Preparative high-speed counter-current chromatography separation of grape seed proanthocyanidins according to degree of polymerization

Abstract

Separation of plant proanthocyanidins remains a major challenge for scientists due to the structural diversity and complexity. In this work, a new and effective method was developed for preparative separation of grape seed proanthocyanidins (GSPs) according to degree of polymerization (DP) by high-speed counter-current chromatography (HSCCC). Under the optimized HSCCC conditions, GSPs could be separated into seven distinct fractions (F1-F7) with mean degree of polymerization in increasing order, from 1.44 to 6.95. High yields for these fractions (53.7, 12.2, 29.5, 30.2, 11.2, 50.8 and 169.8mg, respectively) were achieved by only one-step HSCCC of 400mg of GSPs. Further, seventeen individual proanthocyanidins, most of which are commercially not available, were efficiently isolated by re-chromatography on HSCCC or prep-HPLC; each of the isolated compounds presented high yields (7.1-78.9mg) and high purity (70.0-95.7%). The positive correlation was observed between DP and antioxidant activity of proanthocyanidins.

Keywords: Antioxidant activities; Degree of polymerization; Grape seed; HSCCC; Proanthocyanidins; Procyanidin B1 (PubChem CID: 11250133); Procyanidin B2 (PubChem CID: 122738); Procyanidin B2-3′-O-gallate (PubChem CID: 15593124); Procyanidin B3 (PubChem CID: 146798); Procyanidin B4 (PubChem CID: 147299); Procyanidin C1 (PubChem CID: 169853); Separation.