Simultaneous Separation of Four Flavonoids and Two Astragalosides from Radix Astragali by Semi-Preparative LC

摘要

An effective method for simultaneous separation of four flavonoids and two astragalosides was developed by semi-preparative high-performance liquid chromatography in this work. A crude sample was firstly cleaned-up from ethanol aqueous extract of Radix Astragali by LS-300B resin-based column chromatography and was further isolated by semi-preparative LC with a gradient elution of water–methanol. Six compounds including calycosin (3.5 mg), formononetin (2.6 mg), (6aR,11aR)-10-hydroxy-3,9-dimethoxypterocarpan (2.6 mg), (3R)-7,2′-dihydroxy-3′,4′-dimethoxyisoflavan) (2.0 mg), astragaloside I (5.4 mg) and astragaloside II (9.8 mg) were obtained with a recovery of 67.8, 77.2, 88.4, 85.3, 62.1 and 57.9%, respectively. Their chemical structures were confirmed by MS and NMR analysis. This study developed an effective and rapid method for simultaneous separation of multiple components from Radix astragali.