The LC-ESI/MS/MS determination of procyanidins in grape seed extracts

The extracts of grape seeds are widely used as dietary supplements. They show a number of health beneficial effects including antitumor, chemopreventive, cardioprotective, antioxidant, apoptosis inducing and gene modulating activities [1]. The main chemical constituents responsible for these activities are procyanidins. Their identification and determination in plant material is rather complex. In the present work the liquid chromatography-mass spectrometry technique was applied for identification and determination of procyanidins in alcohol and water extracts from grape seeds. The number of monomer, dimer, trimer, tetramer procyanidins, as well as their gallate derivatives were monitored by direct injection mode ESI-MS (Figure 1)

m/z 289	DP1: catechin, epicatechin
m/z 577	DP2: catechin-catechin	m/z 729	DP2G: catechin-catechin-gallate
m/z 865	DP3: catechin-catechin-catechin	m/z 1017	DP3G: cat-cat-cat-gallate
m/z 1153	DP4: cat-cat-cat-cat	m/z 1305	DP4G: cat-cat-cat-cat-gallate
m/z 1441	DP5: cat-cat-cat-cat-cat	m/z 1593	DP5G: cat-cat-cat-cat-cat-gallate
m/z 1729	DP6: cat-cat-cat-cat-cat-cat	m/z 1881	DP6G: cat-cat-cat-cat-cat-cat-gallate

The amount of procyanidin monomers, dimers and trimers was calculated after LC separation, from the selective ion chromatograms (SIC) using catechin as an external standard. The concentration of procyanidins in grape seed water extract was about 25% of dry matter, while in ethanol extract this was on the level of 10% of dry matter.

References: [1] Bagchi D, Sen Ck, et al. (2003) Mutat. Res. 523–524: 87–97.