Penumaka Nagababu

Antiangiogenic Activity of Mononuclear Copper(II) Polypyridyl Complexes for the Treatment of Cancers

A series of four new mononuclear copper(II) polypyridyl complexes (1-4) have been designed, developed, and thoroughly characterized by several physicochemical techniques. The CT-DNA binding properties of 1-4 have been investigated by absorption, emission spectroscopy, and viscosity measurements. All the complexes especially 1 and 4 exhibit cytotoxicity toward several cancer cell lines, suggesting their anticancer properties as observed by several in vitro assays. Additionally, the complexes show inhibition of endothelial cell (HUVECs) proliferation, indicating their antiangiogenic nature. In vivo chick embryo angiogenesis assay again confirms the antiangiogenic properties of 1 and 4. The formation of excessive intracellular ROS (H2O2 and O2(•-)) and upregulation of BAX induced by copper(II) complexes may be the plausible mechanisms behind their anticancer activities. The present study may offer a basis for the development of new transition metal complexes through suitable choice of ligands for cancer therapeutics by controlling tumor angiogenesis.

Cellular uptake, cytotoxicity, apoptosis and DNA-binding investigations of Ru(II) complexes.

Three new compounds, [Ru(Hdpa)2PyIP](ClO4)2·2H2O (1) [Ru(Hdpa)2FyIP](ClO4)2·2H2O (2) and [Ru(Hdpa)2IIP](ClO4)2·2H2O (3) have been synthesized and characterized by spectroscopic techniques such as elemental analysis, UV/Vis, FT-IR, (1)H NMR, (13)C NMR and mass spectra. The CT-DNA binding properties of 1-3 have been investigated by absorption, emission spectroscopy and viscosity measurements. Experimental results suggested that they can interact with DNA through intercalative mode with different binding strengths. These were found to promote the cleavage of plasmid DNA. Cell viability results indicated that all compounds showed significant dose dependent cytotoxicity in selected cell lines and 1 shown higher cytotoxicity than cisplatin on HeLa cells. Cellular uptake studies were studied by flow cytometry and confocal microscopy.

Ruthenium(II) ethylenediamine complexes with dipyridophenazine ligands: synthesis, characterization, DNA interactions, and antiproliferative activities

Ruthenium(II) complexes, [Ru(en)2dppz]2+ (1), [Ru(en)2qdppz]2+ (2), [Ru(en)2acdppz]2+ (3), and [Ru(en)2actatp]2+ (4), have been synthesized and characterized by IR, 1H, 13C-NMR and LC–MS. The interactions of these complexes with calf thymus (CT) DNA have been investigated by absorption, emission, viscosity, thermal denaturation, and circular dichroism. These techniques reveal that the complexes bind strongly to DNA. The apparent binding constants for the complexes decrease from 1 to 4 and are in the order of 8.5 ± 0.2 × 105 M−1 (1), 7.3 ± 0.8 × 105 M−1 (2), 4.3 ± 0.3 × 105 M−1 (3), and 7.5 ± 0.5 × 104 M−1 (4). The plot of log K versus log [Na+] yield slopes of −1.47, −1.44, −1.36, and −1.24 for 1, 2, 3, and 4, respectively. These complexes promote the photocleavage of pBR322 DNA. Cytotoxicities of these complexes suggest their possible anticancer activity.

Synthesis, Characterization Luminiscence Studies and Microbial Activity of Ethylenediamine Ruthenium (II) Complexes with Dipyridophenazine Ligands

Three symmetric ligands 7-methyl dipyrido-[3,2-a;2′,3′-c]phenazine (dppz-CH3), 7-nitro dipyrido-[3,2-a;2′,3′-c]phenazine (dppz-NO2) and benzo[i]dipyrido-[3,2-a;2′,3′-c]phenazine (dppn) and their ruthenium(II) complexes [Ru(en)2(L)][ClO4]2 (en= ethylenediamine), L= dppz-CH3, dppz-NO2 and dppn have been synthesized and characterized by IR, 1H, 13C NMR and Mass spectra. The interactions of these complexes with calf thymus DNA have been investigated by spectrophotometric, spectrofluorimetric, circular dichroism, viscosity and thermal denaturation studies. As the planar extension of the intercalative ligand increases, the interaction of the complex with DNA increases, indicating that the size and shape of the intercalalative ligand has a marked effect on the strength of interaction. The plot of log K versus log [Na+] yield a slope of -1.26, -1.53, -1.60 for the complexes 1, 2 and 3 respectively. These three complexes have been found to promote the cleavage of plasmid pBR 322 DNA upon irradiation.

DNA-Binding and cytotoxicity of the cobalt(III) ethylenediamine pyrazole complex [Co(en)2(pyz)2]3+

The complex of cobalt(III) ethylenediamine was synthesized, isolated and characterized by UV-Vis, IR, and 1H NMR spectral methods. The binding of the complex with calf thymus DNA was investigated by absorption and emission spectroscopy, viscosity measurements, DNA melting and DNA photocleavage. The spectroscopic studies together with the viscosity measurements and DNA melting studies indicated that the complex binds to calf thymus DNA in a nonintercalative mode. This complex is found to promote photocleavage of the DNA plasmid pBR322 and shows a cytotoxic effect against CHO cells.

DNA Binding and Photocleavage Studies of Cobalt(III) Ethylenediamine Pyridine Complexes: [Co(en)2(py)2]3+ and [Co(en)2(mepy)2]3+.

Two novel cobalt(III) pyridine complexes (1) [Co(en)2(py)2]3+ and (2) [Co(en)2(mepy)2]3+ (en=ethylenediamine, py=pyridine, and mepy=methylpyridine) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photocleavage. Results suggest that the two complexes bind to DNA via groove mode and complex 2 binds more strongly to CT DNA than complex 1. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm, cytotoxicity results of complexes are also showing anticancer activity.

DNA-binding and Photocleavage Studies of Ethylenediamine Cobalt(III) and Ruthenium(II) Mixed Ligand Complexes

,(en=ethylene-diamine, pyip =(pyip = 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]phenanthroline),(aip = 2-(9-anthryl)-1H-imidazo[4,5,-f][1,10] phenanthroline) have been synthe-sized and characterized. The interaction of these complexes with calf thymus DNAwas investigated using absorption (UV/vis) and emission spectroscopy, viscositymeasurements as well as DNA melting and plasmid DNA cleavage studies. Theexperimental results show that the four complexes can bind to DNA in an intercala-tion mode. The DNA-binding affinity of complex

DNA Binding and Photocleavage Studies of Cobalt(III) Ethylenediamine Pyridine Complexes: and

Two novel cobalt(III) pyridine complexes (1) [Co(en)2(py)2]3+ and (2) [Co(en)2(mepy)2]3+ (en=ethylenediamine, py=pyridine, and mepy=methylpyridine) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photocleavage. Results suggest that the two complexes bind to DNA via groove mode and complex 2 binds more strongly to CT DNA than complex 1. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm, cytotoxicity results of complexes are also showing anticancer activity.

DNA Binding and Photocleavage Studies of Cobalt(III) Ethylenediamine Pyridine Complexes: [Co(en)2(py)2]3

Two novel cobalt(III) pyridine complexes (1) [Co(en)2(py)2]3+ and (2) [Co(en)2(mepy)2]3+ (en=ethylenediamine, py=pyridine, and mepy=methylpyridine) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photocleavage. Results suggest that the two complexes bind to DNA via groove mode and complex 2 binds more strongly to CT DNA than complex 1. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm, cytotoxicity results of complexes are also showing anticancer activity.