Cytotoxic Dihydroagarofuran Sesquiterpenoids Isolated From the Roots of Tripterygium wilfordii.

Extraction of the roots of Tripterygium wilfordii afforded ten undescribed dihydro-β-agarofuran derivatives [tripterdines M-V (1-10)], including five sesquiterpene polyesters and five sesquiterpene pyridine alkaloids, along with three known analogues (11-13). Through HRESIMS, spectroscopic analysis (UV, IR, ECD, and 1D/2D NMR), x‑ray crystallography, CD exciton chirality method, and ECD calculations, the structures of these undescribed compounds were elucidated. Four human cancer cell lines (SK-MEL-2, HCC1806, HUH-7, and PANC-1) and one human normal cell line (MRC-5) were used to screen all compounds for in vitro cytotoxicity via the CCK-8 method. Among the tested cell lines, SK‑MEL‑2 was the most sensitive toward undescribed compounds 2, 3, and 5, giving IC50 values of 8.50, 13.30, and 13.28 µM, respectively. Notably, these active compounds displayed no obvious cytotoxicity against normal MRC‑5 cells (IC50>50 µM).