Integrated UHPLC-HRMS and field-induced droplet ionization mass spectrometry for rapid functional screening of photoactive furanocoumarins in Angelica dahurica.

Photoactive constituents in medicinal and edible plants can induce photooxidative reactions and pose potential safety risks, yet their rapid identification remains challenging. Herein, a field-induced droplet ionization mass spectrometry (FIDI-MS)-based strategy was developed to evaluate the photooxidative activity of Angelica dahurica. Ethanol extracts exhibited stronger photooxidative activity than aqueous extracts owing to their higher contents of lipophilic furanocoumarins. Six furanocoumarins, including imperatorin, isoimperatorin, psoralen, bergapten, byakangelicol, and phellopterin, were identified as the major photoactive constituents. Comparative analysis indicated that an intact furanocoumarin chromophore was essential for photooxidative activity, while lipophilicity further influenced the relative oxidation index. FIDI-MS results were consistent with conventional ROS assays. This study provides a rapid platform for identifying photoactive phytochemicals and evaluating the photooxidative risks of medicinal and edible plant resources.