Triterpenoids from Schisandra rubriflora.

Investigation of an organic extract of Schisandra rubriflora led to the isolation of three new highly oxygenated nortriterpenoids, named rubriflorins A-C (1-3), together with six related known compounds (4-9). Their structures were elucidated by spectroscopic evidence. Compounds 1-3 feature the opening of ring A compared with related known nortriterpenoids isolated from the genus Schisandra and showed anti-HIV-1 activities with EC50 values of 10.0, 16.2, and 81.3 microg/mL, respectively.