Cycloartane-type triterpenoids and sesquiterpenoids from the resinous exudates of Commiphora opobalsamum.

Cycloartane-type triterpenoids (1-3), seven sesquiterpenoids (7-13), and five previously reported secondary metabolites, including three cycloartane-type triterpenoids (4-6) and two sesquiterpenoids (14 and 15), were isolated from the resinous exudates of Commiphora opobalsamum. Their structures were elucidated by extensive spectroscopic analysis, including UV, IR, NMR, and MS, and comparison with literature data. The structures of 1, 3, and 7 were confirmed by single-crystal X-ray diffraction analysis. The absolute configuration of 1 was interpreted by the incorporation of CHCl(3) (crystallization solvent) in the crystal and that of 10 was determined by the CD exciton chirality method. Compound 12 represents the first example of a 12-norcadinane-type sesquiterpenoid. Furthermore, compounds 1, 3, 7, and 10-14 were evaluated for cytotoxicity against HeLa and HepG2 cell lines.