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-β-D-xylopyranosyl-6-O-β-D-glucopyranosyl-3β,6α,16β-trihydroxy-24-oxo-20(R),25-epoxycycloartane (1), 3-O-[β-D-glucuronopyranosyl-(1 → 2)-β-D-xylopyranosyl]-3β,16β,24α-trihydroxy-20(R),25-epoxycycloartane (2), 3-O-[β-D-glucuronopyranosyl-(1 → 2)-β-D-xylopyranosyl]-3β,16β,25-trihydroxy-20(R),24(S)-epoxycycloartane (3), 3,25-di-O-β-D-glucopyranosyl-6-O-β-D-xylopyranosyl-3β,6α,16β,25-tetrahydroxy-20(R),24(S)-epoxycycloartane (4), 29-O-α-L-rhamnopyranosyl-abrisapogenol B (5) by 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. The aglycone of compound 1, 3β,6α,16β-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.