Search

Uvod: Bakar(II)-jon je zbog prelazno tvrdo-mekih karakteristika idealan za koordinovanje sa različitim donorskim atomima, a zbog esencijalne uloge koju ima u organizmu njegovi kompleksi su potencijalno manje toksični. Aminokiseline preko atoma azota i kiseonika lako formiraju koordinativno-kovalentne veze sa prelaznim metalima. Zbog biološke aktivnosti i farmakološkog značaja, β-aminokiseline su pogodni ligandi u sintezi potencijalnog leka. Materijal i metode: U okviru ove doktorske disertacije opisani su postupci sinteza β-aminokiselina i odgovarajućih kompleksa bakra(II) sa β-aminokiselinama. Strukture sintetisanih liganada potvrđene su na osnovu infracrvene (IR) i nuklearno- -magnetno-rezonancione spektroskopije (1N i 13S NMR), dok su sastav i strukture sintetisanih kompleksnih jedinjenja pretpostavljene na osnovu rezultata elementalne mikroanalize, infracrvene i elektronsko-paramagnetno-rezonancione spektroskopije (EPR). Stvarna struktura kompleksa bakar(II)-jona i 2-(1-aminocikloheksil)sirćetne kiseline potvrđena je i na osnovu rezultata rendgenske strukturne analize. Interakcije sintetisanih kompleksa sa molekulom DNK utvrđene su na osnovu kinetičkih merenja, apsorpciono spektroskopskih merenja, fluorescentnih merenja i merenja viskoziteta DNK rastvora. Broj i vijabilnost tumorskih ćelija (4T1, CT26, LLC1) nakon primene rastvora kompleksnih jedinjenja određena je kolorimetrijskim MTT testom. Antimikrobna aktivnost sintetisanih jedinjenja ispitana je mikrodilucionom metodom. Rezultati: Potvrđena je kvadratno-planarna struktura sinetisanih kompleksa. Vrednosti konstanti vezivanja, smanjenja intenziteta fluorescencije i povećanje relativnog viskoziteta rastvora DNK ukazuju na interakciju kompleksa i molekula DNK. Od ispitivanih ćelijskih linija najveću osetljivost prema sintetisanim kompleksima pokazale su ćelije karcinoma pluća, LLC1. Oba kompleksa indukuju apoptozu ćelija karcinoma kolona (ST26) i pri nižim koncentracijama imaju bolju aktivnost od cisplatine. I, Introduction: Copper(II)-ion is ideal for coordinating with different donor atoms due to its soft-hard characteristics while transferring, and because of its essential role in organism, its complexes are potentially less toxic. Amino acids, through the atoms of nitrogen and oxygen, easily form coordinate-covalent bonds with transition metals. β-amino acids are suitable ligands in the synthesis of a potential medicine because of their biological activity and pharmacological significance. Materials and methods: This PhD thesis describes the syntheses procedures of β-amino acids and corresponding copper(II)-complexes with β-amino acids. The structures of synthesized ligands were confirmed based on infrared (IR) and nuclear-magnetic-resonance spectroscopy (1Н and 13С NMR), while the composition and the structures of synthesized complex compounds were assumed by the results of elemental microanalysis, infrared and electron paramagnetic resonance (EPR). The real structure of copper(II)-ion complex and 2-(1-aminocyclohexyl) acetic acid was confirmed from the results of Roentgen structural analysis. The interactions of synthesized complexes with the DNA molecule were determined by kinetic measurements, absorption spectroscopic measurements, fluorescent measurements and the measurements of the DNA solution viscosity. The number and the viability of tumor cells (4T1, CT26, LLC1), after applying complex compounds solutions, was determined by МТТ colorimetric technique. Antimicrobial activity of synthesized compounds was examined using microdilution method. Results: Square planar structure of synthesized compounds was confirmed. The values of binding constants, fluorescence intensity reduction and the increase of relative DNA solution viscosity indicated the interaction between complexes and the DNA molecule. From the tested cell lines, lung cancer cells (LLC1) showed the largest sensitivity towards synthesized complexes. Both complexes induced cell apoptosis of colon cancer (С

Interactions of copper(II) complexes which contain S-alkyl derivatives of thiosalicylic acid (alkyl = methyl, ethyl, propyl and butyl; aryl = benzyl), marked as 1–5, with guanosine-5′-monophosphate (5′-GMP) and calf thymus DNA (CT-DNA) were studied. Kinetics of substitution reactions of 1–5 with 5′-GMP and CT-DNA were investigated under pseudo-first-order conditions at 310 K and pH = 7.2 in 25 mM Hepes buffer using stopped-flow method. All complexes have high affinity toward studied bio-molecules. Additionally, interactions with CT-DNA were followed by absorption spectroscopy and fluorescence quenching measurements. The results indicate that complexes bind to DNA exhibiting high binding constants (Kb = 104 M−1). During the examination of competitive reactions with ethidium bromide (EB), results showed that complexes can replace EB-bound DNA. In addition, a new crystal structure of the binuclear Cu(II) complex with S-substituted thiosalicylate derivative has been reported. In the present series of Cu(II) complexes the crystal structure is the first example of a complex comprising an S-aryl derivative of thiosalicylate ligand. Through comparative study of structural properties of six molecules from four crystal structures we examined the structural variations, potentially important for biological activity of these complexes. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.

Interactions of copper(II) complexes which contain S-alkyl derivatives of thiosalicylic acid (alkyl = methyl, ethyl, propyl and butyl; aryl = benzyl), marked as 1–5, with guanosine-5′-monophosphate (5′-GMP) and calf thymus DNA (CT-DNA) were studied. Kinetics of substitution reactions of 1–5 with 5′-GMP and CT-DNA were investigated under pseudo-first-order conditions at 310 K and pH = 7.2 in 25 mM Hepes buffer using stopped-flow method. All complexes have high affinity toward studied bio-molecules. Additionally, interactions with CT-DNA were followed by absorption spectroscopy and fluorescence quenching measurements. The results indicate that complexes bind to DNA exhibiting high binding constants (Kb = 104 M−1). During the examination of competitive reactions with ethidium bromide (EB), results showed that complexes can replace EB-bound DNA. In addition, a new crystal structure of the binuclear Cu(II) complex with S-substituted thiosalicylate derivative has been reported. In the present series of Cu(II) complexes the crystal structure is the first example of a complex comprising an S-aryl derivative of thiosalicylate ligand. Through comparative study of structural properties of six molecules from four crystal structures we examined the structural variations, potentially important for biological activity of these complexes. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.

The biological activities of two binuclear copper(II) complexes containing S-alkenyl derivatives of thiosalicylic acid are reported [alkenyl = propenyl (L1), isobutenyl (L2)]. The structure of the complex with the S-isobutenyl derivative (C2) was confirmed by single-crystal X-ray structure analysis, which revealed that the structure consists of centrosymmetric, dinuclear complex molecules [Cu-2(S-i-butenyl-thiosal)(4)(DMSO)(2)] containing two Cu(II) centers bridged by four S-isobutyl-thiosalicylate ligands in a paddle-wheel type structure. The Cu(II) atom is situated in a distorted square-pyramidal environment formed by carboxylate oxygen atoms in the basal plane and a DMSO ligand in the axial position. The reactivities of the complexes toward guanosine-5-monophosphate (5-GMP) were investigated. Complex C2 ([Cu-2(S-i-butenyl-thiosal)(4)(H2O)(2)]) reacted more rapidly with 5-GMP than complex C1. The interactions of complexes C1 and C2 with calf thymus DNA (CT-DNA) were examined by absorption (UV-Vis) and emission spectral studies (ethidium bromide displacement studies), revealing good DNA interaction abilities. The antimicrobial activities of the free ligands and their complexes were tested by microdilution method, and both minimal inhibitory and microbicidal concentrations were determined. All the tested substances demonstrated selective and moderate antibacterial activity on gram-positive bacteria, but low antibacterial activity on gram-negative bacteria. Also, the tested substances demonstrated low antifungal activity.

The biological activities of two binuclear copper(II) complexes containing S-alkenyl derivatives of thiosalicylic acid are reported [alkenyl = propenyl (L1), isobutenyl (L2)]. The structure of the complex with the S-isobutenyl derivative (C2) was confirmed by single-crystal X-ray structure analysis, which revealed that the structure consists of centrosymmetric, dinuclear complex molecules [Cu-2(S-i-butenyl-thiosal)(4)(DMSO)(2)] containing two Cu(II) centers bridged by four S-isobutyl-thiosalicylate ligands in a paddle-wheel type structure. The Cu(II) atom is situated in a distorted square-pyramidal environment formed by carboxylate oxygen atoms in the basal plane and a DMSO ligand in the axial position. The reactivities of the complexes toward guanosine-5-monophosphate (5-GMP) were investigated. Complex C2 ([Cu-2(S-i-butenyl-thiosal)(4)(H2O)(2)]) reacted more rapidly with 5-GMP than complex C1. The interactions of complexes C1 and C2 with calf thymus DNA (CT-DNA) were examined by absorption (UV-Vis) and emission spectral studies (ethidium bromide displacement studies), revealing good DNA interaction abilities. The antimicrobial activities of the free ligands and their complexes were tested by microdilution method, and both minimal inhibitory and microbicidal concentrations were determined. All the tested substances demonstrated selective and moderate antibacterial activity on gram-positive bacteria, but low antibacterial activity on gram-negative bacteria. Also, the tested substances demonstrated low antifungal activity.

The spectroscopically predicted structure of the obtained copper(II)-complex with S-propyl derivative of thiosalicylic acid was confirmed by X-ray structural study. The binuclear copper(II)-complex with S-propyl derivative of thiosalicylic acid crystallized in two polymorphic forms with main structural difference in the orientation of phenyl rings relative to corresponding carboxylate groups. The antibacterial activity was tested determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) by using microdilution method. The influence on bacterial biofilm formation was determined by tissue culture plate method. In general, the copper(II)-complexes manifested a selective and moderate activity. The most sensitive bacteria to the effects of Cu(II)-complexes was a clinical isolate of Pseudomonas aeruginosa. For this bacteria MIC and biofilm inhibitory concentration (BIC) values for all tested complexes were in the range or better than the positive control, doxycycline. Also, for the established biofilm of clinical isolate Staphylococcus aureus, BIC values for the copper(II)-complex with S-ethyl derivative of thiosalicylic acid, [Cu-2(S-et-thiosal)(4)(H2O)(2)] (C3) and copper(II)-complex with S-butyl derivative of thiosalicylic acid, [Cu-2(S-bu-thiosal)(4)(H2O)(2)] (C5) were in range or better than the positive control. All the complexes acted better against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus aureus ATCC 25923) than Gram-negative bacteria (Proteus mirabilis ATCC 12453, Pseudomonas aeruginosa, and P. aeruginosa. ATCC 27855). The complexes showed weak antioxidative properties tested by two methods (1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing power assay). (C) 2016 Elsevier B.V. All rights reserved.

The spectroscopically predicted structure of the obtained copper(II)-complex with S-propyl derivative of thiosalicylic acid was confirmed by X-ray structural study. The binuclear copper(II)-complex with S-propyl derivative of thiosalicylic acid crystallized in two polymorphic forms with main structural difference in the orientation of phenyl rings relative to corresponding carboxylate groups. The antibacterial activity was tested determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) by using microdilution method. The influence on bacterial biofilm formation was determined by tissue culture plate method. In general, the copper(II)-complexes manifested a selective and moderate activity. The most sensitive bacteria to the effects of Cu(II)-complexes was a clinical isolate of Pseudomonas aeruginosa. For this bacteria MIC and biofilm inhibitory concentration (BIC) values for all tested complexes were in the range or better than the positive control, doxycycline. Also, for the established biofilm of clinical isolate Staphylococcus aureus, BIC values for the copper(II)-complex with S-ethyl derivative of thiosalicylic acid, [Cu-2(S-et-thiosal)(4)(H2O)(2)] (C3) and copper(II)-complex with S-butyl derivative of thiosalicylic acid, [Cu-2(S-bu-thiosal)(4)(H2O)(2)] (C5) were in range or better than the positive control. All the complexes acted better against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus aureus ATCC 25923) than Gram-negative bacteria (Proteus mirabilis ATCC 12453, Pseudomonas aeruginosa, and P. aeruginosa. ATCC 27855). The complexes showed weak antioxidative properties tested by two methods (1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing power assay). (C) 2016 Elsevier B.V. All rights reserved.