Saponins from the roots of Zygophyllum gaetulum and their effects on electrically-stimulated guinea-pig ileum

A new ursanolide, (3 beta -O-alpha -L-rhamnopyranosyl-(1 - > 2)-O-alpha -L- arabinopyranosyl-(1 - > 2)-beta -D-glucopyranosyl)oxy-ursan-20 beta ,28-oli de, zygophyloside N (1), and three known quinovic acid glycosides were isol ated from the methanolic extract of the roots of Zygophyllum gaetulum. The crude extract, some fractions and 3-O-beta -D-glucopyranosyl quinovic acid 28-beta -D-glucopyranosyl ester, significantly and dose-dependently, are ab le to reduce the electrically-induced contractions of isolated guinea-pig i leum. The structure of compound (1) was determined, using 1D and 2D NMR tec hniques. (C) 2001 Elsevier Science Ltd. All rights reserved.