[Purification technology of puerarin by agar gel microspheres]

Puerarin is the main active component of flavonoids in Puerariae Lobatae Radix. In this study, agar gel microspheres bonded with β-cyclodextrin (AG-β-CD) were synthesized by using economical agar, and then high-purity puerarin was obtained with AB-8 through high-yield separation. With purity and yield of puerarin, and chromatographic purity of related impurities as indexes, four macroporous resins of different properties, namely ADS-7 (high polarity), ADS-17 (medium polarity), ADS-21 (polarity) and AB-8 (weak polarity), were selected for separation of puerarin and technological optimization. In addition, the AG-β-CD purification process was optimized and verified. The results showed that, AB-8 resins showed the best effect and selected as the pre-treatment resins for crude puerarin, and puerarin with the purity of 87.68% showed a recovery rate of 89.66%. The optimized purification process parameters of AG-β-CD included mobile phase (15% ethanol), loading capacity (the ratio of loading amount to column volume) (1.33 g•L⁻¹), sample concentration (8 g•L⁻¹) and flow rate (1 mL•min⁻¹), puerarin with the purity of 95% showed a recovery rate of more than 97%.