Moscow University Chemistry Bulletin最新文献

The possibility of identifying and authenticating cow milk powder by the method of chemical colorimetry of the fluorescence of samples using a smartphone camera and chemometric analysis is shown. A fundamental test device for direct colorimetric analysis of milk powder is proposed, excluding the stage of sample preparation. Fluorescence excitation is carried out with a portable source of monochromatic UV radiation (λ = 365 nm). The colorimetric parameters of milk powder fluorescence in RGB space are recorded using a smartphone camera. We use chemometric processing of the calculated analytical signal, which makes it possible to reduce the analysis time and visualize the studied data. The data array of the fluorescence colorimetric parameters (RGB) are evaluated by principal component analysis (PCA) and hierarchical clustering analysis (HCA) using the XLSTAT software.

In accordance with the abiogenic hypothesis of the origin of oil, deposits formed as a result of degassing of the Earth, in particular, due to the interaction of mantle methane and its polycondensation products with elemental sulfur, are thermodynamically open systems. In open systems, self-organization processes are realized and a progressive evolution of the catalyst of the basic reaction occurs, accompanied by an increase in its activity and accumulation in the system. The predominance of vanadium in the trace element composition of sour oils may be due to its catalytic activity in the basic reaction of the formation of C–S bonds.

The synthesis of 2-ethoxy-4-[(3-alkyl-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl)-azomethine]-phenyl 2-methylbenzoates (4) from the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) with 3-ethoxy-4-(2-methylbenzoxy)-benzaldehyde (3) is described. The acetylation reactions of compounds 4 were investigated, and 5 type N-acetyl derivatives were obtained and the newly synthesized compounds were fully characterized. Also, in vitro antibacterial activities of the fourteen new compounds were screened against six bacteria such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and Klebsiella pneumonia according to agar well diffusion method. In addition, the newly synthesized 14 novel compounds were tested for their antioxidant activities using three different methods. Furthermore, to investigate the effects of solvents and molecular structure upon acidity, the compounds 4 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, N,N-dimethylformamide and acetone).

Highly dispersed powders of superparamagnetic iron oxides of various morphologies are obtained by the thermal decomposition of formate and ammonium citrate of iron(III), subjected to cryochemical treatment by the spray cryogenic drying method. The composition and structure of the obtained particles and cryo-modified precursor salts are characterized by the following physicochemical methods: X-ray diffraction analysis, thermoanalytical methods (TG, DSC), IR spectroscopy, scanning electron microscopy, and the chromatographic method for determining the specific surface by the thermal desorption of argon.

The structural geometries of small copper clusters (Cu₂, Cu₃, Cu₁₃) and their complexes with cholesterol (Ch) and thiocholesterol (TCh) ligands are studied by the density functional theory (DFT)/B3LYP5 method. The trends in the geometric structure and interaction energy in the copper cluster–cholesterol ligand systems depending on the size of the metal cluster are accessed. A significant difference in the structures of copper complexes from the complexes of cholesterol ligands with silver clusters is found. In the Ch–Cu₁₃ complex, the icosahedral fragment is significantly stretched along one of the axes n = 3. The biligand complex with the icosahedral copper cluster (TCh)₂Cu₁₃ is the most stable complex.

The superfamily of the protein kinase C (PKC) comprises ten isozymes and is widely known for its key role in signal transduction. Protein kinase Cε (PKCε) is known to play key roles in tumor suppression. PKCε requires activation to interact with RACK2, and the adaptor protein then translocates activated PKCε to subcellular sites within the proximity of their substrates. An EAVSLKPT peptide interferes with the interaction of PKCε and its adaptor protein RACK2. Since signaling in the malignant cells are sufficiently changed then the scope and limitations of PKCe as a anticancer drug target has to be estimated more clearly. Acquiring isozyme-selective inhibitors is a difficult task due to the high sequence similarity within the ten PKCs. Small molecule-disruptors of the PKCε/RACK2 protein–protein interaction could suppress PKCε signaling and reduce malignant properties. The EAVSLKPT peptide was used as a base of a pharmacophore model. Thieno[2,3-b]quinolines as a wide cluster of specific small-molecule inhibitors of the PKCε/RACK2 protein–protein interaction and PKCε signaling were revealed. The structural features of active thieno[2,3-b]quinolines were expanded on the basis of this pharmacophore model. The interaction between PKCε and RACK2 was measured using an ELISA-based assay. It was found that N-(4-acetylphenyl)-3-amino-6,7-ethelendioxy-thieno[2,3-b]quinoline-2-carboxamide (1b) shows promising inhibitory activities on the interaction of PKCε with its adaptor protein, the receptor for activated C-kinase 2 (RACK2), hence interfering with PKCε signaling. Both 1a and 1b did not show some cytotoxic properties on susceptible PC-3 cell line but both active compounds showed a significant antisprouting activity. The quinolines without thiophene ring as “open” analogs of 1b were inactive in primary assays. A structural isomer of (1a meta-acetyl), compound (1b para-acetyl) was found to exhibit, in addition to strong inhibitory activity on PKCε signaling with an IC₅₀ of 4.25 µM, also anti-angiogenic activities. Thus thieno[2,3-b]quinolines 1a and 1b could be reliable and selective biochemical tools to investigate of PKCe/RACK2 effects.

Histone deacetylase inhibitors are the most important class of drugs for the treatment of oncology and other diseases due to their effect on cell growth, differentiation, and apoptosis. Among the known 18 histone deacetylases, histone deacetylase 6 (HDAC6) that is involved in oncogenesis, cell survival, and cancer cell metastasis is most important. A number of adequate classification models of the quantitative structure–activity relationship (QSAR) are proposed using 2D RDKit molecular descriptors and simplex descriptors, as well as methods of random forest (RF), gradient boosting (GBM), and support vectors (SVM). A structural interpretation is carried out for the models constructed using simplex descriptors which makes it possible to describe the molecular fragments that increase and decrease the activity of HDAC6 inhibitors. The results of the structural interpretation are used for the rational molecular design of potential HDAC6 inhibitors, for which the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties are also evaluated. The models constructed using 2D RDKit descriptors are free to access on the GitHub platform at the following URL: https://github.com/ovttiras/HDAC6-inhibitors.

PD-L1 (Programmed death-ligand 1), a membrane protein of the immunoglobulin superfamily, is one of the targets for cancer immunotherapy. A panel of 14 cancer cell cultures with a different constitutive PD-L1 expression level is formed and characterized. The panel is recommended for preclinical studies of a cytostatic drug effect on PD-L1 expression and for predicting the efficacy of their combination with immune checkpoint inhibitors.

The object of the study is spearmint, a polymorphic species, which is characterized by the strong variability of its morphological characteristics and biochemical composition. As a result of studies on the form of M. spicata L. and M. spicata L. cv. Moroccan, it is found that the raw material of this species is characterized by a high content of phenolic compounds (7.94–9.14%), including flavonoids (2.15–4.35%). The content of essential oil reaches the maximum during flowering of 1.54% in the raw material of M. spicata L. and 1.48% in the raw material of M. spicata L. cv. Moroccan. The main components of the essential oil are carvone and dihydrocarvone, the total content of which in the essential oil during the flowering phase reaches 73.51% or more. The content of carvone, depending on the phase of development, increases by the time of flowering from 57.69 to 60.79% in M. spicata L. cv. Moroccan and from 65.32 to 79.8% in the sample of M. spicata L., which is comparable to the content of carvone in caraway seeds. Thus, the raw material M. spicata L. can be considered as a source of carvone on a par with caraway seeds. Thus, the studied spearmint samples can be attributed to the carvone chemotype, and the raw material of M. spicata L. can be considered as a source of carvone on par with caraway seeds.

Technology and equipment are developed for purifying low-pressure gas flows from hydrogen sulfide and mercaptan contaminants. The efficiency of the catalytic desulphurization up to a residual content of sulfur-containing compounds of (SH) < 10 ppm is demonstrated using the example of model mixtures of a low-pressure gas in a disk film apparatus. The prospects for the creation of desulphurization units for the recovery of oil-loading vapors with the production of commercial quality hydrocarbons, as well as for the purification of atmospheric emissions from sulfur-containing ecotoxicants and hydrocarbons, during the oil loading processes are considered.