Cytotoxic ent-kaurane diterpenoids from Isodon racemosa (Hemsl) Hara

摘要

A new ent-kaurane diterpenoid racemosin A (1) and three known compounds,leukamenin E (2),glaucocalyxin A (3) and wangzaozin A (4),have been isolated from the leaves of Isodon racemosa (Hemsl) Hara.The new diterpenoid is identified as 14beta-hydroxy-3beta,7alpha-acetoxy-ent-kaur-16-en-15-one on the basis of spectral data,especially by 2D NMR techniques.Compounds 1-4 show significant cytotoxic activity against Bel-7402 and HO-8910 cells in the range of 1.51-2.57 and 3.33-4.02 mu g/mL,respectively.This may be due to the presence of conjugated exo-methylene systen in an ent-kaurane skeleton.