Separation of chemical constituents in Bidens pilosa Linn. var. radiata Sch. Bip. by elution‐extrusion counter‐current chromatography using two new three‐phase solvent systems

Two new three-phase solvent systems combined with elution-extrusion counter-current chromatography mode were used to study the chemical constituents in Bidens pilosa Linn. var. radiata Sch. Bip. The first novel solvent system consisted of n-hexane, acetonitrile, chloroform, and water in a ratio of 5:5:1:5, which was selected for elution-extrusion counter-current chromatography to separate the n-hexane extraction part. A total of six constituents were obtained from this part in the up phase as the stationary phase and the middle phase as the mobile phase. The second novel solvent system, composed of n-hexane-butyl acetate-acetonitrile-water (3:1:4:3, v/v/v/v), was used for separating ethyl acetate extract of Bidens pilosa Linn. var. radiata Sch. Bip. Eight compounds were successfully isolated using elution-extrusion counter-current chromatography elution-extrusion mode. Fourteen chemical constituents were identified as 2-β-D-glucopyranosytoxy-1-hydroxy-5(E)-tridecene-7,9,11-triyne (Y1), 3-β-D-glucopyranosyloxy -1-hydroxy-6(E)-tetradecene-8,10,12-triyne (Y2), 1, 2-dihydroxy-5(E)-tridecene-7,9, 11-triyne (Y3), isorhamnetin (Y4), kaempferol (Y5), icthyothereolacetate (Y6), quercetin-3-O-β-D- galactopyranosyl-7-O-β-D-glucopyranoside (W1), quercetin 3-O-β-L-rhamnopyranoside (W2), neosperidin dihydrochalcone (W3), quercetin (W4), quercetagetin-3,6,4' -trimethoxyl- 7-O-β-D-glucopyranoside (W5), taxifolin (W6), luteolin (W7), and apigenin (W8) by spectra of 1 H-NMR and 13 C-NMR data. Among them, compounds Y1, Y2, Y3, and Y6 belong to polyacetylene compounds, and the rest were flavonoids. In addition, counter-current chromatography has been used to separate polyacetylene compounds for the first time. All compounds in this method were isolated from Bidens pilosa Linn. var. radiata Sch. Bip. for the first time.