RAPID SEPARATION OF FLAVONOIDS FROM HYDROLYSIS PRODUCTS OF Epimedium koreanum

Abstract

A successful method of preparative high-speed counter-current chromatography (HSCCC) was established for direct isolation and purification of hydrolysis products of Epimedium koreanum Nakai to obtain the secondary glycosides and aglycons of flavonoids in E. koreanum. The two-phase solvent systems of HSCCC composed n-hexane-ethyl acetate-methanol-water at the ratios of 6:3.5:6:5 (v/v) and 6:3.5:8:5 (v/v) were used in a stepwise elution. Totally, 60.1 mg of Fraction I that would be isolated and purified by preparative HPLC, 9.4 mg of icartin (4), 3.5 mg of desmethylicartin (5), 4.7 mg of 3′′-ethyoxyl-icartin (6), 7.3 mg of anhydroicaritin (7), and 10.1 mg of β-anhydroicaritin (8) were obtained in one-step separation from 100 mg of the crude materials with purities of 97.7%, 96.2%, 99.2%, 99.5%, and 91.0%, respectively. And Fraction I of HSCCC was purified by the preparative HPLC to obtain 12.7 mg of pletypetaloside (I-1), 6.8 mg of icariside I (I-2) and 16.3 mg of 3′′-ethyoxyl-pletypetaloside (I-3) with purities of 90.8%, 93.4%, and 99.2%. All of the chemical structures were identified on the basis of widely spectral technology including 2D-NMR. Among them, compounds I-3 and 6 are novel.