BACKGROUNDResveratrol (Res) is promising food functional factor with favorable antioxidant and anti‐inflammatory properties, although its poor water solubility and low bioavailability limit extensive application. Therefore, in combination with another promising polysaccharide (Mesona chinensis polysaccharides, MCP), Res‐loaded food nanocarriers (ResNPs) were developed to increase its water solubility, bioactivity and targeting properties. ResNPs were then applied to alleviate dextran sulfate sodium (DSS)‐induced ulcerative colitis.RESULTSResveratrol can be well encapsulated in MCP‐based nanoparticles in an amorphous state, improving its water solubility. ResNPs showed pH‐response controlled release behavior in the gastrointestinal tract and increased the enrichment of Res in the colon. In vivo experiments of ResNPs against DSS‐induced ulcerative colitis (UC) revealed that ResNPs significantly improved UC symptoms, modulated intestinal inflammation and down‐regulated oxidative stress levels compared to free Res. ResNPs also play an positive role with respect to inhibiting the mitogen‐activated protein kinase pathway and promoting the expression of tight junction proteins. In addition, ResNPs improved the species composition and relative abundance of intestinal flora in UC mice, which effectively regulated the balance of intestinal flora and promoted the production of short‐chain fatty acids.CONCLUSIONThese results suggest that MCP‐based nanoparticles can effectively improve the solubility of resveratrol and enhance its in vivo bioactivity. Moreover, the present study also provides a new strategy for the prevention and treatment of UC with food polyphenol. © 2024 Society of Chemical Industry.