In the investigation of the in vitro neuroprotective property of α-pinene in oxidative damage induced by H2O2 in PC12 (rat pheochromocytoma) cells, it was found that this monoterpene led to an increase in the protein level of redox-regulating enzymes such as CAT, SOD, glutathione reductase, and glutathione peroxidase. The gene discussed is CAT; the disease is pheochromocytoma.