Promoting effect of micellization on lutein absorption and evaluation of its mechanism using a Caco-2 cell model

Abstract Background: Micellization can significantly promote the absorption of lutein. However, the mechanism is still unknown. Methods and Results: This study investigated the effect of micellar treatment on lutein absorption and transmembrane transport mechanism by in vitro digestion and the Caco-2 cell model. The results showed that the bioaccessibility of micellized lutein was 1.42 times that of lutein. The Apparent Permeability Coefficients ( P app ) indicated that the main transmembrane pathway was found as passive transport. While solubility is regarded as a restrictive factor for lutein absorption. Further, nystatin and dynasore dramatically decreased the absorption of lutein micelle. In addition, micellization treatment increased cluster determinant 36 (CD36) expression ( p <0.05). And lutein micelle treatments significantly lower SCARB1, SREBF, and ABCA1 mRNA expression and increased the CD36 mRNA expression ( p <0.05). Conclusions: This study demonstrated that micellization significantly improved the absorption of lutein. The transmembrane absorption pathway in intestinal cells was mainly passive transport, as well as clathrin-mediated and caveolin/lipoprotein-mediated endocytosis.