New Triterpenoid Saponins from Achyrantes aspera Linn.

Two new bisdesmosidic triterpenoid saponins, i.e. 1 and 2 , were isolated, besides the three known saponins 3 – 5 , from the MeOH extract of the aerial parts of Achyranthes aspera Linn. (Amaranthaceae). Their structures were elucidated as β‐D ‐glucopyranosyl 3β‐[O‐α‐L ‐rhamnopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranuronosyloxy]machaerinate ( 1 ) and β‐D ‐glucopyranosyl 3β‐[O‐β‐D ‐galactopyranosyl‐(1→2)‐O‐α‐D ‐glucopyranuronosyloxy]machaerinate ( 2 ) by NMR spectroscopy, including 2D‐NMR experiments (machaerinic acid=3β,21β‐dihydroxyolean‐12‐en‐28‐oic acid). The other saponins were identified as β‐D ‐glucopyranosyl 3β[O‐α‐L ‐rhamnopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranuronosyloxy]oleanolate ( 3 ), β‐D ‐glucopyranosyl 3‐β‐[O‐β‐D ‐galactopyranosyl‐(1→2)‐O‐β‐D ‐glucopyranuronosyloxy]oleanolate ( 4 ), and β‐D ‐glucopyranosyl 3β‐[O‐β‐D ‐glucopyranuronosyloxy]oleanolate ( 5 ) (oleanolic acid=3β‐hydroxyolean‐12‐en‐28‐oic acid).