Lupane Triterpenes from the Leaves of Acanthopanax gracilistylus

The phytochemical study on the leaves of Acanthopanax gracilistylus (Araliaceae) resulted in the discovery of a new lupane-triterpene compound, acangraciligenin S (1), and a new lupane-triterpene glycoside, acangraciliside S (2), as well as two known ones, 3α,11α-dihydroxy-lup-20(29)-en-23,28-dioic acid (3) and acankoreoside C (4). Their chemical structures were elucidated by mass, 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopy. The chemical structures of the new compounds 1 and 2 were determined to be 1β,3α-dihydroxy-lup-20(29)-en-23, 28-dioic acid and 1β,3α-dihydroxy-lup-20(29)-en-23,28-dioic acid 28-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl] ester, respectively. The anti-neuroinflammatory activity of the selective compounds, 1 and 3, were evaluated with lipopolysaccharide (LPS)-induced BV2 microglia. The tested compounds showed moderate inhibitory effect of nitric oxide (NO) production.