Secondary metabolites from the roots of Astragalus trojanus

Six novel cycloartane-type glycosides were isolated from the roots of Astragalus trojanus. Two of these, compounds 1 and 2, have (20R, 24S)-epoxy-3beta,6alpha,16beta,25-tetrahydroxycycloartane as the aglycon, while compounds 3-6 possess 3beta,6alpha,16beta,(24S), 25-pentahydroxycycloartane as the aglycon. The saccharide moieties linked to the C-3, C-6, and C-24 or C-25 positions of the aglycons in 1-6 contained either xylopyranose, glucopyranose, rhamnopyranose, or arabinopyranose units. Structure elucidation of compounds 1-6 was accomplished through the extensive use of 1D and 2D NMR techniques. In addition, a new oleanene glycoside (7) and a new tryptophan derivative (8) were also isolated and characterized.