Incarnolides A and B, Two Schinortriterpenoids with a Tricyclo[9.2.1.02,8]tetradecane-Bridged System from Schisandra incarnata.

Incarnolides A (1) and B (2), two schinortriterpenoids (SNTs) featuring a tricyclo[9.2.1.02,8]tetradecane-bridged system, together with two biosynthetically related known SNTs, lancifonins A (3) and C (4), were isolated from the stems of Schisandra incarnata. Their structures were elucidated by extensive spectroscopic analyses, and the absolute configurations were assigned by single-crystal X-ray diffraction and electronic circular dichroism calculation. The hypothetical biogenetic pathway of 1 and 2 was postulated. Compound 1 exhibited antiviral and neuroprotective activities.