Antigiardial activity of triterpenoids from root bark of Hippocratea excelsa.

Two new triterpenoids, 21 beta-hydroxyolean-12-en-3-one (1) and a seco-dinor derivative of pristimerine named dzununcanone (2), were isolated from the root bark of Hippocratea excelsa. Their structures were assigned on the basis of spectroscopic evidence, mainly 1H and 13C 1D and 2D NMR including DEPT, COSY, ROESY, HSQC, and HMBC experiments, as well as EIMS and HREIMS. The known 21alpha-hydroxy-3-oxofriedelane (3), a compound new to the species, and the known methide quinones pristimerine (4) tingenone (5), and xuxuarine Ebeta (7) were also isolated.