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1.
Yata PK Shilpa M Nagababu P Reddy MR Kotha LR Gabra NM Satyanarayana S 《Journal of fluorescence》2012,22(3):835-847
The three Ru(II) complexes of [Ru(phen)2dppca]2+ (1) [Ru(bpy)2dppca]2+ (2) and [Ru(dmb)2dppca]2+ (3) (where phen = 1,10 phenanthroline, bpy = 2,2-bipyridine, dmb = 2 ,2-dimethyl 2′,2′-bipyridine and polypyridyl ligand
containing a single carboxylate functionality dppca ligand (dipyridophenazine-11-carboxylic acid) have been synthesized and
characterized. These complexes have been shown to act as promising calf thymus DNA intercalators and a new class of DNA light
switches, as evidenced by UV-visible and luminescence titrations with Co2+ and EDTA, steady-state emission quenching by [Fe(CN)6]4− and KI, DNA competitive binding with ethidium bromide, viscosity measurements, and DNA melting experiments. The results suggest
that 1, 2, and 3 complexes bind to CT-DNA through intercalation and follows the order 1 > 2 > 3. Under irradiation at 365 nm,
the three complexes have also been found to promote the photocleavage of plasmid pBR322 DNA. 相似文献
2.
Prof. Dr. Sunney I. Chan Yu‐Jhang Lu Dr. Penumaka Nagababu Dr. Suman Maji Mu‐Cheng Hung Marianne M. Lee Prof. Dr. I‐Jui Hsu Pham Dinh Minh Jeff C.‐H. Lai Kok Yoah Ng Sridevi Ramalingam Prof. Dr. Steve S.‐F. Yu Prof. Dr. Michael K. Chan 《Angewandte Chemie (International ed. in English)》2013,52(13):3731-3735
3.
Ponuganti Pallavi Penumaka Nagababu Sirasani Satyanarayana 《Helvetica chimica acta》2007,90(3):627-639
Pseudo‐first‐order reaction kinetics and binding studies of trans‐[Co(en)2(Et)H2O] complex with 1H‐imidazole, substituted 1H‐imidazoles, histidine, histamine, glycine and glycine ethyl ester were investigated by means of spectrophotometric techniques. Equilibrium constants were determined as a function of pH at 25°. Binding and kinetic studies were correlated to basicity and steric hindrance. From the equilibrium data, it was found that the entering nucleophile is participating in the transition state, an Id mechanism is proposed. The effect of the incoming ligands on the complex was studied by molecular mechanics. The interaction of trans‐[Co(en)2(Et)H2O] with CT DNA was studied spectrophotometrically. 相似文献
4.
C. Shobha Devi Penumaka Nagababu M. Shilpa Y. Praveen Kumar M. Rajender Reddy Nazar Md Gabra S. Satyanarayana 《Journal of the Iranian Chemical Society》2012,9(5):671-680
A series of four polypyridyl Ru(II) complexes such as [Ru(L)4(PIP)]2+ and [Ru(L)4PPIP]2+ where L is 4-amino pyridine and Pyridine (PIP?=?2-phenylimidazo[4,5-f] [1, 10] phenanthroline), (PPIP?=?2-(4??-phenoxy-phenyl) imidazo[4,5-][1, 10]phenanthroline) have been synthesized and characterized by elemental analysis, physicochemical methods such as UV?Cvis, IR and NMR spectroscopic techniques. The DNA-binding behavior of these complexes was investigated by electronic absorption titrations, fluorescence spectroscopy, viscosity measurements and salt-dependent studies. The experimental results indicate that all these complexes can bind to DNA through an intercalation mode, the DNA-binding affinities of these complexes follow the order [Ru(4-APy)4(PPIP)]2+(1)?>?[Ru(Py)4PPIP]2+(2)?>?[Ru(4-APy)4(PIP)]2+(3)?>?[Ru(Py)4PIP]2+(4). Noticeably, these complexes have been found to be efficient photosensitisers for strand scissions in plasmid DNA. Further, all four complexes screened for their antimicrobial activity indicate that the complexes show appreciable activity against Escherichia coli and Neurospora Crassa. In addition, in the presence of Co2+, the emission of DNA-[Ru(L4)PPIP/PIP]2+ can be quenched and recovered by the addition of EDTA, which exhibited the DNA ??light switch?? properties. 相似文献
5.
Ponuganti Pallavi Penumaka Nagababu Kotha Laxmareddy Naishadham Padmaja Sirasani Satyanarayana 《中国化学》2012,30(7):1641-1646
In view of the growing interest for the synthesis of metal complexes and their interaction with DNA, we have synthesized and characterized two complexes containing ruthenium as metal center. The complexes are of the type [Ru(dppz)L4](ClO4)2 where L are biologically important ligands such as pyrazole and dimethylpyrazole. The characterization of these complexes is done by 1H NMR, 13C NMR, elemental analysis and mass spectroscopy. The interaction of these complexes with CT DNA was monitored and binding constants were determined using absorption and fluorescence spectroscopy. The mode of binding was found to be intercalative for both complexes and was determined using hydrodynamic viscosity studies. The complexes were further studied for photocleavage studies with supercoiled plasmid pBR322 DNA. 相似文献
6.
P. Nagababu J. Naveena lavanya latha M. Rajesh S. Satyanarayana 《Journal of the Iranian Chemical Society》2009,6(1):145-152
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. 相似文献
7.
Nagababu P Shilpa M Latha JN Bhatnagar I Srinivas PN Kumar YP Reddy KL Satyanarayana S 《Journal of fluorescence》2011,21(2):563-572
The new ligand 4-(isopropylbenzaldehyde)imidazo[4,5-f ][1,10]phenanthroline (ippip) and its complexes [Ru(phen)2(ippip)]2+(1),[Co(phen)2(ippip)]3+(2),[Ru(bpy)2(ippip)]2+(3),[Co(bpy)2(ippip)]3+(4)(bpy=2,2-bipyridine) and (phen=1,10-phenanthroline) were synthesized and characterized by ES+-MS, 1H and 13C NMR. The DNA binding properties of the four complexes were investigated by different spectrophotometric methods and viscosity
measurements. The results suggest that complexes bind to calf thymus DNA (CT-DNA) through intercalation. When irradiated at
365 nm, the complexes promote the photocleavage of pBR322 DNA, and complex 1 cleaves DNA more effectively than 2, 3, 4 complexes
under comparable experimental conditions. Furthermore, photocleavage studies reveal that singlet oxygen (1O2) plays a significant role in the photocleavage. 相似文献
8.
C. Shobha Devi B. Thulasiram S. Satyanarayana Penumaka Nagababu 《Journal of fluorescence》2017,27(6):2119-2130
This review describes the analytical techniques used to detect DNA-probes such as Ru(II) complexes with hetero cyclic imidazo phenanthroline (IP) ligands. Studies on drug-DNA interactions are useful biochemical techniques for visualization of DNA both in vitro and in vivo. The interactions of small molecules that binds to DNA are mainly classified into two major classes, one involving covalent binding and another non-covalent binding. Covalent binding in DNA can be irreversible and may leads to inhibition of all DNA processes which subsequently leads to cell death. Usually, covalent interactions leads to permanent changes in the structure of nucleic acids. The non-covalent interaction of molecules with DNA can be due to electrostatic interaction, intercalation and groove binding. These interactions of DNA probes can be explored by various spectroscopic techniques viz. UV–visible, emission, emission quenching spectroscopy, viscosity and thermal denaturation measurements. 相似文献
9.
C. Shobha Devi B. Thulasiram Rajeshwar Rao Aerva Penumaka Nagababu 《Journal of fluorescence》2018,28(5):1195-1205
Copper is a part of various enzymes and helps them to function properly. It can be effectively used to produce promising anticancer drugs and presently, many studies are being pursued worldwide on the development of copper-based complexes as potential anticancer drugs. Herein, we briefly discuss the importance of reactive oxygen species in biological applications and copper(II) complexes as anticancer drugs. The anti-angiogenic properties of mono-nuclear copper(II) complexes have been demonstrated by in vivo chick embryo angiogenesis analysis. The plausible mechanism behind anticancer activity of these complexes is by the formation of excessive intracellular Reactive Oxygen Species (ROS). ROS is a composite term used for oxygen derivative non-radicals and free radicals of highly reactive components, that enhances the killing response of immune cells to microbial invasion. Previous reports have shown that ROS plays an important role as a messenger in cell cycling and normal cell signal transduction. 相似文献
10.
Venu Kandula Uppu Nagababu Manoranjan Behera Satyanarayana Yennam Anindita Chatterjee 《Journal of Saudi Chemical Society》2019,23(6):711-717
Ag nanoparticles (AgNPs) catalyst material is bio-synthesized and fully examined using various spectroscopy and microscopy techniques. Further this synthesized material is used for hydroxylation reaction, for this purpose we developed a simple and versatile bio-based method from aryl boronic acids to phenol. The reaction was studied in the presence of low cost ligand in a hydrated reaction medium without any hazardous organic solvents, as a result a finite amount of yield was achieved in short time (<15 min). The hydroxylation reaction is further carried out in a series of different arenes substituted samples with good amount of yields. 相似文献