A dual-task method for the simultaneous detoxification and enrichment of stilbene glycoside from Polygonum multiflorum roots extract by macroporous resin

• A dual-task method for simultaneous detoxification and enrichment was established.
• A modified gradient elution strategy was proposed.
• Accumulative desorption ratio–volume/time curves were plotted.
• The recovered target compound was nearly free of hepatotoxic impurities.

In this study, a dual-task method for the simultaneous detoxification and enrichment of the pharmacologically active compound, 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glycoside (TSG) from crude extract of Polygonum multiflorum roots was established by macroporous resin. The performances of TSG on six macroporous resins were compared with regard to their adsorption and desorption properties. Kinetics tests indicated that the adsorption process fitted the pseudo-second-order model much better than the pseudo-first-order model. The solute affinity of TSG towards the AB-8 resin at different temperatures was described in terms of Langmuir and Freundlich isotherms. The optimal adsorption conditions were: 2.24 mg/mL of TSG in feed solution, 4.5 bed volume (BV) of loading volume, loading time no less than 120 min. The elution conditions were as follows: 6.0 BV of water, followed by 2.5 BV of 40% ethanol with flow rate of 1.5 BV/h. After the AB-8 resin treatment, the concomitant hepatotoxic anthraquinones were almost completely removed. Meanwhile, the purity of TSG was 8.6-fold increased from 7.51% to 64.76% with a recovery of 68.34%. The process fulfilled the task of detoxification and enrichment of TSG, and proved to be a promising basis for pharmaceutical preparations.