RESUMO
BACKGROUND: Oxygen is involved in a variety of physiological reactions in aerobic organisms, such as those produced in the electron transport chain, hydroxylation, and oxygenation. Reactive oxygen species (ROS) are naturally formed as byproducts from these previously reactions involving the O2 molecule; they are made up of superoxide anion (O2-), hydroxyl radical (HO-), hydrogen peroxide (H2O2), nitric oxide (NO), peroxyl (ROO-), and reactive aldehyde (ROCH). Under certain environmental stress conditions, ROS are accumulated causing cellular damage but also triggering the overexpression of several enzyme classes such as superoxide dismutases (SOD), catalases (CAT) and glutathione peroxidases (GPx), which represent an important intrinsic antioxidant defence line. Liver is a key organ in vertebrates including farm animals and human. The oxidative stress plays an important role in systemic malfunctions including hepatic, renal and immunological, disorders. METHODS: This review presents a brief update about the relationship of oxidative stress with hepatic, renal and immunological malfunctions in stressed organisms. Cellular and exogenous hepatoprotective compounds share also the ability to scavenge ROS acting as antioxidants and in many cases as stimulators of immune response in stressed organisms. We present the effect of some hepatoprotectors on the hepatic, renal and immunological function in stressed mice by the jointed evaluation of biological and oxidative stress markers. CONCLUSION: Hepatoprotective effect of several exogenous compounds is very associated with their antioxidant capacity. This fact is relevant for keeping oxidant/antioxidant balance in the respective organs, but also for maintaining the physiological status of the whole organism.