Synthesis, characterization and biological properties of cobalt(II) complexes of 1,10-phenanthroline and maltol

Coordination compounds of biogenic metals as cytotoxic agents in cancer therapy

The review summarizes the data on the structures and methods for the synthesis of compounds with anticancer activity based on biogenic metals, which can replace platinum drugs prevailing in cytotoxic therapy. The main focus is given to the comparison of the mechanisms of the cytotoxic action of these complexes, their efficacy and prospects of their use in clinical practice. This is the first systematic review of cytotoxic zinc, iron, cobalt and copper compounds. The structure – activity relationships and the mechanisms of antitumour action are formulated for each type of metal complexes.

The bibliography includes 181 references.

Synthesis, X-ray structure, antiproliferative activity, interaction with HSA and docking studies of three novel mono and binuclear copper complexes containing the maltol ligand

The present study aims at synthesizing three new copper(ii) complexes of maltol in the presence of 1,10-phenanthroline-, 2,2′-bipyridine- and 4,4-dibromo-2,2′-bipyridine ligands.

Solubilization and Thermodynamic Attributes of Nickel Phenanthroline Complex in Micellar Media of Sodium 2-Ethyl Hexyl Sulfate and Sodium Bis(2-ethyl hexyl) Sulfosuccinate

Micellar solubilization and physicochemical behaviour of [Ni(phen)3]F2 EtOH · MeOH · 8 H2O complex in sodium 2-ethylhexyl sulfate and sodium bis(2-ethyl hexyl) sulfosuccinate is addressed in this paper. The interactions of surfactants in the solution of nickel complex were studied by UV-Vis spectroscopy and electrical conductivity. The extent of solubilization in terms of partitioning and binding parameters was determined by UV-Vis spectroscopy, whereas conductivity data were employed to calculate critical micellar concentration and other thermodynamic parameters of micellization. The value of critical micellar concentration increased in both surfactants due to structure breaking effect of nickel complex. The complex showed significant antioxidant radical scavenging and hemolytic activities, without any substantial cytotoxic activity against 3T3 cell line.

Carbohydrate-based heteronuclear complexes as topoisomerase Iα inhibitor: approach toward anticancer chemotherapeutics

Due to the critical role of cellular enzymes necessary for cell proliferation by deciphering topological hurdles in the process of DNA replication, topoisomerases have been one of the major targets in the anticancer drug development area. A need, therefore, arises for new metallodrugs that specifically recognizes DNA and inhibits the activity of topoisomerase enzymes, herein, we report the synthesis and characterization of new metal-based glycoconjugate entities containing heterobimetallic core Cu^II-Sn^IV (1) and Ni^II-Sn^IV (2) derived from N-glycoside ligand (L). The optimized structure of complex 1 and other significant vibrational modes have been explained using dispersion corrected B3LYP/DFT calculations. In vitro DNA binding profile of the L and both the complexes 1 and 2 were done by various biophysical studies. Complex 1 breaks pBR322 DNA via a hydrolytic means which was validated by T4 DNA enzymatic assay. To get a mechanistic insight of mode of action topoisomerase I (Topo I) inhibition assay was carried out. Also, we have taken the help of molecular modeling studies in accordance with experimental findings. In vitro cytotoxicity of the complex 1 was evaluated against a panel of cancer cells which exhibited remarkably good anticancer activity (GI₅₀ values <10 μg/ml). Moreover, intracellular localization of the complex 1 was visualized by confocal microscopy against HeLa cells.

Allosteric inhibition of topoisomerase I by pinostrobin: Molecular docking, spectroscopic and topoisomerase I activity studies

Cancer, the second major cause of mortality trailing the cardiovascular diseases, is a multifactorial heterogeneous disease and growing public health problem worldwide. Owing to severe adverse effects of currently available therapies, there is a growing interest in natural compounds present in our daily diet. Among various natural products, flavonoids-polyphenolic compounds have attracted much attention and have been well-documented for their biological activities. Some flavonoids may inhibit cancer cell proliferation by modulating the action of different enzymes and signal transduction pathways. In the present study, we have evaluated the effect of pinostrobin, a natural flavonoid, on the catalytic activity of topoisomerase I, an essential enzyme for normal DNA replication. Catalytic inhibition of topoisomerase I activity would impair DNA replication of rapidly dividing cancer cells and hence inhibits tumor progression. Pinostrobin interaction with the topoisomerase I and DNA assessed in silico indicated it to form a ternary complex with both. In silico data also suggested pinostrobin to be an effective allosteric inhibitor for topoisomerase I. Further, in vitro investigations such as ethidium bromide displacement assay and spectroscopic studies supported in silico results on the binding of pinostrobin at the interface of topoisomerase I and DNA. Pinostrobin effectively inhibited topoisomerase I activity in vitro further confirming our in silico and in vitro findings. Since topoisomerase I is essential for DNA replication, inhibition of its activity by pinostrobin highlights the therapeutic potential of pinostrobin as an anti-proliferative agent.

A multifunctional molecular entity CuII–SnIV heterobimetallic complex as a potential cancer chemotherapeutic agent: DNA binding/cleavage, SOD mimetic, topoisomerase Iα inhibitory and in vitro cytotoxic activities

New chiral l-valine-derived Schiff base complexes with the bioactive heterocyclic ligand scaffold pyrazole (Hpz) were designed and synthesized with a view to find their potential as anticancer chemotherapeutic drug candidates.

Chiral heterobimetallic complexes targeting human DNA-topoisomerase Iα

The chiral monometallic Cu(II) (1) and Zn(II) (2) and heterobimetallic Cu(II)-Sn(IV) and Zn(II)-Sn(IV) complexes with tridentate chiral Schiff base -ONO-ligand in the presence of nitrogen donor heterocyclic ligand imidazole; were prepared and characterized by various physico-chemical and spectroscopic methods. Preliminary complex-DNA interaction studies employing optical methods revealed that 3 displayed a higher propensity towards the drug target DNA double helix and recommended predominantly an electrostatic mode of interaction as well as a groove binding affinity of the complex with CT-DNA. This was quantified by Kb and KSV values of complexes 1-4, which demonstrated a multifold increase in complex 3 binding to CT DNA and clearly demonstrates its potency to act as a chemotherapeutic agent. Furthermore, the gel electrophoretic patterns of supercoiled pBR322 DNA with varying concentrations of complex 3 exhibits the ability to cleave DNA and follow a freely diffusible radical mechanism. The antiproliferative effects of complex 3 on human hepatoma cancer cells (Huh7) was investigated. Human Topo I inhibition assay by complex 3 was performed and results confirmed significantly good activity at lower concentrations than some of the classical Topo I inhibitors. Additionally, complex 3 was investigated for the expression of MMP-2 and TGF-β by real time PCR. The cellular uptake of complex 3 by HeLa cells was studied by confocal microscopy.

Molecular drug design, synthesis and structure elucidation of a new specific target peptide based metallo drug for cancer chemotherapy as topoisomerase I inhibitor

To evaluate the biological preference of metallopeptide drugs in cancer cells, a new dinuclear copper(II) complex [Cu(2)(glygly)(2)(ppz)(H(2)O)(4)]·2H(2)O (1) (glygly = glycyl glycine anion and ppz = piperazine), was designed and synthesized as topoisomerase I inhibitor. The structural elucidation of the complex was done by elemental analysis, spectroscopic methods and single crystal X-ray diffraction. The in vitro DNA binding studies of complex 1 with CT DNA were carried out by employing different optical methods viz. UV-vis, fluorescence and circular dichroism. The molecular docking technique was also utilized to ascertain the mechanism and mode of action towards the molecular target DNA and enzymes. Complex 1 cleaves pBR322 DNA via an oxidative mechanism and strongly binds to the DNA minor groove. Furthermore, complex 1 exhibits significant inhibitory effects on the catalytic activity of topoisomerase I at a very low concentration, ~12.5 μM, in addition to its excellent SOD mimics (IC(50)~0.086 μM).