New homodi-and heterotrinuclear metal complexes of Schiff base compartmental ligand: interaction studies of copper complexes with calf thymus DNA

Synthesis, Chemical Characterisation, and DNA Binding Studies of Ferrocene-Incorporated Selenoureas

In this article we have presented the synthesis, chemical characterisation (by NMR and FTIR spectroscopy, atomic absorption spectrophotometry, elemental analysis, and single crystal X-ray diffraction), electrochemistry, and DNA binding studies (with cyclic voltammetry, viscometry, and UV-vis spectroscopy) of six new ferrocene incorporated selenoureas. All the six compounds interact electrostatically with DNA which was evident by a negative shift in the cyclic voltammetry peak potential of the drug–DNA adduct relative to the free drug. The drug–DNA binding constant was calculated by a decrease in peak current after the addition of DNA to the free drug. We have also reported binding site sizes and diffusion coefficients of the synthesised compounds.

Synthesis, characterization, biological screenings and interaction with calf thymus DNA of a novel azomethine 3-((3,5-dimethylphenylimino)methyl)benzene-1,2-diol

The novel azomethine, 3-((3,5-dimethylphenylimino)methyl)benzene-1,2-diol (HL) was synthesized and characterized by elemental analysis, FT-IR, (1)H, (13)C NMR spectroscopy and single crystal analysis. The title compound has been screened for its biological activities including enzymatic study, antibacterial, antifungal, cytotoxicity, antioxidant and interaction with CTDNA, and showed remarkable activities in each area of research. The titled compound interacts with DNA via two binding modes: intercalation and groove binding. In intercalation the compound inserts itself into the base pairs of DNA and the compound-DNA complex is stabilized by π-π stacking. Interaction via groove binding may be due to hydrogen bonding to bases, typically to N3 of adenine and O2 of thymine. The synthesized compound was also found to be an effective antioxidant of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and gives percent inhibition (%I) of 90.7 at a concentration level of 31.3μg/mL.

Design, synthesis, characterization and DNA-binding studies of a triphenyltin(IV) complex of N-glycoside (GATPT), a sugar based apoptosis inducer: in vitro and in vivo assessment of induction of apoptosis by GATPT

The novel organotin complex 1-{(2-hydroxyethyl)amino}-2-amino-1,2-dideoxy-D-glucose triphenyltin(iv) (GATPT) was synthesized by the reaction of N-glycoside ligand and triphenyltin(iv) chloride. GATPT was characterized by elemental analyses, polarimetry, IR, CD, UV and multinuclear ((1)H, (13)C, (119)Sn) 1D and 2D NMR. The interaction of GATPT with calf thymus DNA was studied by using viscometry, absorption, emission and circular dichoric spectral methods. The DNA binding results suggested the intercalative mode of binding for GATPT with DNA along with simultaneous electrostatic interaction between the Sn(iv) center and the phosphate backbone of the DNA helix. GATPT was tested for its cytotoxic properties against SY5Y, PC-12 and N2A neuronal tumor cell lines. GATPT induced significant apoptosis in the PC-12 cell line characterized by DNA fragmentation and chromosome condensation. Treatment of PC-12 cells with GATPT resulted in a dramatic up-regulation of Bax and Bak and down-regulation of the anti-apoptotic factor Bcl-2. Apoptotic induction by GATPT was shown to be mediated in a p53-dependent manner and loss of p53 impaired the release of cytochrome c from mitochondria to cytosol. Caspase-3 was found to be indispensable for the GATPT triggered apoptosis signaling pathway. Furthermore, in vivo studies using a nude mice model revealed that GATPT exhibits significant antiproliferative activity against tumor development with minimal cytotoxicity. These findings warrant further clinical investigations of GATPT as a therapeutic agent for cancer chemotherapy.

Metallation of ethylenediamine based Schiff base with biologically active Cu(II), Ni(II) and Zn(II) ions: synthesis, spectroscopic characterization, electrochemical behaviour, DNA binding, photonuclease activity and in vitro antimicrobial efficacy

A new ligand [C28H20N6O8] (L2) has been synthesized by the condensation reaction of 3-hydroxy-4-nitrobenzaldehydenephenylhydrazine (L1) with diethyloxalate. This ligand L2 is allowed to react with bis(ethylenediamine)Cu(II)/Ni(II)/Zn(II) complexes. It affords [(L2)Cu(en)2]Cl2(1)/[(L2)Ni(en)2]Cl2(2)/[(L2)Zn(en)2]Cl2(3) complexes, respectively. These complexes (1-3) have been characterized by the spectral and analytical techniques. The interaction of these complexes with calf thymus (CT) DNA is characterized by the absorption spectra which exhibit a slight red shift with hypochromic effect. Electrochemical analyses and viscosity measurements have also been carried out to determine the mode of binding. The shift in ΔEp, E1/2 and Ipc values explores the interaction of CT DNA with the above metal complexes. The slight increase in the viscosity of CT DNA indicates that these complexes bind to CT DNA through a partial non-classical intercalative mode. Cleavage experiments using pBR322 DNA in presence of H2O2 indicate that these complexes behave as efficient artificial chemical nucleases in the order of 1>2>3. Moreover, the antibacterial and antifungal studies reveal that complex 1 is highly active against the bacterial and fungal growth.

DNA binding, antioxidant and antimicrobial activities of homo- and heteronuclear copper(II) and nickel(II) complexes with new oxime-type ligands

Some homo- and heteronuclear Cu(II) and Ni(II) complexes of new oxime-type ligands were tested against several pathogenic microorganisms to assess their antimicrobial potentials. The antimicrobial activities of complexes were evaluated in terms of minimum inhibitory concentration (MIC; μg/μL) and it was observed that the complexes possess moderate antimicrobial properties. The binding of the complexes with DNA were also investigated by using UV-Vis spectroscopy. It was seen that three of the complexes could bind to DNA through an intercalative mode while the other complexes could have other mechanisms. Furthermore, the antioxidant efficiencies of the metal complexes were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavening activities. Due to the observed IC(50) values, they are potential drugs to eliminate the radicals.