Macroporous resin purification behavior of phenolics and rosmarinic acid from Rabdosia serra (MAXIM.) HARA leaf

In the present study, the performance and separation characteristics of two macroporous resins for the purification of phenolics from Rabdosia serra were evaluated. Both HP-20 and XAD-7HP resins were effective for phenolics enrichment, with insignificant difference of adsorption/desorption behaviors, according to their chemical and physical properties. The pseudo-second-order kinetics model was the most favorable for illustrating the whole exothermic adsorption process, which was affected by the mutual effects of boundary layer diffusion and intraparticle diffusion kinetics. After treatment with gradient elution on resin columns, phenolics (from 16.66% to 67.87% by HP-20 and to 58.81% by XAD-7HP), antioxidants (3–4 times more than original) and rosmarinic acid (from 10.14% to 67.26% by HP-20 and to 63.16% by XAD-7HP) were enriched in 30% ethanol fractions. The production of highly concentrated phenolics and rosmarinic acid might expand the application of Rabdosia serra as a bioactive agent for both the food industry and pharmacy.

► HP-20 and XAD-7HP had similar phenolics adsorption/desorption behaviors.
► Film diffusion and intra-particle diffusion kinetics affected adsorption process.
► Adsorption equilibriums were well fitted to the Langmuir and Freundlich isotherms.
► Antioxidant-related components were effectively enriched by gradient elution.