Bupleurum chinense Roots: a Bioactivity-Guided Approach toward Saponin-Type NF-κB Inhibitors.

The roots of have a long history in traditional medicine to treat infectious diseases and inflammatory disorders. Two major compounds, saikosaponins A and D, were reported to exert potent anti-inflammatory activity by inhibiting NF-B. In the present study, we isolated new saikosaponin analogues from the roots of interfering with NF-B activity . The methanol-soluble fraction of the dichloromethane extract of Radix Bupleuri was subjected to activity-guided isolation yielding 18 compounds, including triterpenoids and polyacetylenes. Their structures were determined by spectroscopic methods as saikogenin D (), prosaikogenin D (), saikosaponins B (), W (), B (), Y (), D (), A (), E (), B (), B (), and T (), saikodiyne A (), D (), E () and F (), falcarindiol (), and 1-linoleoyl-sn-glycero-3-phosphorylcholine (). Among them, , and are new compounds, whereas previously described as a semi-synthetic compound, is isolated from a natural source for the first time, and - are the first reports of polyacetylenes from this plant. Nine saponins/triterpenoids were tested for inhibition of NF-B signaling in a cell-based NF-B-dependent luciferase reporter gene model . Five of them (, and ) showed strong (> 50%, at 30 µM) NF-B inhibition, but also varying degrees of cytotoxicity, with compounds and (showing no significant cytotoxicity) presenting IC values of 14.0 µM and 14.1 µM in the cell-based assay, respectively.