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Scientific Studies

Proanthocyanidin – Biological Activities Associated with Human Health

Proanthocyanidin – Biological Activities Associated with Human Health


Proanthocyanidins are a class of polyphenols found in a variety of plants. Chemically, they are oligomeric flavonoids.

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 proposed as factors inhibiting urinary tract infections in women.

In nature, proanthocyanidins serve among other chemical defense mechanisms against plant pathogens and predators, such as occurs in strawberries.

Cranberries have A2-type Proanthocyanidins [PACs] and the less common B-type. A-type linkages may be important for the ability to bind to proteins, such as the adhesins present on E. coli fimbriae and may help prevent bacterial infections, especially urinary tract infections. However, clinical trials have been conducted to see if PACs, particularly from cranberries, may offer an alternative methodology to antibiotic prophylaxis and an improvement of UTI symptoms.

Proanthocyanidins are present in fresh grapes, juice, red wine, and other darkly pigmented fruits such as cranberry and elderberry.

Studies with cranberries and cinnamon, both of which contain uniquely linked proanthocyanidins, support a role for bacterial antiadhesion and improved glucose metabolism in type 2 diabetics, respectively. Results from a variety of experiments indicate proanthocyanidins may modulate several reactions involved in cancer processes.

Many other foods and beverages may also contain proanthocyanidins, but few attain the levels found in red grape seeds and skins, which has the highest recorded level of proanthocyanidins among fruits assessed to date (664 milligrams per 100 g).