Triterpene glycosides of Astragalus and their genins XXXVII. Cycloaraloside F from Astragalus amarus and Astragalus villosissimus

Abstract

The glycosides of the plantAstragalus villosissimus Bunge have been studied. Four glycosides have been isolated from the roots of this plant, and two of them have been identified as β-sitosterol β-D-glucopyranoside and cycloaraloside C. The most polar glycoside, which has also been isolated from the roots ofAstragalus amarus Pall., proved to be a new triterpene glycoside of the cycloartane series and has been called cycloaraloside F. It is a trioside of cyclosieversigenin containing two molecules of D-glucose and one molecule of D-apiose. On the basis of chemical transformations and spectral characteristics, the structure of cycloaraloside F has been established as 20R, 24S-epoxycycloartane-3β,6α,16β,25-tetraol 3-0-[O-D-apio-β-D-furanosyl-(1→2)-β-D-glucopyranoside] 25-O-β-D-glucopyranoside.