| Abstract: | The new diterpenoid 6α‐hydroxy‐ent‐kaur‐16‐en‐15‐one ( 1 ) and a diterpenoid with a new skeleton, i.e., amentotaxin BB ( 5 ), as well as three new lanostanoids, i.e., (3β,23R)‐3‐methoxy‐24‐methylenelanost‐8‐en‐23‐ol ( 6 ), (23S)‐23‐methoxy‐24‐methylenelanost‐8‐en‐3‐one ( 7 ), and (3β,24ξ)‐3‐methoxy‐24‐methyl‐9,19‐cyclolanostan‐25‐ol ( 8 ), were isolated from the bark and leaves of Amentotaxus formosana. Their structures, including the relative configurations, were elucidated from spectroscopic data. Compound 1 and a known compound, ent‐kaur‐16‐en‐15‐one ( 2 ), showed potent cytotoxic effects against a number of cancer cells in vitro. |
