Studies on the constituents of Gentiana species. II. A new triterpenoid, and (S)-(+)- and (R)-(-)-gentiolactones from Gentiana lutea.

A new triterpenoid, 12-ursene-3beta, 11alpha-diol 3-O-palmitate (1), has been isolated from the rhizomes and roots of Gentiana lutea, together with the artificial diene derivative, 9 (11), 12-ursadien-3beta-ol 3-O-palmitate (1a) and five known compounds (3-7). Their structures were established on the basis of spectral analysis. In addition, (+/-)-gentiolactone [(+/-)-2], isolated from this plant, was successfully separated into its enantiomers [(+)-2, (-)-2] for the first time, and the absolute configurations at C-9 of (+)-2, (-)-2 were assigned as S and R, respectively, from the optical rotations and the circular dichroism (CD) spectral data.