A new phenanthrene with a spirolactone ring from Dendrobium ochreatum .

Dendroochreatene ( 1 ), a new phenanthrene derivative with a spirolactone ring, was isolated from the whole Dendrobium ochreatum plant together with 11 known compounds ( 2 - 12 ). The structure of the new compound was elucidated spectroscopically and phenolic compounds were firstly reported from D. ochreatum. Moscatilin ( 4 ), major compound isolated from D. ochreatum, was found to be cytotoxic toward H460 lung-cancer cells, with an IC 50 value of 147.3 ± 0.9 µM, while loddigesiinol C ( 7 ), C- α -methoxy derivative was inactive.