Synthesis of carbohydrate-conjugate heterobimetallic CuII–Sn2IV and ZnII–Sn2IV complexes; their interactions with CT DNA and nucleotides; DNA cleavage, in-vitro cytotoxicity

The new heterobimetallic NiII–Sn2IV (1), CuII–Sn2IV (2) and ZnII–Sn2IV (3) complexes, containing d-glucosamine, 1,8-diamino-3,6-diazaoctane and imidazole were isolated and characterized by spectral and analytical methods. The proposed geometry of Ni(II) and Cu(II) in 1 and 2 was square pyramidal, Zn(II) in 3 exhibited tetrahedral while Sn(IV) exhibits hexacoordinate environment, respectively. The X-ray powder diffraction (XRPD) confirmed the amorphous nature of all the complexes. The interaction studies of 2 and 3 with CT DNA were carried out by various biophysical techniques to show the mode of binding. The interaction of 2 and 3 with nucleotides viz 5′-GMP and 5′-TMP, respectively were further confirmed by 1H, 31P and 119Sn NMR spectroscopy. The complex 2 exhibited effective cleavage activity with pBR322 DNA. Furthermore, the cytotoxicity of 2 was examined on a panel of human tumor cell lines of different histological origins and showed good activity against Colo205 and A2780 (GI50 < 10 μg/ml).

Graphical abstractCarbohydrate conjugate heterobimetallic complexes were synthesized. Interaction of complexes with CT DNA and nucleotides were studied with various biophysical techniques. Complex 2 showed good activity against Colo205 and A2780 carcinoma cell lines (GI50 < 10 μg/ml). Figure optionsDownload full-size imageDownload as PowerPoint slide