Oligomeric Proanthocyanidins (OPCs)
• Grape Seed Extract, Pine Bark Extract, Procyanidolic Oligomers (PCOs), Pycnogenol
One of the bestselling herbal products of the early 1990s was an extract of the bark of French maritime pine. This substance consists of a family of chemicals known scientifically as oligomeric proanthocyanidin complexes (OPCs) or procyanidolic oligomers (PCOs). Similar (but not identical) substances are also found in grape seed. The research record is complicated by the fact that certain identically named proprietary products have consisted at different times of various proportions of these related substances.
OPCs are marketed for a wide variety of uses. As yet, however, there is no solid evidence that they are effective for any medical condition.
OPCs aren't a single chemical, but a group of closely related compounds. Several food sources contain similar chemicals: red wine, cranberries, blueberries, bilberries, tea (green and black), black currant, onions, legumes, parsley, and the herb hawthorn
For the treatment of specific medical conditions, studies have used doses of 150 to 300 mg daily. For use as a general antioxidant, 50 mg of OPCs daily are often recommended; however, there is no evidence that this dose provides any health benefits.
The best-documented use of OPCs is to treat
chronic venous insufficiency
, a condition closely related to varicose veins. In both of these conditions, blood pools in the legs, causing aching, pain, heaviness, swelling, fatigue, and unsightly visible veins. Fairly good preliminary evidence suggests that OPCs from pine bark or grape seed can relieve the leg pain and swelling of chronic venous insufficiency.
One large study found some evidence that use of OPCs from pine bark might help prevent the leg blood clots that can develop on a long airplane flight.
In a double-bind, placebo-controlled study of 61 children with
Two small, double-blind pilot studies suggest that OPCs from pine bark might help reduce
OPCs might marginally improve blood sugar control in people with diabetes, according to a double-blind study of 77 people with type 2 diabetes.
Some evidence suggests that OPCs protect and strengthen collagen and elastin.
On the basis of their use in the treatment of varicose veins, OPCs are often recommended as a treatment for
OPCs are strong antioxidants.
OPCs have been tried as a treatment for
What Is the Scientific Evidence for Oligomeric Proanthocyanidins?
Venous Insufficiency (Varicose Veins)
There is fairly good preliminary evidence for the use of OPCs to treat people with symptoms of venous insufficiency .
A double-blind, placebo-controlled study of 71 subjects found that grape seed OPCs, taken at a dose of 100 mg 3 times daily, significantly improved major symptoms, including heaviness, swelling, and leg discomfort.
A 2-month, double-blind, placebo-controlled trial of 40 people with chronic venous insufficiency found that 100 mg of pine bark OPCs 3 times daily significantly reduced edema, pain, and the sensation of leg heaviness.
A placebo-controlled study (blinding not stated) that enrolled 364 people with varicose veins found that treatment with grape seed OPCs produced statistically significant improvements as compared to baseline.
OPCs have also been compared against other natural treatments for venous insufficiency. A double-blind study of 50 people with varicose veins of the legs found that doses of 150 mg per day of grape seed OPCs were more effective in reducing symptoms and signs than the bioflavonoid
Edema After Surgery or Injury
Blood Clots After Plane Flights
It is commonly thought, though not proven, that the immobility endured during a long plane flight can lead to the development of potentially dangerous blood clots in the legs known as
One crossover study of 22 smokers found that 100 mg of OPCs had an equivalent blood thinning effect as 500 mg of aspirin.
Another substantial double-blind study (204 participants) found benefit with a product that contains OPCs combined with nattokinase.
Inflammation of the gums (gingivitis) and plaque formation lead to
OPCs have been extensively tested for safety and are generally considered to be essentially nontoxic. 41
However, one study unexpectedly found that a combination of OPCs and
Maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been established.
OPCs may have some anticoagulant properties when taken in high doses, and therefore should be used only under medical supervision by individuals on blood-thinner drugs, such as warfarin (Coumadin), heparin, clopidogrel (Plavix), ticlopidine (Ticlid), pentoxifylline (Trental), or aspirin.
4. Tixier JM, Godeau G, Robert AM, et al. Evidence by in vivo and in vitro studies that binding of pycnogenols to elastin affects its rate of degradation by elastases. Biochem Pharmacol. 1984;33:3933-3939.
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18. Preuss HG, Wallerstedt D, Talpur N, et al. Effects of niacin-bound chromium and grape seed proanthocyanidin extract on the lipid profile of hypercholesterolemic subjects: a pilot study. J Med. 2000;31:227-246.
19. Bernstein CK, Deng C, Shuklah R, et al. Double blind, placebo controlled (DBPC) study of grapeseed extract in the treatment of seasonal allergic rhinitis (SAR) [abstract]. J Allergy Clin Immunol. 2001;107:1018.
20. Maffei Facino R, Carini M, Aldini G, et al. Free radical scavenging action and anti-enzyme activities of procyanidines from Vitis vinifera . A mechanism for their capillary protective action. Arzneimittelforschung. 1994;44:592-601.
25. Tixier JM, Godeau G, Robert AM, et al. Evidence by in vivo and in vitro studies that binding of pycnogenols to elastin affects its rate of degradation by elastases. Biochem Pharmacol. 1984;33:3933-3939.
26. Bagchi D, Garg A, Krohn RL, et al. Oxygen free radical scavenging abilities of vitamins C and E, and a grape seed proanthocyanidin extract in vitro. Res Commun Mol Pathol Pharmacol. 1997;95:179-189.
32. Pecking A, Desprez-Curely JP, Megret G. Oligomeric grape flavanols (Endotelon) in the treatment of secondary upper limb lymphedemas [translated from French]. Study on file with manufacturer, International Nutrition Company (INC),Vaduz, Liechtenstein. 1989;69-73.
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53. Durackova Z, Trebaticky B, Novotny V, et al. Lipid metabolism and erectile function improvement by pycnogenol extract from the bark of Pinus pinaster in patients suffering from erectile dysfunction—a pilot study. Nutr Res. 2003;23:1189-1198.
60. Ward NC, Hodgson JM, Croft KD, et al. The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens. 2005;23:427-34.
61. Brooker S, Martin S, Pearson A, et al. Double-blind, placebo-controlled, randomised phase II trial of IH636 grape seed proanthocyanidin extract (GSPE) in patients with radiation-induced breast induration. Radiother Oncol. 2006 Mar 16. [Epub ahead of print]
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Last reviewed April 2009 by EBSCO CAM Review Board
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