Guanidine derivatives and their metal complexes as emerging anticancer agents: A comprehensive review

Guanidine and their derivatives have gained considerable attention in medicinal chemistry due to their unique physicochemical properties, high basicity, and versatile hydrogen bonding capabilities. These features have made guanidine-based compounds promising scaffolds in the design of novel anticancer agents. In recent years, both organic guanidine derivatives and their coordination complexes with transition metals have demonstrated significant anticancer activity against a broad spectrum of cancer cell lines, including those resistant to conventional chemotherapy. This review comprehensively summarizes the latest advances in the structural modifications and biological evaluation of guanidine-based anticancer compounds. Emphasis is placed on structure-activity relationships (SAR), mechanisms of action. Special attention is given to metal-guanidine complexes, which often show enhanced cytotoxicity, selectivity, and novel modes of action compared to their parent ligands. The potential of guanidine complexes to overcome drug resistance and their synergistic effects with existing chemotherapeutic agents are also discussed. We hope this review will assist researchers in designing and developing more efficient and selective guanidine-based anticancer agents in the future.