Separation and enrichment of major quinolizidine type alkaloids from Sophora alopecuroides using macroporous resins

Matrine (MT), oxymatrine (OM) and sophoridine (SP) are three bioactive alkaloids in Sophora alopecuroides. In the present study, the chromatographic characteristics of six widely used macroporous resins, namely NKA, NKA-9, HPD-100, HPD-722, HPD-750, and AB-8, respectively, towards the separation and enrichment of the three alkaloids from the aqueous extract of S. alopecuroides are critically evaluated. The results indicated that AB-8 resin offered the best absorption and desorption capacity and its adsorption data fitted best to the Freundlich isotherm. Dynamic adsorption and desorption experiments on packed columns of AB-8 resin have been investigated for optimization of chromatographic parameters. The adsorption of the alkaloids on the resin was best achieved by 5 bed volume (BV) of sample solution of pH 10 with a flow rate of 2 BV/h. The desorption of the compounds from the resin was effectively completed by using 5 BV of 80% ethanol in water at a flow rate of 2 BV/h. After one run of adsorption and desorption, the contents of MT, OM, and SP were increased from 9.30, 8.39 and 9.84% to 22.22, 21.44 and 28.02%, the recovery were 69.4, 78.3 and 72.6%, respectively. This method would provide useful information to the industrial production of the alkaloids from S. alopecuroides