Corylin ameliorates chronic ulcerative colitis via regulating the gut–brain axis and promoting 5-hydroxytryptophan production in the colon

•Corylin alleviates colonic inflammation and neuroinflammation in chronic UC mice.•Corylin improves intestinal mucosal barrier and blood–brain barrier damage.•Corylin reverses level changes of neurotransmitters in the colon, serum, and brain of chronic UC mice.•Binding of corylin to 5-HTPDC induced enzyme degradation resulting in the 5-HTP accumulation.•Corylin modulates the diversity and composition of the intestinal microbiota.