Structures and Antimutagenic Effects of Onoceranoid-Type Triterpenoids from the Leaves of Lansium domesticum.

A methanol extract of the dried leaves of Lansium domesticum showed antimutagenic effects against 3-amino-1,4-dimethyl-5 H-pyrido[4,3- b]indole (Trp-P-1) and 2-amino-1-methyl-6-phenylimidazo[4,5- bI]pyridine (PhIP) using the Ames assay. Nine new onoceranoid-type triterpenoids, lansium acids I-IX (1-9), and nine known compounds (10-16) were isolated from the extract. The structures of the new compounds were elucidated on the basis of chemical and spectroscopic evidence. The absolute stereostructures of the new compounds were determined via their electronic circular dichroism spectra. Several isolated onoceranoid-type triterpeneoids showed antimutagenic effects in an in vitro Ames assay. Moreover, oral intake of a major constituent, lansionic acid (10), showed antimutagenic effects against PhIP in an in vivo micronucleus test.