Cycloartane type triterpenoids from the rhizomes of Polygonum bistorta

Two new compounds, 24(E)-ethylidenecycloartanone (1) and 24(E)-ethylidenecycloartan-3alpha-ol (2) were isolated from the rhizomes of Polygonum bistorta, together with seven known compounds viz., cycloartane-3,24-dione (3), 24-methylenecycloartanone (4), gamma-sitosterol (5), beta-sitosterol (6), beta-sitosterone (7), friedelin (8) and 3beta-friedelinol (9). All the cycloartane type triterpenoids, compounds 7 and 8 are reported for the first time from this plant. A combination of 1D and 2D NMR spectroscopy and MS were mainly used to elucidate the structures of the new compounds 1 and 2.