Acerola (Malpighia emarginata DC.) is a fruit containing abundant ascorbic acid (AsA) and numerous functional phytochemicals. We previously reported that the intake of acerola juice increased the absorption of AsA in plasma of healthy Japanese subjects. The functional phytochemicals in acerola may influence the intestinal epithelial cells to increase the cellular uptake of AsA. Therefore, in this study, we compared the AsA uptake into Caco-2 cells between AsA alone and that in acerola juice at the same concentration using a human intestinal model. Caco-2 cells were incubated with 3 mM AsA and 3 mM AsA in acerola juice. Intracellular AsA contents gradually increased until 24 h upon incubation with both AsA alone and AsA in acerola juice; however, these contents when incubated with AsA in acerola juice, were significantly higher than those incubated with AsA alone at 2, 3, 4, 8, and 24 h. Furthermore, the mRNA expression level of the sodium-dependent vitamin C transporter (SVCT) 1 was significantly higher in the cells incubated with AsA in acerola juice than those incubated with AsA alone. Moreover, polyphenols such as cyanidin-3-glucoside chloride and quercetin enhanced the SVCT1 gene expression in Caco-2 cells. Collectively, these results suggest that acerola polyphenols enhances the SVCT1 gene expression in Caco-2 cells and promotes AsA uptake.
Keywords: Caco-2 cells; SVCT1; acerola; ascorbic acid; functional phytochemical; polyphenol; vitamin C.