New Phenolic Tricyclic Diterpenoids from Rhizomes of Isodon hispida (BENTH.) HARA

Three new phenolic tricyclic diterpenoids, including two sempervirane diterpenoids, hispidanols A and B (1 and 2, resp.), and one totarane diterpenoid, totara-8,11,13-triene-13 -> 16-hemiacetal (3), along with 14 known compounds, 4-17, were isolated from the AcOEt-soluble fraction of the 70%-acetone extract of rhizomes of Isodon hispida. Their structures were elucidated based on the analyses of extensive spectroscopic data and physicochemical properties.