The antioxidant activity and transcellular pathway of Asp-Leu-Glu-Glu in a Caco-2 cell monolayer

Asp-Leu-Glu-Glu (DLEE) is one of the antioxidant peptides purified from Chinese dry-cured Xuanwei ham in our previous study. In the current work, the stability in a simulated digestion system, the transportation pathway and the antioxidant ability of DLEE were further investigated in a Caco-2 cell monolayer. In the simulated gastrointestinal digestion system, no oligopeptides were generated. In the transport trial, the inhibitors cytochalasin D increased the transport of DLEE across the Caco-2 cell monolayer, with P-app values of 3.22x10(-6)cms(-1). A decreased expression occludin was observed with the DLEE incubation in the cell monolayer, and the antioxidant activity showed to be increased gradually in basolateral side. This study indicates that the absorption of DLEE could mainly occur via paracellular transport and provides information about its antioxidant activity after being absorbed across a cell monolayer.