DNA Cleavage Potential Research Articles

Cadmium(II) coordination polymer based on flexible dithiolate-polyamine binary ligands system: Crystal structure, Hirshfeld surface analysis, antimicrobial, and DNA cleavage potential

The mononuclear chelating complex [Cd(i-mnt)(tren)]n (1) fabricated from binary ligand systems 1,1-dicyanoethylene-2,2-dithiolate (i-mnt−2) and diethylenetriamine (tren) has been synthesized and structurally characterized by spectroscopic methods (IR, NMR). The single-crystal X-ray diffraction study reveals that Cd+2 has CdN3S3 coordination kernel having distorted trigonal prism geometry (TP) [twist angle (θ) 37.6(11)0] and the secondary ligand tren influences the ligation pattern of i-mnt−2 towards metal center in the formation of 1D polymeric chain where asymmetric units linked by bridging thiolate S2-atom of each i-mnt−2. The N H···N, N H···S type hydrogen bonds link the 1D polymeric chains in a 3D stacked chain supramolecular arrangement with apparent graph-set-motifs R118, C(4), and C(8). The Hirshfeld surface analysis corroborates well with X-ray data and explores all possible intermolecular interactions especially dominant N···H (16.6%) and H···S (7.3%) contacts. The MIC, MBC and in-vitro antibacterial study against Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) human pathogenic bacterial strains shows promising bactericidal activity. In-vitro antifungal study disclosing more activity against Aspergillus niger compared to Candida albicans at 50 mg/mL. DNA cleavage study (E. coli DNA) via Agarose gel electrophoresis shows DNA cleaving property of the title compound similar to that of H2O2 due to the suitable coordination of Cd(II) metal center.

Green synthesis of hematite nanoparticles using aqueous extract of Teucrium Polium after microwave-assisted extraction: synthesis, characterization and evaluation of some biological activities

This work presented a green approach for the synthesis of hematite (α-Fe2O3) magnetic nanoparticles (MNPs) using the aqueous extract of Teucrium Polium plant. The aqueous extracts were prepared by the maceration and microwave-assisted extraction (MAE) techniques and performed as the natural precursor for one-step green synthesis of α-Fe2O3 MNPs, at room temperature. The as-prepared α-Fe2O3 MNPs were characterized by different techniques including UV-Vis absorption spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray(EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and vibrating sampling magnetometer (VSM). The XRD results confirmed the high crystalline structure of magnetic α-Fe2O3 MNPs. The average particle size of MNPs was obtained around 60 nm. In addition, the antibacterial properties of the as-synthesized α-Fe2O3 MNPs against various pathogenic bacteria were investigated by well-diffusion test. Based on the observations, α-Fe2O3 MNPs were more sensitive against Gram-negative bacteria than the Gram-positive bacteria. Moreover, the DNA cleavage potential of the samples was studied, too.

Ultrasonic assisted preparation of some new zinc complexes of a new tetradentate Schiff base ligand: thermal analyses data, antimicrobial and DNA cleavage potential

AbstractA new tetradentate Schiff base ligand (L) (L = obtained by condensation reaction between triethylenetetraamine and (E)‐3‐(2‐nitrophenyl)acrylaldehyde) and some of its zinc (II) complexes formulated as ZnLX2 in which X = halide/pseudohalide were synthesized and characterized by some physical and spectral techniques such as infra‐red (IR), nuclear magnetic resonance (NMR), UV–Visible, microanalyses, and conductivity measurements. Among the complexes, zinc chloride, iodide, and nitrate complexes were also prepared as nanostructure powder under sonication conditions confirmed by x‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x‐ray analysis (EDAX). Moreover, zinc oxide nanoparticles were prepared by direct thermolysis of nanopowder of ZnLI2 complex under air atmosphere. Moreover, the thermal behaviors of the compounds were studied based on thermo‐gravimetric (TG)/differential thermal gravimetric (DTG)/differential thermal analyses (DTA) analyses data under nitrogen atmosphere. Furthermore, antibacterial/antifungal activities of the ligand and its zinc complexes were screened by the well diffusion method against some bacteria and funguses. Ultimately, the DNA cleavage potential of the compounds was evaluated by gel electrophoresis technique.

Coordination framework of cadmium(II), harvested from dithiolate-imidazole binary ligand systems: Crystal structure, Hirshfeld surface analysis, antibacterial, and DNA cleavage potential

The novel one-dimensional coordination polymer with binuclear building node {[Cd2(i-mnt)2(Im)2]DMF2}n (1) harvested from 1,1-dicyanoethylene-2,2-dithiolate (i-mnt2−) and imidazole (Im) has been systemically designed, synthesized and structurally characterized by elemental analysis, FT-IR and 1H NMR spectroscopy. Single crystal X-ray diffraction analysis revealed that in 1, each Cd(II) is in penta-coordinated environment having slightly distorted square pyramidal geometry (τ5 = 0.24) and have two bridging thiolate ends of i-mnt−2- along with one DMF solvent molecule. The flexible i-mnt2− ligand acts as a tridentate connector by ligating with Cd(II) centers in parallel dimeric units forming a 1D polymeric chain. Hirshfeld surface analyses and two dimensional (2D) finger print plots were employed to decode all types of non-covalent contacts in the crystal frameworks, allowing a systematic evaluation of the crystal structure. From HS analysis, it was observed that N⋯H/H⋯N type interactions (22.1%) have the major contribution compared to overall non-covalent interacrtions. The share of H⋯O/O⋯H interactions of the total surface is only 3.7%, their role is important in the direction and organization of crystal packaging. The in-vitro antimicrobial study of 1 against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (E. coli and P. aeruginosa) human pathogenic bacterial strains show promising antimicrobial activities. Furthermore, DNA cleavage study (E. coli DNA) of 1 using gel electrophoresis method revealed promising DNA cleaver property similar to H2O2 due to the efficient coordination of Cd(II) ion.

A mononuclear copper(II) complex containing benzimidazole and pyridyl ligands: Synthesis, characterization, and antiproliferative activity against human cancer cells

Metal complexes are recently being hybridized with different moieties to discover new drugs due to their advantageous attributes. Among the metals, copper is a good one to synthesize a metal complex due to its being endogenous, redox and DNA cleavage potential, reported anti-cancer efficacies and selective permeability for cancer cells. In this study, first we synthesized a new copper (II) complex and determined its toxic doses on NIH/3T3 normal fibroblast cells, SPC212 mesothelioma and DU145 prostate cancer cells. Then, we ascertained anti-proliferative, apoptotic, morphological, oxidative and endoplasmic reticulum (ER) stress inducing effects of these newly synthesized compounds on DU145 prostate cancer cells. A novel Copper(II)/1-(4-(trifluoromethyl)benzyl)-1H-benzimidazole/2,2′-bipyridyl complex was synthesized and mainly characterized by single crystal X-ray diffraction analysis. Anti-proliferative effect of copper(II) complex was gauged by MTT. Oxidative and ER stress were evaluated by ELISA and Western blot. The morphological effect was examined by microscope analysis. Besides, immunocytochemistry of Bax, a pro-apoptotic protein and PCNA, a proliferation marker protein was performed. As a result, the inhibitory effect of newly synthesized substance was superior to the chemicals from which it was synthesized. Its IC50s against DU145 were 37.0, 21.1 and 10.0 µM for 24, 48 and 72 h-treatments, respectively. Oxidative and ER stress increased after treatment. In microscopy, we observed apoptotic hallmarks like nuclear condensation, cellular shrinkage and membrane blebbings. In immunochemistry, increased Bax and decreased PCNA were apparent. Copper(II) complex with its relatively low IC50 can also be tested on other cancer and normal cell lines.

Synthesis, characterization, DNA binding and cleavage activity of homoleptic zinc(II) β-oxodithioester chelate complexes

New homoleptic zinc(II) complexes, [Zn(L)2], where L = methyl-3-hydroxy-(3-pyridyl)-2-propenedithioate L1 1, and methyl-3-hydroxy-(4-pyridyl)-2-propenedithioate L2 2, have been synthesized and characterized by elemental (C, H, and N) analysis, ESI-MS, and (IR, UV–vis, NMR) spectroscopy; the structure of 1 has been deduced by X-ray crystallography. The DNA binding and cleavage activity of the complexes have been studied. The cleavage potential of pBR322 DNA by 1 and 2 has been checked. Complex 1, which contains nitrogen of the pyridine group in the 3-position enhances DNA cleavage potential in the presence of ascorbic acid; however, the complex is protective against DNA cleavage in the presence of DMSO or H2O2. Also, 1 causes cytotoxicity against the MCF-7 breast cancer cell line. The efficient cytotoxic activity and DNA cleavage ability of 1 in the presence of ascorbic acid shows its potential anticancer properties and the need for further investigations of its potential as an anticancer drug.

Some new 4-coordinated nanostructure cadmium imidazolidine Schiff base complexes: Thermal behavior, antimicrobial, and DNA cleavage potential

In this study, a new series of cadmium halide/pseudohalide complexes with a novel Schiff base ligand containing imidazolidine ring has been successfully synthesized. The structure of the ligand and its complexes was characterized by analysis tools such as Fourier transform infrared, UV-visible, proton and carbon nuclear magnetic resonance spectra, molar conductance, and thermal analysis. Also cadmium bromide and iodide nanostructure complexes have been prepared via sonochemical method. X-ray powder diffraction and scanning electron microscopy techniques confirmed nanostructure sheets for these 2 cadmium complexes. All the newly prepared compounds were screened for their antimicrobial activities, against 4 bacterial and 2 fungal strains using disk diffusion and serial dilution methods. The CdL(N3)2 and CdLCl2 complexes showed the best antimicrobial activity as compared with other compounds. Moreover, DNA cleavage potential of all compounds was investigated by agarose gel electrophoresis method. The results showed remarkable ability of some cadmium complexes for DNA cleavage. Furthermore, thermal behaviors of all cadmium complexes were studied in the range of room temperature to 800°C under nitrogen atmosphere. The complexes were thermally decomposed via 2 to 4 steps. Cadmium metal was suggested as final residue at the end of thermal decomposition process.

Crystal structure, DNA interaction and thermal analysis data of two new antimicrobial active binuclear cadmium and mercury complexes

Two new binuclear Schiff base complexes with the general formula [CdLBr(μ-Br)]2 (1) and [Hg2L(μ-I)2I2] (2) were prepared by the reaction of 2,2-dimethyl-N,N'- bis-(3-phenyl-allylidene)-propane-1,3-diamine (L), CdBr2 and HgI2. The crystal structure of two complexes was determined by X-ray crystallography. The common structures for four-coordinated compounds are square planar or the tetrahedral geometries, which is evaluated by the Houser angular index (τ4). In [CdLBr(μ-Br)]2 (1), each cadmium center is five-coordinated by two iminic nitrogen atoms from Schiff base ligand, two μ2-bridging bromide anions and one terminal coordinating bromide anion. The metal center in this centrosymmetric dimer has a distorted square-pyramidal geometry. [Hg2L(μ-I)2I2] (2) consists of two four-coordinated mercury centers with different coordination spheres (HgN2I2 for Hg1 and HgI4 for Hg2). The TG/DTG diagrams showed that both complexes were completely decomposed under a nitrogen atmosphere. Furthermore, antibacterial activities of compounds have been screened against various bacteria and fungi by Disk diffusion method. Mercury complex inhibited the growth of the microorganisms more efficient than cadmium complex. DNA cleavage potential of compounds was evaluated by agarose gel electrophoresis method. Finally, nano-structure cadmium complex was sono-chemically synthesized and applied as precursor for preparation of cadmium oxide nanoparticles.

Microwave assisted extraction as an efficient approach for biosynthesis of zinc oxide nanoparticles: Synthesis, characterization, and biological properties

In the present study, microwave assisted extraction (MAE) was applied as an efficient, green and rapid approach to prepare the aqueous extract of Suaeda aegyptiaca (SA) plant. The obtained aqueous extracts at two different irradiation power (90 and 270W; 15min) in MAE process as well as maceration method (24h) were used in a green and eco-friendly approach for the synthesis of zinc oxide nanoparticles (ZnO NPs). The synthesized ZnO NPs have been characterized via different techniques including UV–Vis absorption; fluorescence and Fourier transform infrared (FT-IR) spectroscopices, scanning electron microscopy (SEM), and X-ray diffraction (XRD). According to the results, the average size of the prepared ZnO particles was estimated around 60nm. A broad absorption band around 382nm in UV–Vis absorption spectrum and a maximum emission at wavelength of 458nm in fluorescence spectrum clarified the successful biosynthesis of ZnO NPs. Moreover, the biological properties of the extracts and biosynthesized ZnO NPs were investigated by antimicrobial tests (i.e. Well-diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) tests), antifungal and antioxidant tests (total phenolic and flovonoid content, antioxidant activity against dipheny-picrylhydrazyl (DPPH), and ethylbenzothiazolin-6sulphonic acid (ABTS+)). Finally, DNA cleavage potential of the samples was studied, too.

Novel biological active nanostructure cadmium coordination compounds: Thermal analyses data and usage as new precursors for preparation of cadmium oxide nanoparticles

ABSTRACTA new long-chain bidentate Schiff base ligand entitled of N1,N5-bis((E)-3-(4-(dimethylamino)phenyl) allylidene)-2-methylpentane-1,5-diamine(L) was synthesized. Then four novel cadmium coordination compounds of this ligand were prepared. Schiff base ligand and its complexes were characterized by FT-IR, 1H, 13C NMR, UV–Vis spectra and molar conductance measurements.Based on spectral data, the general formula of CdLX2 (X = Cl−, Br−, I−, and SCN−) was proposed for the cadmium complexes. The cadmium compounds in nanostructure size were also prepared by sonochemical method. The nanostructure compounds were characterized by X-ray diffraction (XRD) and scanning electron microscopy. The particle sizes were evaluated to be 28.04, 22.60, 11.30, and 31.85 nm for cadmium chloride, bromide, iodide, and thiocyanate complexes, respectively. Moreover, cadmium oxide nanoparticles with average size of about 26 nm were prepared and were characterized by XRD and transmission electron microscopy. Furthermore, the antimicrobial activity of the ligand and its cadmium complexes against four Gram-positive and Gram-negative bacteria and also two fungi was assessed. Also, electrophoresis method revealed that all compounds have DNA cleavage potential. Finally, thermal behaviors of all compounds were studied by TG/DTG/DTA analyses data.

Crystal structure, DFT study, antimicrobial properties and DNA cleavage potential and thermal behavior of some new mercury complexes

In this study, a new bidentate Schiff base ligand (L) entitled as N,N’-bis(dimethylaminocinnamaldehyde)-2,2-dimethyl-1,3-propanediamine and its mercury complexes were synthesized. The Schiff base ligand and its complexes were characterized using FT-IR, 1H-, 13C-NMR spectroscopy, molar conductivity and electronic spectral study. Regarding physical and spectral data, the general formula for the complexes was suggested as HgLX2 (L = Schiff base ligand and X = Cl−, Br−, I−, SCN−, N3 −). For structural identification of these complexes, crystal structure of mercury iodide complex was analyzed as typical one. In the structure of this complex, Hg ion is surrounded by 2 iodide ions and 2 N atoms from the Schiff base ligand to form a four-coordinated mercury complex in triclinic system with space group of P 1. Angular index (τ 4) value was evaluated equal to 0.85, so the geometry around the mercury ion in this complex can be described as trigonal pyramid. A layered supramolecular structure for HgLI2 complex is stabilized by C–H···I and C–H···π interactions in solid state. DFT study on the ligand and its complexes was also carried out, and then some calculated and experimental structural parameters of HgLI2 were compared. Thermal behaviors of the titled compounds were investigated by thermogravimetric analyses. Furthermore, biological properties of the ligand and its complexes were examined against some Gram-negative and Gram-positive bacteria and also against 2 fungi. Finally, the interaction of the ligand and its complexes with DNA was investigated by electrophoresis method.

Controlled release of drug and better bioavailability using poly(lactic acid-co-glycolic acid) nanoparticles

Tamoxifen (Tmx) embedded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-Tmx) is prepared to evaluate its better DNA cleavage potential, cytotoxicity using Dalton’s lymphoma ascite (DLA) cells and MDA-MB231 breast cancer cells. PLGA-Tmx nanoparticles are prepared through emulsified nanoprecipitation technique with varying dimension of 17–30nm by changing the concentrations of polymer, emulsifier and drug. Nanoparticles dimension are measured through electron and atomic force microscopy. Interactions between tamoxifen and PLGA are verified through spectroscopic and calorimetric methods. PLGA-Tmx shows excellent DNA cleavage potential as compared to pure Tmx raising better bioavailability. In vitro cytotoxicity studies indicate that PLGA-Tmx reduces DLA cells viability up to ∼38% against ∼15% in pure Tmx. Hoechst stain is used to detect apoptotic DLA cells through fluorescence imaging of nuclear fragmentation and condensation exhibiting significant increase of apoptosis (70%) in PLGA-Tmx vis-à-vis pure drug (58%). Enhanced DNA cleavage potential, nuclear fragmentation and condensation in apoptotic cells confirm greater bioavailability of PLGA-Tmx as compared to pure Tmx in terms of receptor mediated endocytosis. Hence, the sustained release kinetics of PLGA-Tmx nanoparticles shows much better anticancer efficacy through enhanced DNA cleavage potential and nuclear fragmentation and, thereby, reveal a novel vehicle for the treatment of cancer.

Antimicrobial activity, DNA cleavage, thermal analysis data and crystal structure of some new CdLX2 complexes: A supramolecular network.

Some new cadmium(II) Schiff base complexes CdLX2 (where X=Cl(-), Br(-), I(-), SCN(-) and N3(-) and L=N,N-bis((E)-3-(4-(dimethylamino)phenyl)allylidene)benzene-1,2-diamine) were synthesized and characterized by elemental analysis, FT-IR, UV-visible, (1)HNMR spectra, and conductivity measurements. Moreover, the structure of the CdLI2 was determined by single crystal X-ray crystallography. CdLI2 crystallizes in a triclinic system with space group P 1̅. The molecular structure shows distorted tetrahedral coordination geometry. The CH....π and π-π stacking interactions connect the molecules to a supramolecular network. The thermal properties of the compounds were investigated from the room temperature to 800 °C with a heating rate of 10 °C/min and decomposition activation parameters were evaluated from the TG/DTG plots. Antibacterial/antifungal activities of the compounds were screened by the disk diffusion method against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis and the fungi strain Aspergillus niger and Candida albicans. The antimicrobial activities were determined for all compounds and the complexation was found to enhance the inhibitory activity. Finally, the DNA cleavage potential of the compounds was investigated by agarose gel electrophoresis method.

Synthesis, spectral, crystal structure, thermal behavior, antimicrobial and DNA cleavage potential of two octahedral cadmium complexes: A supramolecular structure

Two new cadmium(II) complexes with the formula of CdL2(NCS)2 and CdL2(N3)2 (in which L is 2,2-dimethyl-N,N′-bis-(3-phenyl-allylidene)-propane-1,3-diamine) have been synthesized and characterized by elemental analysis, molar conductivity measurements, FT/IR, UV–Visible, 1H and 13C NMR spectra and X-ray studies. The crystal structure analysis of CdL2(NCS)2 indicated that it crystallizes in orthorhombic system with space group of Pbca. Two Schiff base ligands are bonded to cadmium(II) ion as N2-donor chelate. Coordination geometry around the cadmium ion was found to be partially distorted octahedron. The Cd–Nimine bond distances are found in the range of 2.363(2)–2.427(2)Å while the Cd–Nisothiocyanate bond distances are 2.287(2)Å and 2.310(2)Å. The existence of C–H⋯π and C–H⋯S interactions in the CdL2(NCS)2 crystal leads to a supramolecular structure in its network. Then cadmium complexes were screened in vitro for their antibacterial and antifungal activities against two Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus. Moreover, the compounds were subjected for DNA-cleavage potential by gel electrophoresis method. Finally thermo-gravimetric analysis of the complexes was applied for thermal behavior studies and then some thermo-kinetics activation parameters were evaluated.

Synthesis, characterization, and thermal behavior of some new biological-active zinc halide/pseudohalide complexes

A new ligand entitled as N,N’-bis-[3-(4-dimethylaminophenyl)-allylidene]-propane-1,3-diamine(L) was synthesized and then used for preparation of a new series of zinc halide/pseudohalide complexes with general formula of ZnLX2, wherein X is chloride, bromide, iodide, thiocyanate, and azide anions. The ligand and its complexes were characterized by analytical and spectral data such as conductivity measurements, elemental analysis, FT-IR, UV–Visible, and 1H NMR spectroscopy. Elemental analyses (CHN) suggested that the reaction between ligand and zinc salts has been occurred in 1:1 molar ratio. The low values for molar conductivities of the zinc complexes indicated non-electrolyte nature for them. Spectral data confirmed that the ligand behaves as a bidentate chelate and is coordinated via nitrogen atoms of imine groups. Moreover, thermal analysis of ligand and its complexes were studied in the range of room temperature to 1,000 °C with a heating rate of 10 °C min−1. TG/DTG/DTA plots show that the ligand and its complexes are thermally decomposed via 2–4 thermal steps. In final, the ligand and its complexes were subjected to antimicrobial screening by determining of minimum inhibitory concentration (MIC) and inhibition zone of the microbial growth. Also DNA cleavage potential of all compounds was evaluated by gel electrophoresis method.

Some new nano-structure zinc(II) coordination compounds of an imidazolidine Schiff base: Spectral, thermal, antimicrobial properties and DNA interaction

Some novel nano-sized structure zinc complexes of a new Schiff base ligand entitled as (3-nitro-benzylidene)-{2-[2-(3-nitro-phenyl)-imidazolidine-1-yl]-ethyl}-amine(L) with general formula of ZnLX2 wherein X=Cl−, Br−, I−, SCN− and N3− have been synthesized under ultrasonic conditions. The ligand and its complexes have been characterized by elemental analysis, molar conductance measurements, FT-IR, 1H and 13C NMR and UV–Visible spectroscopy. The resulting data from spectral investigation especially 1H and 13C NMR well confirmed formation of an imidazolidine ring in the ligand structure. Transmission electron microscopy (TEM) showed nano-size structures with average particle sizes of 21.80–78.10nm for the zinc(II) Schiff base complexes. The free Schiff base and its Zn(II) complexes have been screened in vitro both for antibacterial activity against some gram-positive and gram-negative bacteria and also for antifungal activity. The metal complexes were found to be more active than the free Schiff base ligand. The results showed that ZnL(N3)2 is the most effective inhibitor against Escherichia coli, Pseudomonas aereuguinosa, Staphylococcus aureus and Candida albicans while ZnLBr2 was found to be more effective against Bacillus subtillis than other compounds. Moreover, DNA cleavage potential of all compounds with plasmid DNA was investigated. The results showed that the ligand and ZnLCl2 complex cleave DNA more efficiently than others. In final, thermal analysis of ligand and its complexes revealed that they are decomposed via 2–3 thermal steps in the range of room temperature to 1000°C. Furthermore some activation kinetic parameters such as A, E*, ΔH*, ΔS* and ΔG* were calculated based on TG/DTA plots by use of coats – Redfern relation. Positive values of activation energy evaluated for the compounds confirmed the thermal stability of them. In addition to, the positive ΔH*, and ΔG* values suggested endothermic character for the thermal decomposition steps.

Synthesis, characterization, and DNA cleavage study of dehydroacetic acid based tridentate Schiff’s base and its metal complexes of first transition series

In search of novel chemical nucleases the synthesis of dehydroacetic acid based tridentate hydrazone Schiff base and its colored complexes with Co(II), Ni(II), Cu(II), Mn(II), and Zn(II) has been achieved. All synthesized compounds were screened for their DNA cleavage potential using the plasmid DNA. The hydrazone Schiff base was synthesized via a condensation reaction between acetic acid hydrazide and dehydroacetic acid. Further, this novel ligand was allowed to react with different transition metal salts in 1:1 and 1:2 ratios, respectively to synthesize metal complexes with a different ligand to metal stoichiometry. All the compounds were characterized on the basis of various spectroscopic techniques. 1H NMR data of complexes showed the coordination of enolic oxygen atom with subsequent lose of proton and IR data shows that the participation of carbonyl oxygen atom of ligand in coordination with metal ion. UV–Visible data reveals the square planner and octahedral geometry of the synthesized metal complexes. Mass spectrum confirms the formation of both 1:1 and 1:2 metals to ligand stoichiometry. Metal complexes were found to exhibit good level of DNA cleaving activities at concentration of 10 μg μl−1.

DNA binding and cleavage behaviors of copper(II) complexes with amidino-O-methylurea and N-methylphenyl-amidino-O-methylurea, and their antibacterial activities

Abstract The two designed copper(II) complexes, [Cu(L 1m ) 2 ]Cl 2 ( 1 ) (L 1m = amidino- O -methylurea) and [Cu(L 2m ) 2 ]Cl 2 ( 2 ) (L 2m = N -methylphenyl-amidino- O -methylurea), have been investigated for their interaction with calf thymus DNA by utilizing the absorption titration method, viscometric studies and thermal denaturation. The cleavage reaction on pBR322 DNA has been monitored by agarose gel electrophoresis. The results suggest that the two complexes can bind to DNA by non-intercalative modes and exhibit nuclease activities in which supercoiled plasmid DNA is converted to the linear form. Complex 2 , with an intrinsic binding constant ( K b ) of 1.16 × 10 5 M −1 , shows a higher binding efficiency and a better nuclease activity than complex 1 , with a K b value of 5.67 × 10 4 M −1 . Their DNA cleavage potential can be significantly enhanced by hydrogen peroxide, indicating an oxidative cleavage process. Further examination of the antibacterial activities against Campylobacter has revealed inhibition zones of 9.0 (for 1 ) and 14.5 mm (for 2 ), which are in agreement with their minimum inhibitory concentration (MIC) values of 1.56 and 0.78 mg mL −1 , respectively. The substantially better reactivity of 2 results from the aromatic moieties on the side chain of the L 2m ligand which act as an additional binding site.

Metal-free artificial nucleases based on simple oxime and hydroxylamine scaffolds

Hydrolysis of DNA is of increasing importance in biotechnology and medicine. In this Letter, we present the DNA-cleavage potential of metal-free hydroxylamines and oximes as new members of nucleic acid cleavage agents.

Benzofused N-substituted cyclic enediynes: Activation and DNA-cleavage potential

The effect of electron withdrawal on the reactivity of N-substituted cyclic enediynes has been studied. These were synthesized via an intramolecular Mitsunobu reaction. The electron withdrawing effect of the nitro groups or the positive charge on the free ammonium salts was found to lower the cyclization temperature for Bergman cyclization. The ammonium salts cleave ds-DNA at nanomolar concentrations.