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

摘要： 从北京地区产兰萼香茶菜[Rabdosia japonica （Burm．f．）Hara var·glaucocalyx（Maxim．）Hara]叶中分得三个对映-贝壳杉烯二萜化合物，其中二个为己知物兰萼甲素(2)和乙素（3），另一个为新化合物，命名为兰萼丙素，经光谱和化学方法证明，其结构为对映-7β，14a，15a-三羟基-16-贝壳杉烯-3-酮（1）。

关键词: 二萜化合物, 对映-贝壳杉烯, 兰萼香茶菜, 兰萼丙素, 1H和13C NMR