Characterization of the interaction between diclofenac sodium and human serum albumin based on network pharmacology, electrochemical analysis, fluorescence spectroscopy, and computational simulations.

Emerging contaminants from pharmaceuticals and personal care products (PPCPs), extensively detected in wastewater, are associated with multiple potential adverse health effects in humans. Among these, diclofenac sodium (DIC) has been detected in wastewater samples from numerous locations. Therefore, to investigate the neurotoxic molecular mechanisms of DIC, this study employed using a multi-technical framework that integrated experimental and computational simulation. Network pharmacology identified human serum albumin (HSA) as a key target in DIC-induced neurotoxicity. Based on this finding, the subsequent studies were designed to elucidate the interaction between HSA and DIC. Electrochemical experiments revealed that DIC formed an electro-inactive complex with HSA. The complex exhibited a 1:1 molar binding ratio with a strong affinity, reflected by a binding constant of 1.18 ± 0.06 × 105 M-1. Esterase activity assays demonstrated that DIC acted as a competitive inhibitor of HSA esterase activity. Computational simulations further characterized binding mechanisms. Molecular docking revealed the binding of DIC to site I of HSA, with π-electrons formed its benzene rings being instrumental in the binding process. Molecular dynamics changes were consistent with CD results and indicated a reduction in structural stability. This study offers innovative strategies for assessing the health and ecological risks posed by environmental contaminants.