Effect of Micellization on Lutein Absorption and Transportation in Caco-2 Epithelial Cells

This study aims to investigate the characteristics of micellarization to promote the transport of lutein in intestinal epithelial cells. We used in vitro digestion to investigate the effects of micellar treatment on lutein bioaccessibility and Caco-2 cell models to explore the effects of micellarization on cellular uptake,apparent permeability coefficients(P_app)and endocytic pathway of lutein. The results showed that the bioaccessibility of micellar lutein increased first and then decreased with the increase of concentration. The bioaccessibility of lutein micelle was the highest when the concentration was 6×10^-5 mol/L,which was 1.42 times that of lutein monomer. Meanwhile,the cell uptake of lutein was significantly improved after micellization,which was 2.6 times that of lutein monomer. The P_app determination showed that the cumulative transport fraction of lutein micelle was greater than 1.5%,and passive diffusion was the main transmembrane transport pathway. Meanwhile,the ratio of P_app(B→A)and P_app(A→B)was significantly lower after micellization. Further,the endocytosis inhibition experiment showed that the migration of micellar lutein was significantly inhibited by Nystain and Dynasore inhibitors(P<0.05),while EIPA had no significant inhibitory effect(P>0.05). Therefore,this study demonstrates that micellization significantly improves the bioavailability of lutein,and its transmembrane absorption pathway in intestinal cells was mainly passive diffusion,as well as clathrin-mediated endocytosis,caveolin/lipoprotein-mediated endocytosis.