Isolation and purification of 12 flavonoid glycosides from Ginkgo biloba extract using sephadex LH-20 and preparative high-performance liquid chromatography.

An efficient and rapid preparative method for the separation and purification of flavonoid glycosides from the extract (E) was developed by sephadex LH-20 and preparative high-performance liquid chromatography (HPLC). 40 g E of 24% flavonoids were loaded onto the sephadex LH-20 column and five fractions (1.15, 2.57, 1.32, 4.45, and 3.31 g) at flavonoid content of 72.3, 54.2, 63.5, 51.2, and 59.2% were produced. Ultimately, 12 flavonoid glycosides that are at least purities of 97.7% were obtained from 100 mg of each fraction by preparative HPLC. The fraction A, B, and D each contained two flavonoids, yielded 35, 30, 23, 20, 25, and 25 mg, respectively. The fraction C and E each contained three flavonoids, produced 20, 13, 15, 18, 15, and 20 mg, respectively. The chemical structures of the purified compounds were identified by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI/MS).