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 Ni-II-Sn-2(IV) (1), Cu-II-Sn-2(IV) (2) and Zn-II-Sn-2(IV) (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 H-1, P-31 and Sn-119 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 mu g/ml). (C) 2010 Elsevier Masson SAS. All rights reserved.