Dry-Cured Ham-Derived Peptide (Asp–Leu–Glu–Glu) Exerts Cytoprotective Capacity in Human Intestinal Epithelial Caco-2 Cells

Dry-cured hams are well-known and highly appreciated products in the Mediterranean and China. The long-term fermentation endows dry-cured hams with a unique flavor and quality. Our previous study has identified Asp–Leu–Glu–Glu (DLEE) from dry-cured Xuanwei ham with remarkable antioxidant capacity. In the current study, the Caco-2 cells were cultured in vitro and treated with different doses of DLEE. The cellular reactive oxygen species (ROS) level and antioxidant enzyme activities were then determined to investigate the intracellular protection effect of DLEE. According to the results, the cellular ROS level was reduced, whereas the antioxidant enzyme activities of glutathione reductase, catalase, and glutathione peroxidase were improved following DLEE treatment. The DLEE treatment also increased the Nrf2 expression, along with downregulating the Keap1 expression. Thus, the dry-cured ham-derived peptide DLEE exhibited excellent bioactive capacity by reducing the ROS level and regulating the antioxidant enzyme activities. In addition, Nrf2/Keap1 was shown to be the main signaling pathway underlying DLEE-induced antioxidant activities in Caco-2 cells.