The application of an aqueous two-phase system combined with ultrasonic cell disruption extraction and HPLC in the simultaneous separation and analysis of solanine and Solanum nigrum polysaccharide from Solanum nigrum unripe fruit.

An aqueous two-phase system was used in conjunction with ultrasonic cell disruption to extract and separate solanine (mainly solasonine and solamargine) and Solanum nigrum polysaccharide from Solanum nigrum unripe fruit. The optimized conditions of the present study were determined by a single-factor experiment and a multifactor experiment. The concentration of ethanol was set at 60% and the duration of the ultrasonic cell disruption extraction was 50 min. In the ethanol-K₂CO₃ aqueous two-phase separation system, the concentration of ethanol was 36%, the concentration of K₂CO₃ was 0.21 mg·mL^-1, and the temperature was 15 °C. The solasonine and solamargine were determined by high-performance liquid chromatography, and the Solanum nigrum polysaccharide was determined by an ultraviolet-visible spectrophotometer in accordance with the phenol-sulfuric acid method. xUnder optimized conditions, the average extraction efficiencies of solasonine, solamargine and Solanum nigrum polysaccharide were 95.86%, 95.95% and 96.95%, respectively, and the average separation efficiencies of solasonine, solamargine and Solanum nigrum polysaccharide were 2.07 mg·g^-1, 2.05 mg·g^-1 and 8.15 mg·g^-1, respectively.