Antioxidant Activity of Silver-containing Bionanocompositions Based on Humic Substances in Cell Culture

Introduction. Silver nanoparticles are promising agents for suppressing resistant strains of microorganisms and accelerating the purulent wounds healing. Oxidative stress disrupts normal wound healing processes, which leads to the formation of chronic non-healing wounds. Therefore, the determination of the ability of new wound healing agents to decrease the production of reactive oxygen species is a relevant task.Aim. The aim of the current study was to investigate the effect of silver-containing bionanocompositions based on humic substances on the basal and tert-butyl hydroperoxide-stimulated production of reactive oxygen species at the normal fibroblasts 3T3-L1 cell culture in vitro.Materials and methods. The study was carried out on 7 samples of initial humic substances and biomaterials with silver nanoparticles synthesized in the Laboratory of Natural Humic Systems, Faculty of Chemistry, Moscow State University named after M. V. Lomonosov. The intracellular production of reactive oxygen species was assessed using a 2,7-dichlorodihydrofluorescein diacetate fluorescent probe. Cells were cultured with samples for 24 h; tret-butyl hydroperoxide was used to stimulate the production of reactive oxygen species. Detection was performed fluorometrically using a microplate reader.Results and discussion. The most pronounced antioxidant activity was demonstrated by three samples of biomaterials with silver nanoparticles ultradispersed in humic substances matrices (CHS-AgNPs, CHP-AgNPs and CHE-AgNPs), which allows us to consider them as the most promising pharmaceutical agents for the treatment of purulent-inflammatory processes. The most probable mechanism of the high antioxidant activity of the studied biomaterials in relation to intracellular reactive oxygen species is the intrinsic activity of humic substances to bind reactive oxygen species, while silver nanoparticles in biomaterials catalyze the reduction processes of their interaction with reactive oxygen species.Conclusion. For the studied samples of biomaterials with silver nanoparticles ultradispersed in matrices of humic substances pronounced antioxidant activity was shown. Together with antibacterial properties, it makes it possible to consider them as potential agents for purulent wounds healing accelerating.

Synthesis and Cross-Linking Properties of Melamine Formaldehyde Oligomers with Peroxy Groups

Melamine formaldehyde oligomers with peroxy groups (MFOP) have been synthesized based on melamine or urea and melamine in the presence of tert-butyl peroxymethanol or tert-butyl hydroperoxide. Zinc oxide was used as a catalyst. The effect of peroxide nature, ratio of the starting components and process time on the characteristics and yield of MFOP has been studied. The structure of the synthesized MFOP was confirmed by IR- and PMR-spectroscopy. The chemistry of the cross-linked structures formation was studied. The possibility of using such oligomers as a cross-linking agent for the mixtures based on TGM-3 oligoesteracrylate is shown.

Chrysin and rutin protect against hydrogen peroxide and tert-butyl hydroperoxide induced oxidative cell damage

Objective: Chrysin and rutin are two dietary flavonoids lying in fruits or honey bee’s products. Their pharmacological properties include antioxidant, anti-inflammatory, anticancer, neuroprotection and immunomodulatory. In the current study, the potentiality of chrysin and rutin to protect human gingival fibroblasts against oxidative cell damage has been investigated in vitro. Method: Human gingival fibroblasts, passage 3, were concomitantly put in contact with the cytotoxic compounds and chrysin or rutin for 24 h at 37 °C, 5% CO2 atmosphere, and 96% humidity. The amount of viable cell after the incubated time was recorded by using the thiazolyl blue tetrazolium bromide (MTT) assay. Results: Chrysin in all tested concentration didn’t exhibit any cytoprotective effect against the tert-butyl hydroperoxide-induced oxidative cell damage. Moreover, chrysin in a low concentration (5 and 10 µg/mL) didn’t protect the fibroblasts against oxidative cell damage induced by the hydrogen peroxide. However, chrysin in a concentration of 20 µg/mL showed a significant cytoprotective activity in the hydrogen peroxide-induced cell damage (p < 0.05). Rutin in all tested concentrations protected fibroblasts against hydrogen peroxide and tert-butyl hydroperoxide-induced oxidative cell damage. The cytoprotective effect of rutin didn’t increase with the increase of the concentration when hydrogen peroxide is used to induce oxidative cell damage. However, rutin has protected cells against the tert-butyl hydroperoxide cytotoxicity in a concentration dependent manner. Conclusion: Given to the interesting cytoprotective activities exhibited by chrysin and rutin, further investigations to highlight their cytoprotective involved mechanisms are justified. Keywords: Chrysin, Cytoprotective, Fibroblasts, Rutin.

Influence of tungsten compounds on reaction of 1-octene epoxidation by tert-butyl hydroperoxide and hydroperoxide decomposition

Catalytic ability of tungsten compounds in the reaction of hydroperoxide epoxidation of 1- octene and tert-butyl hydroperoxide decomposition was investigated. It is shown that the nature of ligand has significant effect on the catalytic activity of tungsten compounds in these reactions. It is established that boride and silicide of tungsten are the best choice for epoxidation reaction, whereas tungsten carbide exhibits poor activity. Tungsten boride is also the most active in the hydroxide decomposition reaction.

The Effect of Oxidative Stress on the Chicken Ovary: Involvement of Microbiota and Melatonin Interventions

The poultry ovary is used as a classic model to study ovarian biology and ovarian cancer. Stress factors induced oxidative stress to cause follicle atresia, which may be a fundamental reason for the reduction in fertility in older laying hens or in aging women. In the present study, we set out to characterize the relationships between oxidative stress and ovarian function. Layers (62 weeks of age; BW = 1.42 ± 0.12 kg) were injected with tert-butyl hydroperoxide (tBHP) at 0 (CON) and 800 μmol/kg BW (oxidative stress group, OS) for 24 days and the role of melatonin (Mel) on tBHP-induced ovary oxidative stress was assessed through ovary culture in vitro. The OS (800 μmol/kg BW tert-butyl hydroperoxide) treatment decreased the reproduction performance and ovarian follicle numbers. OS decreased the expression of SIRT1 and increased the P53 and FoxO1 expression of the ovary. A decreased Firmicutes to Bacteroidetes ratio, enriched Marinifilaceae (family), Odoribacter (genus) and Bacteroides_plebeius (species) were observed in the cecum of the OS group. Using Mel in vitro enhanced the follicle numbers and decreased the ovary cell apoptosis induced by tBHP. In addition, it increased the expression of SIRT1 and decreased the P53 and FoxO1 expression. These findings indicated that oxidative stress could decrease the laying performance, ovarian function and influence gut microbiota and body metabolites in the layer model, while the melatonin exerts an amelioration the ovary oxidative stress through SIRT1-P53/FoxO1 pathway.

Synthesis and Structure of Urea-Formaldehyde Oligomers with Peroxide Groups

The possibility of synthesis in the presence of tert-butyl peroxymethanol (TBPM) or tert-butyl hydroperoxide (TBHP) of urea-formaldehyde oligomers with peroxide groups (UFOP) has been considered. Zinc oxide was used as the reaction catalyst. The effect of the initial components ratio, the reaction temperature and the process time on the characteristics and yield of the obtained oligomers was studied. Methods for obtaining UFOP using a mixture of TBPM and TBHP as a component are proposed. The structure of the synthesized UFOP was confirmed by IR- and NMR-spectroscopic studies.