Moscow University Chemistry Bulletin最新文献

Sorbitol dehydrogenase (SDH) is a metalloenzyme and belongs to the dehydrogenase/reductase enzyme family. It catalyzes the conversion of sorbitol, a sugar alcohol derived from glucose, to fructose in a reversible reaction. This reaction is part of the sorbitol pathway, which is an alternative pathway for glucose metabolism. SDH is found in various tissues throughout the body, including the liver, kidneys, and eyes. Dysregulation of the sorbitol pathway has been implicated in various diseases, including diabetic complications. In conditions such as diabetes mellitus, elevated blood glucose levels can lead to increased sorbitol production, accumulating in tissues and contributing to tissue damage, particularly in the eyes, nerves, and kidneys. Inhibitors of SDH may hold potential for the treatment of diabetic complications and other conditions associated with aberrant sorbitol metabolism. In our study, the inhibitory effects of various plant aqueous extracts and chemicals (acids, metal salts, and vitamins) on SDH activities were investigated in vitro. Among the plant extracts we used, it was found that red pepper inhibited the SDH enzyme to the highest extent. It was also observed that chlorogenic acid from acids, manganese(II) sulfate from metal salts, and vitamin B₂ from vitamins significantly inhibited the SDH enzyme. Overall, SDH plays a significant role in the context of diabetes and its complications. So, the plant extracts and chemical substances showing high levels of SDH inhibition may prevent complications resulting from diabetes and could be used to alleviate the side effects of the disease.

The self-organization of selenohydantoin on the surface of gold is studied with wetting and quartz crystal microbalance methods. Optimal conditions for the formation of a dense monolayer on the metal surface were found, and the possibility of obtaining a metal complex surface during complexation of Cu(II) ions with a monolayer fixed on the surface was shown.

A technique for determining ammonium as an indophenolic dye in soil samples by digital colorimetry using consumer optical means of obtaining raster images is proposed. The developed approach is based on photometric methods for determining ammonium after extraction from soil with potassium chloride. This technique ensures accuracy and provides sensitive digital colorimetric techniques close to spectrophotometric ones. The adequacy of the proposed approach is confirmed by analyzing the standard samples and soil samples collected in the districts of Moscow region.

It is established that several pathogenic bacterial strains, such as ESCAPE, can easily acquire resistance to traditional antibiotics. This leads to the emergence of multidrug resistance without currently available effective treatment of the diseases they cause. Antimicrobial resistance is becoming a global problem and requires a search for new approaches to solve this problem. Research in recent decades has focused on the use of antimicrobial peptides (AMPs) and low-molecular peptidomimetics as compounds with promising potential activity against pathogenic bacteria. This study presents data on the prospects for further development and use of lipodipeptides based on L-lysine derivatives and optical isomers of esters of aliphatic amino acids valine and leucine. It is shown that the synthesized cationic amphiphiles exhibit a high level of activity against test gram-positive and gram-negative bacteria. No significant differences in the efficiency of optical isomers of the two amino acid derivatives are found. The determining factor in the activity of the samples is the slightly higher level of hydrophobicity of the cationic lipodipeptides LysValCn and LysLeuCn with a difference in the length of the hydrocarbon radicals of the obtained compounds.

A spectrophotometric method for quantitative determination of anthocyanins in Malpighia emarginata is developed. The analytical absorption maxima (534 ± 2 nm) of anthocyanins are determined. The optimal conditions for the extraction of anthocyanins from the raw materials of this plant are experimentally substantiated (extractant, ethyl alcohol 40%; raw material to extractant ratio 1 : 50; extraction time 30 min; raw material grinding degree 1.0 mm).

Nanozymes are synthetic nanomaterials with enzyme-like catalytic activity. Since catalytic reactions occur on the surface of nanoparticles, changing their surface properties (charge, chemical composition, adsorbed molecules, etc.) is a tool for tuning the catalytic properties of nanozymes. The review provides a comparative analysis of the chemical composition of nanozymes with various catalytic activities, proposes a classification of approaches to increase the number of active sites on the surface of nanoparticles, and considers the use of nanozymes in different bioanalytical systems.

Interatomic distance histograms (IDHs) are used to calculate the Shannon entropies (H) of a number of molecules. Considering that the H values obtained on the basis of conventional IDHs do not adequately reflect the geometric structure of molecules, it was proposed to use modified histograms of interatomic distances by calculating interatomic distances in the range of 0–10 Å and filling zero bins with low intensity. The main structural factors affecting the H values are revealed. The possibility of using the Shannon entropy as a molecular descriptor in the development of new functional materials is studied.

A novel mechanism has been discovered for the phototransformations of methyl formate radical cations (RCs) wherein an RC that is furnished upon thermally induced 1,2-transfer of an hydrogen atom in the methyl group to the bridging oxygen atom undergoes photoinduced H⁺ transfer to the matrix.

This study carries out calculations of molecular clusters of dioxidine and dioxidine complexes with carbon dioxide (CO₂) using the density functional theory (DFT) method with B3LYP5 parameterization. Based on the obtained data, a model for the phase transition of dioxidine is developed, including the formation of triclinic and monoclinic crystal structures, utilizing a kinetic model of nucleation. The optimized structures of the molecular clusters of dioxidine correspond to the molecular packing of triclinic and monoclinic crystal forms. The energies of these clusters and the dioxidine–CO₂ complexes are compared with the experimental data on the phase composition of dioxidine samples during its cryochemical modification using CO₂ as the carrier gas.

Within the framework of the structural rheological model, viscosity curves are examined for four types of colloidal dispersions of spherical particles, varying in dispersity and composition of the dispersion medium. The study analyzes rheological curves using three types of coordinate axes. Rheological equations of the structural rheological model are used to approximate the data over specific shear rate intervals. At high shear rates, the experimental data align well with the generalized flow equation, indicating that aggregates disintegrate under the influence of tensile hydrodynamic forces. At low shear rates, a rheological equation accounting for additional aggregate formation due to compressive hydrodynamic forces should be applied. The coefficients (parameters) of the rheological equations for the examined colloidal dispersions are consistent with the predictions of the structural rheological model, confirming a common flow mechanism for these dispersions.