Separation of five flavonoids from tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) grains via off-line two dimensional high-speed counter-current chromatography

Abstract An off-line two dimensional (2D) high-speed counter-current chromatography (HSCCC) strategy was successfully used for preparative separation of five flavonoids from tartary buckwheat ( Fagopyrum tataricum (L.) Gaertn) grains with different solvent systems for the first time in this paper. n -Hexane–ethyl acetate–methanol–water 3:5:3:5 (v/v) was selected as the first dimension solvent system to purify quercetin ( 4 ) and kaempferol ( 5 ). The second dimension solvent system, ethyl acetate– n -butanol–water 7:3:10 (v/v), was used to isolate quercetin 3-O-rutinoside-3′-O-β-glucopyranoside ( 1 ), rutin ( 2 ) and kaempferol 3-rutinoside ( 3 ). The purities of these compounds were all above 96.0% and their structures were identified through UV, MS and 1 H NMR. The results indicated that the off-line 2D HSCCC is an efficient technique to isolate flavonoids compounds from grains.