Purification of quercetin-3-O-sophoroside and isoquercitrin from Poacynum hendersonii leaves using macroporous resins followed by Sephadex LH-20 column chromatography.

In China, Poacynum hendersonii is frequently used as a substitute for Apoacynum venetum L (Luobuma), which is a famous traditional Chinese medicine. Quercetin-3-O-sophoroside and isoquercitrin are two major flavonoids in Poacynum hendersonii leaves. In this work, a suitable method was established for the large-scale preparation of quercetin-3-O-sophoroside (QOS) and isoquercitrin (ISO) from Poacynum hendersonii leaves using macroporous resin combined with Sephadex LH-20 column chromatography. The adsorption/desorption capacities and desorption ratios of six macroporous resins were evaluated using static experiments. The HPD-300 resin had the best adsorption performance because it had the largest surface area, and was selected for further study. Compared with pseudo-first-order and intraparticle diffusion kinetics models, the pseudo-second-order model could better fit the adsorption kinetics of both QOS and ISO on the HPD-300 resin. In addition, the adsorption isotherms of the two compounds on the HPD-300 resin were fitted well to the Langmuir model. Under optimal conditions, the purities of QOS and ISO in the product were increased from 2.16% and 1.26% to 21.34% and 10.70% with recovery yields of 82.1% and 77.3%, respectively. Subsequently, Sephadex LH-20 column chromatography was employed for improving the purities of the two compounds. After separation by Sephadex LH-20 column chromatography, the purities of QOS and ISO achieved 93.5% and 95.6%, respectively.