Anti-RAFLS Triterpenoids and Hepatoprotective Lignans From the Leaves of Tujia Ethnomedicine (Xuetong).

A pair of 3,4--cycloartane triterpenoid isomers with a rare peroxy bridge, namely, xuetonins A and B ( and ), four new lignans xuetonlignans A-D (-), a new sesquiterpene xuetonpene (), and a new natural product xuetonin C (), along with 43 known compounds, were obtained from the leaves of Tujia ethnomedicine, . Their structures and configurations were determined with the help of a combination of 1D- and 2D-NMR, HRESIMS spectra, electronic circular dichroism (ECD), and X-ray diffraction data. Compounds , , -, and - showed moderate-to-potent activity against rheumatoid arthritis fibroblast-like synoviocytes (RAFLS) with IC values of 19.81 ± 0.26, 12.73 ± 0.29, 5.70 ± 0.24, 9.25 ± 0.79, 5.66 ± 0.52, 11.91 ± 0.44, 13.22 ± 0.27, and 15.94 ± 0.36 μM, respectively. Furthermore, compounds , , and exhibited significant hepatoprotective effects against -acetyl--aminophenol (APAP)-induced toxicity in HepG2 cells at 10 μM, and the cell viability increased by 12.93, 25.23, and 13.91%, respectively, compared with that in the model group (cf. bicyclol, 12.60%).