Navegando por Autor "Bloch Junior, Carlos"
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Item Polypyridyl ruthenium complexes : novel DNA-intercalating agents against human breast tumor.(2017) Reis, João Paulo Barolli; Correa, Rodrigo de Souza; Miranda, Fabio da Silva; Ribeiro, Juliana Uema; Bloch Junior, Carlos; Ellena, Javier Alcides; Moreno, Virtudes; Cominetti, Márcia Regina; Batista, Alzir AzevedoThis paper describes a new series of four DNA-intercalating agents with promising anticancer activities, based on ruthenium(II) with the planar ligand dpqQX (dpqQX = dipyrido[3,2-a:2',3'-c]quinoxaline[2,3-b]quinoxaline). The complexes identified as trans-[RuCl2(dppb)(dpqQX)], cis-[RuCl2(dppb)(dpqQX)], ct-[RuCl(CO)(dppb)(dpqQX)]PF6 and ct-[RuCl2(PPh3)2(dpqQX)] (dppb = 1,4-bis(diphenylphosphine)butane and PPh3 = triphenylphosphine) were characterized by 31P{1H} nuclear magnetic resonance (NMR) and infrared spectroscopies, cyclic voltammetry, molar conductance measurements, elemental analysis, mass spectrometry and X-ray diffraction analysis for complex ct-[RuCl2(PPh3)2(dpqQX)]. Their in vitro cytotoxic activities against MDA-MB-213 and MCF-7 breast cancer cells were evaluated and compared with normal L-929 cells. Low drug concentration at which 50% of the cells are viable relative to the control (IC50) values were obtained for all four complexes compared with a reference metallodrug, cisplatin. In addition, DNA affinity studies from titrations, as well as the images obtained by atomic force microscopy (AFM) involving pBR322 plasmid DNA, suggest interactions between the metal complexes and the DNA macromolecule, in which they act as intercalating agents. The intercalation of the complexes with DNA was confirmed by viscosity measurements.Item Ruthenium(II) complexes of 1,3-thiazolidine-2-thione : cytotoxicity against tumor cells and anti-Trypanosoma cruzi activity enhanced upon combination with benznidazole(2016) Correa, Rodrigo de Souza; Silva, Monize Martins da; Graminha, Angelica Ellen; Meira, Cássio Santana; Santos, Jamyle Andrade Ferreira dos; Moreira, Diogo Rodrigo de Magalhães; Soares, Milena Botelho Pereira; Poelhsitz, Gustavo Von; Castellano, Eduardo Ernesto; Bloch Junior, Carlos; Cominetti, Márcia Regina; Batista, Alzir AzevedoThree newmixed and mononuclear Ru(II) complexes containing 1,3-thiazolidine-2-thione (tzdtH) were synthesized and characterized by spectroscopic analysis, molar conductivity, cyclic voltammetry, high-resolution electrospray ionization mass spectra and X-ray diffraction. The complexes presented unique stereochemistry and the proposed formulae are: [Ru(tzdt)(bipy)(dppb)]PF6 (1), cis-[Ru(tzdt)2(PPh3)2] (2) and trans- [Ru(tzdt)(PPh3)2(bipy)]PF6 (3), where dppb = 1,4-bis(diphenylphosphino)butane and bipy= 2,2′-bipyridine. These complexes demonstrated strong cytotoxicity against cancer cell lines when compared to cisplatin. Specifically, complex 2 was the most potent cytotoxic agent against MCF-7 breast cells, while complexes 1 and 3 were more active in DU-145 prostate cells. Binding of complexes to ctDNA was determined by UV–vis titration and viscosity measurements and revealed binding constant (Kb) values in range of 1.0–4.9 × 103 M−1, which are characteristic of compounds possessing weak affinity to ctDNA. In addition, these complexes presented antiparasitic activity against Trypanosoma cruzi. Specifically, complex 3 demonstrated strong potency, moderate selectivity index and acted in synergism with the approved antiparasitic drug, benznidazole. Additionally, complex 3 caused parasite cell death through a necrotic process. In conclusion, we demonstrated that Ru(II) complexes have powerful pharmacological activity, while the metal-free tzdtH does not provoke the same outcome.