Natalya I. Krikunova

We investigated the antiradical properties of antioxidants: carnitinate 2-ethyl-6-methyl-3-hydroxypyridine (CAR-3-HP) and carboxychromate-2-ethyl-6-methyl-3-hydroxypyridine (CCR-3-HP), and also assessed the mitochondrial response to stress (hypoxia) by analyzing the intensity of lipid peroxidation, membrane fatty acid composition, and activation of autophagy markers LC3 and Beclin-1 using spectrofluorimetry, chromatography, and immunoblotting, respectively. The studied antioxidants exhibited high antiradical activity, which was reflected in their ability to inhibit lipid peroxidation. Five-day administration of antioxidants to mice at a dose of 2 × 10⁻⁹ mol/kg prevented the activation of lipid peroxidation in liver mitochondrial membranes under conditions of acute hypobaric hypoxia. The drugs also prevented a decrease in C₁₈ and C₂₀ fatty acid levels, and also activated autophagy. In both cases, CAR-3-HP was more effective than CCR-3-HP. This drug increased the lifespan of mice almost twice as effectively under conditions of various types of hypoxias.

Oxidative stress occurs when there is an excess of reactive oxygen species (ROS) in the cell, primarily produced by mitochondria. Excess ROS trigger membrane lipid peroxidation (LPO), cause mitochondrial swelling, and release proapoptotic proteins into the cytoplasm, which can lead to apoptosis. It is assumed that antioxidants that reduce excessive ROS formation by mitochondria can increase the body’s resistance to stress factors. We investigated the effects of hypoxia and the antioxidant Ambiol (2-methyl-4-dimethylaminomethylbenzimidazole-5-ol dihydrochloride) on the functional characteristics of mitochondria, which were assessed by measuring lipid peroxidation intensity using spectrofluorimetry, mitochondrial membranes fatty acid composition using chromatography, mitochondrial morphology using atomic force microscopy, and respiration rate using polarography. Injecting mice with Ambiol at a dose of 10⁻⁶ mol/kg for 5 days prevented the stress-induced activation of lipid peroxidation, a decrease in the unsaturation index of C₁₈ and C₂₀ fatty acids in mitochondrial membranes, and swelling of these organelles. The drug also increased the efficiency of oxidative phosphorylation during the oxidation of NAD-dependent substrates. Furthermore, Ambiol increased the lifespan of mice by 3.0–4.0 times under various types of hypoxia. Ambiol’s ability to maintain initial (control) levels of C₁₈ and C₂₀ unsaturated fatty acids appears to protect against stress-induced mitochondrial dysfunction.

The possibility of using the new antioxidant “Carboxychromanate 2-ethyl-6-methyl-3-hydroxypyridine” (Ch-3HP) to improve plant resistance to stress was investigated. The studies were conducted on the mitochondria of etiolated pea (Pisum sativum L.) seedlings, using water deficiency as a stress model. A 2.4-fold water deficiency activated lipid peroxidation in the membranes of seedling mitochondria. In this case, the double bond index of C₁₈ fatty acids (FA) decreased from 1.33 ± 0.01 to 1.25 ± 0.01, and the double bond index of C₂₀ FA dropped by 45%. Under these conditions, the activity of complex I of the mitochondrial respiratory chain decreased by 29%. Ch-3HP at concentrations of 10^–6 M and 10^–9 M prevented changes in the bioenergetic characteristics of mitochondria. Furthermore, treatment of pea seeds with the preparation prevented activation lipid peroxidation and changes in the FA composition of mitochondrial membranes. The preparation prevented a decrease in seedling growth rates under stressful conditions. Furthermore, application of Ch-3HP to wheat (Triticum aestivum L.) seedlings had a growth-stimulating effect. The preparation can be used as a plant growth regulator.

The antiradical properties and biological activity of Carboxychromanate 2-ethyl-6-methyl-3-hydroxypyridine (ChHP) were studied. The preparation had high antiradical activity. At concentrations of 10^–6 and 10^–9 M, carboxychromanate 2-ethyl-6-methyl-3-hydroxypyridine prevented the activation of lipid peroxidation in the membranes of pea seedlings mitochondria incubated in a hypotonic medium, which probably indicated the presence of antistress properties. These properties were studied under conditions of water deficiency, causing lipid peroxidation. Treatment of pea seeds with 10^–9 M drug prevented the activation of lipid peroxidation in mitochondrial membranes and a decrease in the growth rate of pea seedlings under conditions of water deficiency. It is assumed that the studied preparation is a plant growth regulator.

The article reports on the development of a fundamentally new, effective technology for recycling waste tires using the explosive-circulation technology method, which was implemented in industry at a working factory. The construction of an explosion-circulation reactor, in which tires are destroyed under the influence of an explosion, is described. The main technological stages of the reactor operation include the formation of a tire package with a height of about 2.4 m and a mass of up to 1000 kg; cooling the package by air turbo-cooling machine to a temperature of minus 70–80 °C; placing the package into the reactor; initiating the explosive charge; and removing the tire shedding products with a subsequent granulometric classification of the resulting rubber crumb. The resulting rubber crumb has good wettability, which eliminates the need for an additional technological stage of activating the crumb surface. This made it possible to successfully use the obtained rubber crumb to improve the characteristics of road construction bitumen, the hardness of which at −16 °C decreased from 217 to 161 MPa. Using atomic force microscopy (AFM), gas chromatography, mass spectrometry, GPC, and XPS, it was established that the good wettability of the crumbs is explained by the formation of molecules with polar groups (C-O, C=O, C(O)O, C-S, C-SO_x, Zn-S, O-Si(O)-O) on the crumb surface as a result of the explosion.

The possibility of using antioxidants-derivatives of 3-hydroxypyridine: N-acetylcysteinate 2-ethyl-6-methyl-3-hydroxypyridine and carnitinate 2-ethyl-6-methyl-3-hydroxypyridine as plant growth regulators investigated on the pea seedlings mitochondria (Pisum sativum L.) Flora 2 cultivar. The influence of water deficiency (WD) and 3-HP on the functional state of mitochondria was studied. Water deficiency activated lipid peroxidation and led to mitochondrial swelling. An increase in LPO intensity was associated with significant changes in the content of C₁₈ fatty acids The content of linoleic and linolenic acids in the mitochondrial membranes of seedlings decreased by 12.5 and 22.3%, respectively. There were also changes in the content of C₂₀ FA: the content of 20:2 ω6 and 20:1 ω9 decreased by almost 1.65 times and 1.5 times, respectively. The swelling of mitochondria, probably, resulted in a partial loss of cytochrome C from the intermembrane space of mitochondria into the cytosol, which led to a decrease in the electron transport rates at the end section of the respiratory chain. The treatment of pea seeds with antioxidants led to the prevention of lipid peroxidation, the prevention changes in the composition of FAs membranes and mitochondrial morphology and also restored the rate of electron transport at the end section of the respiratory chain of these organelles. By preventing lipid peroxidation, the drugs helped maintain the functional state of mitochondria under WD conditions, which probably increased the resistance of pea seedlings to stress.

The increased generation of reactive oxygen species (ROS) by mitochondria under stress conditions leads to lipid peroxidation (LPO) as a consequence of the ROS interactions with polyunsaturated fatty acids in the lipid bilayer of cell membranes, causing their damage. It was assumed that chemical preparations that reduce the excessive ROS generation by mitochondria should exhibit protecting properties under oxidative-stress conditions. In this context, the antioxidants resveratrol (RSV) and 2-ethyl-6-methyl-3-hydroxypyridine N-acetylcysteinate (NAC-3-HP) were examined as potential chemical protectors upon the exposure to stress, able to maintain the functional state of mitochondria.

Background: Germanium is a biologically active trace element, and it is present in almost all organs and tissues. Its biological activity was revealed in the 20th century. However, the study on the possibility of using germanium for medical purposes was first undertaken by the Japanese scientist Dr. Kazuhiko Asai in 1940. In 1965, academician M.G.Voronkov and colleagues synthesized tricyclic esters of triethanolamine germanium with the general formula XGe(OCH2CH2)3N and studied their biological activity. However, the adaptogenic properties of these compounds have not been sufficiently studied. In this regard, there is an urgent need to study the adaptogenic properties of these drugs. Objective: As the resistance of the organism to stress factors primarily depends on energy metabolism, the aim of our work was to study the influence of stress and 1- (germatran-1-il) –oxyethylamine (GM) on the functional state of mitochondria. Methods: The functional state of mitochondria was studied as per the rate of mitochondria respiration by the level of lipid peroxidation and fatty acid composition of mitochondrial membranes by chromatography technique. Results: It was shown that the drug in concentrations of 10-5, 10-6, and 10-11M reduced the intensity of LPO in the membranes of "aged" mitochondria. This may serve as evidence regarding the presence of anti-stress properties in the drug. Injection of GM at a dose of 10-5 mol/kg to rats prevented the activation of LPO in the membranes of the liver mitochondria in conditions of acute hypobaric hypoxia. Restricting lipid peroxidation, GM prevented changes in the content of C18 and C22 fatty acids in mitochondrial membranes, which probably contributed to maintaining the bioenergetic characteristics of mitochondria at the control level. Conclusion: It is assumed that the anti-stress activity of the drug is associated with its antioxidant properties and its effect on the complex I of the mitochondrial respiratory chain.

Background: Stress factors lead to a shift in the antioxidant-prooxidant relationship, allowing an increase in the generation of reactive oxygen species (ROS) by mitochondria, which results in the development of oxidative stress. Consequently, it is possible to put forward an as-sumption that drugs which reduce the excessive generation of ROS by these organelles should in-crease the body's resistance to stress factors. Antioxidants can be used as such drugs. In this regard, the aim of this work was to study the bioenergetics characteristic of mitochondria under stress con-ditions and under the action of 2-ethyl-6-methyl-3-hydroxypyridinium hydroxybutanedioate (eth-oxidol). Methods: The antiradical activity of the drug was evaluated by the chemiluminescent method (CL). The functional state of the mitochondria was studied with reference to the level of lipid peroxida-tion by the spectrofluorimetry and in terms of fatty acid composition of mitochondrial membranes using the chromatography technique. The study of mitochondrial morphology was performed em-ploying the method of atomic force microscopy. Results: The injection in mice of ethoxidol at a dose of 10-5 mol/kg for 7 days led to the prevention of the stress-induced increase in the intensity of LPO in the membranes of the mitochondria, and swelling of these organelles; it also prevented a decrease in the content of unsaturated fatty acids, containing 18 and 20 carbon atoms. At the same time, ethoxidol increased the life expectancy of mice by 3.0-4.2 times in conditions of various types of hypoxia. Conclusion: The adaptogenic properties of ethoxidol can be attributed to its antiradical and antiox-idant properties.