Carbohydrate-conjugate heterobimetallic complexes: synthesis, DNA binding studies, artificial nuclease activity and in vitro cytotoxicity

New carbohydrate-conjugated heterobimetallic complexes [C32H62N10O8NiSn2Cl4]Cl2(1) and [C32H62N10O8CuSn2Cl4]Cl2 (2) were synthesized and characterized by spectroscopic (IR, 1H, 13C, and 119Sn NMR, EPR, UV-vis, ESI-MS) and analytical methods. The interaction studies of 2 with CT DNA were studied by using various biophysical techniques, which showed high binding affinity of 2 toward CT DNA. The extent of interaction was further confirmed by the interaction of 2 with the nucleotides viz.; 5′-AMP, 5′-CMP, 5′-GMP, and 5′-TMP, by absorption titration. 1H, 31P, 119Sn NMR spectroscopy further validated the interaction mode of 2 with 5′-GMP. The electrophoresis pattern observed for 2 with supercoiled pBR322 DNA, exhibited significantly good nuclease activity following oxidative pathway. The preferential selectivity of 2 toward the major groove was observed on interaction of 2 with pBR322 DNA, in the presence of standard groove binders viz.; DAPI and methyl green. Additionally, in vitro antitumor activity of 2 was evaluated on a panel of human cancer cell lines, exhibiting remarkable cytotoxicity activity against Colo205 (colon) and MCF7 (breast) cell lines with GI50 values <10 μg/mL.