Nonlinear response surface in the study of aqueous two-phase system and ionic liquid extraction of lignans from Schisandrae chinensis and mechanism clarification

Nonlinear response surface methodology was adopted to investigate complicated interactions of the extraction parameters of aqueous two-phase system and ionic liquids (ILs) to determine their optimum conditions for enhancing the extraction yield and antioxidant activity. Using statistical optimizations of ultrasound-assisted ionic liquid (UAE-ILs), the yield was increased from 8.73 to 10.44 mg g−1, and IC50 value of DPPH was decreased from 0.49 to 0.36 mg mL−1 with minimum cost and pollution. Additionally, the extraction mechanism of different methods was in-depth assessment. Experimental results showed that UAE-ILs in the extraction of lignans from plants can show a great promising prospect.