A Series of Oxyimine-Based Macrocyclic Dinuclear Zinc(II) Complexes Enhances Phosphate Ester Hydrolysis, DNA Binding, DNA Hydrolysis, and Lactate Dehydrogenase Inhibition and Induces Apoptosis

Thiocyanate mediated structural diversity in phenol based "end-off" compartmental ligand complexes of group 12 metal ions: Studies on their photophysical properties and phosphatase like activity

The reaction of a pentadentate compartmental ligand LH, namely 4-tert-Butyl-2,6-bis-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol, with group 12 metal ions (Zn^II, Cd^II, Hg^II) followed by addition of NaSCN afforded one discrete dinuclear complex [Zn₂(L)(SCN)₃](1), and two polymeric 1D species [Cd_2.5(L)(SCN)₃(AcO)]_n (2) and [Hg₂(L)(SCN)₃]_n (3). All the complexes have been structurally characterized by single crystal X-ray diffraction. The crystal structure of the complexes reveals different coordination modes of thiocyanate anion that affect the different topology detected in the compounds: the anions are μ¹-NCS and μ^1,1-NCS connected in complex 1, while μ^1,3-NCS bridging mode is observed in 2, and μ¹-SCN and μ^1,3-NCS in 3. The polymeric Hg complex of the bicompartmental ligand system here reported is unprecedented. Detail study of their photophysical properties including the phosphorescence spectra at 77K has been done. Phosphatase like activity of all the three complexes has been performed in DMSO-H₂O medium and their activity follows the order of 1>2>>3.

DNA and BSA binding and cytotoxic properties of copper(ii) and iron(iii) complexes with arylhydrazone of ethyl 2-cyanoacetate or formazan ligands

Copper(ii) and iron(iii) complexes with arylhydrazone of ethyl 2-cyanoacetate or formazan ligands show DNA and BSA binding and anticancer abilities.

Fluorescence sensor for sequential detection of zinc and phosphate ions

A new, highly selective turn-on fluorescent chemosensor based on 2-(2'-tosylamidophenyl)thiazole (1) for the detection of zinc and phosphate ions in ethanol was synthesized and characterized. Sensor 1 showed a high selectivity for zinc compared to other cations and sequentially detected hydrogen pyrophosphate and hydrogen phosphate. The fluorescence mechanism can be explained by two different mechanisms: (i) the inhibition of excited-state intramolecular proton transfer (ESIPT) and (ii) chelation-induced enhanced fluorescence by binding with Zn(2+). The sequential detection of phosphate anions was achieved by the quenching and subsequent revival of ESIPT.

Synthesis, DNA binding, cellular DNA lesion and cytotoxicity of a series of new benzimidazole-based Schiff base copper(II) complexes

A series of new benzimidazole containing compounds 2-((1-R-1-H-benzimidazol-2-yl)phenyl-imino)naphthol HL(1-3) (R = methyl, ethyl or propyl, respectively) have been synthesized by Schiff base condensation of 2-(1-R-1-H-benzo[d]imidazol-2-yl)aniline and 2-hydroxy-1-naphthaldehyde. The reactions of HL(1-3) with Cu(NO3)2·2.5H2O led to the corresponding copper(II) complexes [Cu(L)(NO3)] 1-3. All the compounds were characterized by conventional analytical techniques and, for 1 and 3, also by single-crystal X-ray analysis. The interactions of complexes 1-3 with calf thymus DNA were studied by absorption and fluorescence spectroscopic techniques and the calculated binding constants (K(b)) are in the range of 3.5 × 10(5) M(-1)-3.2 × 10(5) M(-1). Complexes 1-3 effectively bind DNA through an intercalative mode, as proved by molecular docking studies. The binding affinity of the complexes decreases with the size increase of the N-alkyl substituent, in the order of 1 > 2 > 3, which is also in accord with the calculated LUMO(complex) energies. They show substantial in vitro cytotoxic effect against human lung (A-549), breast (MDA-MB-231) and cervical (HeLa) cancer cell lines. Complex 1 exhibits a significant inhibitory effect on the proliferation of the A-549 cancer cells. The antiproliferative efficacy of 1 has also been analysed by a DNA fragmentation assay, fluorescence activated cell sorting (FACS) and nuclear morphology using a fluorescence microscope. The possible mode for the apoptosis pathway of 1 has also been evaluated by a reactive oxygen species (ROS) generation study.

Synthesis and Characterization of a Walnut Peptides-Zinc Complex and Its Antiproliferative Activity against Human Breast Carcinoma Cells through the Induction of Apoptosis

The walnut peptides and zinc ions were combined to generate a walnut peptides-zinc complex (WP1-Zn) with enhanced antiproliferative ability as well as reduced toxicity. The result indicated that Zn ions were successfully combined with WP1 through Zn-N and Zn-O covalent bonds. WP1-Zn compounds exhibited strong antiproliferative ability against the selected human cell lines, especially MCF-7 cells, whose survival rate reduced to 20.02% after exposure to 300 μg/mL of WP1-Zn for 48 h. WP1-Zn inhibited MCF-7 cell proliferation through inducing cell apoptosis and cell cycle arrest. The results indicated that WP1-Zn induced MCF-7 cell apoptosis via the ROS triggered mitochondrial-mediated pathway and cell surface receptor-mediated pathway. Our work is the first attempt to elucidate the synergic effect of novel walnut peptides and Zn and with the hope of better understanding the antiproliferative action of bioactive peptides and a zinc complex and support the potential application of WP1-Zn as a functional food ingredient or complementary medicine.

Synthesis, characterization, DNA/BSA interactions and anticancer activity of achiral and chiral copper complexes

Six novel copper(ii) complexes of [CuCl]ClO4 (), [Cu(acac)]PF6 (), [CuCl]2(PF6)2 (), [CuCl]2(PF6)2 (), [Cu(acac)]PF6 () and [Cu(acac)]PF6 (), ( = 1-naphthyl-N,N-[bis(2-pyridyl)methyl]amine, = R/S-1-naphthyl-N,N-[bis(2-pyridyl)methyl]ethanamine, acac = diacetone) were synthesized to serve as artificial nucleases. All complexes were structurally characterized using X-ray crystallography. The crystal structures showed the presence of distorted square-planar CuLCl (, and ) and distorted tetragonal-pyramidal CuL(acac) (, and ) geometry. The interaction of these complexes with calf thymus DNA (CT-DNA) was researched by means of several spectroscopy methods, which indicated that the complexes were bound to CT-DNA by an intercalation binding mode. DNA cleavage experiments revealed that the complexes exhibited remarkable DNA cleavage activities in the presence of H2O2, and single oxygen ((1)O2) or hydroxyl radicals may serve as the major cleavage active species. In particular, the in vitro cytotoxicity of the complexes on four human cancer cell lines (HeLa, MCF-7, Bel-7404 and HepG-2) demonstrated that the six compounds had broad-spectrum anti-cancer activity with low IC50 values. The stronger cytotoxicity and DNA cleavage activity of the chiral enantiomers compared with chiral analogues verified the influence of chirality on the antitumor activity of complexes. Meanwhile, the protein binding ability was revealed by quenching of tryptophan emission with the addition of complexes using BSA as a model protein. The results indicated that the quenching mechanism of BSA by the complexes was a static process.

Comparative structure activity relationship for heterogeneous phosphatase-like catalytic activities of one-dimensional Cu(ii) coordination polymers

A structure activity relationship for heterogeneous phosphatase-like activities of one-dimensional Cu(ii) coordination polymers, has been studied. Complex 1 exhibits maximum activity due to coordinated water molecules, shorter metal–metal distance and exposed metal centers.

An experimental and quantum chemical study on the non-covalent interactions of a cyclometallated Rh(iii) complex with DNA and BSA

The interaction of a new cyclometallated Rh(iii) complex with DNA and BSA was investigated. The three-layer ONIOM method was employed to calculate the interaction energy between DNA and the complex.

Role of para-substitution in controlling phosphatase activity of dinuclear NiII complexes of Mannich-base ligands: experimental and DFT studies

Five dinuclear Ni^II complexes synthesized by Mannich reaction portray remarkable phosphatase activity where the tert-butyl complex exhibits the maximum reactivity.

Targeting mitochondrial DNA with a two-photon active Ru(ii) phenanthroline derivative

A novel phenanthroline Ru(ii) derivative for targeting mitochondrial DNA was designed and its potential applications in biological processes were highlighted.

An asymmetric binuclear zinc(ii) complex with mixed iminodiacetate and phenanthroline ligands: synthesis, characterization, structural conversion and anticancer properties

A water-soluble asymmetric binuclear zinc(ii) complex with mixed iminodiacetate and 1,10-phenanthroline ligands exhibited promising anticancer activity and low toxicity, suggesting potential as a chemotherapeutic agent.

Macrocyclic Dizinc(II) Alkyl and Alkoxide Complexes: Reversible CO2 Uptake and Polymerization Catalysis Testing

The synthesis of three new dizinc(II) complexes bearing a macrocyclic [2 + 2] Schiff base ligand is reported. The bis(anilido)tetraimine macrocycle reacts with diethylzinc to form a bis(ethyl)dizinc(II) complex, [L(Et)Zn2Et2] (1). The reaction of complex 1 with isopropyl alcohol is reported, forming a bis(isopropyl alkoxide)dizinc complex, [L(Et)Zn2((i)PrO)2] (2). Furthermore, complex 1, with 2 equiv of alcohol, is applied as an initiator for racemic lactide ring-opening polymerization. It shows moderately high activity, resulting in a pseudo-first-order rate coefficient of 9.8 × 10(-3) min(-1), with [LA] = 1 M and [initiator] = 5 mM at 25 °C and in a tetrahydrofuran solvent. Polymerization occurs with good control, as evidenced by the linear fit to a plot of molecular weight versus conversion, the narrow dispersities, and the limited transesterification. The same initiating system is inactive for the ring-opening copolymerization of carbon dioxide (CO2) and cyclohexene oxide at 80 °C and 1 bar of CO2 pressure. However, stoichiometric reactions between complex 2 and CO2, at 1 bar pressure, result in the reversible formation of new dizinc carbonate species, [L(Et)Zn2((i)PrO)((i)PrOCO2)] (3a) and [L(Et)Zn2((i)PrOCO2)2] (3b), and the reaction was studied using density functional theory calculations. All of the new complexes, 1-3b, are fully characterized, including NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction.

Preparation and Characterization of Dictyophora indusiata Polysaccharide-Zinc Complex and Its Augmented Antiproliferative Activity on Human Cancer Cells

Dictyophora indusiata polysaccharide (DP1) was successfully chelated with zinc chloride to achieve its enhanced antiproliferative activity. The obtained DP1-Zn complex showed significant antiproliferative activity (18.1 ± 2.84% viability of MCF-7 cells at 250 μg/mL) on a group of human cancer cell lines through induction of apoptosis. The pro-apoptotic action of DP1-Zn was confirmed by morphological changes including chromatin condensation, DNA breakage, and S phase cell cycle arrest in human breast adenocarcinoma cells (MCF-7). The DP1-Zn-induced apoptotic pathways were characterized by the activation of caspases-3, -8, and -9, mitochondrial dysfunction, and reactive oxygen species (ROS) overproduction (305 ± 7.06% production of control at 250 μg/mL). This study suggested that DP1-Zn can be developed as a candidate for cancer treatment and prevention, especially human breast adenocarcinoma.

Sol-gel encapsulation of binary Zn(II) compounds in silica nanoparticles. Structure-activity correlations in hybrid materials targeting Zn(II) antibacterial use

In the emerging issue of enhanced multi-resistant properties in infectious pathogens, new nanomaterials with optimally efficient antibacterial activity and lower toxicity than other species attract considerable research interest. In an effort to develop such efficient antibacterials, we a) synthesized acid-catalyzed silica-gel matrices, b) evaluated the suitability of these matrices as potential carrier materials for controlled release of ZnSO4 and a new Zn(II) binary complex with a suitably designed well-defined Schiff base, and c) investigated structural and textural properties of the nanomaterials. Physicochemical characterization of the (empty-loaded) silica-nanoparticles led to an optimized material configuration linked to the delivery of the encapsulated antibacterial zinc load. Entrapment and drug release studies showed the competence of hybrid nanoparticles with respect to the a) zinc loading capacity, b) congruence with zinc physicochemical attributes, and c) release profile of their zinc load. The material antimicrobial properties were demonstrated against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus) and negative (Escherichia coli, Pseudomonas aeruginosa, Xanthomonas campestris) bacteria using modified agar diffusion methods. ZnSO4 showed less extensive antimicrobial behavior compared to Zn(II)-Schiff, implying that the Zn(II)-bound ligand enhances zinc antimicrobial properties. All zinc-loaded nanoparticles were less antimicrobially active than zinc compounds alone, as encapsulation controls their release, thereby attenuating their antimicrobial activity. To this end, as the amount of loaded zinc increases, the antimicrobial behavior of the nano-agent improves. Collectively, for the first time, sol-gel zinc-loaded silica-nanoparticles were shown to exhibit well-defined antimicrobial activity, justifying due attention to further development of antibacterial nanotechnology.

Synthesis, characterization, crystal structure and cytotoxic properties of thiosemicarbazide Ni(II) and Zn(II) complexes

Synthesis of new complexes of Ni(II) (1) and Zn(II) (2) with [1-(2-hydroxy-3,5-diiodobenzylidene)-4-phenylthiosemicarbazide] have been reported. The composition of these two complexes 1 and 2 is discussed on the basis of IR, (1)H NMR and UV spectral data along with their X-ray crystallographic data. The crystal structure of these two complexes has revealed that the free ligand (L) is deprotonated twice at the oxygen and sulfur atoms and they are coordinated with the complexes through phenoxide-O, azomethine-N and thiolate-S atoms. The single-crystal X-ray structures of complex (1) exhibits a square planar structure, while complex (2) reveals trigonal bipyramidal distorted square based pyramidal structure. Anticancer activity of ligand and the complexes 1-2 are evaluated in human adenocarcinoma (MCF-7) cells. The preliminary bioassay indicates that the free ligand and the complexes 1-2 exhibit inhibitory activity against the human adenocarcinoma cancer cell lines.

Synthesis, structure, photoluminescence and antitumour activity of zinc complex based on 2-(2-(1H-benzo-[d]imidazol-2-yl)benzyl)-1H-benzo-[d]imidazole

A new complex [Zn(bbb)Cl2]·DMF, where bbb is 2-(2-(1H-benzo[d]imidazol-2-yl)benzyl)-1H-benzo[d]imidazole, was synthesized and characterized by element analysis, (1)H NMR and X-ray single crystal structure analyses. For complex: crystal system, triclinic, space group, P-1, a=9.4661(13), b=10.3534(14), c=13.0025(18)Å, α=73.477(2), β=80.743(2), γ=88.658(2)°, V=1205.5(3)Å(3), Z=2. In this complex, the Zn(2+) distorted tetrahedron geometry is coordinated by two nitrogen atoms from 2-(2-(1H-benzo[d]imidazol-2-yl)benzyl)-1H-benzo[d]imidazole and two Cl(-). The complex emits yellow green luminescence with the maximal emission peak at 550 nm in DMF solution. The complex exhibits inhibition on the growth of Eca109 cancer cell with IC50 value of 8.9±1.1 μM, which was lower than that of cisplatin (14.3±1.4 μM). This complex has potential application in treatment of esophageal cancer.

Nuclease activity and interaction studies of unsymmetrical binuclear Ni(ii) complexes with CT-DNA and BSA

A new series of binuclear Ni(ii) complexes have been synthesized and their BSA, DNA binding and nuclease activity have been evaluated.