Two New Lanostane Triterpenoids from the Branches and Leaves of Polyalthia oblique

Two new lanostane triterpenoids, 20-hydroxyeuphorbol-7-one 91) and 15 alpha-hydroxyeuphorbol-7,11-dione 92), together with four known triterpenoids, euphorbol-7-one 93), friedelin 94), stigmast-4-ene-6 alpha-ol-3-one 95), stigmasta-4-en-3,6-dione 96), were isolated from ethanol extract of the branches and leaves of Polyalthia obliqua. The structures of 1 and 2 were elucidated on the basis of extensive spectroscopic analysis and comparisons with related known compounds. Antibacterial activities of two new compounds and four known compounds were tested.