Fractionation of apple procyanidins according to their degree of polymerization by normal-phase high-performance liquid chromatography

A new method was developed for the fractionation of procyanidin oligomers a ccording to their degree of polymerization. Monomeric flavan-3-ols and low molecular mass procyanidins were selectively extracted from the lyophilized powder of apple condensed tannins (ACTs) by methyl acetate extraction. Seq uentially, the separation of each oligomer from dimer to pentamer in this e xtract was carried out by normal-phase high-performance liquid chromatograp hy using a silica-beads packed column. The best separation was achieved wit h a mobile phase system containing hexane; (1) hexane-methanol-ethyl acetat e, (2) hexane-acetone, These sequential treatments can be easily adapted to large-scale fractionation. (C) 2000 Elsevier Science B.V. All rights reser ved.