Abstract
An effective method for purifying the total alkaloid components from Piperis longi fructus extract was developed in this study. The adsorption/desorption processes of the total alkaloid components from Piperis longi fructus were established by resin model screening, adsorption kinetics, and adsorption thermodynamics tests. Moreover, the purified powders were analyzed with UPLC-Q-ZENO-TOF-MS/MS and then their antioxidant activity was tested. The Langmuir equation provided a good fit with the experimental results. The thermodynamic study provides a satisfactory fit for the isotherm data, indicating that the adsorption process is characterized by spontaneity (ΔG° < 0), exothermicity (ΔH° < 0), and an increase in entropy (ΔS° < 0). Furthermore, the kinetic adsorption behavior on D101 resin was effectively modeled by pseudo-second-order kinetics. According to this mechanism, we selected the best adsorption parameters and optimized the on-column elution process to effectively enrich the total alkaloid components. The optimal process was as follows: D101 macroporous resin was added to an alcohol solution (crude drug concentration of 2 g/mL) and then concentrated under a vacuum at 45~55 °C (<-0.08~-0.10 MPa) until alcohol-free. Subsequently, the resin was loaded into the column and eluted with 70% ethanol at a flow rate of 2 BV/h for 10 BV to achieve desorption. The present study provides a more efficient method for the enrichment of the total alkaloidal components of Piperis longi fructus, which will lay the foundation for applications in food additives or functional foods in the future.