Investigation of Adsorption and Desorption Properties of Total Ginsenosides on Anion-exchange Resins and Its LC-MS Analysis / 中国实验方剂学杂志

ABSTRACT

Objective:To compare the adsorption and desorption properties of different anion exchange resins for total ginsenosides， clarify their adsorption/desorption mechanism， and establish a simple protocol for the purification of total ginsenosides. Method:The adsorption and desorption properties of five different resins （D301， D315， D312， D330， D201） on total ginsenosides were evaluated with specific adsorption capacity， specific desorption capacity， desorption rate and recovery rate as indices. The adsorption kinetics and thermodynamics of the selected resin and D101 macroporous resin were investigated by pseudo-first-order and pseudo-second-order kinetic models， as well as Langmuir and Freundlich isothermal adsorption models， and the differences of adsorption mechanism between anion exchange resin and conventional macroporous resin were elucidated. The dynamic adsorption and desorption experiments were used to determine the optimum chromatographic parameters for anion exchange resin. After verifying the purification process of total ginsenosides， nine individual ginsenosides were qualitatively and quantitatively analyzed by liquid chromatography-mass spectrometry （LC-MS）. Result:D301 anion exchange resin was obviously superior to the other four kinds of anion exchange resin， the optimum parameters were set as follows：pH 8 of loading solution， loading volume of 2 BV， loading speed of 4 BV·h^-1， eluted with 3 BV of water and 20% ethanol for the impurities， eluted with 8 BV of 80% ethanol with elution speed of 4 BV·h^-1. After purified by D301 resin， the enrichment coefficients of 9 monomer ginsenosides were simultaneously increased to different degrees， the overall enrichment coefficient was up to 5.3， the recovery rate for the total amount of these ginsenosides was calculated to be 80.9%， and the purity of total ginsenosides in Ginseng Radix et Rhizoma extract increased from 17.07% to 91.19%. Conclusion:D301 anion exchange resin is suitable for rapid and practical purification of total ginsenosides， hence allowing for the enrichment of high-purity total ginsenosides from Ginseng Radix et Rhizoma via one-dimensional column chromatography.