Isomeric triterpenoids from Peritassa campestris.

An investigation of the MeOH extract from the roots of Peritassa campestris (Hippocrateaceae) afforded two isomeric seco-A-ring quinonemethide triterpenoids, campestrine-I (1) and -II (2). This appears to be the first report of a C26,-type triterpene carbon skeleton from the Celastraceae or Hippocrateaceae families. The structures were elucidated on the basis of spectral data, particularly HMQC, HMBC and NOE experiments.