Eremopetasitenin A3 and 8-Oxoeremophil-6-en-12-oic Acid from Petasites japonicus ssp. giganteus

Seven eremophilane-type sesquiterpenes have been isolated from Petasites japonicus ssp. giganteus collected in Hokkaido, and two of them have been found to be new. Eremopetasitenin A 3 null was a lactone containing an epoxide at the C-7 and C-8 positions, whose structure was established mainly based on spectroscopic evidence including 2D NMR spectra. The other one was an eremophilane-type carboxylic...