Study on the ultrasonic-assisted deep eutectic solvent extraction of total flavonoids from flos sophorae immaturus

In this paper, four different kinds of deep eutectic solvents were prepared to carry out ultrasonic-assisted extraction of total flavonoids from flos sophorae immaturus . The content of total flavonoids was determined by ultraviolet spectrophotometry. The effects of the type, molar ratio, moisture of deep eutectic solvent, the solid-liquid ratio, the ultrasonic time and the ultrasonic temperature on the extraction of total flavonoids from flos sophorae immaturus were investigated by condition experiment. Meanwhile, the standard addition recovery rate experiment was performed to verify the feasibility of the method. The results showed that the optimal extraction results could be obtained when the moisture was 10%, the molar ratio of choline chloride/1,2-propylene glycol deep eutectic solvent 1:2, the solid-liquid ratio 1:35, the ultrasonic temperature 40℃, and the ultrasonic time 2.5h. Under the optimal conditions, the content of total flavonoids extraction was up to 4.97mg/g, and the standard addition recovery rate reached about 89%.