Study on extraction, purification, and biological activities of forsythiaside A from Forsythia suspensa (Thunb.) Vahl leaf

In this study, a method to enrich forsythiaside A (FA) from the ball-milled powder of Forsythia suspensa leaves was established. Forsythiaside A was extracted by heating and stirring, and the extraction process was optimized by response surface methodology using the independent variables of extraction temperature, extraction time, liquid-to-material ratio, ethanol concentration, and pH value of the solution, respectively. Then five types of macroporous resins with different polarities were studied to explain the adsorption mechanism by static adsorption and desorption experiments. Different models were used to study the static adsorption thermodynamics and kinetic process of AB-8 resin on FA extracts, and optimal conditions of the process were optimized. Finally, the antioxidant abilities of purified FA were evaluated. The results showed that the optimum extraction conditions were 2.2 h, 53.4 °C, 45.7 mL/g, 60