Total Flavonoids of Apocynum venetum Ameliorate High-Fat Diet-Induced Lipid Accumulation in Mice and Hepatocytes by Activating the AMPK Signaling Pathway

Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by abnormal hepatic lipid accumulation and is frequently driven by factors such as a high-fat diet (HFD). Total flavonoids of Apocynum venetum (TFAV), the bioactive constituents of a traditional medicinal plant, have demonstrated antioxidant and lipid-modulating properties. However, their therapeutic potential against MASLD and the underlying mechanisms are not explored. This study aims to evaluate the ameliorative effects of TFAV on HFD-induced MASLD utilizing both in vivo animal and in vitro cellular models. Methods: C57BL/6J were allocated to control, high-fat diet (HFD), TFAV (100 mg/kg/day), and TFAV intervention groups (25, 50, and 100 mg/kg/day). In vitro, WRL68 hepatocytes were stimulated with free fatty acids (FFAs) to establish a cellular model of steatosis. Liver function, serum lipid profiles, hepatic histopathology, and the AMPK signaling pathway were assessed. Results: TFAV intervention significantly improved serum biochemical profiles in the animal models; for instance, co-treatment with 100 mg/kg/day TFAV and HFD reduced TC, TG, and LDL-C levels by 20.59%, 45.26%, and 38.24% respectively (p < 0.05), and effectively alleviated hepatic steatosis and hepatocyte ballooning. Furthermore, TFAV markedly inhibited intracellular reactive oxygen species (ROS) levels and activated the AMPK signaling pathway (p < 0.05). This was accompanied by the downregulation of SREBP-1c and ACC expression (p < 0.05), as well as the upregulation of ATGL and CPT1α expression (p < 0.05). Conclusions: These results demonstrates that TFAV remodel hepatic lipid homeostasis by activating the AMPK signaling pathway, and exerting significant preventive and protective effects against the progression of HFD-induced MASLD in vivo.