Grape seed extract is as follows:
1. Grape seed polyphenols:
A. 95% by UV, folin assay
B. 95% polyphenols with 15% phenolic monomers including
Catechin, epicatechin, ECG, etc. By UV, Folin Assay and HPLC
C. 90% by UV, folin assay
D. 90% polyphenols with 10% phenolic monomers including
Catechin, epicatechin, ECG, etc. By UV, Folin Assay and HPLC
2. Grape seed proanthocyanidins(OPCs) 95% by UV, Beta-Smith Assay