Analysis of isoflavone daidzein in Puerariae radix with micelle-mediated extraction and preconcentration.

Nonionic surfactant oligo(ethylene glycol) monoalkyl ether (Genapol X-080) was employed as an alternative and effective solvent for the extraction of daidzein from Puerariae radix for the first time. Optimum experimental conditions were established. With 5% Genapol X-080 (w/v), liquid/solid ratio of 25:1 (mL/g), and ultrasonic-assisted extraction for 45 min, the extraction percentage of daidzein reached the highest value. For the preconcentration of daidzein by cloud-point extraction (CPE), sodium chloride was added to the solution to facilitate the phase separation and increase the preconcentration factor by reducing the volume of the surfactant-rich phase. The preconcentration factor for daidzein was about 13. Satisfactory results were obtained for the analysis of daidzein from P. radix with this established method.