Selenium as an Antioxidant: A Review

Selenium (Se) is derived from the Greek word 'selene' meaning moon goddess. It was discovered by Jacob Berzelius of Sweden in 1817. Se (The Greek goddess of moon) is a metalloid element with atomic number 34 and an average relative atomic mass of 78.96, melting-point at about 220.5 °C, boiling-point at about 684.9 °C. It belongs to the sulphur family of elements (which also includes oxygen, tellurium and polonium), and has some common properties with sulphur, including valency and the ability to form covalent bonds with carbon. Se is specifically incorporated into proteins in the form of selenocysteine and non-specifically incorporated as selenomethionine in place of methionine. The effects of Se compounds on cells are strictly compositional and concentration-dependent. Selenium is a trace mineral found in soil, water, and some foods. It is an essential element in several metabolic pathways.