Two Novel Sub-skeleton Types of ent-Kauranoids from Isodon gesneroides

摘要

Two novel ent-kauranoids with new sub-skeleton types, gesneroidins G and H were isolated as white powder from the ether extract of the leaves of Isodon gesneroides through normal phase column chromatography. Their structures were elucidated as 3b,6a,7b-triacetoxyl-15-hydroxyl-14-oxo-ent-15,16-seco-kaur-11,17-olide and 1a-hydroxyl-3b,6a,7b,11b-tetraacetoxyl-ent-nor-15,17-kaur-8,16-olide on the basis of the spectral evidences including 1D and 2D NMR spectra.