DETERMINATION OF CATECHINS IN COMMERCIAL GRAPE SEED EXTRACT

An HPLC-UV method with gradient elution for the quantification of catechins [(+)-catechin, (−)-epicatechin and (−)-epicatechin gallate] in grape seed extract was developed. The presence of monomers, dimers, and/or trimers of catechin were assayed with an initial HPLC-APCI-MS analysis, which was followed by isolation, purification, and characterization with spectral (NMR and MS) analyses of the compounds of interest. The results confirmed the presence of above catechin monomers in grape seed extract. Three peaks of interest in HPLC-APCI-MS chromatogram were identified to be gallic acid, procyanidin-B4, and procyanidin-B2, respectively.