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

Abstract

Summary 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 Papp values of 3.22 × 10−6 cm s−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.

Transepithelial transport and cytoprotection of novel antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham

“…Previous studies have shown that molecular weight, amino acid sequence, charge characteristics, hydrogen bonding, non-enzymatic glycosylation and hydrophobicity are key factors for peptides that determine their sensitivity to peptidases and permeability through the intestinal epithelium. 23,26,27 Additionally, it is accepted that peptides with a high portion of hydrophobic amino acids, mainly aromatic and branched amino acids, could readily enter into the membrane, and they can perform free radical scavenging functions with the aid of their hydrophobicity. 28 In this study, the primary structure of the 5 peptides (TK-23, GK-19, FR-27, AR-20 and VR-16) which could be transported by the Caco-2 cells had common features: their C-terminal was rich in basic amino acids Arg (R) and Lys (K).…”

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

“…Wiriyaphan et al [ 26 ] demonstrated that threadfin bream-derived hydrolysate exhibited remarkable protective ability in HepG2 cells, which was related to a higher cell permeability of lower-molecular-weight peptides identified in the hydrolysate. Here, the molecular weight of DLEE was 504 Da, and the P app value of transportation across the Caco-2 cell monolayer was 3.22 × 10 −6 cm/s [ 27 ]. Thus, the intracellular capacity of DLEE may also be explained by its cell permeability in Caco-2 cells.…”

Current Evidence on the Bioavailability of Food Bioactive Peptides

“…In the field of bioactive peptides, over the past 10 years, a high number of studies have evaluated the absorption of these peptides and the mechanisms of transport across Caco-2 cell monolayers ( Table 2 ). Thus, the absorption of intact sequences across Caco-2 cells monolayers has been demonstrated for antioxidant peptides derived from soybean protein [ 140 ], corn gluten [ 141 ], milk proteins [ 89 , 142 , 143 ], and dry-cured Xuanwei ham [ 144 ], and for antihypertensive peptides derived from lactoferrin [ 145 ], ovotransferrin [ 114 ], and ovoalbumin [ 146 ]. Similarly, this model has been used to demonstrate the efficient transport of multifunctional soybean peptide lunasin or its derived fragment RKQLQGVN by paracellular diffusion [ 96 ], and of multifunctional peptides released from lupin storage proteins by digestive enzymes [ 147 ].…”