Glabcensin Q-U, five new ent-kaurane diterpenoids from Isodon angustifolius var. glabrescens

Examination of the diterpenoid constituents of the dried leaves of Isodon angustifolius var. glabrescens led to the isolation of five new ent-kaurane diterpenoids, named as glabcensin Q-U (2-6). The structures were elucidated on the basis of spectroscopic evidences.