Mechanistic analysis of Inonotus hispidus in ameliorating T2DM: Metabolomics and gut microbiota profiling in mice models

Abstract

As a large medicinal fungus, Inonotus hispidus (I. hispidus) has multiple pharmacological effects such as antioxidation, anti-inflammation, and hypoglycemia. However, studies on improving type 2 diabetes mellitus (T2DM) by the secondary metabolites of I. hispidus are still insufficient. In this study, we constructed HepG2-IR, HepG2-NAFLD cell models and a high-fat diet combined with streptozotocin-induced T2DM mice model. Using untargeted metabolomics, 16S rRNA gene sequencing of the gut microbiota, and Q Exactive UPLC-MS/MS analysis, we identified the active components of the I. hispidus ethanol extract (IHE) and elucidated its mechanisms against T2DM. The results showed that I. hispidus exerted hypoglycemic and hypolipidemic effects, and significantly reduced the serum levels of TC, TG, AST, and ALT in T2DM model mice. IHE enhanced antioxidant enzyme activities and reduced serum levels of inflammatory cytokines (IL-6, TNF-α). Mechanistically, it inhibited the TNF-α/NF-κB signaling pathway. Metabolomics combined with 16S amplicon sequencing analysis revealed that I. hispidus can increase the levels of metabolites such as naringenin chalcone and genistein, which have hypoglycemic and anti-inflammatory effects. Furthermore, these differential metabolites were significantly correlated with the increased abundance of Akkermansia and Bacteroides, as well as the decreased abundance of harmful bacterial genera such as Blautia and Desulfovibrio. In addition, 66 compounds were characterized in I. hispidus, with polyphenols being the main chemical constituents exerting therapeutic effects. This study provides an experimental basis for the multi-pathway improvement of T2DM by I. hispidus.