Dammarane- and taraxastane-type triterpenoids from Saussurea oligantha Franch.

A new dammarane triterpenoid oliganthas A (1) and a new taraxastane triterpenoid oliganthas B (2), as well as five known taraxastane triterpenoids, ptiloepoxide (3), taraxast-20(30)ene-3beta,21alpha-diol (4), 22-oxo-20-taraxasten-3beta-ol (5), taraxast-20-ene-3beta,30-diol (6), and taraxastane-3beta,20alpha-diol (7), were isolated from the whole plant of Saussurea oligantha Franch. Their structures were elucidated by a series of spectroscopic methods. These compounds, especially taraxastanes 2, 5, and 6, exhibited significant antibacterial activity against Actinomyces viscosus ATCC27044.