Selection and optimisation of macroporous resin for separation of stilbene glycoside from Polygonum multiflorum Thunb

Background: 2,3,5,4′-Tetrahydroxystilbene-2-O-β-glucopyranoside (SG; a stilbene glycoside) is a major bioactive component of Polygonum multiflorum Thunb. (PM), a popular traditional Chinese herb. In this study a method was developed for the separation of SG from PM on macroporous resins. These were selected and optimised using the linear correlation coefficients of the Langmuir and Freundlich isotherms and a pseudo-first-order model to explain the kinetic results. Then dynamic adsorption and desorption experiments were carried out on a column packed with the chosen resin to optimise the separation process. Results: HPD100 resin gave the best performance in the separation of SG from PM. The optimal parameters were a sample concentration in solution of 3.5 g mL^-1, a pH of 4.8, a flow rate of 1.5 mL min^-1 and an elution solvent of 40% (v/v) ethanol. Using this scaled-up column, a product with a final SG content of 819 mg g^-1 and a recovery yield of 74.7% was achieved. In addition, pure acicular crystals of SG could be obtained from this product. Conclusion: The results showed that HPD100 was the most efficient resin for the separation of SG, which may provide a scientific basis for larger-scale stilbene glycoside production from PM and other plant extracts.