Electrochemistry Coupled to High-Resolution Mass Spectrometry for Phase I and Phase II Metabolic Studies of Bioactive...

An innovative approach combining electrochemistry with online quadrupole time-of-flight-mass spectrometry (EC-MS/MS) was employed to study the oxidative products and metabolic pathways of three bioactive compounds found in Phellodendri Chinensis Cortex, including phellodendrine, obaculactone, and obacunone. This advanced analytical technique provided detailed insights into their transformation processes. The simulation of phase I metabolism reactions was conducted within an electrochemical microreactor system. The heart of this apparatus was a reliably performing boron-doped diamond electrode. Meanwhile, a defined concentration of glutathione (GSH) was injected into the reaction system to obtain phase II metabolites. The metabolites were collected and concentrated for offline electrochemistry-ultra-high-performance liquid chromatography-quadrupole-time of flight-mass spectrometry analysis (EC-UHPLC-MS/MS). The main converted products and metabolic pathways were further verified through in vitro liver microsome incubation experiments. It was revealed that the simulated metabolic process based on the electrochemical system effectively produced a variety of metabolites from the compounds, which were subsequently compared with those obtained from rat liver microsomal incubations. Without matrix interference, the drug metabolic process could be effectively simulated and analyzed using the electrochemical system. The findings underscore the utility of electrochemistry as a robust tool for preliminary investigations into the metabolism of natural products, offering a reliable and efficient alternative to traditional methods.