Abstract:Further investigation on the lsodon adenanthus afforded a new triterpenoid,isodonade-nanthin (1),together with three known ones,ursolic acid 2α-hydroxyl-ursolic acid and 2α,24-dihydrox-yi-ursolic acid.Structured of 1-4 were elucidated on the basis of their spectral prlperties.The cyeoeoxicities of the new compound against three kinds of human tumor cells K562, A549,and T24 were also tested. And 1 showed a certain antitumor activities toward all three kinds of cells