Hydrophobic ionic liquid-based ultrasound-assisted extraction of magnolol and honokiol from cortex Magnoliae officinalis

The hydrophobic ionic liquid of [BMIM][PF(6)] was successfully used for the ultrasound-assisted extraction of hydrophobic magnolol and honokiol from cortex Magnoliae officinalis. To obtain the best extraction efficiencies, some ultrasonic parameters including the concentration of [BMIM][PF(6)], pH, ultrasonic power and ultrasonic time were evaluated. The results obtained indicated that the [BMIM][PF(6)]-based ultrasound-assisted extraction efficiencies of magnolol and honokiol were greater than those of the [BMIM][BF(4)]-based ultrasound-assisted extraction (from 48.6 to 45.9%) and the traditional ethanol reflux extraction (from 16.2 to 13.3%). Furthermore, the proposed extraction method is validated by the recovery, correlation coefficient (R(2)) and reproducibility (RSD, n = 5), which were 90.8-102.6, 0.9992-0.9998, and 1.6-5.4%, respectively.