Supplements

Grapeseed (Oligomeric Proanthocyanidins)

Grapeseed Extract is known primarily for being a rich source of oligomeric proanthoscyanidins (OPCs). OPCs are highly water soluable, unique phytochemicals known as flavonoids that have powerful antioxidant capabilities.

The whole grape fruit has also been used traditional for healingl purposes. Grape leaf sap was used in Europe for eye and skin ailments because the leaves have astringent and hemostatic actions. Grapes that were not yet ripe were used for sore or infected throats. Raisins were used in the treatment of consumption, constipation, and thirst. Ripe grapes had a plethora of applications, including cancer, cholera, smallpox, nausea, ophthalmia, and skin, kidney, and liver diseases. Similar and additional applications were prevalent in the Middle East, India, and China. Grapes have also been listed in many pharmacopeias.

Today, however, grapes are rarely, if ever, used for any of these purposes. Apart from being source materials in the manufacture of food and beverages, grapes are harvested for their oligomeric proanthocyanidins.

These polyphenolic constituents are also found in green tea and maritime pine bark. Extracts made from each of these plants contain similar OPC values and may be used interchangeably for specific indications, including chronic venous insufficiency and some ophthalmologic conditions. Effects have not been evaluated by Germany's Commission E; and in the United States, the use of pine bark (pycnogenol) for OPCs is much more prevalent than grape seed OPCs.

OPCs are able to cross the blood-brain barrier, helping to protect the brain and spinal nerves against free radical damage. OPCs also protect the liver from the damage caused by toxic doses of acetaminophen; they strengthen and repair connective tissue, and they support the immune system.

Pharmacologic activities of OPCs are numerous. In vitro, OPCs' antioxidant activity is 50 times greater than vitamin E's and 20 times greater than vitamin C's, in both lipid and aqueous phases. OPCs significantly and dose-dependently prevent vitamin E loss, and lower blood cholesterol levels through possible reversal of cholesterol transport, and by increasing both intestinal cholesterol absorption and bile acid excretion.

OPCs also inhibit angiotensin I converting enzyme, ascorbic acid oxidase, histidine decarboxylase, and prevents histamine release and arterial damage. OPCs are thought to prevent atherosclerosis by inhibiting platelet aggregation and vascular constriction. They stabilize capillary walls and prevent xylene-induced capillary permeability. OPCs also demonstrate antimutagenic activity, and inhibit carrageenan-induced rat paw edema.

Deficiency: Results from controlled trials support the use of grape seed OPCs for impaired visual function due to macular degeneration and chronic venous insufficiency. In addition, lymphedema, acrocyanosis, varicose veins, telangiectases, capillary fragility and permeability secondary to diabetes, cancer, premenstrual syndrome, and dental caries are some of the many indications for which grape seed OPCs might prove useful.

Sources: Grape seeds and skin of the fruit

Dosage Ranges and Duration of Administration:

• As a preventive for atherosclerosis, ophthalmologic disorders, or other conditions: 50 mg standardized extract/day.
• For therapeutic purposes: 150 to 300 mg/day.