are a class of nutrients that belong to the
flavonoid family.They are also called "OPCs"
for oligomeric procyanidins or "PCOs"
for procyanidolic oligomers. Proanthocyanidins
have a strong antioxidant activity and play
a role in the stabilization of collagen and
maintenance of elastin in connective tissue.
OPCs are found in many woody plants. The two
most common sources of proanthocyanidins are
grape seeds (Vitis vinifera) and the white pine
(Pinus maritima, P. pinaster) of southern Europe.
The chemical structure of proanthocyanidins
which is found in Grape Seed extract is shown