The mechanism of didymin in alleviating non-alcoholic fatty liver disease in rats analyzed by the integrative analysis of untargeted metabolomics and network pharmacology

Objective: To investigate the mechanism of didymin in alleviating lipid metabolism in non-alcoholic fatty liver disease (NAFLD) using integrative analysis of untargeted metabolomics and network pharmacology. Methods: The rats were randomly divided into normal group, model group and didymin group. The model group and didymin group were fed with a high-fat diet (HFD) for 8 weeks to induce NAFLD animal model, followed by the corresponding administration for further 8 weeks. Hematoxylin-eosin (HE) and Oil Red O staining were used to observe the cell morphology and lipid accumulation. Metabolomics of rat liver tissue was examined with highresolution liquid chromatography-mass spectrometry (UPLC-QTOF/MS), and metabolism pathway was analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The overlapping target genes between didymin and NAFLD were predicted by network pharmacology analysis, and the potential targets were further analyzed by the integrative analysis of metabolomics and network pharmacology. Results: Didymin significantly reduced liver injury and inhibited excessive lipid deposition in rats. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed that significant differences in the metabolites between groups. The volcano plots indicated 404 differential metabolites between the normal group and the model group (293 up-regulated and 111 down-regulated), and 147 between the model group and the didymin group (95 up-regulated and 52 down-regulated); metabolic pathway analysis showed that the differential metabolites were mainly enriched in the sphingolipid metabolism pathway. Network pharmacology analysis suggested that there was a total of 139 drug-disease common targets, and further integrative analysis indicated that didymin could regulate the sphingolipid metabolism pathway and insulin resistance by affecting the target genes TNF, Bcl2, Mapk8, Pik3ca, Akt1, mTOR, Gsk3β, respectively. Conclusion: Didymin can regulate lipid metabolism disorder through the pathway of sphingolipid metabolism and insulin resistance, ultimately playing a role in the treatment of NAFLD.