Abstract: Objective: To optimize the conditions for ultrasonic-assisted extraction of aucubin from Eucommia ulmoides Oliv. key fruits. Methods: One-factor-at-a-time method and response surface methodology based on Box-Behnken experimental design were used for process conditions optimization. Results: The optimal extraction conditions were 72.1% aqueous ethanol solution as the extraction solvent, ultrasonic power of 300 W, extraction time of 20.5 min and solid/liquid ratio of 12.3:1 (mL/g). Under these conditions, the extraction yield of aucubin was observed to be 5.91%. Ethanol concentration had the largest impact on the extraction yield of aucubin, followed by solid/liquid ratio and extraction time. Conclusion: Ultrasonic assistance can enhance the extraction of aucubin from Eucommia ulmoides Oliv. key fruits.

Key words: Eucommia ulmoides Oliv. key fruits, aucubin, ultrasonic wave-assisted extraction, response surface methodology