N-Heterocyclic carbene complexes of Au(I), Ag(I), and Cu(I) as potential anticancer agents: a review

The discovery of cisplatin antitumor properties in 1969 encouraged researchers to design metal-based anticancer drugs. Recently, research on N-heterocyclic carbene-based metal complexes was successful due to their excellent anticancer potency and other biological activities, for example antitubercular, antiviral, anti-ulcerogenic, antifungal, antiglycation antimalarial, anti-inflammatory, antineuropathic, antihypertensive, antioxidant, anti-obesity, antibacterial, and analgesic activity. These complexes have excellent anticancer activities, even higher than cisplatin. Herein, we summarize the anticancer activities of N-heterocyclic carbene (NHC) based metal complexes of Au(I), Ag(I), and Cu(I). Further, the mechanism of action and the possible structure-activity relationships (SAR) are discussed. We hope this article will help researchers in designing highly potent Au(I), Ag(I), and Cu(I)-N-heterocyclic carbene complexes for the possible treatment of various types of cancer.