Novel Substituted Azoloazines with Anticoagulant Activity.

Hypercytokinemia, or cytokine storm, often complicates the treatment of viral and bacterial infections, including COVID-19, leading to the risk of thrombosis. However, the use of currently available direct anticoagulants for the treatment of COVID-19 patients is limited due to safety reasons. Therefore, the development of new anticoagulants remains an urgent task for organic and medicinal chemistry. At the same time, new drugs that combine anticoagulant properties with antiviral or antidiabetic activity could be helpfull in the treatment of COVID-19 patients, especially those suffering from such concomitant diseases as arterial hypertension or diabetes. We have synthesized a number of novel substituted azoloazines, some of which have previously been identified as compounds with pronounced antiviral, antibacterial, antidiabetic, antiaggregant, and anticoagulant activity. Two compounds from the family of 1,2,4-triazolo[1,5-a]pyrimidines have demonstrated anticoagulant activity at a level exceeding or at least comparable with that of dabigatran etexilate as the reference compound. 7,5-Di(2-thienyl)-4,5-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine has shown the highest ability to prolong the thrombin time, surpassing this reference drug by 2.2 times. This compound has also exhibited anticoagulant activity associated with the inhibition of thrombin (factor IIa). Moreover, the anticoagulant effect of this substance becomes enhanced under the conditions of a systemic inflammatory reaction.

Consensus Ensemble Multitarget Neural Network Model of Anxiolytic Activity of Chemical Compounds and Its Use for Multitarget Pharmacophore Design.

A classification consensus ensemble multitarget neural network model of the dependence of the anxiolytic activity of chemical compounds on the energy of their docking in 17 biotargets was developed. The training set included compounds thathadalready been tested for anxiolytic activity and were structurally similar to the 15 studied nitrogen-containing heterocyclic chemotypes. Seventeen biotargets relevant to anxiolytic activity were selected, taking into account the possible effect on them of the derivatives of these chemotypes. The generated model consistedof three ensembles of artificial neural networks for predicting three levels of anxiolytic activity, with sevenneural networks in each ensemble. A sensitive analysis of neurons in an ensemble of neural networks for a high level of activity made it possible to identify four biotargets ADRA1B, ADRA2A, AGTR1, and NMDA-Glut, which were the most significant for the manifestation of the anxiolytic effect. For these four key biotargets for 2,3,4,5-tetrahydro-11H-[1,3]diazepino[1,2-a]benzimidazole and [1,2,4]triazolo[3,4-a][2,3]benzodiazepine derivatives, eight monotarget pharmacophores of high anxiolytic activity were built. Superposition of monotarget pharmacophores built two multitarget pharmacophores of high anxiolytic activity, reflecting the universal features of interaction 2,3,4,5-tetrahydro-11H-[1,3]diazepino[1,2-a]benzimidazole and [1,2,4]triazolo[3,4-a][2,3]benzodiazepine derivatives with the most significant biotargets ADRA1B, ADRA2A, AGTR1, and NMDA-Glut.

New Organometallic Ru(II) Compounds with Lonidamine Motif as Antitumor Agents.

The combination of one molecule of organic and metal-based fragments that exhibit antitumor activity is a modern approach in the search for new promising drugs. In this work, biologically active ligands based on lonidamine (a selective inhibitor of aerobic glycolysis used in clinical practice) were introduced into the structure of an antitumor organometallic ruthenium scaffold. Resistant to ligand exchange reactions, compounds were prepared by replacing labile ligands with stable ones. Moreover, cationic complexes containing two lonidamine-based ligands were obtained. Antiproliferative activity was studied in vitro by MTT assays. It was shown that the increase in the stability in ligand exchange reactions does not influence cytotoxicity. At the same time, the introduction of the second lonidamine fragment approximately doubles the cytotoxicity of studied complexes. The ability to induce apoptosis and caspase activation in tumour cell MCF7 was studied by employing flow cytometry.

3-Arylidene-2-oxindoles as Potent NRH:Quinone Oxidoreductase 2 Inhibitors.

The enzyme NRH:quinone oxidoreductase 2 (NQO2) plays an important role in the pathogenesis of various diseases such as neurodegenerative disorders, malaria, glaucoma, COVID-19 and cancer. NQO2 expression is known to be increased in some cancer cell lines. Since 3-arylidene-2-oxindoles are widely used in the design of new anticancer drugs, such as kinase inhibitors, it was interesting to study whether such structures have additional activity towards NQO2. Herein, we report the synthesis and study of 3-arylidene-2-oxindoles as novel NRH:quinone oxidoreductase inhibitors. It was demonstrated that oxindoles with 6-membered aryls in the arylidene moiety were obtained predominantly as E-isomers while for some 5-membered aryls, the Z-isomers prevailed. The most active compounds inhibited NQO2 with an IC50 of 0.368 µM. The presence of a double bond in the oxindoles was crucial for NQO2 inhibition activity. There was no correlation between NQO2 inhibition activity of the synthesized compounds and their cytotoxic effect on the A549 cell line.

Discovery and evaluation of biphenyl derivatives of 2-iminobenzimidazoles as prototype dual PTP1B inhibitors and AMPK activators with in vivo antidiabetic activity.

This work describes the synthesis of series hydrobromides of N-(4-biphenyl)methyl-N'-dialkylaminoethyl-2-iminobenzimidazoles, which, due to the presence of two privileged structural fragments (benzimidazole and biphenyl moieties), can be considered as bi-privileged structures. Compound 7a proved to activate AMP-activated kinase (AMPK) and simultaneously inhibit protein tyrosine phosphatase 1B (PTP1B) with similar potency. This renders it an interesting prototype of potential antidiabetic agents with a dual-target mechanism of action. Using prove of concept in vivo study, we show that dual-targeting compound 7a has a disease-modifying effect in a rat model of type 2 diabetes mellitus via improving insulin sensitivity and lipid metabolism.

Design, Synthesis and Pharmacological Evaluation of Novel C2,C3-Quinoxaline Derivatives as Promising Anxiolytic Agents.

A new series of quinoxaline derivatives, 2a-4b, were synthesized and their anxiolytic potential was evaluated in vivo using elevated plus maze (EPM), open field (OF) and light-dark box (LDB) techniques. According to the results of the EPM, four active compounds were found in 2a, 2b, 2c, 4b. Their anxiolytic properties were confirmed in terms of LDB and the most active was compound 2b. In the OF, only 2c had an influence on the locomotor activity of the rodents. Thus, the most promising substance was determined; this was 2b, which has the structure of 2-(2-{[3-(4-tert-butylphenyl)quinoxaline-2-yl]methyl}-4,5-dimethoxyphenyl)-N-methylethan-1-amine hydrochloride. The obtained data were analyzed with the pharmacophore feature prediction approach, which made it possible to compare the structures of the studied compounds with the reference drug diazepam, and to determine the contribution of pharmacophores to the manifestation of the activity under study. ADMET analysis was carried out for compound 2b and the acute oral toxicity of this substance was also tested in vivo. As a result of the study, a promising compound with a high anxiolytic effect and low level of toxicity 2b was found, which is of interest for further preclinical study of its properties.

Anti-Inflammatory Activity of Soluble Epoxide Hydrolase Inhibitors Based on Selenoureas Bearing an Adamantane Moiety.

The inhibitory potency of the series of inhibitors of the soluble epoxide hydrolase (sEH) based on the selenourea moiety and containing adamantane and aromatic lipophilic groups ranges from 34.3 nM to 1.2 µM. The most active compound 5d possesses aliphatic spacers between the selenourea group and lipophilic fragments. Synthesized compounds were tested against the LPS-induced activation of primary murine macrophages. The most prominent anti-inflammatory activity, defined as a suppression of nitric oxide synthesis by LPS-stimulated macrophages, was demonstrated for compounds 4a and 5b. The cytotoxicity of the obtained substances was studied using human neuroblastoma and fibroblast cell cultures. Using these cell assays, the cytotoxic concentration for 4a was 4.7-18.4 times higher than the effective anti-inflammatory concentration. The genotoxicity and the ability to induce oxidative stress was studied using bacterial lux-biosensors. Substance 4a does not exhibit genotoxic properties, but it can cause oxidative stress at concentrations above 50 µM. Put together, the data showed the efficacy and safety of compound 4a.

CK2 Inhibition and Antitumor Activity of 4,7-Dihydro-6-nitroazolo[1,5-a]pyrimidines.

Today, cancer is one of the most widespread and dangerous human diseases with a high mortality rate. Nevertheless, the search and application of new low-toxic and effective drugs, combined with the timely diagnosis of diseases, makes it possible to cure most types of tumors at an early stage. In this work, the range of new polysubstituted 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines was extended. The structure of all the obtained compounds was confirmed by the data of 1H, 13C NMR spectroscopy, IR spectroscopy, and elemental analysis. These compounds were evaluated against human recombinant CK2 using the ADP-GloTM assay. In addition, the IC50 parameters were calculated based on the results of the MTT test against glioblastoma (A-172), embryonic rhabdomyosarcoma (Rd), osteosarcoma (Hos), and human embryonic kidney (Hek-293) cells. Compounds 5f, 5h, and 5k showed a CK2 inhibitory activity close to the reference molecule (staurosporine). The most potential compound in the MTT test was 5m with an IC50 from 13 to 27 µM. Thus, our results demonstrate that 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines are promising for further investigation of their antitumor properties.

Synthesis of 2-chloropurine ribosides with chiral amino acid amides at C6 and their evaluation as A1 adenosine receptor agonists.

A series of purine ribonucleosides bearing chiral amino acid amides at the C6 position of 2-chloropurine was synthesized. Molecular docking of the synthesized analogs of 2-chloroadenosine by their affinity for A1 adenosine receptors (A1ARs) was conducted. The investigation of A1AR stimulating activity of synthesized nucleosides was carried out in a model of an isolated mouse atrium. We have shown that derivatives with tyrosine, valine, and serine residues exhibit the properties of A1AR partial agonists. Animal experiments in the open field test have shown that these compounds have different profiles of psychoactive action. These nucleosides have an ophthalmic hypotensive effect and reduce intraocular pressure in a manner slightly inferior to that of timolol and brimonidine. The synthesized nucleosides can be the basis for further design and synthesis of new A1AR agonists.

Towards multi-target antidiabetic agents: In vitro and in vivo evaluation of 3,5-disubstituted indolin-2-one derivatives as novel α-glucosidase inhibitors.

Type 2 diabetes mellitus is a chronic progressive disease that usually requires polypharmacological treatment approaches. Previously we have described a series of 2-oxindole derivatives as GSK3ß inhibitors with in vivo antihyperglycemic activity. α-Glucosidase is another antidiabetic target that prevents postprandial hyperglycemia and corresponding hyperinsulinemic response. Herein we report a study of 3,5-disubstituted indolin-2-one derivatives as potent α-glucosidase inhibitors. These inhibitors were identified via efficient synthesis, in vitro screening, and biological evaluation. The most active compound 5f inhibits yeast α-glucosidase with IC50 of 6.78 µM and prevents postprandial hyperglycemia in rats after maltose and sucrose challenge at 5.0 mg/kg dose. Two lead glucosidase inhibitors, 5f and 5m, are also GSK3ß inhibitors with submicromolar potency. Hence, structure-activity studies elucidate foundation for development of dual GSK3ß/α-glucosidase inhibitors for treatment of type 2 diabetes.

Ru(III) Complexes with Lonidamine-Modified Ligands.

A series of bifunctional Ru(III) complexes with lonidamine-modified ligands (lonidamine is a selective inhibitor of aerobic glycolysis in cancer cells) was described. Redox properties of Ru(III) complexes were characterized by cyclic voltammetry. An easy reduction suggested a perspective for these agents as their whole mechanism of action seems to be based on activation by metal atom reduction. New compounds demonstrated a more pronounced antiproliferative potency than the parental drug; individual new agents were more cytotoxic than cisplatin. Stability studies showed an increase in the stability of complexes along with the linker length. A similar trend was noted for antiproliferative activity, cellular uptake, apoptosis induction, and thioredoxin reductase inhibition. Finally, at concentrations that did not alter water solubility, the selected new complex evoked no acute toxicity in Balb/c mice.

Synthesis and Pharmacological Evaluation of Novel 2,3,4,5-tetrahydro[1,3]diazepino[1,2-a]benzimidazole Derivatives as Promising Anxiolytic and Analgesic Agents.

A number of novel 2,3,4,5-tetrahydro[1,3]diazepino[1,2-a]benzimidazole derivatives 2 were obtained by alkylation mainly in the 1H-tautomeric form of 2,3,4,5-tetrahydro[1,3]diazepino[1,2-a]benzimidazole or its 8,9-dimethyl-substituted analog 4-chlorobenzyl bromide, 4-chloroacetic acid fluoroanilide, and 4-tert-butylphenacyl bromide in neutral medium. Compounds 3 were cyclized and synthesized earlier with 11-phenacyl-substituted diazepino[1,2-a]benzimidazoles upon heating in conc. HBr. The chemical structures of the compounds were clarified by using the 1H Nuclear Magnetic Resonance Spectroscopy (1H-NMR) technique. Anxiolytic properties were evaluated using the elevated plus maze (EPM) and open field (OF) tests. The analgesic effect of compounds was estimated with the tail flick (TF) and hot plate (HP) methods. Besides, possible the influence of the test compounds on motor activities of the animals was examined by the Grid, Wire, and Rotarod tests. Compounds 2d and 3b were the most active due to their prominent analgesic and anxiolytic potentials, respectively. The results of the performed in silico analysis showed that the high anxiolytic activity of compound 3b is explained by the combination of a pronounced interaction mainly with the benzodiazepine site of the GABAA receptor with a prominent interaction with both the specific and allosteric sites of the 5-HT2A receptor.

Searching for new anxiolytic agents among derivatives of 11-dialkylaminoethyl-2,3,4,5-tetrahydrodiazepino[1,2-a]benzimidazole.

A study on the anxiolytic activity of the new derivatives of 11-dialkylaminoethyl-2,3,4,5-tetrahydrodiazepino[1,2-a]benzimidazole, containing privileged scaffolds of benzodiazepine and benzimidazole in their structure, was conducted. The cytotoxic properties of low levels of six compounds were preliminary determined in vitro using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide test. The screening of these substances for anxiolytic activity was conducted using elevated plus maze (EPM) test in vivo, and DAB-21 was found to be the most active compound. The acute toxicity of DAB-21 was determined as less toxic than that of diazepam. The dose-dependent effect of the most active compound revealed a minimum dose of 1.26 mg/kg, which resulted in the maximum counterphobic effect. The effect of DAB-21 was superior in a number of tests compared with that of diazepam, which indicated a high level of tranquilizing activity for DAB-21. The results of in silico docking analysis suggest that DAB-21 should have a slightly lower anxiolytic activity than diazepam, but should exhibit greater specific affinity for the benzodiazepine site of the GABAA receptor, in comparison with its GABA-binding site. The interaction between DAB-21 and flumazenil in terms of EPM verifies the GABAergic mechanism of action of DAB-21. Our results highlight the potential of 11-dialkylaminomethyl-2,3,4,5-tetrahydrodiazepino[1,2-a]benzimidazoles as promising compounds in the search for new highly effective anxiolytics.

Ambiguities in Neutrophil Extracellular Traps. Ongoing Concepts and Potential Biomarkers for Rheumatoid Arthritis: A Narrative Review.

OBJECTIVE: This study aims to provide consolidation of current research findings as well as the most important concepts regarding neutrophil extracellular traps (NETs) in rheumatoid arthritis. DATA SOURCES: Relevant publications from 2004 to 2018 were identified using PubMed, Web of Science, Scopus, and eLibrary databases. Primary search terms used were "neutrophil extracellular traps" or "NETs" in combination with "rheumatoid arthritis". DATA SYNTHESIS: NETs are distinctive structures promoting capture and non-phagocytic cleavage of foreign substances. NETs usually consist of thin chromatin fibers decorated with various molecules of granular, cytosolic, and cytoskeletal origin. NETosis can develop in two ways: either with neutrophil death or when the viability of the cell prolongs. ROS generation and pronounced protein citrullination are essential during the initial phase of NETs formation. NETosis is considered to have certain immunological consequences, including DAMPs-mediated signalling, proinflammatory cytokine secretion, and contact of extensively modified self and foreign epitopes with antigen-presenting cells. There are several putative pathogenetic links between NETosis, citrullination, neoepitope formation, and production of anticitrullined autoantibodies that can strongly influence rheumatoid arthritis progression. NET-induced vascular injury in rheumatoid arthritis can arise directly from NETs and indirectly through enhanced thrombosis and atherosclerosis. CONCLUSION: NETs are currently estimated as a possible influential factor of rheumatoid arthritis initiation and/or progression, especially in the context of vascular involvement. NETs can also serve as a source of novel antigenic biomarkers for the diagnosis of rheumatoid arthritis.

Evaluation of Cytotoxicity and α-Glucosidase Inhibitory Activity of Amide and Polyamino-Derivatives of Lupane Triterpenoids.

A series of two new and twenty earlier synthesized branched extra-amino-triterpenoids obtained by the direct coupling of betulinic/betulonic acids with polymethylenpolyamines, or by the cyanoethylation of lupane type alcohols, oximes, amines, and amides with the following reduction were evaluated for cytotoxicity toward the NCI-60 cancer cell line panel, α-glucosidase inhibitory, and antimicrobial activities. Lupane carboxamides, conjugates with diaminopropane, triethylenetetramine, and branched C3-cyanoethylated polyamine methyl betulonate showed high cytotoxic activity against most of the tested cancer cell lines with GI50 that ranged from 1.09 to 54.40 µM. Betulonic acid C28-conjugate with triethylenetetramine and C3,C28-bis-aminopropoxy-betulin were found to be potent micromolar inhibitors of yeast α-glucosidase and to simultaneously inhibit the endosomal reticulum α-glucosidase, rendering them as potentially capable to suppress tumor invasiveness and neovascularization, in addition to the direct cytotoxicity. Plausible mechanisms of cytotoxic action and underlying disrupted molecular pathways were elucidated with CellMinner pattern analysis and Gene Ontology enrichment analysis, according to which the lead compounds exert multi-target antiproliferative activity associated with oxidative stress induction and chromatin structure alteration. The betulonic acid diethylentriamine conjugate showed partial activity against methicillin-resistant S. aureus and the fungi C. neoformans. These results show that triterpenic polyamines, being analogs of steroidal squalamine and trodusquemine, are important substances for the search of new drugs with anticancer, antidiabetic, and antimicrobial activities.

Towards multi-target antidiabetic agents: Discovery of biphenyl-benzimidazole conjugates as AMPK activators.

Type 2 diabetes mellitus is a complex metabolic disorder requiring polypharmacology approaches for effective treatment. Combinatorial library of fifteen new tricyclic benzimidazole derivatives have been designed and synthesized to combine fragments commonly found in allosteric AMPK activators and AT1 receptor antagonists. It was found that 2'-cyanobiphenyl serves as the pharmacophore of AMPK-activating activity, which also increases with the expansion of the external hydrogenated cycle. Also, pronounced antiplatelet activity is characteristic of the studied compounds. One of derivatives was identified as a potent inhibitor of the formation of advanced protein glycation end-products with reactive dicarbonyl scavenging activity. Two submicromolar AMPK activators 2b and 3b prevents inflammatory activation of murine macrophages. Along with good water solubility and synthetic availability, these results render biphenyl derivatives of fused benzimidazoles as a valuable starting point for the development of AMPK activators with multi-target antidiabetic activity.

Synthesis and biological evaluation of 3-substituted 2-oxindole derivatives as new glycogen synthase kinase 3ß inhibitors.

Glycogen synthase kinase 3ß (GSK-3ß) is a widely investigated molecular target for numerous diseases including Alzheimer's disease, cancer, and diabetes mellitus. Inhibition of GSK-3ß activity has become an attractive approach for treatment of diabetes and cancer. We report the discovery of novel GSK-3ß inhibitors of 3-arylidene-2-oxindole scaffold with promising activity. The most potent compound 3a inhibits GSK-3ß with IC50 4.19 nM. In a cell-based assay 3a shows no significant leucocyte toxicity at 10 µM and is moderately cytotoxic against A549 cells. Compound 3a demonstrated high antidiabetic efficacy in obese streptozotocin-treated rats improving glucose tolerance at a dose of 50 mg/kg body weight thus representing an interesting lead for further optimization.

Synthesis, in vitro and in vivo evaluation of 2-aryl-4H-chromene and 3-aryl-1H-benzo[f]chromene derivatives as novel α-glucosidase inhibitors.

Herein we report a study of novel arylchromene derivatives as analogs of naturally occurring flavonoids with prominent α-glucosidase inhibitory properties. Novel inhibitors were identified via simple stepwise in silico screening, efficient synthesis, and biological evaluation. It is shown that 2-aryl-4H-chromene core retains pharmacophore properties while being readily available synthetically. A lead compound identified through screening inhibits yeast α-glucosidase with IC50 of 62.26 µM and prevents postprandial hyperglycemia in rats at 2.2 mg/kg dose.

Author Correction: Pyridoxine dipharmacophore derivatives as potent glucokinase activators for the treatment of type 2 diabetes mellitus.

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6-Nitroazolo[1,5-a]pyrimidin-7(4H)-ones as Antidiabetic Agents.

Prevention of the formation of advanced glycation end-products (AGEs) is a reliable approach to achieve control over hyperglycemia and the associated pathogenesis of diabetic vascular complications. In these terms, new synthetic approaches to 6-nitroazolo[1,5-a]pyrimidines have been developed on the basis of the promising antiglycation activity of their structural analogues, such as azolo[5,1-c][1,2,4]triazine-4(1H)-ones. A number of nitroazolopyrimidines were obtained by using nitration, chlorodeoxygenation, and amination reactions, and their antidiabetic properties were elucidated in vitro. It was shown that triazolo[1,5-a]pyrimidine-7(4H)-ones exhibit a higher antiglycation activity than the corresponding 7-alkylamino analogs and aminoguanidine, as the reference compound. It is suggested that this kind of activity can be associated with the chelating properties possessed by the synthesized 6-nitro-7-oxoderivatives. Furthermore, the compounds obtained were tested for their inhibitory activity against dipeptidyl peptidase 4 (DPP4), glycogen phosphorylase, and α-glucosidase in vitro, but their activities proved to be significantly inferior to those of the reference compounds.