Schilancitrilactones A-C: Three Unique Nortriterpenoids from Schisandra lancifolia

hree unique nortriterpenoids, schilancitrilactones A-C (1-3), were isolated from the stems of Schisandra lancifolia. Compound 1 possesses a 5/517/5/5/5-fused hexacyclic ring system with a C-29 backbone, while 2 and 3 feature a C-27 skeleton with a 5/7/5/5/5-fused pentacyclic ring system. Their absolute stereochemistries were established by CD and single-crystal X-ray diffraction experiments. Compound 3 showed anti-HIV-1 activity with an EC50 value of 27.54 mu g/mL, and 1 exhibited antifeedant activity at 15.73 mu g/cm(2).