A New ent-Kaurane Deterpenoid from Isodon Excisoides(Sun ex C. H. Hu) C. Y. Wu et H. W. Li

A new ent-kaurane diterpenoid, excisoidesin (1), was isolated from the acetone extract of the leaves of Isodon excisoides(Sun ex C. H. Hu) C. Y. Wu et H. W. Li, along with kamebacetal B (2), glaucocalyxin A (3), leukamenin E (4), kamebanin (5) and wangzaozin A (6). The structure of the new compound was determined as 7α,14β,18-trihydroxy-ent-kaur-16-en-3,15-dione by spectroscopic methods. Compound 1–6showed significant cytotoxic activity against human tumor Bel-7402 cells.