The Herb Report: Anthocyanidins and Proanthocyanidins


They might not be easy to pronounce, but lately anthocyanidins and proanthocyanidins have been getting lots of attention. Chemically, they are condensed tannins -- one of the two main categories of tannins -- derived from catechins (the same compounds found in tea). Anthocyanidins produce a deep reddish-blue that colors many vegetables, flowers, and fruits. They give hawthorn their bright red color and make delphiniums and borage a brilliant blue. (This ability gave them their name; anthos is flower and kyanos means a blue substance in Greek.) Anthocyanidins are commercially derived mostly from bilberry and grapes. The closely-related proanthocyanidins (PACs), also called procyanidolic oligomers (abbreviated PCOs or OPCs), are colorless compounds extracted commercially from grape seeds and pine bark. They are also found in the bracts of lime tree and hazel nut tree leaves, and even in some beans.

Like most flavonoids, both anthocyanidins and proanthocyanidins are potent antioxidants that destroy free radicals. The role of antioxidants in slowing the aging process is now widely accepted. Research also associates free radicals with weakened cell membranes, inflammation, genetic mutations, and major health problems such as cancer and cardiovascular disease that can lead to heart attack and stroke.

Anthocyanidins and proanthocyanidins have several other beneficial functions in the body. For example, they increase the amount of vitamin C held in the cells and strengthen and decrease the permeability of capillaries. They also strengthen collagen and elastin -- which maintain the integrity of tendons, ligaments and cartilage and support blood vessels and skin -- and prevent their destruction by certain enzymes. Since collagen and elastin keep skin elastic, they also improve the complexion. The promotional literature even claims that they slow down the formation of wrinkles. In addition, anthocyanidins and proanthocyanidins perform several functions to reduce inflammation. One way they do so is by inhibiting the release of histamine, serine proteases, prostaglandins and leukotrienes, all of which cause inflammation. The combination of strengthening collagen and elastin and reducing inflammations makes anthocyanidins and proanthocyanidins good treatments for emphysema and rheumatoid arthritis. They also help diabetes and inflammatory diseases, in which the permeability of blood vessels is increased. I suspect they also would help people with CFIDS (chronic fatigue) and fibromyalgia since these disorders are associated with collagen destruction and an increase free radical activity.

Is one flavonoid better than the other? All the sale promotion aside, no one knows. Further research may even reveal that the much less expensive flavonoids found in orange peel, the catechins in green tea, of the antioxidant vitamin E are equally effective. There may also be something to be said for using the whole plant rather than these extracted compounds. Just like flavonoids improve vitamin C assimilation, perhaps flavonoids are better assimilated when taken with other natural compounds. Here at the AHA, we promise to keep an eye on new research on these compounds and keep you posted.


Foods containing anthocyanidins have been used throughout the world as medicine. European herbalists suggested elderberries for rheumatism, strawberries for the heart, and raspberries to strengthen the uterus. Purple grapes were known to heal a long list of ailments. In the 17th century, herbalist John Evelyn said that elderberries "greatly assist longevity." In his day, patrons of English coffee houses would toast each other a long life with elderberry cordials. Bilberries are a Russian folk remedy for stomach ulcers and colitis. Hawthorn berries have long been used to help the heart and circulation. Today, pharmaceutical drugs in France, Germany, Italy, and Spain contain anthocyanidins, and several medical patents have been established to heal wounds, stomach and duodenal ulcers, mouth and throat inflammation, circulation disorders, and problems with lipid and glyceride metabolism. In addition, anthocyanidins inhibit some bacteria and yeast.( 1) They have no known toxicity, are considered safe during pregnancy and are even anti-mutagenic to cells.( 2)

Anthocyanidins are best known for their ability to improve the heart and circulation.( 3) They strengthen both capillaries and the blood-brain barrier and reduce their permeability.( 4) During one study on their use, 8,000 patients with various circulation problems, including varicose veins and hemorrhoids, improved 73-97%.( 5) In a clinical study with 54 diabetics (who often experience capillaries thickened from collagen and glycoprotein build-up), collagen returned to normal, and glycoprotein levels dropped 30% after taking 500-600 mg. anthocyanidins daily.( 6) Anthocyanidins stop the enzyme elastase from attacking collagen and elastin.( 7) Studies show anthocyanidins from black currents reverse the effects of a high fat diet by lowering potentially injurious fats such as cholesterol.( 8) Although the cause of arteriosclerosis -- in which artery walls thicken and harden -- is not known, elastase and high cholesterol are both implicated. Anthocyanidins do reduce the risk of developing this disease. They also stop blood cells from clumping together in platelet aggregation, and cause blood vessels to dilate,( 9) reducing the chance of heart attack and blood clots. Bilberries have been shown to improve the rate and strength of heart contractions.( 10)

In various studies, anthocyanidins have helped the strained sight of watchmakers, navigators, computer operators, airline pilots, air traffic controllers, car and truck drivers, as well as students.( 11) During World War II, Royal Air Force pilots in Great Britain were even given bilberry jam to improve their night vision.( 12) Today, ophthalmologists prescribe anthocyanidins, since studies show they not only strengthen blood vessels and improve orculation in the eye but also regenerate visual purple.( 13) This increases the eye's ability to rapidly adapt to the dark and tolerate glare, and reduces eye strain. Combined with anticoagulant drugs, they prevent the retina from hemorrhaging.( 14) Over the course of fifteen years, one doctor who gave 600 mg. anthocyanidins a day to thousands of patients reported that near sightedness and night vision greatly improved.( 15) In a study with 75 people whose eyes were strained from sitting in front of a computer monitor, considerable improvement was experienced after taking 300 mg. of anthocyanidins daily for two months. Their eyes became less sensitive to light contrast and they had fewer related symptoms, such as headaches.( 16) In addition, bilberry increased the range of vision in people who had retinitis, an inflammation of the eye that diminishes vision, makes the eyes sensitive to light, produces blind spots and sometimes causes the size of objects to change.( 17)

Anthocyanidins act as strong antioxidants that reduce the harmful effects of free radicals.( 18) They also have a sedating action on the nervous system and slow muscle spasms.( 19) Grape extract has been shown to reduce pain, nerve sensitivity, skin pricking, night cramps, etc. Studies with bilberries found they increase the blood supply to the central nervous system.( 20) When a group of people took 300 mg. anthocyanidins daily for three months in a double blind, placebo study, their storage of vitamin C increased, especially in the liver and adrenals.( 21) This is important to help both immunity and stress tolerance. Large lymph nodes in women who had breast surgery diminished after they started taking anthocyanidins.( 22) Anthocyanidins help prevent and cure peptic and duodenal ulcers, probably by strengthening the digestive tract's mucus barrier and improving its efficiency.( 23) They also strengthen connective tissue and capillaries there. Studies on anthocyanidins show they slow intestinal spasms and regulate digestive secretions.( 24)


In 1535, French explorer Jacques Cartier and his crew avoided scurvy by using a Native American tea made from the bark and needles of an evergreen tree called anneda. This is thought to have been a pine (Pinus species) or arbor vitae (Thuja occidentalis). While reading about Cartier's expedition, Jacques Masquelier became curious why bark was included in the blend, so began to study it. In 1951, he patented a method of extracting OPCs from pine bark and in 1970 from grape seeds, which has been used for most of the research. Pycnogenol(TM) was trademarked by the Irish company, Horphag Research, Ltd. for their product from the maritime pine from France. This is described as Pinus maritima or more correctly P. pinaster since Hortus Third describes P. maritima as "a name that cannot be used with certainty" that it is often used for P. pinaster. It consists of mostly proanthocyanidins, about 80 to 85%.( 25) The best argument for using grape seeds over pine that I can think of -- one that I never see mentioned -- is that grape seeds are a by-product of the wine industry while obtaining the bark involves the "harvesting" of the pine trees.

Not as many clinical studies have been done on OPCs as anthocyanidins, but they are known to be potent antioxidants.( 26) When diabetic and hypertensive patients with weak capillaries were given OPCs in a placebo study, the treated group had significant improvement.( 27) For chronic blood insufficiency in the veins, OPCs worked as well as the drug diosmin in 50 patients. As an added plus, the OPCs acted faster and their effects were longer-lasting.( 28) Endotelon (a product containing 95% OPCs from grape seeds manufactured by Sanofi/Labaz, France) helped 100 healthy people recover their vision more quickly after being subject to glare. They also were better able to adapt to low lighting.( 29) A group of 165 women with PMS problems, which included breast swelling, pelvic pain, weight gain, and varicose veins took Endoreton. After two menstrual cycles, 61% of the women had fewer and less severe problems. After four cycles, this increased to nearly 80%.( 30) In a double-blind study, the same product helped reduce edema in 32 patients after surgery. On the average, it disappeared in less than twelve days, four days sooner than the control group.( 31)

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(3). Mazzag, G & E Miniti, eds. 1993. Anthocyanins in Fruits. Vegetables & Grains. CRC Press.

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(18). Santrucek, M. et al. 1988. Drugs of the Future 10:974-996.

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(21). Sturua, AS. et al. 1971. Chem. Abs. 76:21575.

(22). Deladroix, P. 1981. Rev. Medecine 27:1793-1802.

(23). Cristoni, A & MJ Magistretti. 1987. Farmaco Ed. Prat. 42:29.

(24). Kyerematen, G & F. Sandberg. 1986. Acta. Pharm. Sueca. 23:101.

(25). Passwater, RA, Pycnogenal: The Super "Protector" Nutrient. Keats Pub. 1994. $4.95.

(26). Tixier, JM, et al. 1984. Biochem Pharmacol 33:3933-3939.

(27). Lagrua, G. et al. 1081. Sem Hop 57:1399-1401.

(28). Delacrois, P. 1981. La Revue De Med 27:28-31.

(29). Corbe, C. et al. 1988. Jour Fr Opthalmol 11:453-460.

(30). Amsellem, M. et al. 1987. Tempo Médical 282.

(31). Baruch, J. 1984. Ann Chit Plast Esthét 4.

Harborne, Jeffrey B. & Herbert Baxter, 1993. Phytochemical Dictionary. Taylor & Francis, Washington, DC. Facino, RM. et al. 1994. Arzneim-Forsch 44:592-601. Werbach, Melvyn & Michael T. Murray. 1994. Botanical Influences on Illness: A Sourcebook of Clinical Research. Third Line Press, Tarzana, CA.

The American Herb Association.


By Kathi Keville

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