The new synthesized Cu(II) chelates of amino acids Schiff bases were studied as a potential radioprotectors. Male albino rats of Wistar strain were exposed to X-ray whole-body irradiation at 4.8 Gy. This dose caused 30% mortality of the animals (LD30). The survival of animals exposed to radiation after preliminary administration of 10 mg/kg Cu(II)(Nicotinyl-L-Tyrosinate)2 or Cu(II)(Nicotinyl-L-Tryptophanate)2 prior to irradiation was registered about 80 and 100% correspondingly. Using spectrophotometric melting and agarose gel electrophoresis methods, the differences between the DNA isolated from irradiated rats and rats pretreated with Cu(II) chelates were studied. The fragments of DNA with different breaks were revealed in DNA samples isolated from irradiated animals. While, the repair of the DNA structure was observed for animals pretreated with the Cu(II) chelates. The results suggested that pretreatment of the irradiated rats with Cu(II)(Nicotinyl-L-Tyrosinate)2 and Cu(II)(Nicotinyl-L-Tryptophanate)2 compounds improves the liver DNA characteristics.

To reveal protective role of the new Mn(II) complexes with Nicotinyl-L-Tyrosinate and Nicotinyl-L-Tryptophanate Schiff Bases against ionizing radiation. The DNA of the rats liver was isolated on 7, 14, and 30 days after X-ray irradiation. The differences between the DNA of irradiated rats and rats pre-treated with Mn(II) complexes were studied using the melting, microcalorimetry, and electrophoresis methods. The melting parameters and the melting enthalpy of rats livers DNA were changed after the X-ray irradiation: melting temperature and melting enthalpy were decreased and melting interval was increased. These results can be explained by destruction of DNA molecules. It was shown that pre-treatment of rats with Mn(II) complexes approximates the melting parameters to norm. Agarose gel electrophoresis data confirmed the results of melting studies. The separate DNA fragments were revealed in DNA samples isolated from irradiated animals. The DNA isolated from animals pre-treated with the Mn(II) chelates had better electrophoretic characteristics, which correspond to healthy DNA. Pre-treatment of the irradiated rats with Mn(II)(Nicotinil-L-Tyrosinate) and Mn(II)(Nicotinil-L-Tryptophanate)2 improves the DNA characteristics.

Bovine serum albumin complexes with water-soluble cationic porphyrins, Cu - and Co-meso-tetra(4- N -hydroxyethylpyridyl)porphyrins ( CuT4OEPyP , CoT4OEPyP ), and their 3- N -analogs, meso-tetra(3- N -hydroxyethylpyridyl)porphyrins ( CuT3OEPyP , CoT3OEPyP ), have been investigated. The porphyrin-bovine serum albumin binding was monitored by the absorption in the visible region at 400-460 nm. The stoichiometry of binding and the binding constants of the porphyrins to bovine serum albumin were determined using binding isotherms and Scatchard plots. The K b values obtained for these porphyrin- bovine serum albumin complexes are 1.7 × 105 M −1, 3.2 × 105 M −1, 1.4 × 105 M −1 and 3 × 105 M −1 respectively. Binding constants are sensitive to pH and ionic strength of the solution.

The silver-containing porphyrin Ag-meso-tetra(4-N-hydroxyethylpyridyl)porphyrin (AgTOEPyP4) was investigated as a potential anticancer drug using spectrophotometric, calorimetric and electrophoretic measurements. The studies were conducted on healthy, cancer-induced, and treated by AgTOEPyP4 white mice. DNA was isolated from the liver and tumor tissues of mice. Melting curves were studied in the presence of various stoichiometric concentrations of Mn2+ ions. The character of the DNA–Mn2+ interaction in the tumor differs from that in the norm due to defects in the secondary structure of tumor DNA, which is expressed in the DNA melting characteristics of DNA. It was revealed that the melting parameters, enthalpy, and electrophoretic mobility of DNA isolated from the tumor-bearing mice tissues differed from healthy DNA. It was shown that all studied parameters of the DNA isolated from the liver and tumor treated by AgTOEPyP4 mice approached the norm. The obtained results revealed that AgTOEPyP4 porphyrin has a pronounced therapeutic effect against sarcoma S180 and requires further investigation as an anticancer drug.

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