Investigation on the bioactivities of clioquinol and its bismuth(III) and platinum(II,IV) complexes

Complexes [Bi(HCQ)2(H2O)Cl3] (1), [Pt(CQ)2]·2KCl (2) and [Pt(CQ)2Cl2]·KCl (3) were obtained with 5-chloro-7-iodo-8-hydroxyquinoline, “clioquinol”, HCQ. Upon coordination to bismuth(III) the antimicrobial activity improved. Complex (1) was 70-fold more active than fluconazole against Candida albicans. HCQ proved to be cytotoxic to HL-60 and Jurkat human leukemia cells. Although coordination to bismuth(III) did not result in significant modification of HCQ’s cytotoxic effect, on coordination to platinum(II, IV) cytotoxicity improved against both cell lines. Complexes (2) and (3) were more active than HCQ against HL-60 cells. Complex (2) also revealed to be the most cytotoxic compound against Jurkat cells, being fivefold more active than cisplatin. Although HCQ and 1 did not show a pro-apoptotic effect, 2 and 3 presented moderate pro-apoptotic activity.