Curcumin-loaded Pickering emulsions stabilized by Spanish mackerel protein-pectin for ameliorating ulcerative colitis through barrier repair and anti-inflammatory effects.

Curcumin (Cur) has gained considerable recognition because of its anti-inflammatory and antioxidant effects as a bioactive compound, but its water insolubility and low bioaccessibility limit its application in food industry. In this study, Pickering emulsion stabilized by Spanish mackerel protein and pectin complex (SMP/PEC) was prepared to deliver curcumin, and its alleviating effects on DSS-induced ulcerative colitis (UC) were investigated. The emulsions stabilized by SMP/PEC 1:1 inhibited phase separation, had good rheological properties and the emulsions were stable at high temperatures, centrifugation, salt ions, and pH conditions. Meanwhile, the bioaccessibility of Cur loaded in the emulsion was 2.6 times higher than that of free Cur in corn oil. Furthermore, in vivo experiments have demonstrated that Cur loaded Pickering emulsion stabilized by SMP/PEC could enhance the proliferation of goblet cells and the expression of tight junction proteins, and restore the structural integrity of colonic tissues. Additionally, it has been shown to downregulate pro-inflammatory cytokines, such as serum IL-6 and TNF-α, and reduce the levels of MPO, NO, and other biomarkers in colonic tissues. Concurrently, gut microbiota demonstrated that emulsion stabilized by SMP/PEC could regulate the relative abundance of intestinal microorganisms, facilitating the increase of beneficial bacteria and reducing the level of harmful bacteria in the gut. In conclusion, the findings of this study indicated that SPECPE might be a potentially beneficial dietary supplement for the prevention of ulcerative colitis.