High antitumor activity of 5,7-dihalo-8-quinolinolato tin(IV) complexes

Three tin(IV) complexes [Sn(ClQ)2Cl2] (1), [Sn(BrQ)2Cl2] (2) and [Sn(ClIQ)2Cl2] (3) were prepared (H-ClQ = 5,7-dichloro-8-hydroxylquinoline, H-BrQ = 5,7-dibromo-8-hydroxylquinoline, H-ClIQ = 5-chloro-7-iodo-8-hydroxylquinoline) and their in vitro cytotoxicities against BEL7404, SKOV-3, NCI-H460, HL-7702 cell lines were evaluated. The complexes showed high anti-proliferative activity toward the tested cell lines with IC50 values ranging from 20 nM to 5.11 μM. Compared with 5,7-dihalo-8-quinolinol, most complexes exhibited significantly enhanced cytotoxicity (except 2 against SKOV-3 and NCI-H460). They also displayed some selective cytotoxicity favoring the tested tumor cells over the normal human liver HL-7702 cells. Compared with their quinolinol ligands, complexes 1–3 bind more strongly with DNA. Intercalation is the most probable binding mode for both the complexes and their quinolinol ligands.

Three non-organotin(IV) complexes with 5,7-dihalo-8-quinolinoline were synthesized. They exhibited enhanced cytotoxicity and selectivity vs. 5,7-dihalo-8-quinolinoline. Intercalation is the most probable binding mode for both the complexes and quinolinoline.Figure optionsDownload as PowerPoint slideHighlights
► Three tin(IV) complexes with 5,7-dihalo-8-quinolinoline were synthesized.
► The tin(IV) complexes exhibited enhanced cytotoxicity and selectivity.
► Intercalation is the most probable binding mode to DNA.