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Progressive water pollution due to anthropogenic impact on the environment is one of the current problems. One of the main types of wastewater pollutants is organic matter. A relatively simple and cheap method of purifying water from them is its biological treatment with aerobic bacteria. However, there are many highly toxic organic impurities, for the decomposition of which this method is in any case in its aerobic guise is unsuitable, and anaerobic processes require too much time and temperature control of processing processes and also become questionable given the required energy costs. Such complex substances, from the point of view of their biological treatment, include organic dyes, which according to world statistics make up 15% of all harmful substances that must be neutralized before entering the aquatic ecosystem. For such waters, their pre-treatment becomes relevant, which will reduce the load on biological treatment plants by oxidation of toxic substances and a general reduction of the organic component, ie reduction of dichromate chemical oxygen demand (HSC). Water treatment with such contaminants can be carried out using technologies that use advanced oxidation processes (AOP). In our work we studied the efficiency of plasma oxidation of wastewater barrier discharge of dye manufacturers, the main component of which is technical 2,4-dinitrotoluene, as well as models of the organic component of NPP wastewater, the main component of which is a phosphate-based detergent containing South Africa - 26.8%. Water films with a thickness of ~ 0.1 mm were treated at a rate of growth of discharge voltage pulses ≈3 • 1011V / s. The energy efficiency of the pulsed barrier discharge at different modes of water treatment with different impurities of organic substances has been studied. To obtain high energy efficiency, water treatment should be carried out at such parameters of the pulse barrier discharge (energy and pulse repetition frequency) and air velocity, so that the specific energy input to the air passing through the chamber does not exceed ~ 100 / l. The highest energy yield of the pulsed barrier discharge, for wastewater samples, at specific energy inputs does not exceed ≈10J / ml.

45 compounds uniting 3 groups of derivatives of cinnamic acid, chalcone and flavanone, have been studied. Each of them includes 15 substances. The analyzed compounds contain a common structural fragment, which is a cinnamic acid residue (cinnamoyl fragment).The aim is to study the quantum-chemical parameters of the listed groups of the compounds in order to predict possible ways of their interaction with the most aggressive and dangerous of the active oxygen species (ROS) – a hydroxyl radical.Materials and methods. For the analyzed structures, the Mulliken charges (a.u.), bond numbers (Nμ), unsaturation index (IUA), and electron density values on all 9-carbon atoms of the cinnamoyl fragment have been determined. The calculations have been carried out on a workstation with an Intel Xeon E5-1620 3.5 GHz processor, 20 GB of RAM. The semi-empirical method PM7 was used (WinMopac 2016 program). The ORCA 4.1 program was used to calculate the energies of homolytic cleavage of the O – H bond.Results. The analysis of Mulliken charges (a.u.), bonded numbers (Nμ), unsaturation indices (IUA), and electron density revealed a number of regularities on the basis of which it can be concluded, that taking into account the nature of the substituent, the most probable for addition in the aryl residueare positions C-1, C-2, C-3, C-4 and C-5. In the propenone fragment, the radical НО∙ first attacks position 8, then 7. For the hydroxy-substituted, the energy of the homolytic breaking of the H – O bond has been determined and it has been established that the spatial difficulty of phenols (compounds 13k, 13x, 13f, 14k, 14x, 14f) H-O bonds are the smallest and on average are -160.63 kJ/mol. It has also been established that the higher the positive Mulliken charge on the carbon atom with which the phenolic hydroxyl is bound, the lower the energy of the homolytic breaking of the H – O bond and the more stable the resulting phenoxy radicalis.Conclusion. The carried out quantum chemical calculations allow us to conclude that the studied classes of compounds can be used to bind the hydroxyl radical formed in the body, causing various kinds of mutations, leading, among other things, to the development of oncological diseases.

At the present time one of the main remediation technologies for such environmental pollutant as 2,4-dinitrotoluene (DNT) is advanced oxidation processes (AOPs). Since hydroxyl radical is the most common active species for AOPs, in particular for Fenton oxidation, the study modeled mechanism of interaction between DNT and hydroxyl radical at SMD(Pauling)/M06-2X/6-31+G(d,p) level. Computed results allow to suggest the most energetically favourable pathway for the process. DNT decomposition consists of sequential hydrogen abstractions and hydroxyl attachments passing through 2,4-dinitrobenzyl alcohol, 2,4-dinitrobenzaldehyde, and 2,4-dinitrobenzoic acid. Further replacement of nitro- and carboxyl groups by hydroxyl leads to 2,4-dihydroxybenzoic acid and 2,4-dinitrophenol, respectively. Reaction intermediates and products are experimentally confirmed. Mostly of reaction steps have low energy barriers, some steps are diffusion controlled. The whole process is highly exothermic.

The activity of free radical processes in liver mitochondria was investigated in rats kept on high-sucrose and low protein/high-sucrose diets. Excess of dietary sucrose caused intensification of free radical processes in liver mitochondria as evidenced by increased hydroxyl radical generation, accumulation of primary (conjugated dienes, ketodienes) and secondary products (TBA-reactive products) of lipid peroxidation, increased cholesterol/phospholipids ratio and also accumulation of oxidative modification products of proteins (carbonyl derivatives). Additional nutritional protein deficiency (low protein/high-sucrose diet) enhanced destructive changes in liver mitochondria. This suggests a critical role of nutrient protein supplementation for maintaining the functional activity of mitochondria. The established changes can be considered as one of possible mechanisms of functional liver activity violation in conditions of nutrient imbalance.

Nucleic acids are the targets for various endogenous and exogenous genotoxic agents, including reactive oxygen species. The appearance of a hydroxyl racial (^( . )OH), the most harmful molecule, next to an oligonucleotide can lead to two types of DNA damage: strand breaks or nucleobase modifications. Since clustered DNA damage is defined as the presence of two or more lesions in one helix turn, purine 5',8-cyclo-2'-deoxynucleosides are recognized as tandem lesions: both sugar moieties and base have been modified within one nucleoside/nucleotide. The hydrogen abstraction from the C5' group of nucleosides/nucleotides by ^( . )OH, with subsequent C8 C5' cyclisation results in purine 5',8-cyclonucleoside formation. Due to its unusual 3D structure and the fact that only one radical hit is needed for purine 5',8-cyclonucleoside formation their influence on genome stability/integrity and DNA repair processes are subjects of medical interest. In the present work the influence of 5',8-cyclo-2'-deoxyadenosine on DNA spatial geometry and DNA repair hinder in connection with human health, such as neurological disorders is discussed.

By steric computer modelling of five types of 2-deoxyribosyl radicals and their molecular products generated in DNA by radiation as a result of R + InH = RH + In reaction the displacement of DNA bases (maximum--for C'1 atoms and minimum for C'3 ones) has been determined. Literature data on the DNA decay in the irradiated cells, and in DNA frozen solutions as well as the data on radiolysis of compounds modelling separate DNA fragments allowed to offer a general scheme of the every 2-deoxyribosyl radical transformation and to calculate a balance between the intermediate and final molecular products (processes) of the 2-deoxyribosyl radiolysis. The DNA conformation change due to the 2-deoxyribosyl stereoisomers formation at C'3 and C'4 atoms is discussed as one of the suggested reasons for genetic radiation mutation.

The effects of different iron chelators on both OH.-generation in Fenton reaction and lipid peroxidation products accumulation in brain homogenate were studied. Intensity of luminol-dependent chemiluminescence was the measure of OH.-radical generation. The rate of lipid peroxidation was estimated as malondialdehyde accumulation. It was shown, that inhibition of chemiluminescence by the tested substances increased in next series: ADP, polyhydroxamic acid (PHA), EDTA, desferal, o-phenanthroline, ascorbate. Inhibition of lipid peroxidation by these substances increased in other order: ADP, Ascorbate, EDTA, PHA, desferal, o-phenanthroline. The results obtained allow to conclude, that antioxidant activity of ascorbate is due to the trapping of OH. radicals; in contrast, inhibition of the free radical processes by other tested substances is due to binding of iron ions. Antioxidant effect of PHA is almost as strong as effects of desferal, o-phenanthroline and EDTA. The lowest antioxidant activity was found in the presence of ADP.

It was shown that superoxide dismutase (SOD) decreased the mutagenic action of sodium azide (NaN3) and N-methyl-N'-nitro-N-nitrosoguanidine in Salmonella typhimurium TA1535. Catalase and quenchers of hydroxyl radicals showed, unlike SOD no effect on the mutagenicity of NaN3. Cell extract from propionic acid bacteria also possessed the antimutagenic activity, only partially depending on the SOD activity.

The hemolysis of rabbit erythrocytes, initiated by streptolysin O purified samples, is appreciably suppressed in the presence of the scavengers of singlet oxygen (sodium azide, histidine, tryptophan), .OH-radical (ethanol, mannitol), O.(2-)-radical (nitrotetrazolium blue, streptokinase), chelating agents (o-phenanthroline, sodium diethyldithiocarbamate) and some oxidoreductants such as K3FeCN6 and riboflavin as well. The streptolysin O hemolytic effect is supposed to be realized due to the participation of active oxygen species and this phenomenon depends upon the presence of the transition metals in the system.

Effect of the complex of antiradical enzymes (superoxide dismutase and catalase in proportion 1:3) was studied on the experimental mode of acute pancreatitis. After thrice repeated administration of a complex of enzymes, antioxidant capacity of the blood serum normalized, activity of the enzymes of antioxidant protection of an organism and that of glucose-6-phosphate dehydrogenase increased, concentration of extra-erythrocytic hemoglobin decreased, contributing to normalization of morphologic structure of the pancreas in 52% of the animals with hemorrhagic and in 70%--with oedematous form pancreatitis. The results obtained are indicative of possible correction of the changes in inflammatory process in the pancreas.

An ESR study of interactions of carnosine and its derivatives with free radicals has been carried out. In model systems the spin trap OH. radical adduct generation has been shown to decrease significantly in the presence of carnosine in a pronounced concentration-dependent manner. A comparative study of effects of some other histidine-containing dipeptides on this process has revealed a similarity in anserine, homocarnosine, and acetylcarnosine actions.

Structural relationships in orthophosphate (PO4)3-, carbonate (CO3)2-, and hydroxyl (OH)- groups were studied in 2 teeth with grave fluorosis manifestations, removed for orthodontic indications, by infrared spectroscopy. Two intact teeth were examined for control. The findings evidence ar elevated protein level in fluorosis-involved dental enamel and impaired enamel microstructure; this may be explained by specific features of fluorosis clinical manifestation and by increased enamel permeability in grave fluorosis.

Administration of scavenger of hydroxyl radicals--dimethylsulfoxide (1 g/kg intraperitoneally, daily for 3 weeks) did not lead to any significant changes in animals behaviour in the open field and in visceral functions (arterial pressure, respiratory rate, heart rate) but prevented shifts of these characteristics caused by chronic 3-week emotional-pain stress. In rats injected with dimethylsulfoxide, an increase was observed of superoxide dismutase activity in the brain and blood serum. Molecular mechanisms are discussed of antistress action of dimethylsulfoxide (scavenge of hydroxyl radicals, activation of superoxide dismutase) and possible role of hydroxyl radicals in realization of damaging action of stress on the organism.

The ability of major serum proteins (albumin, immunoglobulin G) and free radical scavenger proteins (ceruloplasmin, superoxide dismutase, transferrin) to interact with O2-. and OCl- was studied. The interaction between serum proteins and OCl- was shown to be nonspecific and cause protein degradation. During SDS polyacrylamide gel electrophoresis ceruloplasmin and transferrin were degraded in the highest degree. Protein damage was also recorded by fluorescence changes. It is suggested that the damaging influence of active oxygen species secreted by stimulated neutrophils into the extracellular space can be abolished only by ceruloplasmin.

In experiments on dogs using the chemiluminescent method and nitroblue-tetrazole reaction the authors found out that leucocytes while passing through the pulmonary vessels bed, in contrast to the spleen increase the generation of active microbicidal forms of oxygen. Due to this fact we suppose that the lungs may take part in the formation of free radical status and phagocytic antiinfectious defence of the organism.

It has been shown that of active oxygen species regulate the activity of the processes of Con A endocytosis in rat thymus cells.

The influence of emotional painful stress (EPS) and dimethyl sulfoxide (DMSO) treatment on ceruloplasmin-transferrin (Cp-Tr) antioxidant system and superoxide dismutase-like activity (SODLA) of the rat serum was studied. No changes in Cp-Tr and SODLA were observed in EPS. On the contrary, DMSO treatment was followed by a decrease in Cp-Tr activity and an increase in SODLA. It is suggested that Cp-Tr and SODLA systems are two interacting antioxidant systems of the serum.