7α,20-Epoxy-ent-kauranoids from Isodon parvifolius

Nine new 7 alpha, 20-epoxy-ent-kaurane diterpenoids, parvifolines C- K (1-9), together with 12 known analogues, rabdoternin G ( 10), adenolin E ( 11), lasiodonin ( 12), lushanrubescensin F ( 13), parvifoliside ( 14), effusanin A ( 15), effusanin B ( 16), effusanin E ( 17), taibaihenryiin A ( 18), shikokianin ( 19), maoyecrystal J ( 20), and the acetonide of lasiodonin ( 21), were isolated from the leaves of Isodon parvifolius. The structures of compounds 1-9 were determined on the basis of spectroscopic methods including extensive 1D and 2D NMR analysis. The new diterpenoids (1-9) and lasiodonin ( 12) were evaluated for their inhibitory activity against A549, HT-29, and K562 cell lines.