Biological Evaluation of Novel Schiff Base Metal Complexes: A Review

Schiff base metal complexes have emerged as an important class of compounds in medicinal and coordination chemistry owing to their structural versatility, strong metal-binding ability, and diverse biological activities. The presence of the azomethine (–C=N–) functional group enables effective chelation with a wide range of transition metal ions, thereby enhancing the physicochemical stability, lipophilicity, and pharmacological potential of the parent ligands. Metal complexation often results in improved biological efficacy compared to free Schiff bases, attributed to altered electronic properties and enhanced interaction with biological targets. This review summarizes recent developments in the design, synthesis, and physicochemical characterization of novel Schiff base metal complexes. Emphasis is placed on their biological evaluation, including antimicrobial, anticancer, antioxidant, anti-inflammatory, antiviral, and enzyme inhibitory activities. The underlying mechanisms of action, structure–activity relationships (SAR), and the influence of metal ions and ligand architecture on biological performance are critically discussed. Furthermore, current challenges, toxicity considerations, and future perspectives for the development of Schiff base metal complexes as potential therapeutic agents are highlighted.