Inhibition Of Four Flavonoids From Passiflora Edulis Sims Leaves On ?-glucosidase,SGLT1 And GLUT2

Type 2 diabetes?T2DM?is one of the major diseases that endanger human health today.Its main pathology is characterized by persistent hyperglycemia.Studies have shown that the ways of promoting insulin secretion and improving insulin resistance that can reduce blood sugar,but delaying glucose absorption also plays an important role in lowering postprandial blood glucose.A large number of studies have shown that flavonoids play an important role in improving insulin resistance and promoting insulin secretion,but there are few studies on carbohydrate absorption.According to the current research status and with the research direction of the research group,four flavonoids of luteolin,isoquerbutin,isovitexin,and vitexin will be studied in this paper.The effect of flavonoids on?-glucosidase activity and glucose transporter during carbohydrate absorption.The results as follows:.1,Two methods were used to determine the content of luteolin,isoquerbutin,isovitexin,and vitexin in the leaves of Passiflora edulia Sims.The retention times of the four flavonoids were 15,12,20,17min,respectively;The average content of four flavonoids measured was0.0154,0.2114,0.0621,0.1022mg/g,respectively.2,Using PNPG method found that 12.5-200?M four flavonoids have a certain inhibitory effecton?-glucosidase,theIC₅₀valueswere19.39,102.03,163.34,209.57?M.Lineweaver-Burk double reciprocal method was used to judge whether the four kinds of flavonoids inhibited?-glucosidase.The four kinds of flavonoids were all non-competitive reversibleinhibitorytypes.TheirinhibitoryconstantsK_iwere0.28,0.79,6.38,7.99m M,respectively.3,The survival rate of Caco-2 cells after treatment with four flavonoids was the highest in the range of 12.5?M-100?M by CCK-8 method.Using glucose oxidase method,it was found that the four flavonoids at 50?M and 100?M all had inhibitory effects on sucrase and maltase in Caco-2 cells.Among them,luteolin has the highest inhibition rate of sucrase in cells.4,RT-qPCR showed that both luteolin and isoorientin can down-regulate the mRNA expression levels about the sucrase-isomaltase?S-I?,sodium glucose cotransporter 1?SGLT1?and glucose assisted transporter 2?GLUT2?in Caco-2 cells.Western blotting method found that luteolin and isoorientin can downregulate the protein expression of SGLT1,GLUT2 in Caco-2 cells.In conclusion,The four flavonoids of luteolin,isoorientin,isovitexin,vitexin have a certain inhibitory effect on?-glucosidase,and the inhibitory effect of luteolin and isoorientin are the strongest.In addition,luteolin and isoorientin can also down-regulated the mRNA and protein expression levels of SGLT1 and GLUT2,further delaying the absorption of glucose.