Separation and Purification of Four Flavan-3-ols From Iris Lactea Pall. var. Chinensis (Fisch.) Koidz by High-Speed Counter-Current Chromatography with Flow-Rate Gradient

摘要

In this study, we established a flow-rate gradient separation method to isolate four flavan-3-ol compounds with high purity from the seed coat extracts of Iris lactea by high-speed counter-current chromatography (HSCCC). First, the ethyl acetate extract was pre-separated by silica column chromatography fractionation to obtain the enriched flavan-ols sample (EFS). Then, the EFS was separated by HSCCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (0.75:12.5:1:12.5, v/v/v/v) by increasing the flow rate of the mobile phase from 1.5 to 3.0mL/min after 120min. The separation temperature was 30 degrees C, the detection wavelength was 280nm and the revolution speed was 900rpm. By the optimized HSCCC method, 300mg of the EFS was separated, yielding 58mg of procyanidin B3, 72mg of procyanidin B1, 52mg of catechin, and 18mg of procyanidin B7, at a purity of 98.23%, 99.05%, 99.03%, and 96.34% in 240min. In this work, the flavan-3-ols in I. lactea are partly reviewed and the results can provide evidence to look for other rich source of procyanidins.