Current Developments on Synthesis, Redox Reactions and Biochemical Studies of Selenium Antioxidants

In the last one decade, researchers are exploring the possibility of developing less toxic selenium compounds as alternate class of antioxidants. Since most of the biological effects of selenium are mediated through selenoproteins such as glutathione peroxidase (GPx), new organoselenium compounds are being designed that could mimic the activity of GPx enzyme. One of the essential requirements for an antioxidant is its ability to scavenge reactive oxygen species (ROS), therefore studies are also directed to monitor the reactions of free radical and molecular ROS with important selenium compounds. The redox potentials reported for a few selenium compounds provided useful information on predicting their antioxidant activity. Finally the recent in vitro and in vivo biological studies with certain compounds have indicated that selenium not only exhibits potential antioxidant ability but under some conditions shows pro-oxidant effects. Important highlights on these aspects are summarised in the present article.