22 research outputs found

    Mononuclear gold(iii) complexes with l-histidine-containing dipeptides: tuning the structural and biological properties by variation of the N-terminal amino acid and counter anion

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    Gold(III) complexes with different L-histidine-containing dipeptides, [Au(Gly-L-His-N-A,N-P,N3)Cl]Cl center dot 3H(2)O (1a), [Au(Gly-L-His-N-A,N-P,N-3)Cl]NO3 center dot 1.25H(2)O (1b), [Au(L-Ala-L-His-N-A,N-P,N-3)Cl][AuCl4]center dot H2O (2a), [Au(L-Ala-L-His-N-A,N-P,N-3)Cl]NO3 center dot 2.5H(2)O (2b), [Au(L-Val-L-His-N-A,N-P,N-3)Cl]Cl center dot 2H(2)O (3), [Au(L-Leu-L-His-N-A,N-P,N-3)Cl]Cl (4a) and [Au(L-Leu-L-His-N-A,N-P,N-3)Cl][AuCl4]center dot H2O (4b), have been synthesized and structurally characterized by spectroscopic (1H NMR, IR and UV-vis) and single-crystal X-ray diffraction techniques. The antimicrobial efficiency of these gold(III) complexes, along with K[AuCl4] and the corresponding dipeptides, was evaluated against the broad panel of Gram-positive and Gram-negative bacteria and fungi, displaying their moderate inhibiting activity. Moreover, the cytotoxic properties of the investigated complexes were assessed against the normal human lung fibroblast cell line (MRC5) and two human cancer, cervix (HeLa) and lung (A549) cell lines. None of the complexes exerted significant cytotoxic activity; nevertheless complexes that did show selectivity in terms of cancer vs. normal cell lines (2a/b and 4a/b) have been evaluated using zebrafish (Danio rerio) embryos for toxicity and antiangiogenic potential. Although the gold(III) complexes achieved an antiangiogenic effect comparable to the known angiogenic inhibitors auranofin and sunitinib malate at 30-fold higher concentrations, they had no cardiovascular side effects, which commonly accompany auranofin and sunitinib malate treatment. Finally, binding of the gold(III) complexes to the active sites of both human and bacterial (Escherichia coli) thioredoxin reductases (TrxRs) was demonstrated by conducting a molecular docking study, suggesting that the mechanism of biological action of these complexes can be associated with their interaction with the TrxR active site.This is the peer-reviewed version of the following article: Warzajtis, B.; Glišić, B. D.; Savić, N. D.; Pavic, A.; Vojnovic, S.; Veselinović, A.; Nikodinovic-Runic, J.; Rychlewska, U.; Djuran, M. I. Mononuclear Gold(Iii) Complexes with l-Histidine-Containing Dipeptides: Tuning the Structural and Biological Properties by Variation of the N-Terminal Amino Acid and Counter Anion. Dalton Transactions 2017, 46 (8), 2594–2608. [https://doi.org/10.1039/c6dt04862e]Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3108

    Indole Derivatives Bearing Imidazole, Benzothiazole-2-Thione or Benzoxazole-2-Thione Moieties—Synthesis, Structure and Evaluation of Their Cytoprotective, Antioxidant, Antibacterial and Fungicidal Activities

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    In the search for new bioactive compounds, a methodology based on combining two molecules with biological properties into a new hybrid molecule was used to design and synthesize of a series of ten indole derivatives bearing imidazole, benzothiazole-2-thione, or benzoxazole-2-thione moieties at the C-3 position. The compounds were spectroscopically characterized and tested for their antioxidant, antibacterial, and fungicidal activities. The crystal structures were determined for five of them. Comparison of the closely related structures containing either benzothiazole-2-thione or benzoxazole-2-thione clearly shows that the replacement of -S- and -O- ring atoms modify molecular conformation in the crystal, changes intermolecular interactions, and has a severe impact on biological activity. The results indicate that indole-imidazole derivatives with alkyl substituent exhibit an excellent cytoprotective effect against AAPH-induced oxidative hemolysis and act as effective ferrous ion chelating agents. The indole-imidazole compound with chlorine atoms inhibited the growth of fungal strains: Coriolus versicolor (Cv), Poria placenta (Pp), Coniophora puteana (Cp), and Gloeophyllum trabeum (Gt). The indole-imidazole derivatives showed the highest antibacterial activity, for which the largest growth-inhibition zones were noted in M. luteus and P. fluorescens cultures. The obtained results may be helpful in the development of selective indole derivatives as effective antioxidants and/or antimicrobial agents

    Crystal engineering of analogous and homologous organic compounds: hydrogen bonding patterns in trimethoprim hydrogen phthalate and trimethoprim hydrogen adipate

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    BACKGROUND: Trimethoprim [2,4-diamino-5-(3',4',5'-trimethoxybenzyl)pyrimidine] is an antifolate drug. It selectively inhibits the bacterial dihydrofolate reductase (DHFR) enzyme. RESULTS: In the crystal structures of trimethoprim (TMP)-hydrogen phthalate (1) and trimethoprim-hydrogen adipate (2), one of the N atoms of the pyrimidine ring is protonated and it interacts with the deprotonated carboxylate oxygens through a pair of nearly parallel N-H...O hydrogen bonds to form a fork-like interaction. In the compound 1, the pyrimidine moieties of the TMP cations are centrosymmetrically paired through a pair of N-H...N hydrogen bonds involving 4-amino group and the N (N3) atom of the pyrimidine rings to form a 8-membered hydrogen bonded ring [R(2)(2)(8)]. The 4-amino group of one TMP moiety and 2-amino group of another TMP moiety (both moieties are members of a base pair) are bridged by the carbonyl oxygen of the phthalate moiety through N-H...O hydrogen bonds forming 8-membered hydrogen-bonded ring [R(2)(2)(8)]. The characteristic hydrogen-bonded rings observed in the structure aggregate into a supramolecular ladder consisting of a pair of chains, each of which is built up of alternate TMP and hydrogen phthalate ions. In the compound 2, two TMP cations and two hydrogen adipate anions are arranged about an inversion center so that the complementary DDAA (D = donor, A = acceptor) arrays of quadruple hydrogen-bonding patterns are formed. The head-to-tail arrangement of the hydrogen adipate ions leads to a hydrogen-bonded supramolecular chain. From crystal engineering point of view, it is interesting to note that the compound 1 has a hydrogen-bonded network remarkably identical with its aliphatic analogue, trimethoprim hydrogen maleate. Similarly the compound 2, resembles its homolog trimethoprim hydrogen glutarate. CONCLUSION: In the crystal structure of trimethoprim hydrogen phthalate, the hydrogen-bonded network is remarkably identical with its aliphatic analogue, trimethoprim hydrogen maleate. Similarly in the crystal structure of trimethoprim hydrogen adipate the hydrogen bonded network resembles its homolog trimethoprim hydrogen glutarate

    Mononuclear gold(iii) complexes with diazanaphthalenes: The influence of the position of nitrogen atoms in the aromatic rings on the complex crystalline properties

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    © 2020 The Royal Society of Chemistry. A series of mononuclear gold(iii) complexes of the general formula [AuCl3(diazanaphthalene)], where diazanaphthalene is quinazoline (qz, 1), phthalazine (phtz, 2), 1,5-naphthyridine (1,5-naph, 3), 1,6-naphthyridine (1,6-naph, 4) or 1,8-naphthyridine (1,8-naph, 5), were prepared and fully characterized. The complexes 1-5 consist of discrete monomeric species with the Au(iii) cation in a square planar coordination geometry surrounded by three chloride anions and one diazanaphthalene ligand. Crystallographic studies indicate the presence of an extended 4 + 1 or 4 + 2 geometry around the square planar [AuCl3(diazanaphthalene)] center due to Au⋯Cl and Au⋯N interactions. The crystal structures of these complexes are controlled by a variety of intermolecular interactions that utilize the amphiphilic properties of the coordinated chloride anions and involve C-H groups, π-electrons, and an uncoordinated nitrogen atom of the diazanaphthalene ligand. The usual offset π-stacking between the N-heteroaromatic ligands appears to be completely hindered between the 1,5-naph fragments and significantly weakened between the 1,6-naph and 1,8-naph in their respective complexes 3, 4 and 5, for which the average molecular polarizability (α) values are the lowest in the series. It is remarkable that the [AuCl3(benzodiazine)] complexes 1 and 2 form centrosymmetric crystals, but the [AuCl3(naphthyridine)] complexes 3-5 assemble into non-centrosymmetric aggregates, making them potential alternatives to the previously studied systems for application in various fields by taking advantage of their polarity

    Hydrolysis of Methionine- and Histidine-Containing Peptides Promoted by Dinuclear Platinum(II) Complexes with Benzodiazines as Bridging Ligands: Influence of Ligand Structure on the Catalytic Ability of Platinum(II) Complexes

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    Dinuclear platinum(II) complexes, [{Pt(en)Cl}2(μ-qx)]Cl2·2H2O (1), [{Pt(en)Cl}2(μ-qz)](ClO4)2 (2), and [{Pt(en)Cl}2(μ-phtz)]Cl2·4H2O (3), were synthesized and characterized by different spectroscopic techniques. The crystal structure of 1 was determined by single-crystal X-ray diffraction analysis, while the DFT M06-2X method was applied in order to optimize the structures of 1–3. The chlorido Pt(II) complexes 1–3 were converted into the corresponding aqua species 1a–3a, and their reactions with an equimolar amount of Ac–L–Met–Gly and Ac–L–His–Gly dipeptides were studied by 1H NMR spectroscopy in the pH range 2.0 < pH < 2.5 at 37°C. It was found that, in all investigated reactions with the Ac–L–Met–Gly dipeptide, the cleavage of the Met–Gly amide bond had occurred, but complexes 2a and 3a showed lower catalytic activity than 1a. However, in the reactions with Ac–L–His–Gly dipeptide, the hydrolysis of the amide bond involving the carboxylic group of histidine was observed only with complex 1a. The observed disparity in the catalytic activity of these complexes is thought to be due to different relative positioning of nitrogen atoms in the bridging qx, qz, and phtz ligands and consequent variation in the intramolecular separation of the two platinum(II) metal centers
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