A potent drug candidature of Cu(II) pyrazino[2,3-f][1,10]phenanthroline complexes with bioactive ligands: synthesis, crystal structures, biomolecular interactions, radical scavenging and cytotoxicities.

A novel ternary copper(II) complexes, - [Cu(py-phen)(asn)(NO3)(H2O)] (1) and [Cu(py-phen)(trp)(H2O)]NO3 (2)- (py-phen: pyrazino[2,3-f][1,10]phenanthroline, asn: asparagine, trp: tryptophan), have been synthesized and characterized by CHN analysis, ESI-MS, FTIR and single-crystal X-ray diffraction techniques. Interaction of the complexes 1 and 2 with CT-DNA has been investigated by absorption spectral titration, EB and Hoechst 33258 displacement assay. The interaction between the complexes 1 and 2 and BSA was investigated by electronic absorption and fluorescence spectroscopy methods. The experimental outcomes indicate that the fluorescence quenching mechanism between the complexes 1 and 2 and BSA is a static quenching process. The Stern-Volmer constants, binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, ΔS) of BSA + complex systems were determined at different temperatures. The binding distance between the complexes 1 and 2 and BSA was calculated according to FRET. The effect of the complexes 1 and 2 on the conformation of BSA was also examined using synchronous, two dimensional (2D) and three dimensional (3D) fluorescence spectroscopy. Radical scavenging activity of the complex was determined in terms of EC50, using the DPPH and H2O2 method. The anticancer activities of the complexes 1 and 2 were investigated using an XTT assay against three cancer cell lines (MCF-7, Caco-2 and A549) and non-tumor cell line (BEAS-2B). Communicated by Ramaswamy H. Sarma.

New binary copper(II) complexes containing intercalating ligands: DNA interactions, an unusual static quenching mechanism of BSA and cytotoxic activities.

New binary copper(II) complexes - [Cu(4-mphen)2(NO3)]NO3·H2O (1), [Cu(5-mphen)2 (NO3)]NO3·H2O (2), the known complex [Cu(dmphen)2(NO3)]NO3 (3) and [Cu(tmphen)2 (NO3)]NO3·H2O (4) - (4-mphen: 4-methyl-1,10-phenanthroline, 5-mphen: 5-methyl-1,10-phenanthroline, dmphen: 4,7-dimethyl-1,10-phenanthroline, tmphen: 3,4,7,8-tetramethyl-1,10-phenanthroline), have been synthesized and characterized by CHN analysis, ESI-MS, FTIR and single-crystal X-ray diffraction techniques. Interaction of these complexes with calf thymus DNA (CT-DNA) has been investigated by absorption spectral titration, ethidium bromide (EB) and Hoechst 33,258 displacement assay and thermal denaturation measurement. These complexes cleaved pUC19 plasmid DNA in the absence and presence of an external agent. Notably, in the presence of H2O2 as an activator, the cleavage abilities of these complexes are obviously enhanced at low concentration. Addition of hydroxyl radical scavengers like DMSO shows significant inhibition of the DNA cleavage activity of these complexes. BSA quenching mechanism was investigated with regard to the type of quenching, binding constant, number of binding locations and the thermodynamic parameters. The experimental results suggested that the probable quenching mechanism was an unusual static process and hydrophobic forces play a dominant role. The CT-DNA and BSA binding efficiencies of these complexes follow the order: 4 > 3 > 1 > 2. Furthermore, in vitro cytotoxicities of these complexes on tumor cells lines (Caco-2, MCF-7 and A549) and healthy cell line (BEAS-2B) showed that these complexes exhibited anticancer activity with low IC50 values. The effect of hydrophobicity of the methyl-substituted phenanthrolines on DNA and protein binding activities of these complexes is discussed.

Synthesis and crystal structures of novel copper(II) complexes with glycine and substituted phenanthrolines: reactivity towards DNA/BSA and in vitro cytotoxic and antimicrobial evaluation.

New copper(II) complexes-dimeric-[Cu(nphen)(gly)(H2O)]+ (1) and [Cu(dmphen)(gly)(NO3)(H2O)] (2) (nphen = 5-nitro-1,10-phenanthroline, dmphen = 4,7-dimethyl-1,10-phenanthroline, and gly = glycine)-have been synthesized and characterized by CHN analysis, single-crystal X-ray diffraction techniques, FTIR, EPR spectroscopy, and cyclic voltammetry. The CT-DNA-binding properties of these complexes have been investigated by thermal denaturation measurements and both absorption and emission spectroscopy. The DNA cleavage activity of these complexes has been studied on supercoiled pUC19 plasmid DNA by gel electrophoresis experiments in the absence and presence of H2O2. Furthermore, the interaction of these complexes with bovine serum albumin (BSA) has been investigated using absorption and emission spectroscopy. The thermodynamic parameters, free-energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS) for BSA + complexes 1 and 2 systems have been calculated by the van't Hoff equation at three different temperatures (293.2, 303.2, and 310.2 K). The distance between the BSA and these complexes has been determined using fluorescence resonance energy transfer (FRET). Conformational changes of BSA have been observed using the synchronous fluorescence technique. In addition, in vitro cytotoxicities of these complexes on tumor cell lines (Caco-2, A549, and MCF-7) and healthy cells (BEAS-2B) have been examined. The antimicrobial activity of the complexes has also been tested on certain bacteria cells. The effect of mono and dimeric in the above complexes is presented and discussed. New copper(II) complexes-dimeric-[Cu(nphen)(gly)(H2O)]+ (1) and [Cu(dmphen)(gly) (NO3)(H2O)] (2) (nphen = 5-nitro-1,10-phenanthroline, dmphen = 4,7-dimethyl-1,10-phenanthroline and gly = glycine)-have been synthesized and characterized by CHN analysis, single-crystal X-ray diffraction techniques, FTIR and EPR spectroscopy. They have been tested for their in vitro DNA/BSA interactions by the spectroscopic methods. These complexes exhibited higher cytotoxic and antimicrobial activities. Complex 1 shows better DNA / BSA interactions in comparison to complex 2.

Binary and ternary new water soluble copper(II) complexes of l-tyrosine and substituted 1,10-phenanthrolines: effect of substitution on DNA interactions and cytotoxicities.

Binary and ternary water soluble copper(II) complexes - [Cu(nphen)2(H2O)](NO3)2·H2O (1), [Cu(phen)2(H2O)](NO3)2 (2), [Cu(nphen)(l-tyr)(H2O)]NO3·2H2O (3), [Cu(phen)(tyr)(H2O)] NO3·2H2O (4) - and diquarternary salts of nphen and phen (nphen=5-nitro-1,10-phenanthroline, phen=1,10-phenanthroline and tyr=l-tyrosine) have been synthesized and characterized by CHN analysis, (1)H NMR, (13)C NMR and IR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The CT-DNA binding properties of these compounds have been investigated by thermal denaturation measurements, absorption and emission spectroscopy. The supercoiled pUC19 plasmid DNA cleavage activity of these compounds has been explored by agarose gel electrophoresis. The cytotoxicity of these compounds against MCF-7, Caco-2, A549 cancer cells and BEAS-2B healthy cells was also studied by using XTT method. The complexes 1-4 exhibit significant high cytotoxicity with low IC50 values in compared with cisplatin. The effect of the substituents of phen and coordinated amino acid in the above complexes are presented and discussed.

New water-soluble copper (II) complexes including 4,7-dimethyl-1,10-phenanthroline and L-tyrosine: synthesis, characterization, DNA interactions and cytotoxicities.

Two new water-soluble copper(II) complexes, [Cu(dmphen)2(NO3)]NO3 (1), [Cu(dmphen)(tyr)(H2O)]NO3·H2O (2) and the diquarternary salt of dmphen (dmphen = 4,7-dimethyl-1,10-phenanthroline and tyr = L-tyrosine), have been synthesized and characterized by elemental analysis, (1)H NMR, (13)C NMR and IR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The CT-DNA binding properties of these compounds have been investigated by absorption, emission spectroscopy and thermal denaturation measurements. The supercoiled pBR322 plasmid DNA cleavage activity of these compounds has been explored by agarose gel electrophoresis. The cytotoxicity of these compounds against MCF-7, Caco-2, A549 cancer cells and BEAS-2B healthy cells was also studied by the XTT method. Complexes 1 and 2 exhibit significant cytotoxicity, with lower IC50 values than those of cisplatin.