Publications by authors named "Danica Sabolova"

This study focuses on the synthesis and structural characterization of new compounds that integrate thiazolidine-2,4-dione, acridine moiety, and an acetamide linker, aiming to leverage the synergistic effects of these pharmacophores for enhanced therapeutic potential. The newly designed molecules were efficiently synthesized through a multi-step process and subsequently transformed into their hydrochloride salts. Comprehensive spectroscopic techniques, including nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), infrared (IR) spectroscopy, and elemental analysis, were employed to determine the molecular structures of the synthesized compounds.

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Silver(I) complexes with proline and hydroxyproline were synthesized and structurally characterized and crystal structure analysis shows that the formulas of the compounds are {[Ag(Pro)(NO)]NO} (AgPro) (Pro = L-proline) and {[Ag(Hyp)(NO)]NO} (AgHyp) (Hyp = -4-hydroxy-L-proline). Both complexes crystallize in the monoclinic lattice with space group 2 with a carboxylate bidentate-bridging coordination mode of the organic ligands Pro and Hyp (with NH and COO groups in zwitterionic form). Both complexes have a distorted seesaw (C) geometry around one silver(I) ion with values of 58% (AgPro) and 51% (AgHyp).

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A series of novel Ga(III)-pyridine carboxylates ([Ga(Pic)]·HO (GaPic; HPic = picolinic acid), HO[Ga(Dpic)]·HO (GaDpic; HDpic = dipicolinic acid), [Ga(Chel)(HO)(OH)]·4HO (GaChel; HChel = chelidamic acid) and [Ga(Cldpic)(HO)(OH)] (GaCldpic; HCldpic = 4-chlorodipicolinic acid)) have been synthesized by simple one-step procedure. Vibrational spectroscopy (mid-IR), elemental analysis, thermogravimetric analysis and X-ray diffraction confirmed complexes molecular structure, inter and intramolecular interactions and their influence to spectral and thermal properties. Moreover, complex species speciation was described in Ga(III)-HPic and Ga(III)-HDpic systems by potentiometry and H NMR spectroscopy and mononuclear complex species were determined; [Ga(Pic)] (logβ = 16.

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In this study, four hybrid organic-inorganic compounds (8-HQ)[PdCl] (1), (HClQ)[PdCl] (2), (HNQ)[PdCl] (3) and (HMeQ)[PdCl]·2HO (4) (where 8-HQ = 8-hydroxyquinolinium, HClQ = 5-chloro-8-hydroxyquinolinium, HNQ = 5-nitro-8-hydroxyquinolinium and HMeQ = 2-methyl-8-hydroxyquinolinium) were synthesized through organic cation modulation. Single-crystal X-ray structure analysis of compounds 1 and 3 indicates that their structures are planar and consist of [PdCl] anions and 8-HQ or HNQ cations, respectively. Both ionic components are held together through ionic interactions and hydrogen bonds forming infinite chains linked through π-π interactions to form 2D structures.

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Three silver(I) dipeptide complexes [Ag(GlyGly)](NO) (AgGlyGly), [Ag(GlyAla)(NO)] (AgGlyAla) and [Ag(HGlyAsp)(NO)] (AgGlyAsp) were prepared, investigated and characterized by vibrational spectroscopy (mid-IR), elemental and thermogravimetric analysis and mass spectrometry. For AgGlyGly, X-ray crystallography was also performed. Their stability in biological testing media was verified by time-dependent NMR measurements.

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Novel silver(i) aminoacidate complexes {[Ag(HVal)(HO)(NO)]} (AgVal) and {[Ag(HAsp)(NO)]}·nHO (AgAsp) were prepared, investigated and fully characterized by vibrational spectroscopy (mid-IR), elemental analysis, thermogravimetric analysis, X-ray crystallography and mass spectrometry. Their stability in DO and PBS buffer was verified by time-dependent H and C NMR measurements. Their in vitro antibacterial activity (against pathogenic Staphylococcus aureus CCM4223, Escherichia coli CCM4787) and that against probiotic bacteria Lactobacillus plantarum CCM7102 and Lactobacillus reuteri (L26) were determined and potential dosing concentration was evaluated.

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Heterocycles have long been the focus of intensive study in attempts to develop novel therapeutic compounds, and acridine, a polynuclear nitrogen molecule containing a heterocycle, has attracted a considerable amount of scientific attention. Acridine derivatives have been studied in detail and have been found to possess multitarget properties, which inhibit topoisomerase enzymes that regulate topological changes in DNA and interfere with the essential biological function of DNA. This article describes some recent advancements in the field of new 9-substituted acridine heterocyclic agents and describes both the structure and the structure-activity relationship of the most promising molecules.

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Two silver(I) aminoacidate complexes {[Ag(L-HAla)(NO)]NO} (AgAla, complex 1, Ala = alanine) and {[Ag(L-Phe)]} (AgPhe, complex 2, Phe = phenylalanine) were prepared and characterized by elemental, spectral analysis (FT-IR, NMR techniques) and single crystal X-ray analysis in solid state and their solution stability was measured in biological testing time-scale by H NMR. The bridging coordination modes of the zwitterionic Ala and deprotonated Phe ligands led to the formation of 1D polymeric chains of the complexes. The significant argentophilic interactions are presented in the structure of AgAla.

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Proflavine derivatives are extremely interesting chemotherapeutic agents, which have shown promising pharmaceutical potential due to their wide range of biological activities. This review summarizes the current state of research into the anticancer, antimicrobial, antimalarial and antileishmanial properties of these attractive compounds. Our attention has focused on new classes of proflavine conjugates, which display significant levels of anticancer activity.

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In the current study the ability of silver pyridine-2-sulfonate complex to exert multiple biological activities is compared with the pharmacological action of silver sulfadiazine (AgSD). Polymeric form of {[Ag(py-2-SO)]} (AgPS) was synthesized and characterized by analytical techniques (IR, CHN, TG/DTA, MS) and its molecular formula was established. The crystal structure was determined by X-ray diffraction method and the polymeric complex crystallizes in the triclinic P-1 space group.

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This review describes the synthesis of a wide range of novel tetrahydroacridine derivatives (tiocyanates, selenocyanates, ureas, selenoureas, thioureas, isothioureas, disulfides, diselenides and several tacrine homo- and hetro-hybrids). These tacrine congeners exhibit significant anticholinesterase and cytotoxic properties and may therefore be of considerable potential for the development of new drugs for the treatment of Alzheimer's disease.

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Acridines possess two characteristics that have led many researchers to consider the agents interesting targets for future development as potential farmacophores: the planar acridine skeleton, which is able to intercalate into DNA, and the intense fluorescence of the agents. This review offers a study of the multifunctional character of acridines and the synthesis of novel acridine derivatives, with particular focus being placed on isothiocyanates and their congeners, e.g.

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This study introduces a pair of newly synthesized silver complexes, [Ag(HGly)](NO) (1) and [Ag(Nam)]NO·HO (2) (Gly - glycine, Nam - nicotinamide), that were prepared and characterized by relevant methods in solid state (elemental, spectral, thermal and structural analysis) and their stability in solution was verified by H NMR measurements. Moreover, suitable reaction conditions were observed by potentiometry depending on pH in case of binary system Ag-Gly. X-ray analysis confirmed argentophilic interactions in complex 1 with an Ag1-Ag2 distance of 2.

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Starting from well-defined NH(CH)[PdCl(XQ)] complexes, coordination compounds of general formula Cat[PdCl(XQ)] have been prepared by cationic exchange of NH(CH) and Cat cations, where XQ are biologically active halogen derivatives of quinolin-8-ol (5-chloro-7-iodo-quinolin-8-ol (CQ), 5,7-dibromo-quinolin-8-ol (dBrQ) and 5,7-dichloro-quinolin-8-ol (dClQ)) and Cat is K or Cs. The cation exchange of all prepared complexes, K[PdCl(CQ)] (1), K[PdCl(dClQ)] (2), K[PdCl(dBrQ)] (3), Cs[PdCl(CQ)] (4), Cs[PdCl(dClQ)] (5) and Cs[PdCl(dBrQ)] (6) was approved using IR spectroscopy, their structures in DMSO solution were elucidated by one- and two-dimensional NMR experiments, whereas their stability in solution was verified by UV-VIS spectroscopy. Interaction of complexes to ctDNA was investigated using UV-VIS and fluorescence emission spectroscopy.

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A series of new 3d metal complexes with 5-chloro-quinolin-8-ol (ClQ), [Mn(ClQ)2] (1), [Fe(ClQ)3] (2), [Co(ClQ)2(H2O)2] (3), [Ni(ClQ)2(H2O)2] (4), [Cu(ClQ)2] (5), [Zn(ClQ)2(H2O)2] (6), [Mn(ClQ)3]·DMF (7) and [Co(ClQ)3]·DMF·(EtOH)0.35 (8) (DMF=N,N-dimethylformamide), has been synthesized and characterized by elemental analysis, IR spectroscopy and TG-DTA thermal analysis. X-ray structure analysis of 7 and 8 revealed that these molecular complexes contain three chelate ClQ molecules coordinated to the central atoms in a deformed octahedral geometry and free space between the complex units is filled by solvated DMF and ethanol molecules.

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A novel series of trisubstituted acridines were synthesized with the aim of mimicking the effects of BRACO19. These compounds were synthesized by modifying the molecular structure of BRACO19 at positions 3 and 6 with heteroacyclic moieties. All of the derivatives presented in the study exhibited stabilizing effects on the human telomeric DNA quadruplex.

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Three novel palladium(II) complexes, NH2(CH3)2[PdCl2(CQ)] (1) (CQ=5-chloro-7-iodo-quinolin-8-ol), NH2(CH3)2[PdCl2(dClQ)] (2) (dClQ=5,7-dichloro-quinolin-8-ol) and NH2(CH3)2[PdCl2(dBrQ)] (3) (dBrQ=5,7-dibromo-quinolin-8-ol) have been prepared and characterized. Their structures contain square-planar [PdCl2(XQ)](-) complex anions in which deprotonated XQ ligands are coordinated to the Pd atoms via the pyridine nitrogen and the phenolato oxygen atoms, other two cis-positions are occupied by two chlorido ligands. Negative charges of these anions are balanced by uncoordinated dimethylammonium cations.

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Three new acridine-thiazolidinone derivatives (2a-2c) have been synthesized and their interactions with calf thymus DNA and a number of cell lines (leukemic cells HL-60 and L1210 and human epithelial ovarian cancer cell lines A2780) were studied. The compounds 2a-2c possessed high affinity to calf thymus DNA and their binding constants determined by spectrofluorimetry were in the range of 1.37 × 10(6)-5.

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New acridine derivatives bearing two symmetrical imidazolidinone rings, 3,6-bis((1-alkyl-5-oxo-imidazolidin-2-yliden)imino)acridine hydrochlorides 6a-6e (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl), have been prepared and their interactions with calf thymus DNA and selected cell lines were studied. The DNA-binding of 6a-6e to ctDNA was examined by UV-vis, fluorescence, and CD spectroscopy. The binding constants determined by UV-vis spectroscopy were found in the range 1.

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A series of acridin-3,6-diyl-dithiourea hydrochloride derivatives (alkyl-AcrDTU) was prepared and tested against sensitive and drug resistant leukemia cell lines for their cytotoxic/cytostatic activity. The products (ethyl-, n-propyl-, n-butyl-, n-pentyl-AcrDTU) showed high DNA binding affinity via intercalation (K=7.6-2.

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Ten novel, potentially intercalating 4-acridonecarboxamide azomethines and ketimines have been prepared by the condensation reaction of 9-oxo-9,10-dihydroacridine-4-carboxylic acid hydrazide with various aldehydes and ketones. The structures of the compounds were characterized spectroscopically by NMR ((1)H, (13)C, (15)N nuclei and 2D experiments), UV-vis, IR and fluorescence methods and by quantum chemical calculations using DFT at the B3LYP/6-311+G(d,p) level of theory and semiempirical ZINDO and AM1 methods. NMR chemical shift variations for C-4' were assessed due to changes in the polarizability of the imine C(4')=N(3') bond rather than direct inductive effects arising from the C-4' substituents.

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The synthesis of novel 1',1''-(acridin-3,6-diyl)-3',3''-dialkyldiureas was reported. Their biological activity to inhibit cell proliferation was assessed by a MTT assay on two cell lines, HeLa and HCT-116, at micromolar concentration. 1',1''-(Acridin-3,6-diyl)-3',3''-dihexyldiurea hydrochloride was active on a HCT-116 cell line with an IC(50) value of 3.

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Five novel proflavine-dithiazolidinone derivatives 4a-4e have been designed and synthesized by the reaction of dialkyl acridin-3,6-diyl dithioureas 3a-3e with methyl bromoacetate. The binding affinity of dithiazolidinone hydrochlorides 5a-5e with calf thymus DNA and plasmid (pUC19) DNA was investigated by a variety of spectroscopic techniques including UV-vis, fluorescence, and CD spectroscopy. The effects of 5a-5e on the thermal denaturation profiles of calf thymus DNA were also studied.

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Isothiocyanates (ITCs) are phytochemicals with promising cancer-preventive potential. To elucidate the mechanism of cytotoxicity of ITCs, their accumulation by cells and the role of intracellular glutathione, fluorescent 9-isothiocyanatoacridine (AcITC) was synthesized. The kinetic parameters for the reactions of AcITC with thiols were estimated and the influence of AcITC on human chronic myeloid leukemia cell line (K562) in regard to intracellular glutathione was studied.

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