Reactive oxygen species (ROS) are responsible for many of civilization's diseases, including cancer, diabetes, and Alzheimer's disease, decomposition of products in the food industry, and deterioration of physicochemical properties of polymers and nanomaterials. In recent years, several organoselenium compounds have been synthesized and used as peroxide scavengers, which are the source of many antioxidant substances. This review aims to collect and divide the organoselenium compounds obtained in the last twelve years with antioxidant activity, which can prove helpful in a) medicine as supplements preventing diseases caused by oxidative stress, b) as food additives preventing oxidation, or c) in the materials industry as Se-containing nanoparticles and polymers. In addition, the most common methods for determining GPx-like antioxidant activity are presented.

Designing a highly active and selective Se-therapeutic, that mimics the activity of the antioxidant enzyme glutathione peroxidase (GPx), still remains a challenge. Since the discovery of ebselen (N-phenyl-1,2-benzisoselenazol-3(2H)-one) and its ability to act as a GPx mimetic, the search for more effective peroxide scavengers has become a 'hot topic' in this field of research. Herein, we present several modifications of the benzisoselenazolone core that enable to improve the antioxidant and anticancer potential of the basic ebselen structure. These transformations include: (a) installation of chiral terpene skeletons, from p-menthane, pinane and carane systems, on the nitrogen atom; (b) exchange of the carbonyl oxygen atom for sulfur to obtain thiocarbonyl derivatives; (c) oxidation of the selenium moiety resulting in a series of benzenoselenenic acids and their further transformation to corresponding water-soluble potassium salts; (d) attachment of an additional phenyl group leading to variously N-substituted unsymmetrical phenylselenides with an o-amido function. All of the synthetized compounds were tested as antioxidants and antiproliferative agents. Conclusions concerning the structure-activity correlation, including the difference in reactivity of specific Se-moieties (-Se-N-, -SeOOH, -SeOOK, -SePh), N-substituents (the influence of bulky aliphatic moiety and the 3-dimensional orientation of atoms), and incorporated heteroatoms (-C=O, -C=S), are presented.

A series of new chiral benzisoselenazol-3(2H)-ones and their corresponding diselenides bearing an o-amido function substituted on the nitrogen atom with various aliphatic and aromatic moieties were synthesized. All derivatives representing pairs of enantiomers or diastereoisomers were obtained to thoroughly evaluate the three-dimensional structure–activity correlation. First, bensisoselenazol-3(2H)-ones were synthesized by reacting 2-(chloroseleno)benzoyl chloride with an appropriate enantiomerically pure amine. Then, the Se–N bond was cleaved by a reduction–oxidation procedure using sodium borohydride and then air oxidation to obtain the corresponding diselenides. All derivatives were tested as antioxidants and anticancer agents. In general, the diselenides were more reactive peroxide scavengers, with the highest activity observed for 2,2′-diselenobis[N-(1S,2S)-(-)-trans-2-hydroksy-1-indanylbezamide]. The most cytotoxic derivative towards human promyelocytic leukemia HL-60 and breast cancer MCF-7 cell lines was N-[(1S,2R)-(-)-cis-2-hydroksy-1-indanyl]-1,2-benzizoselenazol-3(2H)-one. The structure–activity relationship of the obtained organoselenium derivatives was discussed.

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Irradiation of diaryl diselenides bearing amido groups by 250 nm wavelength UV lamp leads to the rapid and quantitative conversion to form the benzisoselenazolone core through a free radical Se-N...