Inulin may be a promising therapeutic molecule for treating non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanisms of its therapeutic activity remain unclear. To address this issue, a high-fat-diet-induced NAFLD mouse model was developed and treated with inulin. The NAFLD phenotype was evaluated via histopathological analysis and biochemical parameters, including serum levels of alanine aminotransferase, aspartate aminotransferase, liver triglycerides, etc. A serum metabolomics study was conducted using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The results revealed that inulin mitigated NAFLD symptoms such as histopathological changes and liver cholesterol levels. Through the serum metabolomics study, 347 differential metabolites were identified between the model and control groups, and 139 differential metabolites were identified between the inulin and model groups. Additionally, 48 differential metabolites (such as phosphatidylserine, dihomo-γ-linolenic acid, L-carnitine, and 13-HODE) were identified as candidate targets of inulin and subjected to pathway enrichment analysis. The results revealed that these 48 differential metabolites were enriched in several metabolic pathways such as fatty acid biosynthesis and cardiolipin biosynthesis. Taken together, our results suggest that inulin might attenuate NAFLD partially by modulating 48 differential metabolites and their correlated metabolic pathways, constituting information that might help us find novel therapies for NAFLD.

Background/Objectives: Rosiglitazone (RSG), a potent PPARγ agonist for type 2 diabetes mellitus (T2DM), induces adverse adipogenic effects that limit clinical use. We investigated whether emodin (1,3,8-trihydroxy-6-methylanthraquinone, EMO), a natural anthraquinone, mitigates RSG-induced complications while enhancing its insulin-sensitizing benefits in severe obesity. Methods: Male ob/ob mice with established obesity and diabetes were treated for 4 weeks with RSG (10 mg kg⁻¹ day⁻¹), EMO (200 or 400 mg kg⁻¹ day⁻¹) or their combination. Metabolic profiling, organ function, and adipose histology were analyzed. RNA sequencing and mechanistic studies (Western blot, RT-qPCR, luciferase assays) in inguinal subcutaneous adipose tissue (iSAT), epididymal white adipose tissue (eWAT), and 3T3-L1 adipocytes were used to define EMO’s actions. Results: EMO co-treatment dose-dependently reduced RSG-induced weight gain, visceral adiposity (iSAT and eWAT mass, p < 0.05), and ectopic lipid deposition while ameliorating hepatorenal dysfunction. EMO synergistically enhanced RSG’s glucose-lowering effects. Mechanistically, EMO suppressed sterol regulatory element-binding protein 1 (SREBP1)-mediated lipogenesis (Srebp1, Acc, Fasn, Scd1; p < 0.05) and enhanced PPARγ-peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α)-driven thermogenesis via enhanced PPARγ transactivation and nuclear translocation. Thermogenic genes (Ucp1, Ppargc1a, Cidea; p < 0.05) were upregulated, with maximal uncoupling protein 1 (UCP1) induction in iSAT at 400 mg/kg EMO. Conclusions: EMO selectively enhances RSG’s glycemic benefits while attenuating its adipogenic effects in severe obesity by dual PPARγ modulation-inhibiting adipogenic pathways while amplifying thermogenesis. This strategy mitigates RSG’s adverse effects while improving insulin sensitivity, supporting the potential of EMO as a PPARγ adjunct therapy.

Objective: Based on previous findings on the Lingguizhugan (LGZG)-mediated gut–liver axis, this study clarifies the therapeutic mechanisms of LGZG in metabolic dysfunction-associated steatotic liver disease (MASLD), with a focus on the gut microbiota–bile acid–TGR5 (GPBAR1) axis. Methods: C57BL/6J mice were fed a high-fat diet (HFD) for 8 weeks to induce MASLD, followed by 4-week LGZG intervention (21.57 g/kg/day, oral gavage). Metabolic phenotypes, gut microbiota (16S rRNA sequencing), serum/hepatic bile acids (targeted metabolomics), and molecular targets (qPCR/Western blot) were analyzed. Results: LGZG significantly alleviated HFD-induced obesity, insulin resistance, and hepatic steatosis, while enhancing whole-body energy expenditure (increased oxygen consumption (VO₂), and heat production (p < 0.05). It also reduced serum ALT (p < 0.001) and AST levels (p < 0.01). Mechanistically, LGZG remodeled the gut microbiota, specifically increasing Akkermansia, Bifidobacterium and Lachnospiraceae_NK4A236_group while decreasing Lactobacillus. This shift inhibited the intestinal FXR-Fgf15 axis, concurrently activating the hepatic alternative bile acid synthesis pathway (upregulating CYP27A1 and CYP7B1 protein expression; p < 0.001 and p < 0.01, respectively). Consequently, systemic accumulation of non-12α-hydroxylated bile acids (non-12-OH BAs) such as hyocholic acid (HCA) and 7-ketolithocholic acid (7-ketoLCA) occurred—known TGR5 agonists and intestinal FXR antagonists. These changes elevated serum GLP-1 levels (p < 0.05) and activated adipose TGR5-cAMP/PKA/CREB signaling. The metabolic benefits primarily originated from non-12-OH BAs enrichment and TGR5-mediated adipose browning, not hepatic FXR activation. Conclusions: Our findings show that LGZG ameliorates MASLD by remodeling bile acid profiles via intestinal FXR-Fgf15 axis inhibition and hepatic alternative synthesis pathway activation. This study highlights the TGR5-targeting properties of LGZG, providing a mechanistic basis for its therapeutic use in metabolic disorders.