PT  - JOURNAL ARTICLE
AU  - Andrew L. Waterhouse
AU  - Steve Ignelzi
AU  - Joseph R. Shirley
TI  - A Comparison of Methods For Quantifying Oligomeric Proanthocyanidins From Grape Seed Extracts
AID  - 10.5344/ajev.2000.51.4.383
DP  - 2000 Jan 01
TA  - American Journal of Enology and Viticulture
PG  - 383--389
VI  - 51
IP  - 4
4099  - http://www.ajevonline.org/content/51/4/383.short
4100  - http://www.ajevonline.org/content/51/4/383.full
SO  - Am J Enol Vitic.2000 Jan 01; 51
AB  - Grape seed extract (GSE) has become popular in recent years as a nutritional supplement that possesses antioxidant activity. These extracts contain a heterogeneous mixture of monomers, oligomers, and polymers composed of proanthocyanidin (or flavan-3-ol) subunits. The common colorimetric methods for analyzing the procyanidin concentration and/or composition of grape seed extracts and products containing it can give only crude information on the distribution of the sizes of the components. A normal phase HPLC method has proven to be very applicable to analyzing grape seed extract material and products thereof, and monomer, oligomer (2-7 subunits) and polymeric (8-24 subunits, and ∼24+ subunits) fractions can be discriminated. Values ranged from 5% to 30% for monomers, 17% to 63% oliogomers, 11% to 39% polymers and 2% to 50% for the large (24+) polymers. When specific attributes can be defined for particular size fractions, this method can provide the information needed to compare different samples for their relative potential effect.