Abstract: Abstract A new antineoplastic diterpenoid, glaucocalyxin C (.C20[C20H30O4, mp 272-273°C, [α]29/D-109 (C=0.1, MeOH )], was isolated from the leaves of Rabdosia japonica (Burm. f.) Hara var. glaucocalyx (Maxim.) Hara (Labia-tae) collected Beijing area and the structure has been shown to be that in the ent-7β, 14α, 15 α-trihydroxy-16-kauren-3-one (1) from spectral and chemical evi-dence. Two known ent-kaurenoids, glaucocalyxin A (2) and B ( 3 ) were also isolated from the same plant.

Key words: Diterpenoid