The reactivities
of halido[1,3-diethyl-4,5-diphenyl-1H-imidazol-2-ylidene]gold(I)
(chlorido (5), bromido (6), iodido (7)), bis[1,3-diethyl-4,5-diphenyl-1H-imidazol-2-ylidene]gold(I)
(8), and bis[1,3-diethyl-4,5-diphenyl-1H-imidazol-2-ylidene]dihalidogold(III) (chlorido (9),
bromido (10), iodido (11)) complexes
against ingredients of the cell culture medium were analyzed by HPLC.
The degradation in the RPMI 1640 medium was studied, too. Complex6quantitatively reacted with chloride to5,
while7showed additionally ligand scrambling to8. Interactions with non-thiol containing amino acids could
not be detected. However, glutathione (GSH) reacted immediately with5and6yielding the (NHC)gold(I)-GSH complex12. The most active complex8was stable underin vitroconditions and strongly participated on the biological
effects of7. The gold(III) species9–11were completely reduced by GSH to8and are
prodrugs. All complexes were tested for inhibitory effects in Cisplatin-resistant
cells, as well as against cancer stem cell-enriched cell lines and
showed excellent activity. Such compounds are of utmost interest for
the therapy of drug-resistant tumors.