Hepatoprotective effects of tetrahydropalmatine against NAFLD through autophagy activation and lipid metabolic reprogramming via the AMPK–mTOR–Sirt1 axis

ETHNOPHARMACOLOGICAL RELEVANCE: Corydalis yanhusuo W. T. Wang (C. yanhusuo) is a traditional Chinese medicinal herb commonly used in clinical practice for liver protection and lipid-lowering. Tetrahydropalmatine (THP), one of the major active components of C. yanhusuo, has been demonstrated to exert significant anti-inflammatory and lipid-lowering effects. AIM OF THE STUDY: This study aimed to systematically investigate the effects of THP on non-alcoholic fatty liver disease (NAFLD) through both in vivo and in vitro experiments, and to elucidate its potential underlying mechanisms. MATERIALS AND METHODS: We constructed palmitic acid/oleic acid (PO)-induced HepG2 cell and high-fat diet (HFD) mouse models, combined with metabolomics, network pharmacology, Seahorse analysis, and validation using autophagy/AMPK modulators. RESULTS: THP significantly reduced lipid accumulation in vitro and in vivo, while CQ attenuated its lipid-lowering effect, indicating autophagy dependence. Network pharmacology identified MTOR and SIRT1 as central nodes. THP increased AMPK phosphorylation, inhibited mTOR, and upregulated ATG5, ATG9, Beclin 1, and LC3-II, restoring autophagic flux. Metabolomic analysis revealed significant remodeling of glycerophospholipid, linoleic acid, and glutathione metabolism, optimizing membrane lipid composition for autophagosome formation and enhancing antioxidant capacity. Seahorse analysis showed that THP not only significantly reduced the extracellular acidification rate (ECAR) but also enhanced both basal and maximal oxygen consumption rates (OCR). In addition, THP upregulated Sirt1 expression and the p-ACC/ACC ratio, while downregulating SREBP-1c and FAS, thereby inhibiting lipid deposition. CONCLUSION: THP exerts hepatoprotective effects in NAFLD by activating autophagy and reprogramming lipid metabolism through the AMPK-mTOR-Sirt1 axis.