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.