Synthesis, Structural Characterization, Cytotoxicity, and Antibacterial Properties of Gold(III) Complexes with Hydrazones Derived from Vitamin B6

The rise in the number of cancer cases and the dissemination of strains with multiple drug resistance in the world pose a serious threat to public health care and human well-being. The design and study of new chemotherapeutic agents for cancer and infectious diseases are hot topics in science. Hydrazones, a versatile and diverse class of chemical compounds, gained a lot of attention as a promising base for future drugs. In this paper, we report on the synthesis of eight new gold(III) complexes with hydrazones derived from pyridoxal-5′-phosphate and pyridoxal. The complexes are thoroughly characterized using IR, 1H, 31P NMR, and mass spectroscopy. The cytotoxic effect of twelve various hydrazones derived from pyridoxal 5′-phosphate on both immortalized (HEK293T) and tumor (HCT116) human cell lines was estimated using the MTT assay. In addition, this contribution describes the antibacterial action of complexes of gold(III) and pyridoxal and pyridoxal 5′-phosphate-derived hydrazones, as well as the mixtures of the solutions containing tetrachloroaurate(III) and hydrazones, using the zone of inhibition test. Gold(III) complexes exhibit moderate antibacterial activity against both Gram-positive and Gram-negative bacteria, while free hydrazones show low cytotoxicity and thus could be considered relatively safe for humans.