Quinazolin-4(3H)-one derivatives exhibiting a wide spectrum of a pharmacological activity, represent a promising class of substances used to obtain antibacterial agents, which is especially important in the context of the emergence of pathogenic microorganisms’ resistance to drugs used in medicine. It has been proved that compounds having a naphthyl radical in the molecule, as well as an amide group bound to the benzene ring as quinazolinone substituents, are characterized by a pronounced antimicrobial activity againstStaphylococcus aureusandStreptococcus pneumoniae.The aimof the research is a primary microbiological screening of thein vitroantimicrobial activity of new quinazolin-4(3H)-one derivatives againstStaphylococcus aureusandStreptococcus pneumoniae, as well as the assessment of the relationship between the pharmacological effect and the structural transformation of the substance molecule, lipophilicity and the possibility of forming resistance to them.Materials and methods.The experimental studies have been carried out using well-known nosocomial pathogens of infectious and inflammatory diseasesStaphylococcus aureusandStreptococcus pneumoniaeby a serial dilution method.Results.A compound containing a naphthyl radical in its structure, which contributes to an increase in the hydrophobicity of the substance and its solubility in the membrane of a bacterial cell, has a bacteriostatic effect against bothStaphylococcus aureusandStreptococcus pneumoniae.A similar pharmacological effect is exhibited by a derivative with an amide group as a substituent of the quinazolinone nucleus linked to a phenyl radical, which probably contributes to an increase in the degree of binding to active sites of enzymes involved in the DNA replication, and protein synthesis. Obviously, the increased lipophilicity, which promotes better binding to the efflux protein, cannot serve as objective characteristics of the emergence possibility of the pathogen’s resistance to this substance.Conclusion.Among the synthesized compounds, the leading substances that exhibit an antimicrobial activity againstStaphylococcus aureusandStreptococcus pneumonia,have been identified.The assessment of the chemical structure made it possible to substantiate their pharmacological action and draw conclusions about the possibility of developing resistance to it in microbial cells.

Quinazolines are a rich source of bioactive compounds. Previously, we showed NHE-1 inhibitory, anti-inflammatory, antiplatelet, intraocular pressure lowering, and antiglycating activity for a series of quinazoline-2,4(1H,3H)-diones and quinazoline-4(3H)-one guanidine derivatives. In the present work, novel $N^1$,$N^3$-bis-substituted quinazoline-2,4(1H,3H)-dione derivatives bearing two guanidine moieties were synthesized and pharmacologically profiled. The most potent NHE-1 inhibitor 3a also possesses antiplatelet and intraocular-pressure-reducing activity. Compound 4a inhibits NO synthesis and IL-6 secretion in murine macrophages without immunotoxicity and alleviates neutrophil infiltration, edema, and tissue lesions in a model of LPS-induced acute lung injury. Hence, we considered quinazoline derivative 4a as a potential agent for suppression of cytokine-mediated inflammatory response and acute lung injury.

Due to the rapid growth in the number of patients with diabetes in a complicated epidemiological picture, the question of the possibility of exposure of a substance to several targets becomes more important. It is noted that the most common infectious diseases in patients with diabetes mellitus are infections of the respiratory and urinary tract, skin and soft tissues, diabetic foot ulcers, otitis media and periodontal infections. Antimicrobial agents can have both direct and indirect hypoglycemic effects. Quinazolinones belonging to the group of heterocyclic derivatives exhibit a wide range of pharmacological activity. The use of the PASS program for the purpose of computer prediction of pharmacological activity showed a high probability of the hypoglycemic effect of new derivatives. The obtained results motivated the authors to search for the relationship between antimicrobial action and hypoglycemic effect within the general direction of studying the multi-targeting of drug ligands. Analysis of the literature data, as well as own studies of new quinazolinone derivative pharmacological activity make it possible to divide all ligands into functional groups that cause additional binding to the target molecule. The quinazolinone fragment, characterized by the uniqueness of its structure, can be reasonably attributed to multi-target ligands. The triazole cycle and the sulfonamide group can also purposefully bind to the target molecule. A carbamide residue, a fragment of sulfonylurea and an acetamide group, depending on the structure of the substance they are part of, can function both as a specific ligand and as a functional group involved in the stabilization of the intermediate transition state. The results obtained by the authors, as well as other researchers, allow us to formulate an assumption about the relationship between the mechanisms of antimicrobial and hyperglycemic activity.

Objective: Synthesis of new compounds, melatonin isosters, and study of their ability to reduce intraocular pressure. Materials and methods: Based on the previously made forecast and on the similarity with the selected compounds, the synthesis of new compounds was carried out – melatonin isosters having a 2,3-dihydro-1,4-benzodioxin cycle connected by a linker of various chemical structure with a nitrogen-containing heterocyclic core. The structure of the synthesized compounds was proved by 1H- and 13C- NMR spectroscopy, purity and individuality – by chromatographic methods. Intraocular pressure in laboratory animals was measured using a contact veterinary tonometer Tonovet (Finland). Cytotoxicity was assessed using MTT test on normal rat skin fibroblasts. Results: Derivatives (benzodioxane-2-yl)methanol reduced the level of IOP in varying degrees of severity. The VMA-22-37 compound showed the greatest activity. With topical application of a 0.4% solution, the compound reduced the intraocular pressure of intact rats by 26.6%, while not affecting the control eye. This compound also has low cytotoxicity. Conclusion: Derivatives (benzodioxane-2-yl)methanol is promising for the search for compounds capable of reducing increased intraocular pressure.

One of the critical challenges in the development of sodium-hydrogen exchanger 1 (NHE-1) inhibitors is the risk of non-specific cytotoxicity, which significantly limits their therapeutic potential. Most well-known representatives of this class exert damaging effects on cell membranes within the micromolar concentration range, necessitating the search for novel chemical scaffolds that combine high pharmacological activity with the absence of cytotoxic properties. Purpose: The aim of this work was to comprehensively evaluate the cytotoxicity of new selective NHE-1 inhibitors − quinazoline-2,4(1H,3H)-dione derivatives designated as VMA 21-14 and VMA 21-10 − under both basal conditions and LPS stimulation using an in vitro primary culture model of peritoneal macrophages to determine their therapeutic safety margin. Materials and methods: The study was conducted on a model of activated peritoneal macrophages harvested from outbred mice. Cell viability was evaluated following a prolonged 72-hour exposure to the compounds at a concentration of 100 muM. The analysis included the assessment of membrane structural integrity (LDH assay) and mitochondrial metabolic activity (MTT assay) in both intact culture and under lipopolysaccharide (LPS)-induced inflammatory stress. Amiloride, zoniporide, rimeporide, and dexamethasone were used as reference drugs. Results and discussion: The findings indicate that both investigated quinazoline-2,4(1H,3H)-dione derivatives are completely devoid of cytotoxicity. In the intact cell culture, membrane integrity for compounds VMA 21-14 and VMA 21-10 was 95,03 % and 104,75 %, respectively, which statistically exceeds the performance of the reference drugs. In the MTT assay, compound VMA 21-10 demonstrated stable metabolic inertness (102,22 %), whereas compound VMA 21-14 induced a moderate activation of energy metabolism (145,82 %). Under exposure to the bacterial endotoxin (LPS), both compounds maintained a high safety profile. Conclusion: The investigated compounds VMA 21-14 and VMA 21-10 are characterized by a complete absence of non-specific cytotoxicity at concentrations that far exceed their effective doses. These data confirm that the pharmacological effects of the investigated compounds result from highly specific interactions with the NHE-1 target rather than from a disruption of cellular homeostasis, thereby justifying the prospects for their further in vivo preclinical evaluation.