Procyanidin size and composition by thiolysis with cysteamine hydrochloride and chromatography

Abstract

Cysteamine hydrochloride is shown to be an alternative thiol reagent to toluene-α-thiol for the estimation of structural parameters (mean size, galloylation) of plant polymeric procyanidins. Acid depolymerization in the presence of the thiol yields mixtures which may be directly analysed by RPHPLC. Alternatively, the terminal units of the polymer may be separated from the extension units by cation-exchange chromatography previous to RPHPLC. High reaction-recovery yields (ca. 90% thiolysis and RPHPLC, ca. 69% thiolysis, cation exchange and RPHPLC) are obtained and both procedures are precise.