Osteoclast-inhibiting saikosaponin derivatives from Bupleurum chinense

Five new saikosaponins, saikosaponin w (1), 21β-hydroxysaikosaponin b2 (2), 6″-O-acetylsaikosaponin e (3), 6″-O-acetylsaikosaponin b1 (4), and 6″-O-acetylsaikosaponin b3 (5), along with twenty-two known ones (6-27), have been isolated from the roots of Bupleurum chinense. Their structures were elucidated on the basis of detailed spectroscopic analysis, including mainly 1D and 2D NMR and HRESI-MS, qualitative chemical methods, and comparison with the literatures. Osteoclast-inhibiting activity of some of the isolated compounds was evaluated in vitro, with five ones have shown significant activity by inhibitory rates ranging from 48.3% to 56.1% at the concentration of 10μM and with significant differences among groups observed.