Synthesis and cytotoxicity study of water soluble 8-hydroxyquinoline stabilized zirconium(Ⅳ) complexes

Abstract

Three octacoordinated zirconium(IV) tetrakis-(8-hydroxyquinolinate) complexes [(L1-3)4Zr(IV)] were synthesized smoothly in THF at room temperature using ZrCl4 as a starting material with yields ranging from 74% to 83%. Their structures were characterized by 1H, 13C NMR and X-ray diffraction spectroscopy. [(L1-3)4Zr(IV)] exhibited excellent solubility and stability in H2O and DMSO, and they have demonstrated enhanced cytotoxicity against human Hep G2, Hela S3 and PC9 cells than cisplatin. Among them, [(L1)4Zr(IV)] bearing non-substituted 8-hydroxyquinoline showed about 2 orders of magnitude higher inhibition activity against Hep G2 cells than cisplatin (IC50: 0.14 ± 0.1 μM, cisplatin: 13.82 ± 1.3 μM). The selectivity towards tumor cells was preliminary evidenced by their partial or completely vanished inhibition activity against AML12 cells. Additionally, [(L1)4Zr(IV)] could almost exclusively induce the apoptosis of Hep G2 cells.