Sculponins A-C, three new 6,7-seco-ent-kauranoids from Isodon sculponeatus

Three new 6,7-seco-ent-kauranoids (1-3) were isolated and structures were elucidated from Isodon sculponeatus. Diterpenoids 1-3 possessing multicyclic skeletons formed via oxygen atoms are all unprecedented among ent-kauranes. Compound 1 displayed significant cytotoxic activity against K562, A549, and HepG2 human tumor cell lines, with IC50 values of 1.4, 2.3, and 2.0 μM, respectively, equal to the positive control. Plausible pathways for the biosynthesis of 1 and 2 from one related diterpenoid were also postulated.

Three new 6,7-seco-ent-kauranoids (1-3) were isolated and structures were elucidated from Isodon sculponeatus. Diterpenoids 1-3 possessing multicyclic skeletons formed via oxygen atoms are all unprecedented among ent-kauranes. Compound 1 displayed significant cytotoxic activity against K562, A549, and HepG2 human tumor cell lines, with IC50 values of 1.4, 2.3, and 2.0 μM, respectively, equal to the positive control. Plausible pathways for the biosynthesis of 1 and 2 from one related diterpenoid were also postulated.