantly lower and stable when compared with the untreated group.The peak PBG of STZ induced diabetic model rats was as high as 34.04 mmol/L after a single intragastric administration of starch,while the peak concentration of high dosage of DC-5 and acarbose treated group were 27.41 mmol/L and 34.04 mmol/L respectively.Long-term intragastric administration of DC-5 significantly reduced the FBG（fasting blood glucose）of the diabetic rats.After 30days of intragastric administration,the FBG of the high-dose group was 16.16 mmol/L,while the FBG of model group remained at a high level of 27.01 mmol/L.Furthermore,after 30-day treatment by DC-5,the PBG of each dose group restored to a similar level of FBG within 3 hours.In addition,long-term administration of DC-5 could significantly alleviate the typical symptoms of diabetic rats.（2）Identification of the main metabolites and analysis of metabolic pathway of DC-5in rats:UPLC-Q-TOF-MSMS（ultra performance liquid chromatography quadrupole time of flight tandem mass spectrometry）was used to detect and identify the main metabolites of DC-5 in rats treated with a single gastric administration,and the metabolic pathways of DC-5 were analyzed at the same time.Results showed that there were four main metabolites in rat blood,including hydrogenated,methylated,sulfonated and glucuronidated DC-5.There might be three main metabolic pathways in rats:the first one was the hydrogenation which was followed by a further methylation;the second was the methylation followed by a sulfonation,or methylation and sulfonation occured simultaneously;the third was the introduction of glucuronic acid group into DC-5molecule under the catalysis of glucuronidase.（3）Absorption,tissue distribution and excretion of DC-5 in rats:the concentration of DC-5 in blood,heart,liver,lung,stomach and small intestine reached the peak in 0.5 h after intragastric administration of DC-5,while the concentration summit in spleen and kidney appeared in 1 h.Peak concentration of DC-5 in blood was 162.76 ng/ml,and the T_1/2（half-life）and MRT（mean residence time）were 30.66 h and 11.41 h respectively.Feces were the main excretion pathway of DC-5.The excretion amount by feces was2.26%of gavage dose,which was significantly higher than the 0.0156%by urine.Results of pharmacokinetic analysis showed that the bioavailability of DC-5 in rats was 1.47%.（4）Effects of long-term gastric administration of DC-5 on the biochemical indexes and main organs of rats:results showed that long-term gastric administration of DC-5could alleviate and improve the adverse symptoms of the increased blood lipid level and lipid metabolism disorder in diabetic rats,decrease the concentration of TG,TC and LDL-C and enhance HDL-C in blood;meanwhile,long-term DC-5 treatment reduced the level of BUN and CRE,showing a positive effect on improving renal function.According to our determination data,long-term DC-5 treatment had no effect on levels of ALT and AST.After long-term administration of DC-5,the ratio of liver to body slightly decreased（about 1%）,and similar result was observed on the ratio of kidney to body.Results of organ slice observation suggested that DC-5 could relieve the pathological changes of liver,kidney and small intestine of diabetic rats,alleviate the symptoms of atrophy in liver and kidney cells,excess fat vacuoles between cells and necrosis in small intestinal villi.The above mentioned results indicated that long-term DC-5 treatment not only had little effect on the organs of rats,but also showed positive effects on the symptoms of diabetic rats.（5）Effects of long-term gastric administration of DC-5 on the intestinal flora of diabetic rats was studied using the 16S r DNA detection and second generation microbiome analysis technology.The results showed that DC-5 improved the disorder of intestinal flora in diabetic rats,increased the ratio of Firmicutes to Bacteroides and the abundance of verruca microflora,and normalized the species richness and diversity of the flora.In conclusion,DC-5 had a good inhibitory effect on the PBG of normal and model rats.Long term feeding could decrease the FBG of diabetic rats,alleviate the pathological changes of organs of diabetic rats,improve the intestinal flora,meanwhile show no detectable adverse effects on the biochemical indexes and main organs.Therefore,DC-5had a good application prospect in the control of postprandial blood glucose.