Analysis of melatonin simulated metabolism based on electrochemistry coupled online with high performance liquid chromatography-mass spectrometry

Online electrochemistry coupled with high-performance liquid chromatography-mass spectrometry (EC-HPLC-MS) technology has emerged as a powerful tool for simulating biological metabolism and pollutant degradation research due to its unique complementary advantages. This study focuses on melatonin, an important endogenous neuroendocrine hormone characterized by its indole ring structure, as a model compound to investigate electrochemical metabolic simulation. The metabolic process of melatonin was mimicked through linear sweep or constant-potential electrolysis, with the resulting electrolysis products directly transferred to an MS or HPLC-MS system for real-time separation and detection. Additionally, comparison with metabolites obtained <i>via in vitro</i> cultured liver microsome assays demonstrated substantial similarity in their phase I metabolite profiles. Electrochemically simulated metabolites exhibited markedly enhanced MS ion responses under optimized conditions. In contrast, phase II metabolites derived from electrochemical simulation diverged completely from microsomal metabolites, with both methods producing limited product diversity. The proposed EC-MS and EC-HPLC-MS approaches effectively address key limitations of traditional metabolic studies, including challenges in biological sample acquisition and metabolic process control, thereby offering a robust and reproducible alternative for metabolism research. It provides a promising strategy for further exploration of metabolic mechanisms, which is worthy of further improvement and promotion in pharmaceutical and environmental research.