Triazenos e complexos triazenidos de ouro(I) e cobre(II): atividade antileucêmica e antibacteriana in vitro

Abstract

Cancer represents one of the leading causes of death worldwide and efforts to discover more effective anticancer therapies have led to the synthesis of a wide diversity of molecular species. Furthermore, the increase of the bacterial resistance has motivated the screening of new antimicrobial agents. Notably, triazenes are a class of compounds with great pharmacological versatility, presenting considerable antitumor and antibacterial activities. Similarly, complexes of gold(I) and copper(II) have been widely targeted as potential therapeutic agents due to the promising results found in several research studies. Thereby, in this work we describe the in vitro antileukemic and antibacterial activity of the 1-(4-amidophenyl)-3-(4-acetylphenyl)triazene and related complex [1-(4-amidophenyl)-3-(4-acetylphenyl)triazenido-N3](triphenylfosphine-P)gold(I) as well as of 1,2,3-benzotriazin-4(3H)-one and three related triazenide complexes of copper(II). The antiproliferative effects on bone marrow cells of the patients with hematological malignancies and of the patients without cancer were evaluated using the bioassay of the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide - MTT). Mononuclear cells were incubated with different concentrations of compounds (100 50 12.5 μmol mL-1) during 24 h. Antibacterial activity against Gram-positive and Gram-negative bacteria by the microdilution technique in Mueller Hinton broth was also evaluated. The results revealed that the sensitivity of tumor cells to the complexes was higher than to the free ligands. The best results in terms of in vitro antileukemic activity were achieved with copper(II) complexes, and, among them, the compound named Bis{[1,2,3-benzotriazenide-4-one)-N3](phenanthroline-N1,N10)(μ2-[1,2,3-benzotriazenide-4-one]-N2, N3)}copper(II) was found to be the most efficient. Moreover, this compound had a remarkable activity against Gram-positive and Gram-negative bacteria. The complex [1-(4-amidophenyl)-3-(4-acetylphenyl)triazenido-N3](triphenylfosphine-P)gold(I) exhibited expressive antiproliferative effects, especially on cells from patient with myelodysplastic syndrome (IC50 = 7.72 μmol mL-1). In particular, its cytotoxic activity was significantly higher against tumor cells than against normal cells. In addition, this compound showed pronounced activity against Staphylococcus epidermidis ATCC 12228, Enterococcus faecalis ATCC 29212 and E. faecalis ATCC 51288 (MIC = 8 μg mL-1). Thus, these results suggest that both triazenide complex including the [(triphenylphosphine)gold(I)]-fragment as the triazenide complex of copper(II) with 1,10-phenanthroline provide a strategy for the architecture of new anticancer drugs and antibacterial agents.