Proanthocyanidins

Proanthocyanidins are a class of polyphenols found in a variety of plants. Chemically, they are oligomeric flavonoids. Many are oligomers of catechin and epicatechin and their gallic acid esters. More complex polyphenols, having the same polymeric building block, form the group of tannins.

Proanthocyanidins were discovered in 1947 by Jacques Masquelier, who developed and patented techniques for the extraction of oligomeric proanthocyanidins from pine bark and grape seeds. Often associated with consumer products made from cranberries, grape seeds or red wine, proanthocyanidins were once proposed as factors inhibiting urinary tract infections in women, but this research has been refuted by expert scientific committees.

Proanthocyanidins, including the lesser bioactive and bioavailable polymers (four or more catechins) represent a group of condensed flavan-3-ols, such as procyanidins, prodelphinidins and propelargonidins, that can be found in many plants, most notably apples, maritime pine bark and that of most other pine species, cinnamon,aronia fruit, cocoa beans, grape seed, grape skin (procyanidins and prodelphinidins), and red wines of Vitis vinifera (the European wine grape). However, bilberry, cranberry, black currant, green tea, black tea, and other plants also contain these flavonoids. Cocoa beans contain the highest concentrations. Proanthocyanidins also may be isolated from Quercus petraea and Q. robur heartwood (wine barrel oaks).Açaí oil, obtained from the fruit of the açaí palm (Euterpe oleracea), is rich in numerous procyanidin oligomers.

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