Triterpenoids from the bark of Entandrophragma angolense

Two new triterpenoids, entanolide (1) and methyl 3,4-secotirucalla-23-oxo-4(28),7,24-trien-21-al-3-oate (2), together with nine known compounds (3-11), were isolated from the bark of Entandrophragma angolense. Their structures were elucidated based on spectroscopic analyses, mainly 1 D and 2 D NMR spectral data. Compounds 1-6 and 8 were evaluated for their cytotoxicity against HepG2 cells, and compounds 2-5 exhibited weak activities.