Structurally Diverse Highly Oxygenated Triterpenoids from the Roots of Ailanthus altissima and Their Cytotoxicity

Ten new triterpenoids, ailanaltiolides A–J (1–10), and three known analogues (11–13) were isolated from the roots of Ailanthus altissima. Compounds 1–7 are apotirucallane-type, compounds 8 and 9 are tirucallane-type, and compound 10 is a trinordammarane-type triterpenoid. This is the first study indicating the genus Ailanthus as a potential source for apotirucallane derivatives, which contain an α,β-unsaturated-ε-lactone A-ring and diversely modified C-17 side chains. Spectroscopic data interpretation, electronic circular dichroism analysis, and X-ray crystallographic data defined the structures and absolute configurations of these triterpenoids. Compounds 2, 7, and 8 showed cytotoxicity against four tumor cell lines (HeLa, 786-O, HepG2, and A549). In particular, compound 2 exhibited the highest activity against 786-O cells with an IC50 value of 8.2 μM in vitro.