Four new dammarane-type triterpenoid saponins from Gynostemma pentaphyllum (Thunb.) Makino

Damarane-type triterpene saponins are the main active ingredients in Gynostemma pentaphyllum (Thunb.) Makino. By using D101 macroporous adsorption resin and silica gel open-columns, C18 medium-pressure column chromatography, and preparative high performance liquid chromatography, we isolated four compounds from the leaves of G. pentaphyllum planted in Guangxi Zhuang Autonomous Region. Their structures were determined by comprehensive analyses of MS, NMR data and circular dichroism spectroscopy and identified as (3β, 12β)-dihydroxy-25-peroxyhydrohydrodammarane-20, 23-diene-3-O-β-D-glucopyranosyl(1→2)-β-D-glucopyranoside (1), (3β, 12β, 24S)-trihydroxydammarane-20, 25-diene-3-O-β-D-glucopyranosyl(1→2)-β-D-glucopyranoside (2), (3β, 20α)-dihydroxy-24-en-12β, 22S-epoxydammarane-3-O-β-D-glucopyranosyl(1→2)-β-D-glucopyranoside (3), (3β, 12β, 20S)-trihydroxydammarane-24-en-3-O-6-O-acetyl-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl-20-O-β-D-xylopyranosyl(1→3)-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside (4). Compounds 1-4   are new dammarane-type triterpene saponins.