Oregano extract induces apoptosis and inhibits autophagy in HepG2 cells via the PI3K/AKT pathway

Abstract

Hepatocellular carcinoma (HCC) remains one of the most common and highly lethal malignancies globally. Conventional therapeutic approaches are often limited by suboptimal efficacy and significant toxicity, driving the search for alternative strategies, particularly those derived from natural products. This study aimed to evaluate the antitumor activity and underlying molecular mechanisms of the ethyl acetate extract of “Origanum vulgare” L (EAO) in human hepatocellular carcinoma cells. Our findings demonstrate that EAO markedly suppressed HepG2 and Huh7 cell proliferation and promoted apoptosis, accompanied by increased reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential, and ATP depletion. Additionally, EAO inhibited autophagy, as indicated by decreased LC3-II expression and increased p62 accumulation. Mechanistic investigations revealed that EAO inactivated the PI3K/AKT signaling pathway, and these effects were reversed by the ROS scavenger N-acetylcysteine (NAC), confirming ROS-dependent suppression of this pathway. Both network pharmacology and RNA-sequencing analyses further supported PI3K/AKT as a critical regulatory node. In summary, EAO exerts potent antitumor effects against hepatocellular carcinoma by inducing mitochondrial dysfunction and apoptosis, while concurrently suppressing autophagy through ROS-mediated inhibition of the PI3K/AKT pathway. These results highlight EAO as a promising low-toxicity candidate for the treatment of liver cancer.