Study On The Interaction Between Flavonoids And Small Intestinal Oligopeptide Transporter PEPT1

Flavonoids exist in a variety of plants and have a wide range of sources.As a natural compound,they have a variety of biological functions,such as antioxidation,anti-tumor,antiinflammatory,and protection of cardiovascular and cerebrovascular functions.A variety of fruits and vegetables contain flavonoids,and the nutrients of fruits and vegetables are generally absorbed through the gastrointestinal tract.Therefore,the gastrointestinal environment is very important for the absorption and utilization of nutrients in fruits and vegetables.PEPT1 is the most important active transporter protein in the intestinal tract.Studying the interaction between PEPT1 and flavonoids can more effectively develop the utilization value of flavonoids.Small intestinal oligopeptide transporters(PEPT1)are a class of active transporters that are highly expressed in human and other mammalian intestinal epithelial cells.Dipeptides and tripeptides hydrolyzed in food can be transported through PEPT1,and can also be widely recognized for binding to compounds with similar structures or other small molecule compounds.Based on PEPT1,the interaction between PEPT1 and flavonoids has been studied in this paper.The main experimental results are as follows:1.Effect of PEPT1 on cell uptake of Flavonoid:The uptake of Flavonoid in the overexpression and overexpression of PEPT1 cell models was investigated.The results showed that the cell uptake of Apigenin and Isorhamnetin varied with the expression of PEPT1,while the cell uptake of Quercetin and kaempferol could be inhibited by the classic substrate Gly Sar of PEPT1,and the uptake of luteolin and apigenin was less.It is suggested that the cellular uptake of Apigenin,Quercetin,Isorhamnetin and kaempferol may depend on PEPT1.2.Effects of Flavonoid on PEPT1:(1)Effects of Flavonoid on glycidyl Sarcosine(Gly Sar)and D-Ala Lys AMCA,the characteristic substrates of PEPT1 transport: The constructed HEK-293T-PEPT1 cell model overexpressing PEPT1,incubated Flavonoid with Gly Sar and D-Ala Lys AMCA,the typical substrates of PEPT1,respectively,to investigate the effects of Flavonoid on the transport capacity of Gly Sar and D-Ala Lys AMCA.The concentrations of Gly Sar and D-Ala Lys AMCA in cell lysate were detected by LC-MS/MS method and fluorescence spectrophotometer.The results showed that Apigenin and Isorhamnetin significantly inhibited their substrate transport,and Quercetin and kaempferol significantly promoted their substrate transport.3.Effects of flavonoids on mTOR signaling pathway at transcriptional and translational levels:Fluorescence quantitative PCR and Western blot were used to detect the expression of key signal molecules in the mTOR signaling pathway at both the transcription and translation levels.The results showed that the four flavonoids can promote the expression of key signal molecules in the mTOR signaling pathway at both the transcription and translation levels.