Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Jul 1, 2009
Ten novel, potentially intercalating 4-acridonecarboxamide azomethines and ketimines have been pr... more 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. In concert with this was the reversed order observed for the N-3' chemical shifts with DFT-calculated atomic charges confirming the bond polarization. Both intra- and intermolecular hydrogen bonds between the acridone NH hydrogen and the amidic carbonyl oxygen were found to exist by FT-IR spectroscopy. Quantum chemical calculations were used to evaluate the configurational, tautomeric, conformational and hydrogen bonding states of the molecules as well as predict the NMR and IR data. The hypsochromic shifts observed in the UV-vis spectra upon changing from m-cresol to DMA, DMF or methanol were evaluated in terms of solvent polarity (giving rise to solvated excited state destabilization) and solvent aromaticity (giving rise to solvated excited state stabilization). The fluorescence of the compounds were modest, except for the 2,6-dichloro derivative, with respect to 9-isothiocyanatoacridine.
Proceedings of the 2020 2nd International Conference on Modern Educational Technology, 2020
In 2014, the OECD team warned that regular assessment of students in Slovakia is not formative en... more In 2014, the OECD team warned that regular assessment of students in Slovakia is not formative enough and proposed introducing "formative assessment elements" into the Slovak system of education. An inherent part of formative assessment is students' self-assessment, and one of its techniques is the self-assessment card. The goal of this research was to determine the correlation between students' self-assessment using the self-assessment card and their level of conceptual understanding. The method used to achieve this goal was a single-group quasi-experiment performed at a selected Slovak grammar school in Rožňava. The analysis results show that the dependency between students' results and their self-assessment is significant, direct, and high. Further results showed no statistically significant difference between students' self-assessment and the difficulty of the tasks (from remembering to analysis). It means that the students were capable of objective self-assessment at all levels of conceptual task difficulty from remembering to analysis -- they neither overestimate, nor underestimate themselves.
A series of four new 3,6,9-trisubstituted acridine derivatives (two with fluorine substituents on... more A series of four new 3,6,9-trisubstituted acridine derivatives (two with fluorine substituents on phenyl ring) were synthesized and their interaction with calf thymus DNA and HSA was investigated using a combination of biochemical, biophysical and biological techniques. Analysis using fluorescent spectra provided valuable information about the formation of the acridine–DNA complex, while several other experiments suggest that acridine may bind to DNA through intercalation. These observations are further supported by LD spectral analysis, viscosity measurements and DNA melting studies. The interaction between HSA and four compounds were studied by fluorescence quenching spectra. In addition, the method was used for the calculation of characteristic binding parameters. These result and result obtained by synchronous fluorescence spectra of acridines with HSA determined that compounds create complexes with HSA and induce conformational changes. K B values were found to be of 1.51–7.34 × 10 6 M −1 . The studied 8c compound were the most sensitive against S. epidermidis ATCC 12228.
A series of novel 3,9-disubstituted acridines were synthesized and their biological potential was... more A series of novel 3,9-disubstituted acridines were synthesized and their biological potential was investigated. The synthetic plan consists of eight reaction steps, which produce the final products, derivatives 17a–17j, in a moderate yield. The principles of cheminformatics and computational chemistry were applied in order to study the relationship between the physicochemical properties of the 3,9-disubstituted acridines and their biological activity at a cellular and molecular level. The selected 3,9-disubstituted acridine derivatives were studied in the presence of DNA using spectroscopic (UV-Vis, circular dichroism, and thermal denaturation) and electrophoretic (nuclease activity, relaxation and unwinding assays for topoisomerase I and decatenation assay for topoisomerase IIα) methods. Binding constants (2.81–9.03 × 104 M−1) were calculated for the derivatives from the results of the absorption titration spectra. The derivatives were found to have caused the inhibition of both to...
A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoiso... more A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoisomerase I/II inhibitors, and their binding (calf thymus DNA—ctDNA and human serum albumin—HSA) and biological activities as potential anticancer agents on proliferation of A549 and CCD-18Co have been evaluated. The acridine-DNA complex 3b (-F) displayed the highest Kb value (Kb = 3.18 × 103 M−1). The HSA-derivatives interactions were studied by fluorescence quenching spectra. This method was used for the calculation of characteristic binding parameters. In the presence of warfarin, the binding constant values were found to decrease (KSV = 2.26 M−1, Kb = 2.54 M−1), suggesting that derivative 3a could bind to HSA at Sudlow site I. The effect of tested derivatives on metabolic activity of A549 cells evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT assay decreased as follows 3b(-F) > 3a(-H) > 3c(-Cl) > 3d(-Br). The derivatives 3c and 3d in vitro ac...
In this paper, we describe the biochemical properties and biological activity of a series of chol... more In this paper, we describe the biochemical properties and biological activity of a series of cholinesterase reactivators (symmetrical bisquaternary xylene-linked compounds,K106–K114) with ctDNA.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Jul 1, 2009
Ten novel, potentially intercalating 4-acridonecarboxamide azomethines and ketimines have been pr... more 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. In concert with this was the reversed order observed for the N-3' chemical shifts with DFT-calculated atomic charges confirming the bond polarization. Both intra- and intermolecular hydrogen bonds between the acridone NH hydrogen and the amidic carbonyl oxygen were found to exist by FT-IR spectroscopy. Quantum chemical calculations were used to evaluate the configurational, tautomeric, conformational and hydrogen bonding states of the molecules as well as predict the NMR and IR data. The hypsochromic shifts observed in the UV-vis spectra upon changing from m-cresol to DMA, DMF or methanol were evaluated in terms of solvent polarity (giving rise to solvated excited state destabilization) and solvent aromaticity (giving rise to solvated excited state stabilization). The fluorescence of the compounds were modest, except for the 2,6-dichloro derivative, with respect to 9-isothiocyanatoacridine.
Proceedings of the 2020 2nd International Conference on Modern Educational Technology, 2020
In 2014, the OECD team warned that regular assessment of students in Slovakia is not formative en... more In 2014, the OECD team warned that regular assessment of students in Slovakia is not formative enough and proposed introducing "formative assessment elements" into the Slovak system of education. An inherent part of formative assessment is students' self-assessment, and one of its techniques is the self-assessment card. The goal of this research was to determine the correlation between students' self-assessment using the self-assessment card and their level of conceptual understanding. The method used to achieve this goal was a single-group quasi-experiment performed at a selected Slovak grammar school in Rožňava. The analysis results show that the dependency between students' results and their self-assessment is significant, direct, and high. Further results showed no statistically significant difference between students' self-assessment and the difficulty of the tasks (from remembering to analysis). It means that the students were capable of objective self-assessment at all levels of conceptual task difficulty from remembering to analysis -- they neither overestimate, nor underestimate themselves.
A series of four new 3,6,9-trisubstituted acridine derivatives (two with fluorine substituents on... more A series of four new 3,6,9-trisubstituted acridine derivatives (two with fluorine substituents on phenyl ring) were synthesized and their interaction with calf thymus DNA and HSA was investigated using a combination of biochemical, biophysical and biological techniques. Analysis using fluorescent spectra provided valuable information about the formation of the acridine–DNA complex, while several other experiments suggest that acridine may bind to DNA through intercalation. These observations are further supported by LD spectral analysis, viscosity measurements and DNA melting studies. The interaction between HSA and four compounds were studied by fluorescence quenching spectra. In addition, the method was used for the calculation of characteristic binding parameters. These result and result obtained by synchronous fluorescence spectra of acridines with HSA determined that compounds create complexes with HSA and induce conformational changes. K B values were found to be of 1.51–7.34 × 10 6 M −1 . The studied 8c compound were the most sensitive against S. epidermidis ATCC 12228.
A series of novel 3,9-disubstituted acridines were synthesized and their biological potential was... more A series of novel 3,9-disubstituted acridines were synthesized and their biological potential was investigated. The synthetic plan consists of eight reaction steps, which produce the final products, derivatives 17a–17j, in a moderate yield. The principles of cheminformatics and computational chemistry were applied in order to study the relationship between the physicochemical properties of the 3,9-disubstituted acridines and their biological activity at a cellular and molecular level. The selected 3,9-disubstituted acridine derivatives were studied in the presence of DNA using spectroscopic (UV-Vis, circular dichroism, and thermal denaturation) and electrophoretic (nuclease activity, relaxation and unwinding assays for topoisomerase I and decatenation assay for topoisomerase IIα) methods. Binding constants (2.81–9.03 × 104 M−1) were calculated for the derivatives from the results of the absorption titration spectra. The derivatives were found to have caused the inhibition of both to...
A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoiso... more A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoisomerase I/II inhibitors, and their binding (calf thymus DNA—ctDNA and human serum albumin—HSA) and biological activities as potential anticancer agents on proliferation of A549 and CCD-18Co have been evaluated. The acridine-DNA complex 3b (-F) displayed the highest Kb value (Kb = 3.18 × 103 M−1). The HSA-derivatives interactions were studied by fluorescence quenching spectra. This method was used for the calculation of characteristic binding parameters. In the presence of warfarin, the binding constant values were found to decrease (KSV = 2.26 M−1, Kb = 2.54 M−1), suggesting that derivative 3a could bind to HSA at Sudlow site I. The effect of tested derivatives on metabolic activity of A549 cells evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT assay decreased as follows 3b(-F) > 3a(-H) > 3c(-Cl) > 3d(-Br). The derivatives 3c and 3d in vitro ac...
In this paper, we describe the biochemical properties and biological activity of a series of chol... more In this paper, we describe the biochemical properties and biological activity of a series of cholinesterase reactivators (symmetrical bisquaternary xylene-linked compounds,K106–K114) with ctDNA.
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