Ent-kaurene diterpenes from Sideritis athoa

Abstract

Two new and six known ent-kaurene diterpenes were isolated from the whole plant of Sideritis athoa and their structures were elucidated as ent-3 alpha,18-dihydroxykaur-16-ene (1), athonolone (2), ent-3 beta-hydroxykaur-16-ene (3) ent-3 beta,7 alpha-dihydroxykaur-16-ene (4), 7-epicandicandiol (5), linearol (8), foliol (7) and sidol (8) based on 1D and 2D NMR techniques and HRMS.