ABSTRACT
Objective:To explore the macroporous resin adsorption and the membrane separation technologies for the purification of saponins water extract of Anemarrhena asphodeloides. Methods:Ten-fold amount of water was used to extract twice for 120 min each time to extract saponins from Anemarrhena asphodeloides. The macroporous resin adsorption(HP-20,HPD-600,D101,AB-8) and the membrane separation technologies (ceramic microfiltration membranes 0.8 μm and 0.05 μm, and hollow fiber ultrafiltration mem-branes 50,10 and 6 kDa) were adopted to purify the saponins water extract liquid. The physicochemical parameters including electri-cal conductivity,viscosity and turbidity were measured,as well as the contents of total saponins,proteins and polysaccharides were de-termined. Results:The viscosity and turbidity decreased,the value of pH increased and the electrical conductivity of the saponins puri-fication liquid changed irregularly after the membrane filtration. The microfiltration membrane was more advantageous than the ultrafil-tration membrane in removing macromolecular substances. The smaller the pore diameter of microfiltration membrane, the smaller the intercepted molecular weigh,the higher the removal ratio of proteins and the higher the penetration rate of the total saponins,while the polysaccharides content was stable, which was consistent with the results of physicochemical parameters. The ceramic microfiltration membrane could obtain clearer extract,while the ultrafiltration membrane was more suitable for the enrichment of saponins when the in-tercepted molecular weight was 6 kDa. The macroporous resin HPD-600 was the best for the purification of timosaponin water extraction liquid.Conclusion:The selection of membrane for the separation and purification of different substances is particularly important. The change of physicochemical parameters and the content decrease of macromolecular substances have obvious corresponding relationship. Ultrafiltration membrane is better than microfiltration membrane for the purification of timosaponin water extract liquid.