Diterpenoids from Isodon sculponeatus

Further investigation on the leaves of Isodon sculponeatus afforded two new ent-kaurane diterpenoids, sculponeatins J and K. Their structures were elucidated on the basis of their spectral properties, as well as X-ray crystallographic analysis. The cytotoxicities of these two new compounds against human tumor cells K562 and T24 were also tested, and sculponeatin J showed significant inhibitory effects with IC50 values less than 1.0 μg/mL.