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Photocytotoxic and anaerobic DNA cleavage activity of binuclear 3,3 '-dithiodipropionic acid cobalt(II) complexes having phenanthroline bases

Lahiri, Debojyoti and Bhowmick, Tuhin and Banik, Bhabatosh and Railkar, Reema and Ramakumar, Suryanarayanarao and Dighe, Rajan R and Chakravarty, Akhil R (2010) Photocytotoxic and anaerobic DNA cleavage activity of binuclear 3,3 '-dithiodipropionic acid cobalt(II) complexes having phenanthroline bases. In: Polyhedron, 29 (12). pp. 2417-2425.

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Official URL: http://dx.doi.org/10.1016/j.poly.2010.05.008

Abstract

Dicobalt(II) complexes [{(B)Co-11)(2)(mu-dtdp)(2)] (1-3) of 3,3'-dithiodipropionic acid (dtdp) and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 2) and dipyrido13,2-a:2',3'-clphenazine (dppz in 3), have been prepared, characterized and their photo-induced anaerobic DNA cleavage activity studied. The elemental analysis and mass spectral data suggest binuclear formulation of the complexes. The redox inactive complexes have magnetically non-interacting dicobalt(II) core showing magnetic moment of similar to 3.9 p per cobalt(II) center. The complexes show good binding propensity to calf thymus DNA giving K-b values within 4.3 x 10(5)-4.0 x 10(6) M-1. Thermal melting and viscosity data predict DNA groove binding and/or partial intercalative nature of the complexes. The complexes show significant anaerobic DNA cleavage activity in green light under argon atmosphere possibly involving radical species generated from the disulfide moiety in a type-I pathway. The DNA cleavage reaction under aerobic medium in green light is found to involve hydroxyl radical species. The dppz complex 3 exhibits significant photocytotoxicity in HeLa cervical cancer cells with an IC50 value of 2.31 mu M in UV-A light of 365 nm, while it is essentially non-toxic in dark giving an IC50 value of >200 mu M. A significant reduction of the dark toxicity of the organic dppz base (IC50 = 8.3 mu M in dark) is observed on binding to the cobalt(II) center while essentially retaining its photocytotoxicity in UV-A light (IC50 = 0.4 mu M). (C) 2010 Elsevier Ltd. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: Dicobalt(II) complexes; Anaerobic DNA photocleavage; Disulfide bond activation; 3,3′-Dithiodipropionic acid; Phenanthroline bases; Photocytotoxicity
Department/Centre: Division of Biological Sciences > Molecular Reproduction, Development & Genetics (formed by the merger of DBGL and CRBME)
Division of Information Sciences > BioInformatics Centre
Division of Physical & Mathematical Sciences > Physics
Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited: 02 Sep 2010 09:48
Last Modified: 19 Sep 2010 06:15
URI: http://eprints.iisc.ernet.in/id/eprint/31962

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