The number of infections caused by microorganisms that are resistant to antibiotics and synthetic antibacterial drugs is growing fast worldwide. This is one of the most important and urgent problems in health care. The main efforts of researchers around the world are focused on solving this issue. Nitrofurans represent one of the most effective classes of antibacterial drugs. We have synthesized 4 analogues of nifuroxazide-a well known nitrofuran antibiotic-and confirmed their structures by NMR, IR spectroscopy, and mass-spectrometry. All of the obtained compounds were studied for antimicrobial and antifungal activity. Activity against Escherichia coli, Staphylococcus aureus, Staphylococcus haemolyticus, and Pseudomonas aeruginosa was evaluated by the agar diffusion method. The synthesized compounds suppressed the growth of all the studied bacterial strains except Escherichia coli; the diameter of the inhibition zones ranged from 13.5 to 28 mm depending on the concentration of the tested compound and bacterial strain. One of the compounds studied in this project-the pyridine analogue of nifuroxazide-exceeded the activity of the standard (nifuroxazide) against the Staphylococcus aureus. The inhibitory activity of the synthesized compounds against the Candida albicans and Cryptococcus neoformans yeasts was determined using the microdilution method. The results were assessed according to the indicator color change. None of the studied compounds showed activity against these cultures. The obtained results confirm that substituted nifuroxazides have significant antimicrobial activity and, therefore, can be considered as promising candidates for developing new antibacterial drugs.

This study discusses the role of oxidative stress and inflammation in the development of severe acute respiratory syndrome (SARS) associated with COVID-19 caused by the novel SARS-CoV-2 coronavirus. An analysis of the literature revealed that the development of respiratory viral infections, including COVID-19, is usually accompanied by the accumulation of acidic metabolic products in the blood and tissues and, accordingly, oxidative stress and increased levels of cytokines. In this regard, it seems appropriate to use the second-generation low-toxic antioxidant Ethoxidol, manufactured in Russia, which reduces the intensity of inflammation, and also improves blood oxygen saturation.

Objective - to study the effect of three different concentrations of the drug "ASD-2B drops" on the growth of M. tuberculosis strain № 22063. Materials and methods. The effect of three different concentrations of "ASD-2B drops" on the growth of M. tuberculosis strain № 22063 with a single addition of the drug into the reaction mixture was evaluated. Cultivation was carried out in Dubos broth for growing mycobacteria at 37°C for 20 days with periodic assessment of the turbidity index using a densitometer. Results. "ASD-2B drops" at a concentration of 750 µl in 10 ml of the reaction mixture after a single addition at the zero point inhibited the growth and accumulation of biomass of M.tuberculosis strain № 22063 for 10 days compared with the control. "ASD-2B drops" in lower concentrations (37.5 µl and 75 µl) contributed to an increase in the growth and accumulation of biomass of M.tuberculosis strain № 22063 compared with the control. Conclusion. The experiment demonstrated the ability of "ASD-2B drops" with a single addition to influence the growth and accumulation of biomass of M. tuberculosis strain № 22063, depending on the concentration of the drug. The presence of an inducing effect on the M. tuberculosis strain № 22063 provides a basis for further studies of the drug "ASD-2B drops".

Background: A cellular model of oxidative stress induced by hydrogen peroxide in the primary culture of myoblasts was obtained by in vitro experiments, and the possibility of exogenous regulation of the cytotoxic effect using 2-ethyl-6-methyl-3-hydroxypyridine malate (ethoxidol) was studied. Moreover, the influence of oxidative stress and the effect of ethoxidol on the intracellular expression of such an important biomarker as myostatin was investigated. Methods: Hydrogen peroxide was used to induce oxidative stress. The effect of hydrogen peroxide on the rate of myoblast proliferation was studied by measuring the reduction level of (3-(4,5- dimethylthiazole-2-yl))-2,5-diphenyltetrazolium bromide. To measure the expression of myostatin, a real-time polymerase chain reaction (PCR-RV) method was used. Results: During the work, it was clearly demonstrated that hydrogen peroxide has a significant cytostatic effect on myoblasts in vitro, inhibiting their proliferation. Ethoxidol in physiological concentration did not show toxic effects and did not inhibit cell proliferation. This antioxidant revealed a statistically significant protective effect on the cytostatic effect of hydrogen peroxide on myoblasts. In addition, this compound inhibited the expression of myostatin mRNA caused by exposure to hydrogen peroxide as a negative regulator of growth and differentiation of muscle tissue that occurs in response to exposure to reactive oxygen species. Conclusion: Hydrogen peroxide is one of the highly active forms of oxygen and has a significant cytostatic effect on myoblasts in vitro, suppressing their proliferation. 2-ethyl-6-methyl-3- hydroxypyridine malate neutralizes the toxic effect of peroxide, thereby indirectly having a positive effect on the rate of myoblast proliferation in vitro.