Schiglautone A, a new tricyclic triterpenoid with a unique 6/7/9-fused skeleton from the stems of Schisandra glaucescens.

Schiglautone A (1), a unique 6/7/9-fused tricyclic carbon backbone triterpenoid, was isolated from the stems of Schisandra glaucescens. Its structure was determined on the basis of spectroscopic analysis and single-crystal X-ray crystallography. A hypothetical biosynthetic pathway of 1 was postulated.