Adsorption separation of 3β-D-monoglucuronyl-18βglycyrrhetinic acid from directional biotransformation products of glycyrrhizin

3β-D-monoglucuronyl-18β-glycyrrhetinic acid (GAMG) can be obtained on a large scale by directional hydrolysis of glycyrrhizin (GL) with β-glucuronidases, which has more physiologically potential application than GL in a wide range of biological activities. In this study, the preparative separation of GAMG in hydrolysates of GL by macroporous resins (NKA-9, D4020, HZ-803, 1300, HP-20 and X-5) were studied systematically, and the column packed with selected resin was used to perform dynamic adsorption and desorption tests to optimize the separation process. The results shown that NKA-9 resins was the appropriate resin for the separation of GAMG and GL under pH 5, which adsorption data fitted to the Freundlich isotherm equation and pseudo-second-order kinetic model at 25oC. While with desorption of 70-90% ethanol-water solution, GAMG with the purity of 85.02% was obtained on a NKA-9 resins packed column. Comparing with conventional methods, the developed method can successfully improve product yield and reduce the consumption of raw materials in the biotransformation process of GL. The structure identification of each pure fraction was carried out by 1H and 13C NMR.