A virtual database and structural feature-based analytical strategy for in-depth characterization of triterpenoids from Astragalus membranaceus (Fisch.) Bge roots and leaves.

Systematic characterization of natural product components is essential for product development and quality control. The root (AMR) and leaf (AML) of Astragalus membranaceus (Fisch.) Bge are used in food and health-related products. However, the composition of triterpenoids in AMR and AML has not been completely clarified. This study proposes a strategy that integrates a virtual database with aglycones to systematically identify triterpenoids in AMR and AML. The aglycones, substituents and sugar moieties of triterpenoids were summarized by integrating previously reported triterpenoids to construct a virtual database. Subsequently, the raw data was compared with a virtual database, and false positives were eliminated by detecting aglycones in the MS/MS spectra, thereby screening for potential triterpenoids. A total of 421 potential triterpenoids were identified, of which 158 were from AMR and 283 were from AML. Among these, 319 triterpenoids were considered potential new compounds. In addition, 6 triterpenoids were identified as chemical markers distinguishing AMR from AML. This study systematically characterized the triterpenoids in AMR and AML, enhancing our understanding of triterpenoids in both AMR and AML, and established a foundation for the further development of AMR and AML. Furthermore, this study developed a workflow for in-depth mining of unknown compounds using data independent acquisition mode to systematically characterize natural products.