A new triterpenoid saponin and a new natural saponin from the roots of Bupleurum scorzonerifolium willd

Sixteen triterpenoid saponins were isolated from the roots of Bupleurum scorzonerifolium Willd., including a new triterpenoid saponin and new natural saponin that was characterised by NMR for the first time, along with 14 known triterpenoid saponins. The structures of the compounds were established by 1D and 2D NMR spectroscopy, HR-ESI-MS, and comparison with the literature. The cytotoxic activity of the compounds against 4T1 cells was determined using the CCK8 method. Compounds 9 and 6 showed the strongest cytotoxic activity with IC50 values of 2.75 ± 0.86 and 3.78 ± 0.50 μM, respectively. Compounds 2–5 and 8 showed potent cytotoxic activity. Compounds 14 and 16 showed moderate cytotoxicity.