Structurally Diverse Highly Oxygenated Triterpenoids from the Roots of <i>Ailanthus altissima</i> 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