ABSTRACT
Objective:To investigate the transport mechanism of punicalagin in MDCK monolayer model .Methods:The safe con-centration of punicalagin in MDCK cells was determined by CCK8 assay.Millicell -ERS was used to measure cell monolayer TEER value to determine the integrity of the cell monolayer .The effects of direction , drug concentration , time, P-gp inhibitor and EDTA-Na2 on the absorption and transport of punicalagin were studied systematically .And then the drug concentration was analyzed by HPLC to calculate the apparent permeability coefficient (Papp) and efflux ratio(ER).Results: Punicalagin transport in MDCK cells was time and concentration dependent .Punicalagin showed poor absorption in MDCK cells .Papp from apical to basolateral side ( AP-BL) within the concentration range of 100-300μg· ml-1 was (6.13 ±0.12) ×10 -7 cm· s-1 , (6.96 ±0.26) ×10 -7 cm· s-1 and (5.94 ±0.10) ×10 -7 cm· s-1 , respectively .P-gp inhibitor and EDTA-Na2 could significantly increase the transport of punicalagin in AP-BL direc-tion, while the transport decreased at 4℃.Conclusion:The transport mechanism of punicalagin might be passive diffusion as the dom-inating process involving active transportation .Punicalagin is one of P-gp substrates with exocytosis and absorbed via the paracellular route.