Metal based photosensitizers of tetradentate Schiff base: Promising role in anti-tumor activity through singlet oxygen generation mechanism

Pradeepa, SM and Naik, Bhojya HS and Kumar, Vinay B and Priyadarsini, Indira K and Barik, Atanu and Naik, Ravikumar TR and Prabhakara, MC (2013) Metal based photosensitizers of tetradentate Schiff base: Promising role in anti-tumor activity through singlet oxygen generation mechanism. In: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, 115 . pp. 12-21.

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Abstract

In the present investigation, a Schiff base N'(1),N'(3)-bis(Z)-(2-hydroxynapthyl)methylidene]benzene-1,3-dicarbod ihydrazide (L-1) and its Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized as novel photosensitizing agents for photodynamic therapy (PDT). The interaction of these complexes with calf thymus DNA (CT DNA) has been explored using absorption, thermal denaturation and viscometric studies. The experimental results revealed that Co(II) and Ni(II) complexes on binding to CT DNA imply a covalent mode, most possibly involving guanine N7 nitrogen of DNA, with an intrinsic binding constant K-b of 4.5 x 10(4) M-1 and 4.2 x 10(4) M-1, respectively. However, interestingly, the Cu(II) complex is involved in the surface binding to minor groove via phosphate backbone of DNA double helix with an intrinsic binding constant K-b of 5.7 x 10(4) M-1. The Co(II), Ni(II) and Cu(II) complexes are active in cleaving supercoiled (SC) pUC19 DNA on photoexposure to UV-visible light of 365 nm, through O-1(2) generation with quantum yields of 0.28, 0.25 and 0.30, respectively. Further, these complexes are cytotoxic in A549 lung cancer cells, showing an enhancement of cytotoxicity upon light irradiation. (C) 2013 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	Copyright for this article belongs to Science Direct
Keywords:	Schiff base; Photosensitizer; DNA photocleavage; Singlet oxygen; Cytotoxicity
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	25 Oct 2013 06:49
Last Modified:	25 Oct 2013 06:49
URI:	http://eprints.iisc.ac.in/id/eprint/47562

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