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

•Resins coupled with sephadex LH-20 were used for purification of QOS and ISO.•Adsorption isotherms and kinetics were systematically investigated.•An efficient method for the separation of QOS and ISO was developed.

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.