A semisynthetic approach for the simultaneous reaction of grape seed polymeric procyanidins with catechin and epicatechin to obtain oligomeric procyanidins in large scale

Abstract

Polymeric procyanidins (PPCs) were the major constituents of procyanidins, while they have poor bioactivity. To better utilize PPCs, a semisynthetic approach for converting PPCs to oligomeric procyanidins (OPCs) was proposed. Grape seed PPCs were simultaneously reacted with catechin (C) and epicatechin (EC) under acid condition. Combining response surface methodology (RSM) and single-factor experiments, an optimized semisynthetic condition was confirmed with the ratio of PPCs with C and EC of 1:1:1, temperature of 40 °C, reaction time of 20 min and 0.1 M methanolic HCl. High-speed counter-current chromatography (HSCCC) was adopted to obtain three fractions from semisynthetic products and preparative-HPLC was used to isolate individual procyanidins. Thirteen B-type procyanidins including monomers, dimers and trimers were got with high yield of 0.8-17.8 mg from 200 mg semisynthetic products and high purity over 91%. The developed semisynthesis combined with separation method was efficient to obtain individual OPCs in preparative scale.

Keywords: (+)-Catechin (PubChem CID: 107957); (−)-Epicatechin (PubChem CID: 72276); Catechin; Epicatechin; Grape seed; HSCCC; Polymeric procyanidins; Procyanidin B1 (PubChem CID: 11250133); Procyanidin B1 3-gallate (PubChem CID: 72193635); Procyanidin B2 (PubChem CID: 122738); Procyanidin B3 (PubChem CID: 146798); Procyanidin B4 (PubChem CID: 147299); Procyanidin C1 (PubChem CID: 169853); Semisynthesis.