ABSTRACT
Oxidative stress is defi ned as a disturbance in the balance between the production of reactive oxygen species (ROS) and antioxidant defenses. ROS are constantly generated in aerobic organisms as a consequence of normal metabolism and include free radicals, such as superoxide anion (O2•), hydroxyl radical (•OH), nitric oxide (NO), as well as nonradicals, such as hydrogen peroxide (H2O2), organic hydroperoxides and peroxinytrites. Among the antioxidant defenses, there are non enzymatic molecules including vitamin C, vitamin E and glutathione; and enzymatic molecules, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), paraoxonases (PON), glucose-6-phosphate dehydrogenase (G6PD)
1Health Sciences Postgraduate Program, Health Sciences Center, State University of Londrina, Av. Robert Koch, 60, ZIP code: 86.038-440, Londrina, Paraná, Brazil. aEmail: anapaulakallaur@yahoo.com.br bEmail: sayonarauel@hotmail.com 2Department of Pathology, Clinical Analysis, and Toxicology, Health Sciences Center, State University of Londrina. Av. Robert Koch, 60, ZIP code: 86.038-440, Londrina, Paraná, Brazil. Email: reiche@sercomtel.com.br *Corresponding author
and glutathione reductase (GR). The high-density lipoprotein (HDL) also neutralizes free radicals and prevents the oxidative stress response (Halliwell 1999, Storz 2005).
