Selenium-Functionalized molecules (SeFMs) as potential drugs and nutritional supplements

Abstract

Selenium (Se) is an essential element to humans and animals. Since its diverse functions were discovered, its importance has been more and more revealed. After the discovery of selenium as a key component of many proteins, significant research efforts have been focused on its therapeutic and nutritional potentials and possible impacts on human and animal health. To date, 25 selenoprotein genes have been identified in humans and animals, where selenium exists in the form of an amino acid, selenocysteine (Sec). Sec incorporation into selenoproteins occurs through a unique process by recognizing UGA stop codon via the Sec-charged tRNA for delivering Sec into proteins. Most selenoproteins are antioxidant proteins and play critical roles in maintaining redox balance in living systems by removing reactive oxygen species (ROS) and/or reactive nitrogen species (RNS). These reactive species are major threats to bio-macromolecules, such as DNAs, RNAs, proteins, lipids, and carbohydrates. They may cause molecular oxidation and DNA damage/mutation, alter gene expression patterns, weaken the immune system, and even lead to neurological disorders and other pathological conditions. As potential drugs and/or nutritional supplements, selenium-functionalized molecules (SeFMs) have shown benefits in preventing and/or treating many diseases, such as cancer, cardiovascular diseases, thyroid diseases, diabetes, AIDS, rheumatoid arthritis (RA), and neurodegenerative diseases. These promising results and therapeutic potentials of SeFMs have attracted tremendous attention from academia and pharmaceutical and biotech industries. However, further fundamental research and investigation are required to discover the ideal chemical, biochemical, and biological forms of selenium, appropriate dosages, and mechanisms of the selenium biological actions, since the tolerance window of selenium in humans may be limited.