Isolation and purification of phenylethanoid glycosides from Cistanche deserticola by high-speed counter-current...

Five phenylethanoid glycosides (PhGs), echinacoside, cistanoside A, acteoside, isoacteoside and 2'-acetylacteoside, were isolated and purified from Cistanche deserticola for the first time by high-speed counter-current chromatography (HSCCC) using two biphasic systems, one consisting of ethyl acetate-ethanol-water (5:0.5:4.5, v/v/v) and another of ethyl acetate-n-butanol-ethanol-water (0.5:0.5:0.1:1, v/v/v/v). A total of 28.5mg of echinacoside, 18.4mg of cistanoside A, 14.6mg of acteoside, 30.1mg of isoacteoside and 25.2mg of 2'-acetylacteoside were purified from 1412mg of the n-butanol extract of C. deserticola, each at over 92.5% purity as determined by HPLC. The structures were identified by their retention time, UV, LC-ESI-MS in the negative ion mode, and confirmed by NMR experiments. The characteristic LC-ESI-MS(n) fragmentation pattern of the five compounds is discussed, and found to be a very specific and useful tool for the structural identification of PhGs from this important medicinal plant.