A series of isonicotinoyl hydrazones have been synthesized via template method and were complexed to Cu(II). The ligands are coordinated to Cu(II) ion through the enolic oxygen and azomethine nitrogen resulting in a square planar geometry. The CT-DNA and bovine serum albumin binding propensities of the compounds were determined spectrophotometrically, the results of which indicate good binding propensity of complexes to DNA and BSA with high binding constant values. Furthermore, the compounds have been investigated for their cytotoxicities on A549 human lung cancer cell. Also the mode of cell death was examined employing various staining techniques and was found to be apoptotic. 1. Introduction A wide range of Schiff’s bases with their reactive azomethine linkage show interesting inhibitory activity against tumor cells. Schiff’s bases could be hydrolyzed selectively by the tumor cells to act as alkylating agents; at the same time the active amine becomes free to act as antimetabolite [1]. Studies show that the metal complexes of Schiff’s base ligands have better antimicrobial and anticancer activities as compared to Schiff’s bases [2]. Copper is well known as a bioessential element and its complexes have proven to be excellent candidates for biological applications due to their binding ability and positive redox potential [3–6]. Cu(II) complexes containing heterocyclic bases have been extensively explored in virtue of their strong interactions with DNA and cytotoxic activity [7–9]. They can act as chemical nucleases [10, 11] and their cytotoxicity has been proposed to be caused by their ability to bind and cleave DNA that leads to cell cycle arrest and apoptosis or generation of reactive oxygen species (ROS) that in turn leads to cell death [12]. Literature has shown that Cu(II)-based complexes exhibit antineoplastic potency towards human ovarian carcinoma (CH1), murine leukemia (L1210), and various cervicouterine carcinomas which is comparable to or even higher than that of cisplatin [13, 14]. Fei et al. in their article [15] have reported the in vitro cytotoxicity of two copper-2,2′-bipyridine complexes towards five selected tumor cell lines HepG-2, HeLa, NCI-H460, MCF-7, and HL-6 with IC50 value at a concentration of 50？μM. Cu(II) complexes of Schiff bases can show their antibacterial and antiproliferative activities because of the properties of the metal center or the coordinated ligands alone, as well as the structural and electronic properties which is ascribed to the coordination [16–21]. Several Schiff base ligands and their Cu(II) complexes
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