Five new schinortriterpenoids from Schisandra propinqua var. propinqua

Five new schinortriterpenoids, propinqtrilactones A and B (1 and 2) with rare lancischiartane scaffold, and propindilactones V-X (3-5), were isolated from the stems and leaves of Schisandra propinqua var. propinqua. Their structures were elucidated on the basis of comprehensive spectroscopic and mass spectrometric analysis. The absolute configurations of 1-5 were determined by CD methods, X-ray diffraction analysis and theoretical calculations. 4 was tested for its cytotoxic activities against five human tumor cell lines.