Synthesis, characterizations, and anticancer properties of bifunctional system based on gold(I) alkynyl and antipyrine

A Gold(I)-antipyrine conjugate compound {Au(PPh₃)(C[tbnd]CC₆H₄–4-CH[dbnd]N-antipyrine) (4) was synthesized and the new complex was characterized by different spectroscopic techniques. DNA-binding and BSA-binding were performed for the Au-antipyrine compound (4), showing that the synthesized complex exhibits better binding affinities against BSA compared to Au(PPh₃)(C[tbnd]CPh) (5) while both have comparable DNA-binding. The gold(I)-antipyrine compound was tested against HepG2 and MCF-7 human cancer cell lines, exhibiting better cytotoxic effects compared to its ligand but comparable to that of Au(PPh₃)(C[tbnd]CPh) (5). Despite the comparable anticancer properties of both 4 and 5 described herein, the presence of the antipyrine moiety altered the biomolecule-binding of gold(I) alkynyl complexes. Compared to cisplatin, the gold(I) complexes possess slightly less anticancer properties against both cell lines. Flow cytometry analysis was performed for Au-antipyrine complex, indicating apoptotic cell death pathway (late apoptosis) but via different mechanisms from that of cisplatin (early apoptosis) as can be seen from the differences in the cell cycle analysis at different cell phases.