Copper(II) complexes of terpyridine derivatives: A footstep towards development of antiproliferative agent for breast cancer

The Therapeutic Potential in Cancer of Terpyridine-Based Metal Complexes Featuring Group 11 Elements

Terpyridine-based complexes with group 11 metals emerge as potent metallodrugs in cancer therapy. This comprehensive review focuses on the current landscape of anticancer examples, particularly highlighting the mechanisms of action. While Cu(II) complexes, featuring diverse ancillary ligands, dominate the field, exploration of silver and gold species remains limited. These complexes exhibit significant cytotoxicity against various cancer cell lines with a commendable selectivity for non-tumorigenic cells. DNA interactions, employing intercalation and groove binding, are pivotal and finely tuned through terpyridine ligand functionalization. In addition, copper complexes showcase nuclease activity, triggering apoptosis through ROS generation. Despite silver's high affinity for nitrogen donor atoms, its exploration is relatively sparse, with indications of acting as intercalating agents causing DNA hydrolytic cleavage. Gold(III) compounds, overshadowing gold(I) due to stability concerns, not only intercalate but also induce apoptosis and disrupt the mitochondrial membrane. Further investigations are needed to fully understand the mechanism of action of these compounds, highlighting the necessity of exploring additional biological targets for these promising metallodrugs.

Copper(II) Complexes with 2,2':6',2″-Terpyridine Derivatives Displaying Dimeric Dichloro-μ-Bridged Crystal Structure: Biological Activities from 2D and 3D Tumor Spheroids to In Vivo Models

Eight 2,2':6',2″-terpyridines, substituted at the 4'-position with aromatic groups featuring variations in π-conjugation, ring size, heteroatoms, and methoxy groups, were employed to enhance the antiproliferative potential of [Cu2Cl2(R-terpy)2](PF6)2. Assessing the cytotoxicity in A2780 (ovarian carcinoma), HCT116 (colorectal carcinoma), and HCT116DoxR (colorectal carcinoma resistant to doxorubicin) and normal primary fibroblasts revealed that Cu(II) complexes with 4-quinolinyl, 4-methoxy-1-naphthyl, 2-furanyl, and 2-pyridynyl substituents showed superior therapeutic potential in HCT116DoxR cells with significantly reduced cytotoxicity in normal fibroblasts (42-129× lower). Besides their cytotoxicity, the Cu(II) complexes are able to increase intracellular ROS and interfere with cell cycle progression, leading to cell death by apoptosis and autophagy. Importantly, they demonstrated antimetastatic and antiangiogenic properties without in vivo toxicity. In accordance with their nuclear accumulation, the Cu(II) complexes are able to cleave pDNA and interact with bovine serum albumin, which is a good indication of their ability for internalization and transport toward tumor cells.

Antitumor activity of synthetic three copper(II) complexes with terpyridine ligands

Three new synthetic terpyridine copper(II) complexes were characterized. The copper(II) complexes induced apoptosis of three cancer cell lines and arrested T-24 cell cycle in G1 phase. The complexes were accumulated in mitochondria of T-24 cells and caused significant reduction of the mitochondrial membrane potential. The complexes increased both intracellular ROS and Ca²⁺ levels and activated the caspase-3/9 expression. The apoptosis was further confirmed by Western Blotting analysis. Bcl-2 was down-regulated and Bax was upregulated after treatment with complexes 1-3. The in vivo studies showed that complexes 1-3 obviously inhibited the growth of tumor without significant toxicity to other organs.

Bio-inspired nickel nanoparticles of pyrimidine-Schiff base: In vitro anticancer, BSA and DNA interactions, molecular docking and antioxidant studies

In this work, interactions of pyrimidine derivative Schiff base ligand (DMPMM) were studied and its stabilized powder nickel nanoparticles (DMPMM-NiNPs) were synthesized and various biological studies were evaluated. DNA binding studies of CT-DNA with prepared compounds in Tris-HCl/NaCl buffer were carried out by traditional UV-Visible and fluorescence spectroscopic methods, viscosity measurements and cyclic voltammetry. Results showed that the small scale of DMPMM had less activity to interact with biological systems and when it assembled on nickel nanoparticles surface the activity increased. Thermal denaturation and sonochemical denaturation studies of DNA with the presence and the absence of our compounds also were done by UV-Visible spectroscopic method and its results indicated that the synthesized compounds increased the denaturation temperature. BSA binding studies of synthesized compounds were done by UV-Visible and fluorescence spectroscopy. Molecular docking of prepared ligand and its nanoparticles with biomolecules (DNA and BSA) were studied. Antimicrobial studies of the DMPMM and DMPMM-NiNPs were carried out by Agar-Agar well diffusion method. Anticancer studies results evidenced that the synthesized DMPMM-NiNPs had good selectivity to control the growth of cancer cells without damaging the normal cells. Various antioxidant scavenging studies results have shown that DMPMM and DMPMM-NiNPs have significant antioxidant activity. HighlightsStable and solid nickel nanoparticles were prepared.The size of the prepared nickel nanoparticles was nearly 3 to 8 nm.Organic ligand capped nickel nanoparticles interacted with DNA and BSA.Ni nanoparticles increased the denaturation temperature of DNA.It was found to have good anticancer activity with fewer side effects than cisplatin.Communicated by Ramaswamy H. Sarma.

Design and Synthesis of Carbothioamide/Carboxamide-Based Pyrazoline Analogs as Potential Anticancer Agents: Apoptosis, Molecular Docking, ADME Assay, and DNA Binding Studies

To discover anticancer drugs with novel structures and expand our research scope, pyrazoline derivatives (3a-3l) were designed and synthesized through cyclization of chalcones with thiosemicarbazide/semicarbazide in CH₃COOH as a solvent. All newly synthesized pyrazoline derivatives were fully characterized using several spectroscopic experiments such as ¹H, ¹³C NMR, FT-IR spectroscopy, and mass analysis. By HPLC, the purity of all analogs was found above 95% and both lead compounds (3a and 3h) were also validated by HRMS. Anticancer activity of synthesized pyrazoline derivatives (3a-3l) was investigated by the MTT assay against the human lung cancer cell (A549), human cervical cancer cell (HeLa), and human primary normal lung cells (HFL-1). Staurosporine (STS) was used as a standard drug. The anticancer results showed that two potent analogs 3a and 3h exhibit excellent activity against A549 (IC₅₀ = 13.49 ± 0.17 and 22.54 ± 0.25 μM) and HeLa cells (IC₅₀ = 17.52 ± 0.09 and 24.14 ± 0.86 μM) and low toxicity against the HFL-1 (IC₅₀ = 114.50 ± 0.01 and 173.20 ± 10 μM). The flow cytometry was further used to confirm the anticancer activity of potent derivatives against the A549 cancer cell line. DNA binding interaction of anticancer agents 3a and 3h with Ct-DNA has been carried out by absorption, fluorescence, EtBr (dye displacement assay), circular dichroism, cyclic voltammetry and time-resolved fluorescence, which showed noncovalent binding mode of interaction. Anticancer activity of both lead compounds (3a and 3h) may be attributed to DNA binding. The evaluation of the antioxidant potential of pyrazoline analogs 3a and 3h by 2,2-diphenyl-1-picrylhydrazyl free radical showed promising antioxidant activity with IC₅₀ values of 0.132 ± 0.012 and 0.215 ± 0.025 μg/mL, respectively. In silico molecular docking of pyrazoline derivatives was also performed using autodock vina software against the DNA hexamer with PDB ID: 1Z3F and ADMET properties to explore their best hits.

Synthesis, Characterization, Crystal Structure, DNA and HSA Interactions, and Anticancer Activity of a Mononuclear Cu(II) Complex with a Schiff Base Ligand Containing a Thiadiazoline Moiety

A mononuclear Cu(II) complex [Cu(HL)(o-phen)]·H₂O (1) [H₃L =, o-phen = 1,10-phenanthroline] was isolated from methanol, and its X-ray single-crystal structure was determined. Frozen glass X-band EPR of 1 in dimethylformamide (DMF) at LNT showed a spectrum that is characteristic of a monomeric tetragonal character with g _∥ = 2.164, g _⊥ = 2.087, A _∥ = 19.08 mT, and A _⊥ ≤ 4 mT. Electronic spectroscopic studies using calf thymus DNA (CT-DNA) showed strong binding affinity of 1 as reflected from its intrinsic binding constant (K _b) value of 2.85 × 10⁵ M^-1. Competitive behavior of 1 with ethidium bromide (EB) displayed intercalative binding of DNA (K _app = 1.3 × 10⁶ M^-1). The compound displayed significant oxidative cleavage of pUC19 DNA. The interaction between HSA and complex 1 was examined by employing fluorescence and electronic absorption spectroscopic experiments. The secondary and tertiary structures of HSA were found to be altered as suggested by three-dimensional (3D) fluorescence experiments. The affinity of 1 to bind to HSA was found to be strong as indicated from its value of the binding constant (K _a = 2.89 × 10⁵ M^-1). Intrinsic fluorescence of the protein was found to be reduced through a mechanism of static quenching as suggested from the k _q (2.01 × 10¹³ M^-1 s^-1) value, the bimolecular quenching constant. The Förster resonance energy transfer (FRET) process may also be accounted for such a high k _q value. The r value (2.85 nm) calculated from FRET theory suggested that the distance between complex 1 (acceptor) and HSA (donor) is quite close. Complex 1 primarily bound to HSA in subdomain IIA as suggested by molecular docking studies. IC₅₀ values (0.80 and 0.43 μM, respectively) obtained from the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with HeLa and MCF7 cells suggested remarkable in vitro anticancer activity of 1. Nuclear dual staining assays revealed that cell death occurred via apoptosis in HeLa cells and reactive oxygen species (ROS) accumulation caused apoptosis induction. On treatment with a 5 μM dose of 1 in HeLa cells, the cell population significantly increased in the G2/M phase, while it was decreased in G0/G1 and S phases as compared to the control, clearly indicating G2/M phase arrest.

Terpyridines as promising antitumor agents: an overview of their discovery and development

INTRODUCTION

The fused aromatic system of terpyridines makes them good, innocent ligands for various metals. The resulting complexes have been extensively studied for both their biological activity and physico-chemical properties. However, although free ligands also have an interesting biological activity, their share in recent research is considerably limited.

AREAS COVERED

This review covers the literature on the anticancer activity of terpyridines with special attention being paid to their use as free ligands. Whenever possible, the mechanism of action has been discussed, thereby providing evidence of the substantial differences between sole ligands or less stable complexes and those that have heavier elements.

EXPERT OPINION

The existing literature indicates that there is a specific attitude for investigating terpyridines and their transition metal complexes. While the latter have been well explored and recognized in the scientific community, the free terpyridines are considered to be useful solely due to their complexing ability. At the same time, terpyridines could have similar or even higher anticancer potency than their complexes. Moreover, a mechanistic analysis of the stability and intracellular activity would provide information that would be useful for designing new drugs.

Copper in tumors and the use of copper-based compounds in cancer treatment

Copper homeostasis is strictly regulated by protein transporters and chaperones, to allow its correct distribution and avoid uncontrolled redox reactions. Several studies address copper as involved in cancer development and spreading (epithelial to mesenchymal transition, angiogenesis). However, being endogenous and displaying a tremendous potential to generate free radicals, copper is a perfect candidate, once opportunely complexed, to be used as a drug in cancer therapy with low adverse effects. Copper ions can be modulated by the organic counterpart, after complexed to their metalcore, either in redox potential or geometry and consequently reactivity. During the last four decades, many copper complexes were studied regarding their reactivity toward cancer cells, and many of them could be a drug choice for phase II and III in cancer therapy. Also, there is promising evidence of using ⁶⁴Cu in nanoparticles as radiopharmaceuticals for both positron emission tomography (PET) imaging and treatment of hypoxic tumors. However, few compounds have gone beyond testing in animal models, and none of them got the status of a drug for cancer chemotherapy. The main challenge is their solubility in physiological buffers and their different and non-predictable mechanism of action. Moreover, it is difficult to rationalize a structure-based activity for drug design and delivery. In this review, we describe the role of copper in cancer, the effects of copper-complexes on tumor cell death mechanisms, and point to the new copper complexes applicable as drugs, suggesting that they may represent at least one component of a multi-action combination in cancer therapy.

Peculiar DNA partial threading intercalative ability of tetradentate copper complex based on ONO hydrazone backbone and an ancillary ligand

Multidentate copper metal complexes have been in the limelight in the area of DNA interaction studies exhibiting intercalation, groove binding and cross linking modes. Design of metal complex based on the versatile ligands decides their mode of DNA binding behavior. Based on this, a tetradentate Copper (II) complex, [Cu(L)(4,4'-bpy)], is synthesized using ONO hydrazone ligand and ancillary ligand, 4,4'-bipyridine. It is characterized by physico-chemical and UV-Visible, FTIR, Mass and EPR spectroscopic techniques. The binding pattern of the characterized complex with DNA has been assessed by UV absorption and fluorescence spectral titrations as well as viscosity studies and it has exhibited peculiar threading intercalation. The binding constant, K_b value of the synthesized complex was found to be (4.38 ± 0.09) × 10⁴ M^-1, greater than that of the hydrazone ligand (K_b = 2.29 × 10⁴ M^-1) and lesser than the classical intercalator ethidium bromide - EtBr (K_b = 10⁷). The fluorescence quenching assays in the presence of ethidium bromide and viscometric studies show threading intercalative mode of binding of the complex to the DNA base pairs. Molecular docking studies further supports such a binding pattern with the bipyridine ring of the complex intercalating with deoxycytosine nucleobase of DNA. ADME (Absorption, Distribution, Metabolism and Excretion) parameters of the complex and ligand were predicted to get an idea of drug likeliness and to correlate the structural properties with semi DNA intercalative pattern of the same.

Bioactive Zinc(II) complex incorporated PCL/gelatin electrospun nanofiber enhanced bone tissue regeneration

Bone tissue regeneration is augmented by biocompatible nanofiber scaffolds, that supports reliable and enhanced bone formation. Zinc is an essential mineral that is vital for routine skeletal growth and it emerges to be able to improve bone regeneration. Phytochemicals, particularly flavonoids have achieved prominent interest for their therapeutic ability, they have demonstrated promising effects on bone by encouraging osteoblastogenesis, which finally leads to bone formation. In this study, we have synthesized bioactive zinc(II) quercetin complex material and used for nanofibers scaffold fabrication to enhance bone tissue regeneration property. Two derivatives of zinc(II) quercetin complexes [(Zn(quercetin) (H₂O)₂) (Zn+Q), and Zn(quercetin)(phenanthroline) (Zn+Q(PHt)) have been synthesized and characterized using UV-Visible spectrophotometer and Fourier Transform-IR spectroscopy. The UV-Visible absorption and IR spectra prove the B-ring chelation of the flavonoid quercetin to zinc(II) rather C-ring chelation. The potential ability of the above synthesized metal complexes on osteogenesis and angiogenesis have been studied. Besides the bioactivity of the metal complexes, the control quercetin has also been examined. The chick embryo chorioallantoic membrane (CAM) assay demonstrated that the angiogenic parameters were increased by the (Zn+Q(PHt)) complex. Amongst, (Zn+Q(PHt)) complex showed significant activity and thereby this complex has been further examined for the bone tissue activity by incorporating the complex into a nanofiber through electrospinning method. At the molecular level, Runx2, mRNA and protein, ALP and type 1 collagen mRNAs, and osteoblast-specific microRNA, pre-mir-15b were examined using real time RT-PCR and Western blot assay. Histology studies showed that the (PCL/gelatin/Zn+Q(PHt)) was biocompatibility in-ovo. Overall, the present study showed that quercetin-zinc complex (Zn+Q(PHt)) incorporated into PCL/gelatin nanofiber can act as a pharmacological agent for treating bone associated defects and promote bone regeneration.

Pyrazoline analogs as potential anticancer agents and their apoptosis, molecular docking, MD simulation, DNA binding and antioxidant studies

N-formyl pyrazoline derivatives (3a-3l) were designed and synthesized via Michael addition reaction through cyclization of chalcones with hydrazine hydrate in presence of formic acid. The structural elucidation of N-formyl pyrazoline derivatives was carried out by various spectroscopic techniques such as ¹H, ¹³C NMR, FT-IR, UV-visible spectroscopy, mass spectrometry and elemental analysis. Anticancer activity of the pyrazoline derivatives (3a-3l) was evaluated against human lung cancer (A549), fibrosarcoma cell lines (HT1080) and human primary normal lung cells (HFL-1) by MTT assay. The results of anticancer activity showed that potent analogs 3b and 3d exhibited promising activity against A549 (IC₅₀ = 12.47 ± 1.08 and 14.46 ± 2.76 µM) and HT1080 (IC₅₀ = 11.40 ± 0.66 and 23.74 ± 13.30 µM) but low toxic against the HFL-1 (IC₅₀ = 116.47 ± 43.38 and 152.36 ± 22.18 µM). The anticancer activity of potent derivatives (3b and 3d) against A549 cancer cell line was further confirmed by flow cytometry based approach. DNA binding interactions of the pyrazoline derivatives 3b and 3d have been carried out with calf thymus DNA (Ct-DNA) using absorption, fluorescence and viscosity measurements, circular dichroism and cyclic voltammetry. Antioxidant potential of N-formyl pyrazoline derivatives (3a-3l) has been also estimated through DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical and H₂O_2. Results revealed that all the compounds exhibited significant antioxidant activity. In silico molecular modelling and ADMET properties of pyrazoline derivatives were also studied using PyRx software against topoisomerase II receptor with PDB ID: 1ZXM to explore their best hits. MD simulation of 3b and 3d was also carried out with topoisomerase II for structure-function correlation in a protein. HuTopoII inhibitory activity of the analogs (3a-3l) was examined by relaxation assay at varying concentrations 100-1000 µM.

Biochemical pathways of copper complexes: progress over the past 5 years

Copper is an essential trace element with vital roles in many metalloenzymes; it is also prominent among nonplatinum anticancer metallodrugs. Copper-based complexes are endogenously biocompatible, tenfold more potent than cisplatin, exhibit fewer adverse effects, and have a wide therapeutic window. In cancer biology, copper acts as an antitumor agent by inhibiting cancer via multiple pathways. Herein, we present an overview of advances in copper complexes as 'lead' antitumor drug candidates, and in understanding their biochemical and pharmacological pathways over the past 5 years. This review will help to develop more efficacious therapeutics to improve clinical outcomes for cancer treatments.

Pyrimidine Derivative Schiff Base Ligand Stabilized Copper and Nickel Nanoparticles by Two Step Phase Transfer Method; in Vitro Anticancer, Antioxidant, Anti-Microbial and DNA Interactions

Pyrimidine derivative Schiff base ligand (DPMC) stabilized metal nanoparticles of copper (DPMC-CuNPs) and nickel (DPMC-NiNPs) were synthesized by modified Brust-Schiffrin technique, which is a two-step phase transfer assisted synthesis. The prepared metal nanoparticles were confirmed by UV-Visible and Infrared spectroscopy. The size, surface morphology and the quality of the DPMC and its MNPs were analyzed by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) methods respectively. Electrochemical behavior of the DPMC-CuNPs and DPMC-NiNPs was analyzed by cyclic voltammetry method. DNA binding studies of the synthesized compounds with CT-DNA were examined by four different techniques such as UV-Visible and emission spectroscopy, cyclic voltametry and viscometric measurments. Thermal denaturation and sono-chemical denaturation studies of DNA with the DPMC, DPMC-CuNPs and DPMC-NiNPs results also suggest the synthesized compounds have good DNA binding ability. Various antioxidant scavenging studies results shows that DPMC and its copper and nickel nanoparticles have significant antioxidant activity. Antimicrobial studies of the DPMC and its MNPs were studied by Agar-Agar well diffusion method. Anticancer studies of the DPMC and its MNPs show that the DPMC-CuNPs and DPMC-NiNPs have significant anticancer activity with least toxicity than the standard drug cis-platin. Graphical Abstract.

Antiproliferative Activities of Diimine-Based Mixed Ligand Copper(II) Complexes

A series of Cu(diimine)(X-sal)(NO₃) complexes, where the diimine is either 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) and X-sal is a monoanionic halogenated salicylaldehyde (X = Cl, Br, I, or H), have been synthesized and characterized by elemental analysis and X-ray crystallography. Penta-coordinate geometries copper(II) were observed for all cases. The influence of the diimine coligands and different halogen atoms on the antiproliferative activities toward human cancer cell lines have been investigated. All Cu(II) complexes were able to induce a loss of A2780 ovarian carcinoma cell viability, with phen derivatives more active than bpy derivatives. In contrast, no in vitro antiproliferative effects were observed against the HCT116 colorectal cancer cell line. These cytotoxicity differences were not due to a different intracellular concentration of the complexes determined by inductively coupled plasma atomic emission spectroscopy. A small effect of different halogen substituents on the phenolic ring was observed, with X = Cl being the most highly active toward A2780 cells among the phen derivatives, while X = Br presented the lowest IC₅₀ in A2780 cells for bpy analogs. Importantly, no reduction in normal primary fibroblasts cell viability was observed in the presence of bpy derivatives (IC₅₀ > 40 μM). Mechanistically, complex 1 seems to induce a stronger apoptotic response with a higher increase in mitochondrial membrane depolarization and an increased level of intracellular reactive oxygen species (ROS) compared to complex 3. Together, these data and the low IC₅₀ compared to cisplatin in A2780 ovarian carcinoma cell line demonstrate the potential of these bpy derivatives for further in vivo studies.

Evaluation of the accumulation of disulfiram and its copper complex in A549 cells using mass spectrometry

The famous alcohol-aversion drug disulfiram (DSF) is a promising candidate for repurposing in cancer therapy, as indicated by many ongoing and completed clinical trials. Existing researches focus on demonstrating that the anti-cancer activity of DSF is enhanced by copper ions, or solving the problem that DSF is easily decomposed in the body to lose its activity. However, the metabolic kinetics of its ultimate anti-cancer metabolite DDC-Cu (bis-diethyldithiocarbamate-copper) in cells and how it exerts anti-cancer mechanisms remain unclear. In this work, mass spectrometric evaluation of the intracellular and extracellular accumulation of DSF and its copper complex DDC-Cu was performed. Combined with cytotoxicity assay, staining analysis and flow cytometry, we found that DDC-Cu could easily pass through the cell membrane of A549 cells, and accumulate intracellularly for a long time. This process can lead to cellular morphological changes, an increase in ROS content, cell cycle arrest in the G0/G1 phase and apoptosis. Besides, molecular cancer-relevant targets of DDC-Cu in cancer cells were further discussed. This work investigated the cytotoxic mechanism of DDC-Cu, which has important clinical significance for its application in cancer therapy.

Copper(ii) complexes with 2,2′:6′,2′′-terpyridine, 2,6-di(thiazol-2-yl)pyridine and 2,6-di(pyrazin-2-yl)pyridine substituted with quinolines. Synthesis, structure, antiproliferative activity, and catalytic activity in the oxidation of alkanes and alcohols with peroxides

The toxicity of six new Cu(ii) complexes was evaluated in cancer derived cell lines. A model of competitive interaction of hydroxyl radicals with CH₃CN and RH in the catalyst cavity has been proposed.

A combined experimental and theoretical approach to investigate the structure, magnetic properties and DNA binding affinity of a homodinuclear Cu(ii) complex

A dicopper(ii) complex of a flexible amino alcohol anchored with an acetate auxiliary was designed and characterized by spectral, X-ray crystallographic, magnetic and DFT studies; moreover, it was evaluated for its DNA binding properties. The experimental results are supported by theoretical analyses.

Chromo-luminescent selective detection of fluoride ions by a copper(ii) bis(terpyridine) complex solution via a displacement approach

(1) For the first time a terpyrideine-Cu(ii) complex was used for the selective detection of F⁻ ions. (2) A dual mode detection method comprising chromo-luminescent techniques was used to evaluate the sensing mechanism. (3) The limit of detection was found to be 5.07 μM which is within the permissible level of F⁻ ions in drinking water according to the WHO.

Evaluation of antioxidant, DNA targeting, antimicrobial and cytotoxic studies of imine capped copper and nickel nanoparticles

In this work, we have synthesized pyrimidine derivatives of Schiff base ligand 2-(4,6-dimethoxypyrimidin-2-ylimino)methyl)-6-methoxyphenol (DPMM) stabilized copper nanoparticles (DPMM-CuNPs) and nickel nanoparticles (DPMM-NiNPs) by modified Brust-Schiffrin technique as two step phase transfer assisted method and confirmed by UV-Visible, SEM and TEM analysis. The free radical scavenging activity of DPMM, DPMM-CuNPs &DPMM-NiNPs with 2, 2'-diphenylpicryl hydrazyl (DPPH), hydrogen peroxide (H₂O₂) super oxide dismutase (SOD) and nitric oxide (NO) shows that the antioxidant activity of DPMM-CuNPs is higher than DPMM &DPMM-NiNPs. Interaction study of DPMM-CuNPs &DPMM-NiNPs with CT-DNA has been investigated by absorption spectral titration, fluorescence studies, cyclic voltammetry and viscometric measurements. Dose dependent antibacterial and antifungal studies of DPMM-CuNPs & DPMM-NiNPs against five different bacteria Shigella sonnei, Staphylococcus aureus, Escherichia coli, Klepsiella pneumoniae, Pseudomonas fluoroscens and five different fungi Aspergillus niger, Candida albicans, Candida tropicalis, Mucor indicus and Rhizopus show that the compounds have significant antibacterial and antifungal activity. Cytotoxicity studies of DPMM-CuNPs &DPMM-NiNPs on human breast cancer cell line (MCF-7) were studied by 3-(4, 5-dimethylthiazol-2-yl-)-2, 5-diphenyltetrazolium bromide (MTT) assay. 50% cell viability was found at 25μg/mL for DPMM-CuNPs and 300μg/mL for DPMM-NiNPs. Collective biological results reveal that the synthesized DPMM-CuNPs is more biologically active than DPMM-NiNPs.

Mixed-ligand copper(II) complex of quercetin regulate osteogenesis and angiogenesis

Copper(II) complex of quercetin Cu+Q, mixed ligand complexes, quercetin-Cu(II)-phenanthroline [Cu+Q(PHt)] and quercetin-Cu(II)-neocuproine [Cu+Q(Neo)] have been synthesized and characterized. From the FT-IR spectroscopic studies, it was evident that C-ring of quercetin is involved in the metal chelation in all the three copper complexes. C-ring chelation was further proven by UV-Visible spectra and the presence of Cu(II) from EPR spectroscopic investigations. These complexes were found to have osteogenic and angiogenic properties, observed through in vitro osteoblast differentiation and chick embryo angiogenesis assay. In osteoblast differentiation, quercetin-Cu(II) complexes treatment increased calcium deposition and alkaline phosphatase activity (ALP) activity at the cellular level and stimulated Runx2 mRNA and protein, ALP mRNA and type 1 collagen mRNA expression at the molecular level. Among the complexes, Q+Cu(PHt) showed more effects on osteoblast differentiation when compared to that of other two copper complexes. Additionally, Q+Cu(Neo) showed more effect compared to Q+Cu. Furthermore, the effect of these complexes on osteoblast differentiation was confirmed by the expression of osteoblast specific microRNA, pre-mir-15b. The chick embryo angiogenesis assay showed that angiogenic parameters such as blood vessel length, size and junctions were stimulated by these complexes. Thus, the present study demonstrated that quercetin copper(II) complexes exhibit as a pharmacological agent for the orthopedic application.

Cell cycle specific radiosensitisation by the disulfiram and copper complex

The disulfiram and copper complex (DSF:Cu) has emerged as a potent radiosensitising anti-cancer agent. The ability of copper to stabilise DSF in a planar conformation and to inhibit DNA replication enzymes stimulated our investigation of the effect of DSF:Cu on cell cycle regulation. Flow cytometry and immunoblotting were used to assess the effect of DSF:Cu on cell cycle progression of the neuroblastoma cell line SK-N-BE(2c) and the glioma cell line UVW. Treatment with 0.1 and 0.3 μM DSF:Cu inhibited DNA synthesis in SK-N-BE(2c) and UVW cells, respectively. The increased potency of ionising radiation treatment induced by DSF:Cu and/or gemcitabine was determined by clonogenic assay. Treatment with 0.3 μM DSF:Cu resulted in greater radiation kill, exemplified by dose enhancement factor values of 2.64 and 2.84 in SK-N-BE(2c) and UVW cells, respectively. Although DSF:Cu failed to sensitise S phase cells to irradiation, we observed that DSF:Cu radiosensitisation was potentiated by the S phase-specific cytotoxic drug gemcitabine. The efficacy of the combination treatment consisting of DSF:Cu, gemcitabine and ionising radiation was schedule-dependent. Together, these results describe cell cycle specific radiosensitisation by DSF:Cu. The well-established toxicity profiles of DSF and gemcitabine should facilitate their evaluation as a combination treatment in patients undergoing radiotherapy.

Interaction of Cd(ii) and Ni(ii) terpyridine complexes with model polynucleotides: a multidisciplinary approach

The study of the intercalation of both complexes, evidenced by CD and fluorescence spectroscopy and supported by QM/MM calculations, broadens the experimental and theoretical background on drugs/DNA interactions.

Heteroleptic Cu(ii)–polypyridyl complexes as photonucleases

Four new copper(ii)–polypyridyl complexes having tail groups with increasing aromaticity, hydrophobicity and planarity are synthesized. These complexes are found to be avid DNA binders and show efficient nuclease activity under either chemical stimulus or UV-A light irradiation.

Characterization of antiproliferative potential and biological targets of a copper compound containing 4'-phenyl terpyridine

Several copper complexes have been assessed as anti-tumor agents against cancer cells. In this work, a copper compound [Cu(H2O){OS(CH3)2}L](NO3)2 incorporating the ligand 4'-phenyl-terpyridine antiproliferative activity against human colorectal, hepatocellular carcinomas and breast adenocarcinoma cell lines was determined, demonstrating high cytotoxicity. The compound is able to induce apoptosis and a slight delay in cancer cell cycle progression, probably by its interaction with DNA and induction of double-strand pDNA cleavage, which is enhanced by oxidative mechanisms. Moreover, proteomic studies indicate that the compound induces alterations in proteins involved in cytoskeleton maintenance, cell cycle progression and apoptosis, corroborating its antiproliferative potential.