Optimize the process of ionic liquid-based ultrasonic-assisted extraction of aesculin and aesculetin from Cortex fraxini by response surface methodology

► Aesculin and aesculetin were first extracted by ionic liquids solution. ► Extraction time has been reduced to 44 min, whereas the conventional is about 4 h. ► The proposed approach was confirmed by good recovery and reproducibility. Ionic liquid-based ultrasonic-assisted extraction as an effective method was first successfully developed at room temperature to extract aesculin and aesculetin from the traditional Chinese medicine Cortex fraxini....