Antioxidant Organoselenium Molecules

A number of selenoenzyme mimics, mostly of glutathione peroxidase (GPx), have been developed in decades so as to probe the molecular mechanism of the catalytic cycle as well as to utilize them as selenium antioxidants (SeAO), expecting that those organoselenium compounds would reduce reactive oxygen species (ROS) in living cells. Meanwhile, the design of antioxidant selenoenzyme mimics has encountered several problems relating to the biologically multimodal functions of SeAO. In this chapter, recent progress in the development of SeAO as ROS scavengers is overviewed. After brief explanation for the regulation of oxidative stress by SeAO, biological effects of SeAO and the proposed action mechanisms are described. Possible prooxidant (PO) effects of selenium compounds are also surveyed. Finally, the SeAO are classified in two types, i.e., type A which is easily reducible to selenolate species (RSe^-) and type B which is not easily reducible, on the basis of their AO and PO functions in order to summarize the current status in the SeAO design and give some guidelines for the future study.

Keywords: Biomimetic, Bio-logic, Artificial enzymes, GPx mimics, Selenocystine, Selenomethione, Selenyl radicals, 2-Center-3-electron bond, Cytotoxicity, Time-resolved pulse radiolysis.