Low and High Molecular Weight Chitosan Analogues of Imidazole-2-Thiosemicarbazones and Their Copper(II) Complexes: Synthesis, Characterization, and Antitumorigenic Activity in vitro

The current study aims at comprehensive study of the effects of Mw and DDA of chitosan on antitumorigenic activity of chitosan thiosemicarbazones and their copper(II) complexes. It has been anticipated that the antitumorigenic activity be enhanced with the synergistic effects upon the functionalization of chitosan as chitosan thiosemicarbazones and the complexes could show more potent antitumorigenic activity. Chitosan oligosaccharide and high molecular weight crab shell chitosan were functionalized as imidazole-2-carboxaldehyde chitosan thiosemicarbazones and their copper(II) complexes were synthesized. The synthesized compounds were characterized by FT-IR, 13C NMR, EPR spectroscopy, powder X-ray diffraction (PXRD) analysis, elemental analysis and magnetic susceptibility measurements. The low molecular weight chitosan thiosemicarbazones showed higher in vitro inhibitory activity as studied by MTT assay against the tumorigenic epithelial Madin-Darby Canine Kidney (MDCK) cell line than the corresponding high molecular weight chitosan derivative. The antitumorigenic enhancement upon the complex formation was revealed by the better inhibitory activity of copper(II) chitosan thiosemicarbazone chelates.