Synthesis, characterization, DNA binding and cleavage, BSA interaction and anticancer activity of dinuclear zinc complexes

Abstract

Three new zinc(II) complexes: [Zn(2)(L(1))(2)Cl(2)](ClO(4))(2)·C(2)H(5)OH (1) and [ZnL(2)X(4)]·2CH(3)CN (X = Br for 2, Cl for 3), utilizing two new and interrelated di-nucleating polypyridyl ligands (L(1), L(2)), have been synthesized and characterized by using various physico-chemical techniques. The interactions of three complexes with CT-DNA have been explored by using absorption, emission and CD spectral methods, which reveal that three complexes bind to CT-DNA by partial intercalation binding modes. Notably, in the presence of H(2)O(2) as a revulsant or an activator, the cleavage abilities of all complexes are obviously enhanced. The hydrolytic mechanism was demonstrated by adding standard radical scavengers and anaerobic reaction. Further, the protein binding ability has been monitored by quenching of tryptophan emission in the presence of complexes using BSA as a model protein. The quenching mechanisms of BSA by the complexes are static procedures. In addition, the in vitro cytotoxicity of the complexes on three human tumor cells lines (HeLa, MCF-7 and RL952) and the apoptosis-inducing activity of were assessed by MTT, Clonogenic assay, Hoechst 33342 staining, Cell cycle and Annexin V binding experiments.

Alpha-lipoic acid-loaded nanostructured lipid carrier: sustained release and biocompatibility to HaCaT cellsin vitro

“…Afterwards ALA-NLC were respectively added to the treated group, which were incubated for a further 48 h. After the incubation the culture medium was removed and the cells were rinsed thoroughly with phosphate buffered saline (PBS) and then exposed to Hoechst 33342 for 20 min at 37 C in the dark. The cells were then observed and photographed with the assistance of a fluorescence microscope (Nikon, Tokyo, Japan) after a final wash with PBS (Gao et al, 2012;Tabata et al, 2012;Wang et al, 2012c). To obtain sufficient cells information for the assessment, five randomly selected areas per well were photographed.…”

New anticancer zinc(II) complexes comprising thiosemicarbazones of saturated ring: structure, DNA/protein binding, DNA cleavage, topoisomerase‐1 inhibition and anti‐proliferation studies

“…Since serum albumin constitutes ca 55% of the total protein in blood plasma and plays an indispensable role in drug distribution and absorption, it is essential to study the interaction these zinc(II) complexes with serum albumin. The investigation was carried out using a tryptophan fluorescence quenching assay with BSA as the model protein.…”

“…In fact, many proven anticancer drugs are topoisomerase‐I inhibitors . Furthermore, zinc(II) complexes are known for their DNA‐binding, nuclease‐mimicking, cancer‐anti‐proliferating and apoptosis‐regulating activities …”

A novel Schiff base derived from the gabapentin drug and copper (II) complex: Synthesis, characterization, interaction with DNA/protein and cytotoxic activity

“…The obtained values of quenching constants (k q ), were 2.8 × 10 12 for the ligand and 3.9 × 10 12 for the Cu complex, respectively. However, the maximum scatter collision quenching constant, K q , for various quenchers with the biopolymer is 2 × 10 10 M − 1 s − 1 [77]. Thus, the rate constant calculated by the protein quenching procedure is 100-fold higher than K q of the scatter procedure.…”