RESUMO
The cobalt(II), copper(II) and zinc(II) complexes of 1,10-phenanthroline (phen) and maltol (mal) (complexes 1, 2, 3 respectively) were prepared from their respective metal(II) chlorides and were characterized by FT-IR, elemental analysis, UV spectroscopy, molar conductivity, p-nitrosodimethylaniline assay and mass spectrometry. The X-ray structure of a single crystal of the zinc(II) analogue reveals a square pyramidal structure with distinctly shorter apical chloride bond. All complexes were evaluated for their anticancer property on breast cancer cell lines MCF-7 and MDA-MB-231, and normal cell line MCF-10A, using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and morphological studies. Complex 2 was most potent for 24, 48 and 72 h treatment of cancer cells but it was not selective towards cancer over normal cells. The mechanistic studies of the cobalt(II) complex 1 involved apoptosis assay, cell cycle analysis, dichloro-dihydro-fluorescein diacetate assay, intracellular reactive oxygen species assay and proteasome inhibition assay. Complex 1 induced low apoptosis, generated low level of ROS and did not inhibit proteasome in normal cells. The study of the DNA binding and nucleolytic properties of complexes 1-3 in the absence or presence of H2O2 or sodium ascorbate revealed that only complex 1 was not nucleolytic.
Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Fenantrolinas/farmacologia , Pironas/farmacologia , Antineoplásicos/síntese química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Cobalto/química , Complexos de Coordenação/síntese química , Cobre/química , DNA/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Humanos , Fenantrolinas/síntese química , Inibidores de Proteassoma/síntese química , Inibidores de Proteassoma/farmacologia , Pironas/síntese química , Espécies Reativas de Oxigênio/metabolismo , Zinco/químicaRESUMO
This study reported on the feasibility and practicability of Cr(NO3)3 hydrolysis to isolate cellulose nanocrystals (CNCCr(NO3)3) from native cellulosic feedstock. The physicochemical properties of CNCCr(NO3)3 were compared with nanocellulose isolated using sulfuric acid hydrolysis (CNCH2SO4). In optimum hydrolysis conditions, 80 °C, 1.5 h, 0.8 M Cr(NO3)3 metal salt and solid-liquid ratio of 1:30, the CNCCr(NO3)3 exhibited a network-like long fibrous structure with the aspect ratio of 15.7, while the CNCH2SO4 showed rice-shape structure with an aspect ratio of 3.5. Additionally, Cr(NO3)3-treated CNC rendered a higher crystallinity (86.5% ± 0.3%) with high yield (83.6% ± 0.6%) as compared to the H2SO4-treated CNC (81.4% ± 0.1% and 54.7% ± 0.3%, respectively). Furthermore, better thermal stability of CNCCr(NO3)3 (344 °C) compared to CNCH2SO4 (273 °C) rendered a high potential for nanocomposite application. This comparable effectiveness of Cr(NO3)3 metal salt provides milder hydrolysis conditions for highly selective depolymerization of cellulosic fiber into value-added cellulose nanomaterial, or useful chemicals and fuels in the future.
