Design, synthesis, MTT assay, DNA interaction studies of platinum(II) complexes

<p>The square planar Pt(II) complexes of the type [Pt(L<sup><i>n</i></sup>)(Cl<sub>2</sub>)] (where L<sup><i>n</i></sup> = L<sup>1−3</sup> = thiophene-2-carboxamide derivatives and L<sup>4−6</sup> = thiophene-2-carbothioamide derivatives) have been synthesized and characterized by physicochemical and various spectroscopic studies. MIC method was employed to inference the antibacterial potency of complexes in reference to free ligands and metal salt. Characteristic binding constant (<i>K</i><sub>b</sub>) and binding mode of complexes with calf thymus DNA (CT-DNA) were determined using absorption titration (0.76–1.61 × 10<sup>5</sup> M<sup>−1</sup>), hydrodynamic chain length assay and fluorescence quenching analysis, deducing the partial intercalative mode of binding. Molecular docking calculation displayed free energy of binding in the range of –260.06 to –219.63 kJmol<sup>−1</sup>. The nuclease profile of complexes towards pUC19 DNA shows that the complexes cleave DNA more efficiently compared to their respective metal salt. Cytotoxicity profile of the complexes on the brine shrimp shows that all the complex exhibit noteworthy cytotoxic activity with LC<sub>50</sub> values ranging from 7.87 to 15.94 μg/mL. The complexes have been evaluated for cell proliferation potential in human colon carcinoma cells (HCT 116) and IC<sub>50</sub> value of complexes by MTT assay (IC<sub>50</sub> = 125–1000 μg/mL).</p>