PPARA and ulcerative colitis: Previous studies indicate that HQD ameliorates ulcerative colitis through various mechanisms, including the regulation of fatty acid metabolism to promote M2 macrophage polarization via the FFAR1/FFAR4-AMPK-PPARα pathway, modulation of gut microbiota, and amino acid metabolism, as well as activation of the mTOR signaling pathway to restore epithelial barrier function [29,30].