In vitro neuroprotective potential of the monoterpenes α-pinene and 1,8-cineole against H2O2-induced oxidative stress in PC12 cells.

Oxidative stress is involved in the pathogenesis of several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Natural products are considered as therapeutically useful antioxidant agents against reactive oxygen species (ROS). We have evaluated the antioxidant and protective potential of the monoterpenes 1,8-cineole and α-pinene against H2O2-induced oxidative stress in PC12 (rat pheochromocytoma) cells. Pretreatment with these monoterpenes was found to attenuate the loss of cell viability and the changes in cell morphology. Moreover, they inhibited the intracellular ROS production and markedly enhanced the expression of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and heme-oxygenase 1 (HO-1). In addition, they were able to decrease apoptosis as is evident from reduced capase-3 activity. The mechanisms of their antioxidant action appear to involve ROS scavenging and induction of the nuclear Nrf2 factor. This study demonstrates the potential beneficial therapeutic effect of these common monoterpenes on the oxidant/antioxidant balance in diseases of the nervous system.