Synthesis and characterization of cobalt(II), nickel(II) and copper(II)-based potential photosensitizers: Evaluation of their DNA binding profile, cleavage and photocytotoxicity

Metal-based photosensitizers of the type [Co(L)Cl-2] (1), [Ni(L)Cl-2] (2) and [Cu(L)]Cl-2 (3), where L = N-'1, N-'3-bis[(E)-thiophen-2-ylmethylidene]benzene-1,3-dicarbohydrazide have been synthesized and characterized by advanced spectroscopic and analytical techniques. The interactions of the complexes with CT DNA were investigated by viscosity analysis, thermal denaturation and absorption spectroscopic techniques. Absorption spectral (K-b = 5.57 x 10(4) M-1 (1), 4.45 x 10(4) M-1 (2), 2.8 x 10(4) M-1 (3)), thermal denaturation and viscosity measurements reveal that 1, 2 and 3 interact with DNA through intercalation. The complexes are photocleavers of SC pUC19 DNA in UV-A light forming O-1(2) as the reactive oxygen species. The in-vitro cytotoxicity of 1, 2 and 3 towards MCF-7 tumor cell lines has been evaluated by MTT method, and show an enhancement of cytotoxicity in UV-A light. The results revealed that complex 1 has superior prospectus to act as cancer chemotherapeutic candidate than that of complex 2 and complex 3. (C) 2015 Elsevier B.V. All rights reserved.