[The Antioxidant and Geroprotective Properties of an Extract of Mountain Ash (Sorbus aucuparia L.) Fruits].

Plant polyphenols are characterized by a wide range of biological activities, including antioxidant properties, and have a high geroprotective potential. The purpose of this work was to investigate the effect of the extract of rowan berries (Sorbus aucuparia L.) on the lifespan and stress resistance of Drosophila melanogaster with the identification of possible mechanisms of its biological activity. It has been established that an ethanol extract of S. aucuparia berries, the main components of which are rutin and cyanidin-3-rutinoside, has a pronounced antioxidant activity in vitro. At the same time, treatment with rowan berry extract increased the resistance of D. melanogaster males to starvation, but reduced resistance to hyperthermia. In females, the extract reduced resistance to oxidative stress but increased resistance to hyperthermia. The effects of rowan berry extract on longevity depended both on its concentration and on the sex of fruit flies. In response to treatment with rowan berry extract, D. melanogaster males and females showed slight differences in the background level of expression of cellular stress response genes, including heat shock genes (hsp27, hsp68, and hsp83), oxidative stress resistance genes (hif1, nrf2, and sod1), circadian rhythm genes (clk and per), and the longevity gene sirt1, which may explain the differences in the observed effects.

Formation of gallic acid layer on γ-AlOOH nanoparticles surface and their antioxidant and membrane-protective activity.

In the reported study we prepared gallic acid modified γ-AlOOH nanoparticles. We proposed mechanism of phenolic compounds binding on the alumina, suggesting covalent and electrostatic interactions. Most of the properties of alumina nanoparticles (NPs) are unchanged, but there is partial reduction of surface charge. Prepared samples are colloidally stable hydrosols. It allowed us to perform biological studies on cellular and non-cellular models, which showed nontoxicity of both pure and hybrid γ-AlOOH nanoparticles. Furthermore, pure alumina NPs exhibit antioxidant properties, which are enhanced after gallic acid immobilization on their surface. Also, hybrid alumina-gallic acid NPs showed membrane-protective activity.

[Some aspects of structural alterations of erythrocyte membranes under the effect of uranyl chloride at low concentrations].

The influence of nanomolar concentrations of the uranyl ion on the parameters of some membrane structures of rodent erythrocytes (laboratory mice and tundra voles--classical objects of radioecological monitoring) was investigated in vitro. A high sensitivity of the tundra vole red blood cells to the uranyl influence was shown. This fact may be determined by the cross-species difference in the membrane structures of erythrocytes--the low sphingomyelin content in tundra voles. Investigation into the phospholipid composition of the erythrocytes incubated in vitro with uranyl ions demonstrates the absence of the membrane lipid component reactions "typical" for the cells circulating in blood and also the changes pointing to the initial stages of eryptosis. Latent alterations in the membrane structure of red blood cells of both species induced by a short time contact with uranyl ions were confirmed by the increase in their sensitivity to nonionic detergent Triton X-100 and indicate the changes in orderliness of the membrane lipid phase.

[Antioxidant properties of conjugates of polyethylene glycols, having a terpenophenolic fragments].

A series of water-soluble conjugates has been synthesized from polyethylene glycols of various lengths and 4-bromomethyl-2,6-diisobornylphenol. Evaluation of membrane protective and antioxidant activity of synthesized products on the model of H2O2-induced hemolysis of blood erythrocytes showed that conjugates have considerable antioxidant activity. A significant membrane protective effect was showed in conjugates with 0.2 and 0.8 mass. % of 2,6-diisobornyl-4-methylene fragments.

[The influence of uranyl in nanomolar concentrations on erythrocyte sensitivity (in vitro) to factors inducing acute oxidative stress].

The influence of nanomolar concentrations of UO2Cl2 on the erythrocyte sensitivity (in vitro) to the factors inducing acute oxidative stress was investigated. It was shown that even a short-run exposure of uranyl ions resulted in the changes of the physico-chemical properties of the membrane. It can affectnot only the survival of cells but significantly modify their reaction on the effect of damaging factors, particularly on the impact of oxidative stress inductors. The character of modification depends on a radical source and results from the mechanisms of their effects on the cell and the ability of uranyl to catalyze ROS-forming processes. The detailed investigation into the mechanisms of the effect of uranyl ions at low concentration on cells is required.

[Surface active properties of isobornylphenols in systems with different degrees of complexity].

Interrelations between the structure of the semi-synthetic phenolic antioxidants -- isobornylphenols and their surface active properties were studied in the chemical (the lecithin aggregation in hexane) and biological (the incubation with the blood erythrocytes) model systems. It has been shown that all studied compounds are able to affect the lecithin aggregation in hexane: the share of the main fraction of the L micelles decreases with increasing the share of particles of greater size. The effect substantially depends on hindered OH group and the presence of the intramolecular hydrogen bond in molecule. The cytotoxic properties of isobornylphenols (the concentration is 100 M) are predominantly due to the molecule structure. The interrelation between the aggregate size of the main fraction of L in the presence of the studied compounds and the discocyte share during mice blood erythrocyte incubation in their presence for 4 h is revealed. Thus, this provides the possibility to assume that the ability of the different biological active substances to affect the lecithin aggregation in non-polar solvent could be used as a model system for the initial assessment of their surface active properties.

[Monitoring of tundra vole (Microtus oeconomus Pall.) population inhabiting areas with increased radiation background]. / Monitoring populiatsii polevok-ékonomok (Microtus oeconomus Pall.), obitaiushchikh v usloviiakh povyshennogo radiatsionnogo fona.

The data of complex examinations of morphophysiological state of Tundra vole (Microtus oeconomus Pall.), the lipid peroxidation (LPO) processes and the energy exchange in their organs, the cytogenetic analysis of marrow cells and the process of multiplication in populations inhabiting areas with increased natural radiation background more 50 years are generalized. The data obtained support the existence of qualitative differences of Tundra vole subpopulations inhabiting control and radioactive nuclide contaminating areas. They allow to suppose that the process of adaptation to chronic low intensity radiation effect of Tundra vole in natural conditions involves the transition of the LPO and another regulatory systems to different level of function and is directed on population survival and homeostasis maintenance in changing radioecological conditions.