13,27-Cycloursane, ursane and oleanane triterpenoids from the leaves of Lucuma nervosa.

One hitherto unknown 24-nor-13,27-cycloursane-type triterpenoid, lucumic acid A (1), one new 24-nor-ursane triterpenoid, lucumic acid B (2), along with six known triterpenoids were isolated from the ethanol extract of the leaves of Lucuma nervosa. Their structures were established on the basis of spectroscopic data interpretation. Lucumic acid A (1) is the first example of a 24-nor-triterpenoid with a 13,27-cyclopropane ring.