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References
1- Wichtl, M. 1996. Monographien—Kommentar. In: Braun, R. et al. 1997. Standardzulassungen f r Fertigarzneimittel—Text and Kommentar. Stuttgart: Deutscher Apotheker
Verlag.
2- Leung, A.Y. and S. Foster. 1996. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2nd ed. New York: John Wiley & Sons, Inc. 84–85.
3- Azar, M., E. Verette, S. Brun. 1987. Identification of some phenolic compounds in bilberry juice Vaccinium myrtillus. J Food Sci 52(5):1255–1257.
4- Friedrich, V.H. and J. Schˆnert. 1973. Untersuchungen ber einige Inhaltsstoffe der Bl‰tter und Fr chte von Vaccinium myrtillus [Phytochemical investigation of leaves
and fruits of Vaccinium myrtillus]. Planta Med 24(1):90–100.
5- H‰nsel, R., K. Keller, H. Rimpler, G. Schneider (eds.). 1992–1994. Hagers Handbuch der Pharmazeutischen Praxis, 5th ed. Vol. 4–6. Berlin-Heidelberg: Springer Verlag
6- Meyer-Buchtela, E. 1999. Tee-Rezepturen—Ein Handbuch f r Apotheker und ƒrzte. Stuttgart: Deutscher Apotheker Verlag.
7- Morazzoni, P. and E. Bombardelli. 1996. Vaccinium myrtillus L. Fitoterapia 67(1):3–29.
8- Barrette, E.P. 1999. Bilberry fruit extract for night vision. Alternative Medicine Alertô 2(2):20– 21.
9- Cunio, L. 1993. Vaccinium myrtillus. Aust J Med Herbalism 5(4):81–85.
10- Flynn R, Roest M. Your guide to standardized herbal products. Prescott, AZ: One World Press, 1995.
11- Weiss RF. Herbal medicine. Gothenburg, Sweden: AB Arcanum, 1988.
12- Peirce A. The American Pharmaceutical Association practical guide to natural medicines. New York: William Morrow and Company, Inc., 1999.
13- Blumenthal M. The complete German Commission E monographs : therapeutic guide to herbal medicines. Austin: American Botanical Council, 1998.
14- Cluzel, C., P. Bastide, P. Tronche. 1969. [Phosphoglucomutase and glucose-6-phosphatase activities of the retina and anthocyanoside extracts from Vaccinium
myrtillus (study in vitro and in vivo)] [In French]. C R Seances Soc Biol Fil 163(1):147–150.
15- Lietti, A., A. Cristoni, M. Picci. 1976. Studies on Vaccinium myrtillus anthocyanosides. I. Vasoprotective and antiinflammatory activity. Arzneimforsch 26(5):829–832.
16- Colantuoni, A., S. Bertuglia, M.J. Magistretti, L. Donato. 1991. Effects of Vaccinium myrtillus anthocyanosides on arterial vasomation. Arzneimforsch 41(9):905–909.
17- Tyler, V.E. 1994. Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York: Pharmaceutical Products Press.
18- Caselli L. Clinical and electroretinographic study on activity of anthocyanosides. Arch Med Int 985;37:29-35.
19- Wegmann R, Maeda K, Tronch P, Bastide P. Effects of anthocyanosides on photoreceptors. Cytoenzymatic aspects. Ann Histochim 1969;14:237-256.
20- Jayle GE, Aubert L. Action des glucosides d’anthocyanes sur la vision scotopique et mesopique du sujet normal. Therapie 1964:19:171-185. [Article in French]
21- Terrasse J, Moinade S. Premiers resultats obtenus avec un nouveau facteur vitamininique P “les anthocyanosides” extraits du Vaccinium myrtillus. Presse Med 1964;72:
397-400. [Article in French]
22- Sala D, Rolando M, Rossi PL, Pissarello L. Effect of anthocyanosides on visual performances at low illumination. Minerva Oftalmol 1979;21:283-285.
23- Gloria E, Peria A. Effect of anthocyanosides on the absolute visual threshold. Ann Ottalmol Clin Ocul 1966;92:595-607. [Article in Italian]
24- Muth ER, Laurent JM, Jasper P. The effect of bilberry nutritional supplementation on nightvisual acuity and contrast sensitivity. Altern Med Rev 2000;5:164-173.
25- Junemann G. On the effect of anthocyanosides on hemeralopia following quinine poisoning. Klin Monatsbl Augenheilkd 1967;151:891-896. [Article in German]
26- Pautler EL, Ennis SR. The effect of diet on inherited retinal dystrophy in the rat. Curr Eye Res 1984;3:1221-1224.
27- Hess H, Knapka JJ, Newsome DA, et al. Dietary prevention of cataracts in the pink-eyed RCS rat. Lag Anim Sci 1985;35:47-53.
28- Bravetti G. Preventive medical treatment of senile cataract with vitamin E and anthocyanosides: clinical evaluation. Ann Ottalmol Clin Ocul 1989;115:109. [Article in
Italian]
29- Scharrer A, Ober M. Anthocyanosides in the treatment of retinopathies. Klin Monatabl Augenheilkd 1981;178:386-389. [Article in German]
30- Perossini M, et al. Diabetic and hypertensive retinopathy therapy with Vaccinium myrtillus anthocyanosides (Tegens): Double-blind placebo controlled clinical trial. Ann
Ottalmol Clin Ocul 1987;113:1173. [Article in Italian]
31- Lietti A, Cristoni A, Picci M. Studies on Vaccinium myrtillus anthocyanosides. I. Vasoprotective and anti-inflammatory activity. Arzneim Forsch 1976;26:829-832.
32- Colantuoni A, Bertuglia S, Magistretti MJ, Donato L. Effects of Vaccinium myrtillus anthocyanosides on arterial vasomotion. Arzneim Forsch 1991;41:905-909.
33- Pennarola R, et al. The therapeutic action of the anthocyanosides in microcirculatory changes due to adhesiveinduced polyneuritis. Gazz Med Ital 1980;139:485-491.
[Article in Italian]
34- Ghiringhelli C, Gregoratti L, Marastoni F. Capillarotropic activity of anthocyanosides in high doses in phlebopathic stasis. Minerva Cardioangiol 1978;25:255-276.
35- Bratman S, Kroll D. The Natural Pharmacist: Clinical Evaluation of Medicinal Herbs and Other Therapeutic Natural Products. Roseville, CA: Prima Publishing 1999:
Bilberry 1-5.
36- Allen FM. Blueberry leaf extract. Physiologic and clinical properties in relation to carbohydrate metabolism.JAMA 1927;89:1577-1581.
37- Bever B, Zahnd G. Plants with oral hypoglycemic action. Quart J Crude Drug Res 1979;17:139-196.
38- Rao CN, Rao VH, Steinman B. Influence of bioflavonoids on the collagen metabolism in rats with adjuvant induced arthritis. Ital J Biochem 1981;30:54-62.
39- Puilleiro G, et al. Ex vivo study of the inhibitory effects of Vaccinium myrtillus anthocyanosides on human platelet aggregation. Fitoterapia 1989;60:69-75.
40- Magistretti MJ, Conti M, Cristoni A. Antiulcer activity of anthocyanidin from Vaccinium myrtillus. Arzneim Forsch 1988;38:686-690.
Bilberry
41- Laplaud PM, Lelubre A, Chapman MJ. Antioxidant action of Vaccinium myrtillus extract on human low density lipoproteins in vitro: initial observations. Fundam Clin
Pharmacol 1997;11:35-40.
42- Braun, R. et al. 1997. Standardzulassungen f r Fertigarzneimittel—Text and Kommentar. Stuttgart: Deutscher Apotheker Verlag.
43- Bruneton, J. 1995. Pharmacognosy, Phytochemistry, Medicinal Plants. Paris: Lavoisier Publishing
44- Anderhuber, R. 1991. Vaccinium myrtillus. Aust J Med Herbalism 3:13–14
45- Pizzorno, J.E. and M.T. Murray. 1992. A Textbook of Natural Medicine. Seattle, WA: Bastyr University Publications
46- The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999
47- Lietti A, Forni G. Studies on Vaccinium myrtillus anthocyanosides. II. Aspects of anthocyanins pharmacokinetics in the rat. Arzneimittelforschung 1976;26:832-5.
48- Eandi M. Post-marketing investigation on Tegens“ preparation with respect to side effects. 1987. Cited in Morazzoni P, Bombardelli E. Vaccinium myrtillus I. Fitoterapia
1996;67:3-29.
49- Cignarella A, Nastasi M, Cavalli E, Puglisi L. Novel lipid-lowering properties of Vaccinium myrtillus L. leaves, a traditional antidiabetic treatment, in several models of
rat dyslipidaemia: a comparison with ciprofibrate. Thromb Res 1996;84(5):311-22.
50- Friedrich H, Schonert J. Tannin-producing substances in the leaves and fruits of the bilberry. Arch Pharm (Weinheim) 1973; 306:611-8.
51- Bissett NG. Herbal drugs and phytopharmaceuticals. Stuttgart: MedPharm CRC Press, 1994:566.
52- Colombo D, Vescovini R. Controlled trial of anthocyanosides from Vaccinium myrtillus in primary dysmenorrhea. G Ital Ost Ginecol 1985;7:1033-1038l.
1- Wichtl, M. 1996. Monographien—Kommentar. In: Braun, R. et al. 1997. Standardzulassungen f r Fertigarzneimittel—Text and Kommentar. Stuttgart: Deutscher Apotheker
Verlag.
2- Leung, A.Y. and S. Foster. 1996. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2nd ed. New York: John Wiley & Sons, Inc. 84–85.
3- Azar, M., E. Verette, S. Brun. 1987. Identification of some phenolic compounds in bilberry juice Vaccinium myrtillus. J Food Sci 52(5):1255–1257.
4- Friedrich, V.H. and J. Schˆnert. 1973. Untersuchungen ber einige Inhaltsstoffe der Bl‰tter und Fr chte von Vaccinium myrtillus [Phytochemical investigation of leaves
and fruits of Vaccinium myrtillus]. Planta Med 24(1):90–100.
5- H‰nsel, R., K. Keller, H. Rimpler, G. Schneider (eds.). 1992–1994. Hagers Handbuch der Pharmazeutischen Praxis, 5th ed. Vol. 4–6. Berlin-Heidelberg: Springer Verlag
6- Meyer-Buchtela, E. 1999. Tee-Rezepturen—Ein Handbuch f r Apotheker und ƒrzte. Stuttgart: Deutscher Apotheker Verlag.
7- Morazzoni, P. and E. Bombardelli. 1996. Vaccinium myrtillus L. Fitoterapia 67(1):3–29.
8- Barrette, E.P. 1999. Bilberry fruit extract for night vision. Alternative Medicine Alertô 2(2):20– 21.
9- Cunio, L. 1993. Vaccinium myrtillus. Aust J Med Herbalism 5(4):81–85.
10- Flynn R, Roest M. Your guide to standardized herbal products. Prescott, AZ: One World Press, 1995.
11- Weiss RF. Herbal medicine. Gothenburg, Sweden: AB Arcanum, 1988.
12- Peirce A. The American Pharmaceutical Association practical guide to natural medicines. New York: William Morrow and Company, Inc., 1999.
13- Blumenthal M. The complete German Commission E monographs : therapeutic guide to herbal medicines. Austin: American Botanical Council, 1998.
14- Cluzel, C., P. Bastide, P. Tronche. 1969. [Phosphoglucomutase and glucose-6-phosphatase activities of the retina and anthocyanoside extracts from Vaccinium
myrtillus (study in vitro and in vivo)] [In French]. C R Seances Soc Biol Fil 163(1):147–150.
15- Lietti, A., A. Cristoni, M. Picci. 1976. Studies on Vaccinium myrtillus anthocyanosides. I. Vasoprotective and antiinflammatory activity. Arzneimforsch 26(5):829–832.
16- Colantuoni, A., S. Bertuglia, M.J. Magistretti, L. Donato. 1991. Effects of Vaccinium myrtillus anthocyanosides on arterial vasomation. Arzneimforsch 41(9):905–909.
17- Tyler, V.E. 1994. Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York: Pharmaceutical Products Press.
18- Caselli L. Clinical and electroretinographic study on activity of anthocyanosides. Arch Med Int 985;37:29-35.
19- Wegmann R, Maeda K, Tronch P, Bastide P. Effects of anthocyanosides on photoreceptors. Cytoenzymatic aspects. Ann Histochim 1969;14:237-256.
20- Jayle GE, Aubert L. Action des glucosides d’anthocyanes sur la vision scotopique et mesopique du sujet normal. Therapie 1964:19:171-185. [Article in French]
21- Terrasse J, Moinade S. Premiers resultats obtenus avec un nouveau facteur vitamininique P “les anthocyanosides” extraits du Vaccinium myrtillus. Presse Med 1964;72:
397-400. [Article in French]
22- Sala D, Rolando M, Rossi PL, Pissarello L. Effect of anthocyanosides on visual performances at low illumination. Minerva Oftalmol 1979;21:283-285.
23- Gloria E, Peria A. Effect of anthocyanosides on the absolute visual threshold. Ann Ottalmol Clin Ocul 1966;92:595-607. [Article in Italian]
24- Muth ER, Laurent JM, Jasper P. The effect of bilberry nutritional supplementation on nightvisual acuity and contrast sensitivity. Altern Med Rev 2000;5:164-173.
25- Junemann G. On the effect of anthocyanosides on hemeralopia following quinine poisoning. Klin Monatsbl Augenheilkd 1967;151:891-896. [Article in German]
26- Pautler EL, Ennis SR. The effect of diet on inherited retinal dystrophy in the rat. Curr Eye Res 1984;3:1221-1224.
27- Hess H, Knapka JJ, Newsome DA, et al. Dietary prevention of cataracts in the pink-eyed RCS rat. Lag Anim Sci 1985;35:47-53.
28- Bravetti G. Preventive medical treatment of senile cataract with vitamin E and anthocyanosides: clinical evaluation. Ann Ottalmol Clin Ocul 1989;115:109. [Article in
Italian]
29- Scharrer A, Ober M. Anthocyanosides in the treatment of retinopathies. Klin Monatabl Augenheilkd 1981;178:386-389. [Article in German]
30- Perossini M, et al. Diabetic and hypertensive retinopathy therapy with Vaccinium myrtillus anthocyanosides (Tegens): Double-blind placebo controlled clinical trial. Ann
Ottalmol Clin Ocul 1987;113:1173. [Article in Italian]
31- Lietti A, Cristoni A, Picci M. Studies on Vaccinium myrtillus anthocyanosides. I. Vasoprotective and anti-inflammatory activity. Arzneim Forsch 1976;26:829-832.
32- Colantuoni A, Bertuglia S, Magistretti MJ, Donato L. Effects of Vaccinium myrtillus anthocyanosides on arterial vasomotion. Arzneim Forsch 1991;41:905-909.
33- Pennarola R, et al. The therapeutic action of the anthocyanosides in microcirculatory changes due to adhesiveinduced polyneuritis. Gazz Med Ital 1980;139:485-491.
[Article in Italian]
34- Ghiringhelli C, Gregoratti L, Marastoni F. Capillarotropic activity of anthocyanosides in high doses in phlebopathic stasis. Minerva Cardioangiol 1978;25:255-276.
35- Bratman S, Kroll D. The Natural Pharmacist: Clinical Evaluation of Medicinal Herbs and Other Therapeutic Natural Products. Roseville, CA: Prima Publishing 1999:
Bilberry 1-5.
36- Allen FM. Blueberry leaf extract. Physiologic and clinical properties in relation to carbohydrate metabolism.JAMA 1927;89:1577-1581.
37- Bever B, Zahnd G. Plants with oral hypoglycemic action. Quart J Crude Drug Res 1979;17:139-196.
38- Rao CN, Rao VH, Steinman B. Influence of bioflavonoids on the collagen metabolism in rats with adjuvant induced arthritis. Ital J Biochem 1981;30:54-62.
39- Puilleiro G, et al. Ex vivo study of the inhibitory effects of Vaccinium myrtillus anthocyanosides on human platelet aggregation. Fitoterapia 1989;60:69-75.
40- Magistretti MJ, Conti M, Cristoni A. Antiulcer activity of anthocyanidin from Vaccinium myrtillus. Arzneim Forsch 1988;38:686-690.
Bilberry
41- Laplaud PM, Lelubre A, Chapman MJ. Antioxidant action of Vaccinium myrtillus extract on human low density lipoproteins in vitro: initial observations. Fundam Clin
Pharmacol 1997;11:35-40.
42- Braun, R. et al. 1997. Standardzulassungen f r Fertigarzneimittel—Text and Kommentar. Stuttgart: Deutscher Apotheker Verlag.
43- Bruneton, J. 1995. Pharmacognosy, Phytochemistry, Medicinal Plants. Paris: Lavoisier Publishing
44- Anderhuber, R. 1991. Vaccinium myrtillus. Aust J Med Herbalism 3:13–14
45- Pizzorno, J.E. and M.T. Murray. 1992. A Textbook of Natural Medicine. Seattle, WA: Bastyr University Publications
46- The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999
47- Lietti A, Forni G. Studies on Vaccinium myrtillus anthocyanosides. II. Aspects of anthocyanins pharmacokinetics in the rat. Arzneimittelforschung 1976;26:832-5.
48- Eandi M. Post-marketing investigation on Tegens“ preparation with respect to side effects. 1987. Cited in Morazzoni P, Bombardelli E. Vaccinium myrtillus I. Fitoterapia
1996;67:3-29.
49- Cignarella A, Nastasi M, Cavalli E, Puglisi L. Novel lipid-lowering properties of Vaccinium myrtillus L. leaves, a traditional antidiabetic treatment, in several models of
rat dyslipidaemia: a comparison with ciprofibrate. Thromb Res 1996;84(5):311-22.
50- Friedrich H, Schonert J. Tannin-producing substances in the leaves and fruits of the bilberry. Arch Pharm (Weinheim) 1973; 306:611-8.
51- Bissett NG. Herbal drugs and phytopharmaceuticals. Stuttgart: MedPharm CRC Press, 1994:566.
52- Colombo D, Vescovini R. Controlled trial of anthocyanosides from Vaccinium myrtillus in primary dysmenorrhea. G Ital Ost Ginecol 1985;7:1033-1038l.
Bilberry anthocyanidins have demonstrated a variety of physiological effects. They may prevent angina episodes as exhibited by
the prevention of lactate dehydrogenase liberation from cardiac isoenzymes in vitro experiments (2). Retinal protection may be
aided by anthocyanidinic retinal phosphoglucomutase
and glucose-6-phosphatase inhibition (14). The anthocyanidins also stimulate prolonged capillary resistance, and are
vasoprotective, antiedematous, and vasodilative (15). They inhibit platelet aggregation and thrombus formation, interacting with
vascular prostaglandins(4). In one study, an injected proprietary
bilberry preparation altered the rhythmic changes in the diameter of mouse cheek pouch and terminal arterioles, which was
beneficial to microvascular blood flow and interstitial fluid formation (16). These findings, have largely employed animal or in vitro
conditions (17)
Ophthalmologic Disorders
The mechanisms of action behind bilberry’s beneficial effect on the eye are not completely understood. They include the ability to
improve oxygen and blood delivery to the eye and to scavenge free radicals that can disrupt collagen structures and contribute to
conditions such as cataracts and macular degeneration. In
addition, the anthocyanosides have an affinity for the pigmented epithelium (visual purple) area of the retina, the portion of the
retina responsible for vision and adjustments to light and dark. (18,19) Vision Improvement Bilberry extract’s visual enhancement
properties were first studied by French researchers on Royal Air Force pilots during World War II. Administration of bilberry extract
resulted in improved nighttime visual acuity, faster adjustment to darkness, and faster restoration of visual acuity after exposure to
glare. (20,21) Later studies confirmed this effect, (22,23) although a subsequent double-blind, placebocontrolled, crossover study
conducted on U.S. Navy SEAL personnel did not. Fifteen male subjects given 160 mg bilberry extract (standardized to 25-percent
anthocyanosides) three times daily for three weeks, showed no significant improvement in either night visual acuity or night
contrast sensitivity compared to placebo.(24) Conversely, studies of bilberry extract on individuals with retinitis igmentosa and
hemeralopia (inability to see distinctly in bright light) demonstrated a significant improvement in visual performance.(23.20) It may
be the most significant effects will be observed in those with impaired visual acuity.
Pharmacological properties
Glaucoma
Consumption of bilberry extracts may offer significant protection against the development of glaucoma due to its collagen-
enhancing and antioxidant properties. The reduced tensile strength and integrity of aging eye tissue may result in the increased
intraocular pressure and loss of peripheral vision seen in glaucoma. In one study, eight patients with glaucoma were given a
single oral dose of 200 mg Vaccinium myrtillus anthocyanosides and demonstrated improvement based on electroretinography.
(18) A collagen-stabilizing effect on the trabecular meshwork, facilitating aqueous outflow, may provide a potential mechanism.
Cataracts Bilberry anthocyanosides may offer therapeutic benefit in prevention of cataracts. Animal studies show diets high in
anthocyanoside flavonoids retard the development of cataracts in rats.(26,27) A clinical study, in which bilberry extract (180 mg
twice daily of a 25-percent anthocyanoside extract) was given with vitamin E, demonstrated arrested cataract formation in 48 of 50
patients with senile cortical
cataracts.(28) Diabetic Retinopathy In Europe, bilberry anthocyanoside extracts are recognized as highly effective in preventing
diabetic retinopathy, with several clinical studies supporting its use.(29,30) In a double-blind study, 14 patients with diabetic
and/or hypertensive retinopathy were supplemented with bilberry extract equivalent to 115 mg anthocyanosides daily (or placebo)
for one month. Significant improvements were observed in the ophthalmoscopic parameters of 11 subjects receiving bilberry, and
12 patients showed improvement in angiographic parameters.(31) Additional clinical studies of bilberry’s positive effects in treating
retinopathy have been conducted in Europe.
Vascular Disorders
Bilberry extracts improve microcirculation. Animal studies have shown it to be of benefit in decreasing vascular permeability and
improving vascular tone and blood flow. (30,32) Clinical trials in humans have yielded similar results. Fifteen patients with
polyneuritis due to peripheral vascular insufficiency were given 480 mg/day of bilberry extract and significant improvement was
noted in microcirculation. (33) In
another study, the same dosage of bilberry extract given to 47 patients with various venous diseases resulted in reduced capillary
flow as well as an elimination of microstagnation and blood stasis of the foot (34) A review of uncontrolled trials from 1979 to 1985
on a total of 568 patients with venous insufficiency of the lower limbs showed bilberry extract was effective in rapidly decreasing
symptomology and improving both venous microcirculation and lymph drainage.(35)
Diabetes Mellitus
Bilberry leaf decoctions have a long history of folk use as a hypoglycemic agent. Research demonstrates that oral administration
of bilberry leaf decoctions reduce hyperglycemia in dogs, even in the presence of concurrently injected glucose.(36,37)This effect
is attributed to the myrtillin anthocyanoside, apparently
the most active hypoglycemic component. (37) In addition, bilberry anthocyanosides enhance collagen integrity, stabilize capillary
permeability, and inhibit sorbitol accumulation, thus providing protection against vascular and neurological sequelae of diabetes.
Other Effects
Bilberry extracts have demonstrated anti-inflammatory properties in animals, and thus may be useful in the treatment of conditions
such as rheumatoid arthritis.(38) Additionally, women with dysmenorrhea were given bilberry extract (115 mg anthocyanosides per
day) for three days before and during menstruation. A
significant improvement in pelvic/lumbosacral pain, mammary tension, nausea, and lower-limb heaviness was noted.(52) Bilberry
extracts have also been shown to have strong antiplatelet aggregating activity in humans when given at doses of 480 mg daily for
30-60 days.(39) The antiulcer activity of one of bilberry’s
anthocyanosides has been demonstrated in various experimental models. Magistretti et al demonstrated that Bilberry extract
decreased the incidence and severity of numerous forms of experimentally induced ulcers in Sprague Dawley and Wistar rats.(40)
Another significant property of bilberry extracts is the capability to exert potent protective action on LDL particles during copper-
mediated oxidation. This was accomplished using only trace amounts of V. myrtillus extract (15 to 20 mcg/mL); therefore, the
extract may be even more potent than ascorbic acid in protecting LDL from oxidative stress.(41) Tannins are used medicinally as
astringents and to treat diarrhea4. When tannin concentrations exceed 10%, they may cause significant gastrointestinal distress;
amounts in bilberry are typically less than 10% (11,50). Bilberry’s tannin content probably accounts for its historical use in treating
diarrhea, oral ulcers and sore throats (51).
the prevention of lactate dehydrogenase liberation from cardiac isoenzymes in vitro experiments (2). Retinal protection may be
aided by anthocyanidinic retinal phosphoglucomutase
and glucose-6-phosphatase inhibition (14). The anthocyanidins also stimulate prolonged capillary resistance, and are
vasoprotective, antiedematous, and vasodilative (15). They inhibit platelet aggregation and thrombus formation, interacting with
vascular prostaglandins(4). In one study, an injected proprietary
bilberry preparation altered the rhythmic changes in the diameter of mouse cheek pouch and terminal arterioles, which was
beneficial to microvascular blood flow and interstitial fluid formation (16). These findings, have largely employed animal or in vitro
conditions (17)
Ophthalmologic Disorders
The mechanisms of action behind bilberry’s beneficial effect on the eye are not completely understood. They include the ability to
improve oxygen and blood delivery to the eye and to scavenge free radicals that can disrupt collagen structures and contribute to
conditions such as cataracts and macular degeneration. In
addition, the anthocyanosides have an affinity for the pigmented epithelium (visual purple) area of the retina, the portion of the
retina responsible for vision and adjustments to light and dark. (18,19) Vision Improvement Bilberry extract’s visual enhancement
properties were first studied by French researchers on Royal Air Force pilots during World War II. Administration of bilberry extract
resulted in improved nighttime visual acuity, faster adjustment to darkness, and faster restoration of visual acuity after exposure to
glare. (20,21) Later studies confirmed this effect, (22,23) although a subsequent double-blind, placebocontrolled, crossover study
conducted on U.S. Navy SEAL personnel did not. Fifteen male subjects given 160 mg bilberry extract (standardized to 25-percent
anthocyanosides) three times daily for three weeks, showed no significant improvement in either night visual acuity or night
contrast sensitivity compared to placebo.(24) Conversely, studies of bilberry extract on individuals with retinitis igmentosa and
hemeralopia (inability to see distinctly in bright light) demonstrated a significant improvement in visual performance.(23.20) It may
be the most significant effects will be observed in those with impaired visual acuity.
Pharmacological properties
Glaucoma
Consumption of bilberry extracts may offer significant protection against the development of glaucoma due to its collagen-
enhancing and antioxidant properties. The reduced tensile strength and integrity of aging eye tissue may result in the increased
intraocular pressure and loss of peripheral vision seen in glaucoma. In one study, eight patients with glaucoma were given a
single oral dose of 200 mg Vaccinium myrtillus anthocyanosides and demonstrated improvement based on electroretinography.
(18) A collagen-stabilizing effect on the trabecular meshwork, facilitating aqueous outflow, may provide a potential mechanism.
Cataracts Bilberry anthocyanosides may offer therapeutic benefit in prevention of cataracts. Animal studies show diets high in
anthocyanoside flavonoids retard the development of cataracts in rats.(26,27) A clinical study, in which bilberry extract (180 mg
twice daily of a 25-percent anthocyanoside extract) was given with vitamin E, demonstrated arrested cataract formation in 48 of 50
patients with senile cortical
cataracts.(28) Diabetic Retinopathy In Europe, bilberry anthocyanoside extracts are recognized as highly effective in preventing
diabetic retinopathy, with several clinical studies supporting its use.(29,30) In a double-blind study, 14 patients with diabetic
and/or hypertensive retinopathy were supplemented with bilberry extract equivalent to 115 mg anthocyanosides daily (or placebo)
for one month. Significant improvements were observed in the ophthalmoscopic parameters of 11 subjects receiving bilberry, and
12 patients showed improvement in angiographic parameters.(31) Additional clinical studies of bilberry’s positive effects in treating
retinopathy have been conducted in Europe.
Vascular Disorders
Bilberry extracts improve microcirculation. Animal studies have shown it to be of benefit in decreasing vascular permeability and
improving vascular tone and blood flow. (30,32) Clinical trials in humans have yielded similar results. Fifteen patients with
polyneuritis due to peripheral vascular insufficiency were given 480 mg/day of bilberry extract and significant improvement was
noted in microcirculation. (33) In
another study, the same dosage of bilberry extract given to 47 patients with various venous diseases resulted in reduced capillary
flow as well as an elimination of microstagnation and blood stasis of the foot (34) A review of uncontrolled trials from 1979 to 1985
on a total of 568 patients with venous insufficiency of the lower limbs showed bilberry extract was effective in rapidly decreasing
symptomology and improving both venous microcirculation and lymph drainage.(35)
Diabetes Mellitus
Bilberry leaf decoctions have a long history of folk use as a hypoglycemic agent. Research demonstrates that oral administration
of bilberry leaf decoctions reduce hyperglycemia in dogs, even in the presence of concurrently injected glucose.(36,37)This effect
is attributed to the myrtillin anthocyanoside, apparently
the most active hypoglycemic component. (37) In addition, bilberry anthocyanosides enhance collagen integrity, stabilize capillary
permeability, and inhibit sorbitol accumulation, thus providing protection against vascular and neurological sequelae of diabetes.
Other Effects
Bilberry extracts have demonstrated anti-inflammatory properties in animals, and thus may be useful in the treatment of conditions
such as rheumatoid arthritis.(38) Additionally, women with dysmenorrhea were given bilberry extract (115 mg anthocyanosides per
day) for three days before and during menstruation. A
significant improvement in pelvic/lumbosacral pain, mammary tension, nausea, and lower-limb heaviness was noted.(52) Bilberry
extracts have also been shown to have strong antiplatelet aggregating activity in humans when given at doses of 480 mg daily for
30-60 days.(39) The antiulcer activity of one of bilberry’s
anthocyanosides has been demonstrated in various experimental models. Magistretti et al demonstrated that Bilberry extract
decreased the incidence and severity of numerous forms of experimentally induced ulcers in Sprague Dawley and Wistar rats.(40)
Another significant property of bilberry extracts is the capability to exert potent protective action on LDL particles during copper-
mediated oxidation. This was accomplished using only trace amounts of V. myrtillus extract (15 to 20 mcg/mL); therefore, the
extract may be even more potent than ascorbic acid in protecting LDL from oxidative stress.(41) Tannins are used medicinally as
astringents and to treat diarrhea4. When tannin concentrations exceed 10%, they may cause significant gastrointestinal distress;
amounts in bilberry are typically less than 10% (11,50). Bilberry’s tannin content probably accounts for its historical use in treating
diarrhea, oral ulcers and sore throats (51).
