Two new triterpene lactones from the stems of Kadsura polysperma

Two new triterpene lactones, polysperlactones A (2) and B (3), were isolated from the stems of Kadsura polysperma, together with the known compounds heteroclitalactone D (1) and schisanlactone E (4). Their structures were elucidated by spectroscopic methods, including 2D-NMR and HR-MS techniques. The configuration of 1 was confirmed by X-ray analysis. Compounds 2 and 3 are members of a rare class of 3,4-secolanostane metabolites with ring-expanded or cyclized structures, respectively.