ESR, electrochemical and reactivity studies of antitrypanosomal palladium thiosemicarbazone complexes

Cyclic voltammetry (CV) and electron spin resonance (ESR) techniques were used in the investigation of novel palladium complexes with bioactive thiosemicarbazones derived from 5-nitrofurane or 5-nitrofurylacroleine. Sixteen palladium complexes grouped in two series of the formula [PdCl2HL] or [PdL2] were studied. ESR spectra of the free radicals obtained by electrolytic reduction were characterized and analyzed. The ESR spectra showed two different hyperfine patterns. The stoichiometry of the complexes does not seem to affect significantly the hyperfine constants however we observed great differences between 5-nitrofurane and 5-nitrofurylacroleine derivatives. The scavenger properties of this family of compounds were lower than Trolox.This research was supported by FONDECYT 1071068 grant (Chile), CSIC and PDT 10002-04 (Uruguay) and TWAS 04-205 RG/CHE/LA grant

Platinum-based complexes of bioactive 3-(5-nitrofuryl)acroleine thiosemicarbazones showing anti-Trypanosoma cruzi activity

Eight new platinum(II) complexes with 3-(5-nitrofuryl)acroleine thiosemicarbazones showing anti-trypanosomal activity were synthesized, characterized and in vitro evaluated. Most of the complexes showed IC50 values in the micromolar range against two different strains of Trypanosoma cruzi, causative agent of Chagas disease (American Trypanosomiasis). In addition, most of the newly developed complexes, together with the analogous platinum 5-nitrofuraldehyde containing thiosemicarbazones previously reported, resulted more active than the reference trypanocidal drug nifurtimox on the infective trypomastigote form of the parasite. Their capacity to produce free radicals that could lead to parasite death was evaluated by ESR experiments in the parasite and by respiration measurements. Compounds were tested for their DNA interaction ability. Results showed that some of the compounds could act as dual inhibitors in the parasite, through production of toxic free radicals and interaction with

Effect of the metal ion on the anti T. cruzi activity and mechanism of action of 5-nitrofuryl-containing thiosemicarbazone metal complexes

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major health problem worldwide. In this work, we report the development of palladium and platinum metal complexes with 5-nitrofuryl-containing thiosemicarbazones (L) as bioactive ligands against T. cruzi and PTA (1,3,5-triaza-7-phosphaadamantane) as co-ligand. Eight new complexes of the formula [MCl(L)(PTA)] with M = Pd or Pt were synthesized and fully characterized. Most complexes showed similar activities against T. cruzi to those of the corresponding free thiosemicarbazone ligands. No significant differences between palladium and platinum complexes were observed. Metal compounds with the phenylthiosemicarbazone derivative were the most active ones (IC50 = 9.84 +/- 0.32 and 4.94 +/- 0.24 mu M for Pd2+ and Pt2+, respectively). The prepared complexes were not toxic on mammalian cells, showing selective indexes of more than 10-20. The ability of the complexes to be reduced in the parasite, which leads to toxic free radical species, was confirmed by the detection of OH center dot and nitroanion free radical species by ESR spectroscopy experiments. Gel electrophoresis and fluorescence experiments were consistent with an intercalating-like mode of DNA interaction for the complexes, but DNA interaction does not seem to be the main mechanism of anti T. cruzi action for these compounds. The results obtained show that complexation of the bioactive ligands with the selected metals is a valid strategy to obtain improved metal-based antiparasitic compounds

A new ruthenium cyclopentadienyl azole compound with activity on tumor cell lines and trypanosomatid parasites

<div><p>As part of our efforts to develop organometallic ruthenium compounds bearing activity on both trypanosomatid parasites and tumor cells, a new Ru(II)–cyclopentadienyl clotrimazole complex, [RuCp(PPh₃)₂(CTZ)](CF₃SO₃), where Cp = cyclopentadienyl, CTZ = clotrimazole, was synthesized and characterized. The compound was evaluated <i>in vitro</i> on <i>T. cruzi</i> (Y strain), the infective form of <i>T. brucei brucei</i> strain 427 (cell line 449), on three human tumor cell lines with different sensitivity to cisplatin (A2780, ovary; MCF7, breast; HeLa, cervix) and on J774 murine macrophages as mammalian cell model. The new compound is more cytotoxic on <i>T. cruzi</i> and on the tumor cell lines than the reference drugs (Nifurtimox and cisplatin, respectively). In addition, complexation of the bioactive CTZ to the {RuCp(PPh₃)} moiety leads to significant increase of the antiparasitic and antitumoral activity. To get insight into the potential “dual” mechanism of antiparasitic action emerging from the presence of Ru(II) and CTZ in a single molecule, the inhibitory effect of this new complex on the biosynthesis of <i>T. cruzi</i> sterols of membrane and the interaction with DNA were studied. Although the tested complex does not affect DNA, it affects the <i>T. cruzi</i> biosynthetic pathway of conversion of squalene to squalene oxide. According to the results reported here, [RuCp(PPh₃)₂(CTZ)][CF₃SO₃] could be considered a prospective antiparasitic and/or antitumoral agent that deserves further evaluation.</p></div

Gu?a r?pidas de consultor?a telef?nica m?dica y de enfermer?a

Gu?a de consulta para o persoal m?dico e de enfermar?a que desenvolve o seu traballo en centros de coordinaci?n telef?nica para a atenci?n ?s urxencias e ?s emerxencias sanitarias. Est? estruturada en 12 cap?tulos nos que describen os principais protocolos de actuaci?n para a asistencia ?s patolox?as m?is com?ns atendidas no ?mbito de urxencias extra hospitalarias.Gu?a de consulta para el personal m?dico y de enfermer?a que desarrolla su trabajo en centros de coordinaci?n telef?nica para la atenci?n a las urgencias y a las emergencias sanitarias. Est? estructurada en 12 cap?tulos en los que describen los principales protocolos de actuaci?n para la asistencia a las patolog?as m?s comunes atendidas en el ?mbito de urgencias extra hospitalarias