Antioxidant Activity and Cytotoxicity of Selenium Incorporated Biologically Inspired N-Heteroaryl Compounds

Selenium is one of the essential trace elements in humans and animals. It is incorporated in the redox-active selenocysteine (Sec), the 21st proteinogenic amino acid, which is found in a limited number of proteins/enzymes. The reactivity of the Sec residue in these proteins allows them to perform diverse functions such as reducing oxidative stress, maintaining redox homeostasis, and thyroid hormone metabolism. An important family of biomolecules is derived from pyridyl-based systems (e.g., 2-pyridinol, 2-nicotinamide). Several of these molecules are also responsible for a wide range of biological activities like redox reactions (e.g., NAD ⇌ NADH; NADP⁺ ⇌ NADPH). Due to their presence in natural systems, these scaffolds are widely used as pharmaceutical motifs in drug design and development. This is supported by the FDA database which reveals that over 60% of small molecule drugs contain N-heterocycles. Thus, a variety of selenium-incorporated pyridyl derivatives with reference to their antioxidant activity have been synthesized and studied. Antioxidant activity and cytotoxicity of these compounds have also been investigated in cellular models. The nature of the substituent at the C-3 position of the pyridine ring significantly influences the structure of the molecule as well as its antioxidant activity and cytotoxic properties. In this article, the work published by us and other groups on pyridyl selenium compounds is reviewed.