Preparation of main iridoid glycosides in Fructus Corni by macroporous resin column chromatography and countercurrent chromatography

Loganin, sweroside, and morroniside, three main iridoid glycosides from Fructus Corni were successfully separated by macroporous resin column chromatography and countercurrent chromatography (CCC). In the first step, D101 macroporous resin was selected for cleaning-up, water was used to elute the column to remove the undesired constituents and then 50% aqueous ethanol was used to elute the targets. The total content of three iridoid glycosides was 51.1% in this process. In the second step, the obtained crude sample was then isolated by CCC using a two-phase solvent system composed of dichloromethane-methanol-n-butanol-water-acetic acid (5:5:2:4:0.1, v/v/v/v/v). From 100 mg of a crude sample, 12.6 mg of loganin, 5.9 mg of sweroside, and 28.5 mg of morroniside were obtained with purities of 98.6%, 97.3%, and 99.1% and total recoveries of 90.4%, 91.8%, and 89.1%, respectively, after a two-step purification. The HPLC quantitative analysis and response surface methodology were used for optimization of the separation condition and the target compounds were identified by ESI-MS, 1H NMR, and 13C NMR