A novel polydentate chelating antioxidant ligand and series of organotin complexes on its base were synthesized and characterized by NMR ¹H, ¹³C, ¹¹⁹Sn, IR spectroscopy, X-ray, and elemental analysis. Their antioxidant activity was evaluated in DPPH and NBT-tests, and as lipoxygenase inhibitory activity. It was shown that ligand alone is a radical scavenger, while introducing tin in the structure of the compound significantly decreases its activity. For the ligand alone the ability to strongly suppress the formation of advanced glycation end products (AGEs) was shown, which may be associated with the established antiradical activity. All synthesized compounds appeared to be moderate lipoxygenase inhibitors. The stability of compounds to hydrolysis under different pH was estimated. The ligand undergoes decomposition after about an hour, while organotin complexes on its base demonstrate vast stability, showing signs of decomposition only after 5 h of experimentation. Cytotoxicity of compounds was studied by standard MTT-test, which showed unorthodox results: the ligand itself demonstrated noticeable cytotoxicity while the introduction of organotin moiety either did not affect the toxicity levels or reduced them instead of increasing. Organotin complexes possess luminescence both as powders and DMSO solutions, its quantum yields reaching 67% in DMSO. The combination of luminescence with unique cytotoxic properties allows us to propose the synthesized compounds as perspective theranostic agents.

Bisbenzimidazoles have a broad spectrum of potential applications: radioprotectors, drug delivery vectors, antiviral agents, etc. At the same time, they seem to be promising fluorescent probes for radiation measurements. Therefore, in the present work, a fluorescent response to X-ray irradiation of Hoechst 33258, one of the most widely known representatives of the bisbenzimidazole family, was studied for the first time. Irradiation of the dye was performed in aqueous and organic solutions (DMSO and glycerol), as well as in their mixtures. It is shown that the reaction of the dye to radiation exposure is very versatile and may be controlled by the solvent properties, which makes it possible to build relationships between the absorbed dose and a wide variety of parameters of its fluorescence signal. For example, irradiation may induce fluorescence quenching caused by the degradation of the dye, a change in the position of the fluorescence band maximum due to the modification of the dye molecules or to the radiation-induced changes in the properties of the medium, as well as a fluorescence flare-up mediated by the changes in pH.

New compounds consisting of 2,6-di-tert-butylphenol and isomeric pyridinecarboxamide moieties as well as their water-soluble hydrochlorides were synthesized. The compounds appeared to be potent antioxidants and radioprotectors, with no significant difference in activity between the pyridine bases and their salts. The cytotoxicity assay showed no significant toxic impact from any of the substances, making them promising candidates for further investigation.

Novel complexes of lanthanum and cerium possessing antioxidant 2,6-di-tert-butylphenol moiety have been synthesized and characterized using NMR, IR spectroscopy, thermogravimetry and elemental analysis. Their redox properties have been investigated using cyclic voltammetry. Antioxidant activity has been evaluated in a series of model reactions in vitro. The affinity of the compounds for single electron transfer has been estimated in the CUPRAC test, while their radical scavenging capacity has been monitored in the DPPH test and their interaction with the superoxide radical anion has been investigated in the NBT test. It has been demonstrated that both complexes exhibit extraordinary antioxidant activity far surpassing that of known standards. The cerium complex appears to be 20 times more effective at scavenging superoxide radical anions than its lanthanum counterpart, which may be due to the unique +4 oxidation state of cerium. Biological activity has also been estimated in numerous in vitro assays. The ability of the complexes to inhibit lipoxygenase LOX-1B has been observed in a corresponding assay, showing mild inhibitory activity for both compounds. Cytotoxicity was evaluated using the common MTT assay, and the cytoprotective properties of the compounds were investigated using clonogenic analysis. Both compounds were found to be non-toxic at operating concentrations, and the cerium complex showed cytoprotective activity at radiation doses of about 2 Gy. These findings suggest that the synthesized complexes have the potential to be effective antioxidants and low-toxic cytoprotectors.

Complexes of various metals have a broad scope of applicability as luminescent materials. These compounds are used both as components of displays, batteries, and semiconductors and in the fields of biology and medicine. This review describes complexes containing group 13, 14, and 15 elements in the molecules, which can be considered as promising luminophores. Their photophysical properties and some aspects of physiological activity are presented.

New vitamin E hydrazone analogues bearing (2-hydroxyaryl) methylene moieties were obtained from Trolox hydrazide and the corresponding 2-hydroxyarenecarbaldehydes. The compounds demonstrated effective antioxidant activity and selective action against cancer cells, suggesting their potential as supportive pharmacological agents in oncology.