Targeted isolation of ursane-type triterpenoids from Tragopogon porrifolius based on Feature-Based Molecular Networking

Feature-Based Molecular Networking (FBMN) approach was applied for the phytochemical investigation of Tragopogon porrifolius L., which led to the targeted isolation of eleven ursane-type triterpenoids. Their structures were elucidated through extensive analysis of NMR and HRMS spectra data. All the compounds were reported for the first time from this plant while compounds 2, 3, and 6-9 represent unusual (18α,19β)-ursane-type triterpenes. All the isolated compounds were tested for their antioxidant activities. The DPPH free radical scavenging ability of 11 ursane-type triterpenoids of T.porrifolius is related to hydroxyl radical, compared to the positive control, compound 3 showed high antioxidant activity in the DPPH assay, with IC50 values of 24.19 ± 0.42 % at 50 μM.