Diterpenoids from the roots of Suregada glomerulata

Six new diterpenoids, 7 beta,8 alpha-dihydroxy-12-oxo-ent-abietan-16,14-olide (1), 3,4,18 beta-cyclopropa-7 beta,17-dihydroxy-ent-abieta-8(14),13(15)-dien-16,12-olide (2), 3 alpha L,7 beta-dihydroxy-ent-abieta-8(14),13(15)-dien-16,12-olide (3), 3-oxo-8 beta,14 beta-epoxy-ent-abieta-11,13(15)-dien-16,12-olide (4), 17-hydroxy-ent-pimara-8(14),15-di,en-3-one(5), and 3 alpha,6 beta-dihydroxy-ent-kaur-16-ene (6), and two known compounds, 7 beta-hydroxy-ent-abieta-8(14),13(15)-dien-16,12-olide (7) and jolkinolide 13, were isolated from roots of Suregada glomerulata. The structures of the new compounds were elucidated on the basis of ID and 2D NMR and other spectroscopic studies. The structure of compound I was confirmed by X-ray crystallography. Cytotoxic activities were evaluated against five human tumor cell lines.