Lactucin alleviates lipid accumulation via AMPK-mediated autophagy and fatty acid β-oxidation in FFA-induced HepG2 cells

Lactucin is a natural sesquiterpene lactone isolated from Cichorium glandulosum Boiss. et Huet (CG) has unique biological and pharmaceutical properties. This study was designed to investigate the mechanisms by which Lactucin inhibits lipid accumulation in free fatty acid (FFA)-treated HepG2 cells. We demonstrated that Lactucin exerts a protective effect against hepatic steatosis in vitro. In FFA-induced HepG2 cells, Lactucin effectively ameliorated lipid accumulation, oxidative stress, and mitochondrial dysfunction. Mechanistically, we showed that activation of AMP-activated protein kinase (AMPK) and hormone-sensitive lipase (HSL) by Lactucin promoted lipolysis and further enhanced fatty acid β-oxidation (FAβO) by increasing the activity of FAβO-related enzymes, thereby contributing to the reduction of lipid accumulation. Moreover, Lactucin activated autophagy and modulated the AMPK/mammalian target of rapamycin (mTOR) signaling pathway. Notably, we found that Lactucin-induced autophagy played a significant role in decreasing lipid droplet accumulation, suggesting it may be a key underlying mechanism. These findings, for the first time, provide new insights into the pharmaceutical mechanism of Lactucin in protecting against nonalcoholic fatty liver disease (NAFLD).