Cycloartane triterpene glycosides from Astragalus siculus

Based on spectroscopic analysis and chemical degradation, the structures of two saponins isolated from the methanol extract of fresh roots of Astragalus siculus Biv. were established to be that of astrasieversianin II and astragaloside I (also known as astrasieversianin IV), two saponins previously isolated from A. sieversianus Pall and A. membrenaceus Benge. A complete assignment of NMR data to the two compounds 1 and 2 is reported for the first time.