Licorice flavonoid alleviates gastric ulcers by producing changes in gut microbiota and promoting mucus cell regeneration

Licorice flavonoid (LF) is the main component of Glycyrrhizae Radix et Rhizoma, a "medicine food homology" herbal medicine, which has anti-digestive ulcer activity, but the mechanism in anti-gastric ulcer (GU) remains to be elucidated. In this study, we manifested that LF increased the viability of human gastric mucosal epithelial (GES-1) cells, attenuated ethanol (EtOH)-induced manifestations, reduced histological injury, suppressed inflammation, and restored gastric mucosal barrier in GU rats. After LF therapy, the EtOH-induced gut dysbiosis was partly modulated, and short-chain fatty acids (SCFAs) like butyric acid, propionic acid, and valeric acid were found in higher concentrations. We discovered that the majority of genera that increased in the GU group had a negative correlation with SCFAs in the intestinal tract. In addition, LF-upregulated SCFAs boosted mucus secretion in the gastric epithelium and the expression of mucoprotein (MUC) 5AC and MUC6, particularly the MUC5AC in the gastric foveola. Moreover, LF triggered the EGFR/ERK signal pathway which promoted gastric mucus cell regeneration. Therefore, the findings indicated that LF could inhibit inflammation, promote mucosal barrier repair and angiogenesis, regulate gut microbiota and SCFA metabolism; more importantly, promote epithelial proliferation via activation of the EGFR/ERK pathway, exerting a protective and regenerative effect on the gastric mucosa.