Synthesis and cytotoxic activities of chloropyridylimineplatinum(II) and chloropyridyliminecopper(II) surface-functionalized poly(amidoamine) dendrimers

The preparations of novel platinum and copper metallodendrimers are reported. Surface modified first generation (G0) poly(amidoamine) (PAMAM) dendritic Schiff base, prepared via a condensation reaction was coordinated with platinum chloride and copper chloride yielding [G0-Py₄-[PtCl₂]₄] (4D) and [G0-Py₄-[CuCl₂]₇] (7E) respectively. These functionalized hyper-branched complexes were characterized by IR spectroscopy and CHN analysis. 4D was further characterized through ¹H and ¹³C spectroscopy, while 7E was characterized using matrix-assisted laser desorption ionization time-of-flight (MALDI/TOF) Mass Spectrometer. The cytotoxic effects of the compounds against cells of neoplastic origin (MOLT-4, MCF-7) and cells of benign origin (Chang Liver) were studied. Their cytotoxicities were then compared to their mono-nuclear analogues, [(MeCONHCH₂CH₂N{double bond, long}CHPy)(PtCl₂)] (1D) and [(MeCONHCH₂CH₂N{double bond, long}CHPy)(CuCl₂)] (1E). The multi-nuclear complexes showed increased cytotoxic activities as compared to their respective mono-nuclear compounds. Most notably, significant inhibitions were observed for 7E on all cell lines, in which its IC₅₀ values were 11.1 ± 0.6, 10.2 ± 1.5 and 8.7 ± 0.7 μM against MOLT-4, MCF-7 and Chang Liver cells respectively. The multi-nuclear copper-based complexes (7E) are therefore most effective against a cancer cell line (MOLT-4) and a cisplatin-resistant cell line (MCF-7).