Daniela R. Lachter

Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil

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Publications (3)7.53 Total impact

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    ABSTRACT: Quinolones are known for their antimicrobial and antitumor activities. Gold(III) compounds constitute an emerging class of biologically active substances, of special interest as potential anticancer agents. In this work three gold(III) complexes of the fluoroquinolones antimicrobial agents norfloxacin (NOR), levofloxacin (LEVO) and sparfloxacin (SPAR) were prepared and characterized with physicochemical and spectroscopic techniques. In these complexes, NOR, LEVO and SPAR act as bidentate neutral ligands bound to gold(III) through the nitrogen atoms of the piperazine ring, which is an unusual mode of coordination for this class of compounds. Two chloride ions occupy the remaining coordination sites. The cytotoxic activity of the fluoroquinolones and their gold(III) complexes was tested against the A20 (murine lymphoma), B16-F10 (murine melanoma) and K562 (human myeloid leukemia) tumor cell lines as well as the L919 (murine lung fibroblasts) and MCR-5 (human lung fibroblasts) normal cells lines. All complexes were more active than their corresponding free ligands. Complex [AuCl(2)(LEVO)]Cl was selected for DNA fragmentation and cell cycle analysis. Spectroscopic titration with calf-thymus DNA (CT DNA) showed that the complexes can bind weakly to CT DNA, probably by an external contact (electrostatic or groove binding). The complexes exhibit good binding propensity to bovine serum albumin (BSA) having relatively high binding constant values.
    European Journal of Medicinal Chemistry 07/2012; 55:67-73. DOI:10.1016/j.ejmech.2012.07.004 · 3.43 Impact Factor
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    ABSTRACT: [MnCl2(NOR)(H2O)2] (1), [MnCl2(SPAR)(H2O)2] (2), [CoCl2(NOR)(H2O)2] (3) [CoCl2(SPAR)(H2O)2] (4), [CuCl2(phen)(NOR)] (5) and [CuCl2(phen)(SPAR)] (6) complexes with norfloxacin (NOR) and sparfloxacin (SPAR) were obtained from MnCl2·4H2O, CoCl2·4H2O and CuCl2(phen). In all cases the NOR and SPAR coordinate in the neutral zwitterionic form. The electron paramagnetic resonance spectra of the Cu(II) complexes (5) and (6) in aqueous and DMSO solutions indicate mixture of mononuclear and binuclear complex. Complexes (1–6), together with the corresponding ligands were evaluated for their in vitro trypanocidal effect, against both bloodstream trypomastigotes and intracellular forms of Trypanosoma cruzi. SPAR and NOR were poorly effective upon T. cruzi, complexes (3) and (4) were active against intracellular forms of the parasite. The complexes (5) and (6) displayed a higher activity upon both bloodstream and intracellular forms. The potency of fluoroquinolones, specially those coordinated to Cu(II)–phen justify further trypanocidal screening assays with this compounds in vitro as well as upon experimental models of T. cruzi infection.Graphical abstractActivity of SPAR, NOR, Mn-SPAR, Co-SPAR, Mn-NOR, Co-NOR, Cu-phen-SPAR and Cu-phen-NOR, CuCl2 upon bloodstream and intracellular forms of T. cruzi in vitro.Highlights► Microanalyses suggest the formation of compounds. ► The molar conductivity data indicate that all complexes are non electrolytes. ► The potency of fluoroquinolones justifies trypanocidal screening.
    Polyhedron 06/2011; 30(10):1718-1725. DOI:10.1016/j.poly.2011.04.001 · 2.05 Impact Factor
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    ABSTRACT: Thiosemicarbazones are known to be active against different pathogenic microorganisms including Trypanosoma cruzi, the etiological agent of Chagas disease. In the search for new therapeutic drugs against this illness, the complexes [Mn(H4NO2Fo4M)2Cl2] (1), [Mn(H4NO2Ac4M)2Cl2] (2) and [Mn(H4NO2Bz4M)2Cl2] (3) of N4-methyl-4-nitrobenzaldehyde thiosemicarbazone (H4NO2Fo4M), N4-methyl-4-nitroacetophenone thiosemicarbazone (H4NO2Ac4M) and N4-methyl-4-nitrobenzophenone thiosemicarbazone (H4NO2Bz4M) were obtained and screened in vitro against bloodstream and intracellular forms of T. cruzi. H4NO2Fo4M, H4NO2Ac4M and their Mn(II) complexes displayed poor effect on bloodstream trypomastigotes, with IC50 values ranging from 68 to >200μM. However, although H4NO2Bz4M was also not active, its corresponding Mn(II) complex presented high effect on this T. cruzi form, with an IC50 value of 19μM. The effect of complex (3), against trypomastigotes of T. cruzi supports further in vitro as well as in vivo studies.
    Polyhedron 07/2010; 29(10):2232-2238. DOI:10.1016/j.poly.2010.04.023 · 2.05 Impact Factor