The gut microbiota-mediated ferroptosis pathway: a key mechanism of ginsenoside Rd against metabolism-associated fatty liver disease

Background: Ginsenoside Rd (G-Rd), found in Panax species, has shown therapeutic potential against metabolism-associated fatty liver disease (MAFLD), but its mechanism has not been well elucidated. This study investigated the key mechanisms of G-Rd in modulating the gut microbiome and lipid peroxidation-mediated ferroptosis pathway in MAFLD. Methods: A high-fat diet-induced MAFLD model was established. Ultrastructural changes in liver tissue were observed using transmission electron microscopy. Metagenomics were employed to detect alterations in gut microbiota and their metabolites. Biochemical analysis and immunohistochemistry were used to examine liver injury, blood lipids, lipid peroxidation-related indicators, and tissue iron content. Results: G-Rd significantly reduced liver injury and steatosis in MAFLD mice and downregulated the elevated relative abundance of Firmicutes and the Firmicutes/Bacteroidetes ratio. It also significantly reduced the abundances of Faecalibaculum rodentium while increasing Muribaculum intestinale, with its functional role being relevant to lipid metabolism regulation. Moreover, G-Rd ameliorated mitochondrial damage and inhibited the ferroptosis pathway in the liver, which was associated with antioxidant-related factors mediated by Nrf2 signaling. The liver protective effect of G-Rd was driven by the regulation of gut microbiota, as demonstrated by antibiotic cocktail treatment and fecal microbiota transplantation. Conclusions: G-Rd attenuated HFD-induced MAFLD by alleviating liver oxidative stress, lipid peroxidation, and ferroptosis through modulation of the gut microbiota. The antioxidant and anti-ferroptotic actions of G-Rd, mediated via the Nrf2 pathway, were found to contribute to the amelioration of liver injury and hepatic steatosis in MAFLD.