Carboxymethyl β-cyclodextrin-loaded buffalo milk peptide nanoparticles ameliorate dextran sodium sulfate-induced intestinal mucosal injury in mice.

Buffalo milk-derived active peptides have a variety of important regulatory functions for the body, but their poor oral stability leads to low bioavailability. Herein, the in vivo stability of peptides DN8 and YR9 screened from buffalo milk was enhanced using encapsulation, and the effects of these peptides on ameliorating intestinal mucosal injury in mice were investigated. The binding of peptides DN8 and YR9 to carboxymethyl beta-cyclodextrin (CMβ-CD) was mainly through electrostatic adsorption and hydrogen bonding forces to form robust nanoparticles (NP) associated with changes in O-H, C=O, and C-H bonds. The average particle size of NP CMβ-CD-DN8 and CMβ-CD-YR9 were 75.03 nm and 41.71 nm, and the encapsulation rates were 82.513% ± 4.617% and 90.974% ± 0.421%, respectively. The NP CMβ-CD-DN8 and CMβ-CD-YR9 demonstrated stability and nonhemolytic properties at the tested concentrations in vitro and effectively reduced the secretion of proinflammatory cytokines NO, IL-6, and TNF-α in LPS-stimulated RAW264.7 cells. Peptides DN8 and YR9 in NP were released in small amounts in the stomach but rapidly in the intestine. Furthermore, the NP CMβ-CD-DN8 and CMβ-CD-YR9 were found to be effective in attenuating dextran sodium sulfate-induced epithelial barrier injury in mice by increasing the expression of occludin and ZO-1. This research provides insights for the development of oral food-borne active peptides with high bioavailability.