Triterpenoid saponins from Astragalus trigonus.

One new, 3-O-[[[-alpha-L-rhamnopyranosyl-(1-->2)]-[beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl]-3beta,22alpha,24-trihydroxyolean-12-ene and two known triterpenoid saponins, 3-O-[[alpha-L-rhamnopyranosyl-(1-->2)]-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl]-3beta,22beta,24-trihydroxyolean-12-ene (azukisaponin V) and 3,16-di-O-beta-D-glucopyranosyl-3beta,6alpha,16beta-trihydroxycycloart-24-ene have been isolated from Astragalus trigonus. The structures were determined primarily by NMR spectroscopy. The assignment of NMR signals was performed by means of 1H-1H COSY, NOESY, ROESY, TOCSY, HMQC and HMBC experiments.