Preparative separation of flavonoids in plant extract of Smilacis Glabrae Roxb. by high performance counter-current...

Four flavonoids, isoastilbin, astilbin, isoengelitin, and engelitin were isolated and purified simultaneously from Smilacis Glabrae Roxb. for the first time by high performance counter-current chromatography using a system consisting of n-hexane-n-butanol-water (1:2:3, v/v/v). A total of 392.6 mg of astilbin, 71.4 mg of isoastilbin, 47.4 mg of engelitin, and 10.3 mg of isoengelitin were purified from 1.89 g of the ethyl acetate extract of Smilacis Glabrae Roxb. in six runs, each at over 94.51% purity as determined by HPLC. The structures of the four compounds were identified by their retention time, the LC-ESI-MS(n) in the negative ion mode, and confirmed by (1)H-NMR experiments. The characteristic LC-ESI-MS fragmentation patterns of the four compounds were discussed.