Isolation, Characterization and Crystal Structure of Cytotoxic ent-Kaurane Diterpenoids from Isodon weisiensis C.Y. Wu

Abstract

The new ent-kaurane diterpenoid weisiensin C (1) (1α,7α,14β ,18,20-pentahydroxy-ent-kaur-16- en-15-one), together with four known ent-kaurene diterpenoids, glaucocalyxin A (2), kamebanin (3), macrocalyxin D (4), and excisanin K (5), was isolated from the leaves of Isodon weisiensis C.Y. Wu. The structure of the new constituent (1) was elucidated by spectroscopic methods and confirmed by single-crystal X-ray diffraction.