Anti-Inflammatory Cycloartane-Type Saponins of Astragalus membranaceus

A new cycloartane-type triterpene glycoside, agroastragaloside V (1) was isolated from the roots of Astragalus membranaceus. The structure was identified as 3-O-β-(2'-O-acetyl)-d-xylopyranosyl-6-O-β-d-glucopyranosyl-(24S)-3β,6α,24α,25-tetrahydroxy-9,19-cyclolanostane, by means of spectroscopic methods, including HR-FAB/MS, 1D NMR ((1)H, (13)C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. Four known cycloartane glycosides, namely, agroastragaloside I (2), agroastragaloside II (3), isoastragaloside II (4) and astragaloside IV (5) were also isolated. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.