Diterpenoids from Isodon eriocalyx.

Three new diterpenoids, eriocalyxins C-E (1-3), were isolated from Isodon eriocalyx. Their structures were elucidated as 6 beta-hydroxy-15 beta-acetoxy-3 alpha,20-epoxy-16 beta,17-epoxy-ent-kaur-1,7-dione (1), 1 alpha,7 beta-dihydroxy-6 beta,15 beta-diacetoxy-7,20-epoxy-ent-kaur-16-ene (2), and 15 beta-acetoxy-1,6-dioxo-6,7-seco-ent-kaur-2,16-dien-7,20-olide (3), respectively, by means of spectroscopic methods, including one- and two-dimensional NMR techniques.