Selected Metal (Au, Ag, and Cu) Complexes of N-heterocyclic Ligands as Potential Anticancer Agents: A Review

Nitrogen-based organic heterocyclic compounds are an important source of therapeutic agents. About 75% of drugs approved by the FDA and currently available in the market are N-heterocyclic organic compounds. The N-heterocyclic organic compounds like pyridine, indole, triazoles, triazine, imidazoles, benzimidazoles, quinazolines, pyrazoles, quinolines, pyrimidines, porphyrin, etc. have demonstrated significant biological activities. These heterocyclic organic compounds also coordinate with various metal ions and form coordination compounds. Most of them have shown improved biological activities. The research on the metal complexes of these compounds reported their significant biological activities. N-heterocyclic-based metal complexes showed outstanding anticancer activities against different cancer cell lines, including VEGFR-2, HT-29, MDA-MB-231, MCF-7 K562, A549, HepG2, HL60, A2780, WI-38, Colo-205, PC-3, and other cancer cell lines. Some of these compounds showed better anticancer activity than cisplatin. In this review, we summarized the anticancer properties of N-heterocyclic-based gold (Au), silver (Ag), and copper (Cu) complexes and explored the mechanisms of action and potential structure-activity relationships (SAR) of these complexes. Our goal is to assist researchers in designing highly potent N-heterocyclic-based Au, Ag, and Cu complexes for the potential treatment of various cancers.