SOD2 and hepatocellular carcinoma: Röhrdanz et al. (2003) reported that quercetin, when administered at concentrations ranging from 5 to 100 μM, significantly reduced the mRNA expression of key antioxidant enzymes in rat hepatoma H4IIE cells, specifically manganese superoxide dismutase (MnSOD), glutathione peroxidase (GPx), and copper–zinc superoxide dismutase (CuZnSOD) by 30–40% [45].