STUDIES ON THE ANTITUMOR DITERPENOID CONSTITUENTS OF RABDOSIA JAPONICA (BURM.F) HARA Ⅱ. THE STRUCTURES OF RABDOSIN C

Rabdosin C, a new diterpenoid having a B-seco-ent-(—)-Kaurene skeleton, and three diterpenoids, Epinodosin (Ⅰ), Lasiokaurin (Ⅱ) and Oridonin (Ⅲ), have been isolated from the ethereal extract of the leaves of Rabdosia japonica (Burm. f) Hara (Labiatae) collected in Henan.On the basis of chemical and spectroscopic data, the chemical structures of Rabdosin C was established as (Ⅵ).