Effect Of Four Flavonoids From Propolis On Improvement Of Insulin Resistance In HepG2 Cell

The incidence of diabetes is increasing year by year,and it is necessary to find natural products that can cure and prevent insulin resistance in type 2 diabetes.Propolis is rich in flavonoids and other bioactive ingredients,with antibacterial,anti-inflammatory,improve immune and other functional activity.This paper is in order to explore four kinds of flavonoids(pinobanksin,galangin,chrysin,pinocembrin)from propolis with high content to the improvement of insulin resistance,which provided reference for the deep development of propolis product..The effects of pinobanksin,galangin,chrysin and pinocembrin on the glucose metabolism of IR-HepG2 cells were evaluated by establishing an insulin resistance cell model.The effects of glycosylation on the glycogen synthesis,hexokinase and pyruvate kinase in IR-HepG2 cells were determined as indexes.The relative phosphorylation of Akt Ser473,GSK3?Ser21,GSK3?Ser9,Ins RTyr1162/Tyr1163,IRS1Ser312,m TORSer2448,p70S6KThr412,PTENSer380,RPS6Ser235/Ser236 and TSC2Ser939 were detected by multivariate detection technique.The main results of this paper are as follows:(1)The optimal concentration and time for the insulin resistant of HepG2 cell model was 5×10-6mol/L and 36 h.The model was stable within 36 h.(2)Screening out effective flavonoids to increase the glucose consumption.Galangin and pinocembrin could increase the glucose consumption in different degrees,while the effect of chrysin and pinocembrin was not significant.In the treatments group of galangin,the glucose consumption and the glycogen content increased with its concentration.The glucose consumption and glycogen content were 4.64 times and 1.43 times higher than that of the insulin resistance model at 80 ?mol/L,respectively.The enzyme activity of hexokinase(HK)and pyruvate kinase(PK)increased at 80 ?mol/L were 21.94% and 27.52%,respectively,which is significantly higher than the model group.In the treatments group of pinocembrin,the levels of glucose consumption and glycogen content were 1.42 and1.49 times at the concentration of 4 ?mol/L.And the activity of HK and PK increased by 11.26% and17.94% at 4 ?mol/L,respectively,which were significantly higher than those in the model group.(3)The mechanism of action of galangin and pinocembrin on AKT/m TOR signaling pathway in insulin resistant HepG2 cells were investigated.In the galangin-treated group,the relative phosphorylation expression of p-IRS-1ser636,p-RPS6 ser235/236,p-GSK3?Ser21 and p-GSK3?Ser9were significantly down-regulated,while p-Ins RTyr1162/Tyr1163,p-Akt Ser473 and p-m TORSer2448 were significantly up-regulated.In the pinocembrin-treated group,the phosphorylation relative expression of of the p-Akt Ser473 was up-regulated,and the p-IRS-1ser636,p-GSK3?Ser9 and p-p70S6 Kinase Thr412 was down-regulated.In summary,the screening of galangin and pinocembrin in propolis can improve the glucose consumption of insulin resistance of HepG2 cells by enhancing the activity of hexokinase and pyruvate kinase and improving the regulation of glycogen synthesis.Galangin and pinocembrin can regulate the AKT/m TOR signaling pathway to improve insulin resistance.The results also show that propolisimprove insulin resistance is the result of multi-component multi-target synergies.