DNA/BSA binding study of N-benzylthiabendazole and its mononuclear silver(I) complex

The antimicrobial properties of silver(I) ions have been recognized since ancient times. In recent decades, silver(I) complexes have been extensively studied for their antimicrobial activity. The ligand plays a crucial role not only in stabilizing the complex but also in modulating its physicochemical properties, such as solubility, lipophilicity, and the ability to release silver(I) ions under biological conditions. In addition to their broad spectrum of applications, silver(I) complexes are noted for their low toxicity to human cells and the remarkably low tendency of microorganisms to develop resistance. These characteristics make silver(I) complexes promising candidates for the development of novel antimicrobial agents, particularly in the fight against bacterial resistance to clinically used antibiotics. The possible mechanism of the antimicrobial activity of silver(I) complexes can be attributed to their interactions with biological molecules, including DNA and proteins. Thiabendazole is a benzimidazole derivative widely used as a pesticide, known for its potent antifungal and anthelmintic activities. Due to its favorable pharmacological profile, thiabendazole has attracted attention as a structural scaffold for the development of metal complexes with potential biological activity. In this study, we employed a benzyl-substituted derivative of thiabendazole, N-benzylthiabendazole (N-BzTBZ), as a ligand to synthesize a novel mononuclear silver(I) complex, [Ag(N-BzTBZ)₂]CF₃SO₃, exhibiting a distorted trigonal planar geometry. The binding affinity of both the free ligand and the synthesized complex with biologically relevant targets, bovine serum albumin (BSA) and calf thymus DNA (ct-DNA), were investigated using fluorescence emission spectroscopy.