Ursolic acid partially mimics low-glucose effects in a senescence-like alpha mouse liver 12 (AML12) hepatocyte model

Aging is linked to progressive declines in cellular and mitochondrial function, partly due to impaired nutrient-sensing pathways. Caloric restriction (CR) mitigates these effects by enhancing mitochondrial efficiency and metabolic flexibility. Ursolic acid (UA), a dietary pentacyclic triterpenoid found in fruits and herbs, has been proposed as a CR mimetic. This study investigated whether UA reproduces CR benefits in a senescent-like hepatocyte model. Senescence-like (SEN) features were induced in AML12 hepatocytes using intermittent low-dose H 2 O 2 (750–1000 μmol/L) over 6 days. SEN cells were treated with 5 μmol/L UA (5UA), and low-glucose conditions (LG) served as a CR-like reference. Non-stressed cells (CON) were included for baseline comparison. Nutrient-sensing signalling, mitochondrial biogenesis, lipid accumulation, and energy metabolism were assessed. SEN cells displayed increased β-galactosidase activity, upregulation of genes encoding p16 Ink4a and p21 Cip1 , and ∼50% lower cell numbers after 48 h versus CON. Intracellular triglycerides were twofold higher in SEN, reduced by 25% with 5UA and 45% under LG. SEN induction did not markedly impair CR-related signalling except for reduced sirtuin 1 (SIRT1) activity. LG restored SIRT1 activity and doubled AMP-activated protein kinase (AMPK) phosphorylation relative to SEN, whereas UA did not exert comparable effects. Neither UA nor LG altered mitochondrial biogenesis markers. Functionally, only LG increased ATP production (+48% vs. SEN). LG conditions improved mitochondrial energy production in a senescence-like hepatocyte model, whereas UA produced only partial metabolic benefits. These data indicate that UA does not fully mimic CR-mediated nutrient-sensing activation, suggesting that sustained nutrient reduction is required to overcome stress-induced metabolic rigidity.