Oligomeric proanthocyanidins, also oligomeric procyanidins, OPC or PCO, are naturally occurring substances in plants, which belong to the group of flavanols and are to be assigned to the superordinate polyphenols. In animal experiments, he discovered that the cuticles contained substances that were well suited for the treatment of venous diseases. They are found in many other plants and have always been part of human food. Especially in grape seeds, the skin and leaves of red grapes, in the red peanuts, in coconuts, in ginkgo leaves, in apples, larch wood and in the bark of the beach pine. Especially the outer plant parts such as bark or shells, but also cores and core housings contain larger amounts of OPC.
Depending on their location, oligomeric proanthocyanidins can also be found in varying concentrations in red wines and significantly less in white wines. Oligomeric proanthocyanidins, like many other secondary plant substances, are mainly used by plants to protect them from UV radiation, climatic conditions and predators. Biological effect OPC may be catalysts that can enhance the positive effects of vitamins A, C and E. An expert group from the Mount Sinai School of Medicine, New York, found in animal experiments that polyphenols in grape seed extract could prevent or at least delay plaque formation as a precursor for Alzheimer’s and thus typical memory loss. These substances include ascorbic acid, taxifolin, rutin, hesperidin and quercetin as well as other bioflavonoids. Only about 80 % pure Taxifolin contains OPC as well as other polyphenols and has a broad spectrum of action on the human organism.