Preparative isolation of three flavonoids from Flos Gossypii by high-speed counter-current chromatography

Three flavonoids, tiliroside, quercetin and kaempferol were isolated and purified from Flos Gossypii (FG) by high-speed counter-current chromatography (HSCCC). The target compounds were finally isolated and purified with a solvent system composed of n-hexane–ethyl acetate–methanol–water (1:2:0.8:0.9, v/v/v/v). In a single operation, 80 mg of the extracts of FG was separated to yield 2.9 mg of tiliroside, 20 mg of quercetin and 6.1 mg of kaempferol with the purity of 98.3%, 98.5% and 97.6%, respectively. The HSCCC fractions were analyzed by high-performance liquid chromatography (HPLC) and the chemical structures of the three flavonoids were identified by 1H NMR and 13C NMR analysis. Tiliroside and kaempferol were obtained from the FG for the first time.