Publications by authors named "Gustavo Von Poelhsitz"

We describe the synthesis, physicochemical characterization, and antitumor assays of four novel analogous ruthenium(II) complexes with general formula -[Ru(N-L)(P-P)]PF, where P-P = bis(diphenylphosphine)methane (dppm, in complexes 1 and 2) or bis(diphenylphosphine)ethane (dppe, in complexes 3 and 4) and N-L = 5,6-diphenyl-4,5-dihydro-2-[1,2,4]triazine-3-thione (Btsc, in complexes 1 and 3) or 5,6-diphenyltriazine-3-one (Bsc, in complexes 2 and 4). The data were consistent with arrangement of the biphosphine ligands. For the Btsc and Bsc ligands, the data pointed to monoanionic bidentate coordination to ruthenium(II) through , and ,, respectively.

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Chikungunya fever is a disease caused by the Chikungunya virus (CHIKV) that is transmitted by the bite of the female of sp. mosquito. The symptoms include fever, muscle aches, skin rash, and severe joint pains.

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Ruthenium complexes have been extensively explored as potential molecules for cancer treatment. Considering our previous findings on the remarkable cytotoxic activity exhibited by the ruthenium (II) complex 3-hydroxy-4-methoxybenzoate (hmxbato)-cis-[Ru(ŋ-OCCHO)(dppm)]PF against Leishmania promastigotes and also the similar metabolic characteristics between trypanosomatids and tumor cells, the present study aimed to analyze the anticancer potential of hmxbato against lung tumor cells, as well as the partial death mechanisms involved. Hmxbato demonstrated selective cytotoxicity against A549 lung tumor cells.

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Some metallodrugs that exhibit interesting biological activity contain transition metals such as ruthenium, and have been extensively exploited because of their antiparasitic potential. In previous study, we reported the remarkable anti-Leishmania activity of precursor cis-[RuCl(dppm)], where dppm = bis(diphenylphosphino)methane, and new ruthenium(II) complexes, cis-[Ru(η-OCCH)(dppm)]PF (bbato), cis-[Ru(η-OCCHS)(dppm)]PF (mtbato) and cis-[Ru(η-OCCHO)(dppm)]PF (hmxbato) against some Leishmania species. In view of the promising activity of the hmxbato complex against Leishmania (Leishmania) amazonensis promastigotes, the present work investigated the possible parasite death mechanism involved in the action of this hmxbato and its precursor.

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This paper describes on the interaction studies of carbonyl heterobimetallic compounds of Ru(II)/Fe(II) containing polypyridyl ligands, with general formula ct-[RuCl(CO)(N-N)(dppf)]PF, N-N = 1,10-phenanthroline (phen) 5; dipyrido[3,2-f:2',3'-h]quinoxaline (dpq) 6; dipyrido[3,2-a:2',3'-c]phenazine (dppz) 7; dipyrido[3,2-f:2',3'-h]quinoxalino[2,3-b]quinoxaline (dpqQX) 8 and dppf = 1,1'-bis(diphenylphosphino) ferrocene], with calf thymus DNA (ct-DNA) and bovine serum albumin (BSA). Also, it describes the cellular viability assays of these complexes in tumorigenic and non-tumorigenic cell lines. The carbonyl complexes 5-8 and their respective precursors with formula cis-[RuCl(N-N)(dppf)], N-N = phen (1), dpq (2), dppz (3) and dpqQX (4), were characterized by elemental analysis and spectroscopic techniques (FTIR, UV-vis, H and P{H} NMR).

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Leishmaniasis, a neglected tropical disease caused by protozoans of the genus Leishmania, kills around 20-30 thousand people in Africa, Asia, and Latin America annually and, despite its potential lethality, it can be treated and eventually cured. However, the current treatments are limited owing to severe side effects and resistance development by some Leishmania. These factors make it urgent to develop new leishmanicidal drugs.

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The complexes -[Ru(quin)(dppm)]PF and -[Ru(kynu)(dppm)]PF (quin = quinaldate; kynu = kynurenate; dppm = (diphenylphosphino)methane) were prepared and characterized by elemental analysis, electronic, FTIR, H, and P{H} NMR spectroscopies. Characterization data were consistent with a arrangement for the dppm ligands and a bidentate coordination through carboxylate oxygens of the quin and kynu anions. These complexes were not able to intercalate CT-DNA as shown by circular dichroism spectroscopy.

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Leishmaniasis is a parasitic disease caused by protozoa of the genus Leishmania. The many complications presented by the current treatment - including high toxicity, high cost and parasite resistance - make the development of new therapeutic agents indispensable. The present study aims to evaluate the anti-Leishmania potential of new ruthenium(II) complexes, cis‑[Ru(η-OCR)(dppm)]PF, with dppm=bis(diphenylphosphino)methane and R=4-butylbenzoate (bbato) 1, 4-(methylthio)benzoate (mtbato) 2 and 3-hydroxy-4-methoxybenzoate (hmxbato) 3, in promastigote cytotoxicity and their effect on parasite-host interaction.

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Three new mixed 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.

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This study describes the synthesis of a new ruthenium nitrosyl complex with the formula [RuCl(2)NO(BPA)] [BPA = (2-hydroxybenzyl)(2-methylpyridyl)amine ion], which was synthesized and characterized by spectroscopy, cyclic voltammetry, X-ray crystallography, and theoretical calculation data. The biological studies of this complex included in vitro cytotoxic assays, which revealed its activity against two different tumor cell lines (HeLa and Tm5), with efficacy comparable to that of cisplatin, a metal-based drug that is administered in clinical treatment. The in vivo studies showed that [RuCl(2)NO(BPA)]is effective in reducing tumor mass.

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The synthesis and characterization of ruthenium compounds of the type [RuCl(2)(NO)(dppp)(L)]PF(6) [dppp=1,3-bis(diphenylphosphino)propane; L=pyridine, 4-methylpyridine, 4-phenylpyridine and dimethyl sulfoxide] are described. The complexes were characterized by elemental analysis, UV/Vis and infrared spectroscopy, cyclic voltammetry, and X-ray crystallography for the complexes with the pyridine and 4-methylpyridine ligands. In vitro evaluation of these nitrosyl complexes revealed cytotoxic activity from 7.

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The synthesis, characterization and the anti-Mycobacterium tuberculosis (MTB) activities of three ruthenium complexes containing the 2-pyridinecarboxylic acid anion (picolinate), with formulae cis- [Ru(pic)(dppm)(2)]PF(6) (1), cis- [Ru(pic)(dppe)(2)]PF(6) (2) and [Ru(pic)(2)(PPh(3))(2)] (3) [pic=2-pyridinecarboxylate; dppm=bis(diphenylphosphino)methane; dppe=1,2-bis(diphenylphosphino)ethane; PPh(3)=triphenylphosphine] are reported in this article. The complexes were characterized by elemental analysis, spectroscopic and electrochemical techniques. Their in vitro antimycobacterial activity was determinated as the Minimum Inhibitory Concentration (MIC) for MTB cell growth, measured by the REMA method.

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Three novel polymetallic ruthenium (III) meso-tetra(4-pyridyl)porphyrins containing peripheral "RuCl(3)(dppb)" moieties have been prepared and characterized. The X-ray structure of the tetraruthenated {NiTPyP[RuCl(3)(dppb)](4)} porphyrin complex crystallizes in the triclinic space group P1. This structure is discussed and compared with the crystal data for the mer-[RuCl(3)(dppb)(py)].

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The reaction of cis-[RuCl(2)(dppb)(N-N)], dppb=1,4-bis(diphenylphosphino)butane, complexes with the ligand HSpymMe(2), 4,6-dimethyl-2-mercaptopyrimidine, yielded the cationic complexes [Ru(SpymMe(2))(dppb)(N-N)]PF(6), N-N=bipy (1) and Me-bipy (2), bipy=2,2'-bipyridine and Me-bipy=4,4'-dimethyl-2,2'-bipyridine, which were characterized by spectroscopic and electrochemical techniques and X-ray crystallography and elemental analysis. Additionally, preliminary in vitro tests for antimycobacterial activity against Mycobacterium tuberculosis H37Rv ATCC 27264 and antitumor activity against the MDA-MB-231 human breast tumor cell line were carried out on the new complexes and also on the precursors cis-[RuCl(2)(dppb)(N-N)], N-N=bipy (3) and Me-bipy (4) and the free ligands dppb, bipy, Me-bipy and SpymMe(2). The minimal inhibitory concentration (MIC) of compounds needed to kill 90% of mycobacterial cells and the IC(50) values for the antitumor activity were determined.

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Trans-[RuCl(NO)(dppe)2]2+ species were prepared. The complexes have been characterized by microanalysis, IR and 31P[1H] NMR spectroscopy and cyclic voltammetry. The trans-[RuCl(NO)(dppe)2](ClO4)2 complex shows a reversible one-electron-reduction process at E(1/2) = 0.

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