Hydrosoluble trehalose lipid (a biosurfactant) was employed for the first time as a green extraction solution to extract the main antioxidant compounds (geniposidic acid, chlorogenic acid, caffeic acid, and rutin) from functional plant tea (Eucommia ulmoides leaves). Single-factor tests and response surface methodology were employed to optimize the extraction conditions for ultrasound-assisted micellar extraction combined with ultra-high-performance liquid chromatography in succession. A Box-Behnken design (three-level, three-factorial) was used to determine the effects of extraction solvent concentration (1-5 mg/mL), extraction solvent volume (5-15 mL), and extraction time (20-40 min) at a uniform ultrasonic power and temperature. In consequence, the best analyte extraction yields could be attained when the trehalose lipid solution concentration was prepared at 3 mg/mL, the trehalose lipid solution volume was 10 mL and the extraction time was set to 35 min. In addition, the recoveries of the antioxidants from Eucommia ulmoides leaves analyzed by this analytical method ranged from 98.2 to 102%. These results indicated that biosurfactant-enhanced ultrasound-assisted micellar extraction coupled with a simple ultra-high-performance liquid chromatography method could be effectively applied in the extraction and analysis of antioxidants from Eucommia ulmoides leaf samples.
Keywords: biosurfactants; experimental design; functional plant tea; response surface methodology; trehalose lipid.
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