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 IC 50 value of 8.2 μM in vitro.