FFAR2 and colitis: It was found that the GPR41/43 pathway is necessary to prevent indigo-induced DSS-induced colitis, and the change of indigo-induced microflora may be a key regulator for this effect by increasing the production of SCFAs, especially butyric acid [97], which suppresses the activation of GPR43-NLRP3 signaling pathway and reduces the level of pro-inflammatory cytokines, thereby improving DSS-induced colitis symptoms.