The First Kynurenine 3-Monooxygenase Activator with an Undescribed Skeleton Provides Insight into the Toxicological Mechanism of <i>Gelsemium elegans</i>

Liquid chromatography-mass spectrometry-guided phytochemical isolation led to the discovery of four dimeric <i>Gelsemium</i> alkaloids, gelselegangmines A-D (<b>1</b>-<b>4</b>) from <i>Gelsemium elegans</i>. These dimers were connected by pyrrole rings. Their formation mechanism may include oxidation, hydrolysis, nucleophilic addition, etc. Bioactivity screening and verification disclosed alkaloid <b>2</b> as the first kynurenine 3-monooxygenase activator, providing insight into the toxicological mechanism of this famous plant.