Fig. 1

Effect of the type of ionic liquid. Extraction process was performed in an ultrasound unit with a power of 100 W and the concentration of each ILs methanol solution was 0.8 mol/L. 50 mg of the A. rugosa powder of passing through 50-mesh sieve, solid–liquid ratio 1:20 (g/mL), ultrasonic for 30 min. The extraction yield was expressed as the observed values of target analytes (mg/g), the content of tilianin and acacetin per gram of A. rugosa powder