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)-3 beta ,22 alpha ,24-trihydroxyolean-12-ene and two known triterpenoid saponins, 3-O-{[alpha -L-rhamnopyranosyl-(1 -->2)]-[beta -D-glucopyranosyl-(1 -->2)]-beta -D-glucuronopyranosyl}-3 beta ,22 beta ,24-trihydroxyolean-12-ene (azukisaponin V) and 3,16-di-O-beta -D-glucopyranosyl-3 beta ,6 alpha ,16 beta -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 H-1-H-1 COSY, NOESY, ROESY, TOCSY, HMQC and HMBC experiments.