Research On Hypoglycemic Activity In Vivo And Chemical Constituents Of Physalis Alkekengi

Physalis alkekengi(P.alkekengi),has long been used as an edible fruit of Traditional Chinese Medicine(TCM),which rich in flavonoids,physalins,phenolic acids and other chemical constituents.It has shown various pharmacological and physiological effects such as diuretic,anti-oxidation and adjust the glycolipid metabolism.Diabetes mellitus(DM)is a serious and global health problem.Although many drugs were used to treat DM,most of them has side effects.It is an urgent task for the medical researchers to find new antidiabetic drug with efficient and low toxicity.Based on the guidance of activity screening in vitro,this study was designed mainly to investigate the antidiabetic potential of ethyl acetate(EA)extract of P.alkekengi in vivo and the possible underlying mechanisms.Finally,the chemical constituents of EA extract were identified by HPLC-HRMS-SPE-NMR,which provided the basis for the antidiabetic mechanism of P.alkekengi.The main content of this research including the following five parts:1.Dry plant(7 kg)and fruit(3 kg)of P.alkekengi were extracted with 75% ethanol three times at 60 °C.Then the extracting solution was respectively extracted by petroleum ether(PE)and EA.Eventually six fractions of P.alkekengi extract were collected(PE of plant,EA of plant,aqueous extract(AQ)of plant,PE of fruit,EA of fruit,and AQ of fruit).2.Effect of the EA extract on glucose uptake in vitro.The HepG2 cells were cultivated by the EA of plant(EAP)and fruit(EAF),to evaluate the uptake of a fluorescent D-glucose analog,2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose(2-NBDG).The results showed that EAP could effectively promote the uptake of glucose and augment peripheral glucose.3.The preventive effect of the EA extract on diabetes.The experimental rats were dietary obese rats induced by high fat diet(HFD).FP group and PP group rats were given EAF and EAP respectively with the dose of 300 mg/kg by gavage 4 weeks.A range of parameters were tested including fasting blood glucose(FBG),serum total cholesterol(TC),triglycerides(TG),fasting serum insulin(FINS)and glycosylated serum protein(GSP).The results showed that the EA extract could effectively alleviate the symptoms of hyperglycemia,hyperlipidemia and promote insulin secretion.These results clearly prove that P.alkekengi has good preventive effect on diabetes.4.The therapeutic effect of the EA extract on diabetes.The diabetic rats were induced by high fat diet(HFD)and intraperitoneal injection of streptozotocin(STZ).Rosiglitazone group(ROS group)was given rosiglitazone with the dose of 4 mg/kg daily.Low dose of EAF(LEAF group)and EAP(LEAP group)rats were given EAF and EAP respectively with the dose of 300 mg/kg daily,HEAF group and HEAP group rats were treated at the dose of 600 mg/kg daily.The indexs of FBG,TC,TG,GSP and FINS were observed in 4 weeks to evaluate the therapeutic effect.The results showed that the EA extract of P.alkekengi could alleviate the hyperglycemia and hyperlipidemia to a certain extent,reduce the production of GSP,promote the secretion of INS and improve the insulin resistance.Interesing,based on the above results,it was inferred that the EAP could prevent the occurrence of DM by improving the metabolism of glycolipids.From these results,P.alkekengi,especially the HEAP group,had the significantly hypoglycemic effect,which was similar to the rosiglitazone,by inhibiting the glycosylation and protecting pancreatic ? cells,reducing the free radical production,improving the sensitivity of insulin.5.The chemical constituents of EAP were identified by HPLC-HRMS-SPE-NMR.A total of 45 chemical constituents were identified,including 10 flavonoids,24 physalins and 7 phenolic acids.Among them,10 compounds were found in the P.alkekengi for the first time,including 3-caffeoylquinic acid,apigenin-8-C-glucoside,3,4-di-caffeoylquinic acid,apigenin 7-O-glucoside,25-hydroxy-physalin F,physain G and so on.These finding provide a new point into the anti-diabetic application for the P.alkekengi in clinic and display the potential of the P.alkekengi as a new drug candidate or dietary supplement for the treatment of DM.