Bioactive cycloartane-type triterpene glycosides from Astragalus elongatus.

Together with two known cycloartane-type glycosides, askendosides D (3-O-[alpha-arabinopyranosyl-(1-->2)-beta-xylopyranosyl]-6-O-beta-xylopyranosyl-cycloastragenol, 2) and G (3-O-[alpha-arabinopyranosyl-(1-->2)-beta-xylopyranosyl]-16-O-beta-glucopyranosyl-3 beta,6 alpha,16 beta,24(R),25-pentahydroxycycloartane, 3), also a new monodesmosidic cycloartane-type glycoside, elongatoside (1), was isolated from the roots of Astragalus elongatus and identified as 3-O-[alpha-arabinopyranosyl-(1-->2)-beta-xylopyranosyl]-cycloastragenol. All structures were unambiguously determined by means of spectroscopic and spectrometric methods (1D and 2D NMR, ESI-MS). The isolated compounds were tested for the inhibition of proliferation and ICAM-1 expression in vitro using the human microvascular endothelial cell line (HMEC-1). 1 showed weak activity in the ICAM-1 assay.