RESUMO
The title compound, C(20)H(30)O(6), a natural ent-kaurane diterpenoid, named nervosanin B, was obtained from the medicinal plant Isodon serra. It is composed of four rings with the expected trans and cis junctions. One of the six-membered rings is in a chair conformation, the other two are in boat conformations and the five-membered ring adopts an evenlope conformation. The mol-ecules stack along the a axis and are linked together by inter-molecular O-Hâ¯O hydrogen bonds. Two intramolecular O-Hâ¯O interactions also occur.
RESUMO
Two new ent-kaurane diterpenoids, 6,20,15alpha-trihydroxy-6,7-seco-1alpha,7-olide-ent-kaur-16-ene (1) and 7beta,12alpha-dihydroxy-6beta,15beta-diacetoxy-7alpha,20-epoxy-ent-kaur-2,16-dien-1-one (2), together with the six known compounds, were isolated from the aerial part of Isodon nervosus. The structures of the new compounds were determined by spectral methods (1D, 2D NMR, and MS). Six compounds were assayed for their cytotoxicity against HL60, SMMC-7721, and HeLa human cell lines. Compounds 5, 7, and 8 showed significant cytotoxicity.
