Cycloartane and oleanane-type glycosides from Astragalus pennatulus

Four new cycloartane and one new oleanane-type glycosides were isolated from Astragalus pennatulus along with five known cycloartane-type glycosides. The structures of the new compounds were established as 3-O-beta-Dxylopyranosyl-6-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta-trihydroxy-24-oxo-20(R),25-epoxycycloartane (1), 3-O-[beta-D-glucuronopyranosyl-(1 -> 2)-beta-D-xylopyranosyl]-3 beta,16 beta,24 alpha-trihydroxy-20(R),25-epoxycycloartane (2), 3-O-[beta-D-glucuronopyranosyl-(1 -> 2)-beta-D-xylopyranosyl]-3 beta,16 beta,25-trihydroxy-20(R),24(S)-epoxycycloartane (3), 3,25-di-O-beta-D-glucopyranosy1-6-O-p-D-xylopyranosyl-3 beta,6 alpha,16 beta,25-tetrahydroxy-20(R),24(S)-epoxycycloartane (4), 29-O-alpha-L-rhamnopyranosyl-abrisapogenol B (5) by 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. The aglycone of compound 1, 3 beta,6 alpha,16 beta-trihydroxy-24-oxo-20(R),25-epoxycycloartane, is reported for the first time. The cytotoxic activity of the isolated compounds was evaluated against three cancer cell lines including A549 (human lung adenocarcinoma), A375 (human melanoma) and DeFew (human B lymphoma) cells. None of the tested compounds caused a significant reduction of the cell number. (C) 2016 Elsevier B.V. All rights reserved.