Photobucket

Thursday, February 26, 2009

Ginkgo biloba in Herbal Medicine

Overview:

Ginkgo (Ginkgo biloba) is one of the oldest living tree species and its leaves are among the most extensively studied botanicals in use today. Unlike many other medicinal herbs, ginkgo leaves are not frequently used in their crude state, but rather, in the form of a concentrated, standardized ginkgo biloba extract (GBE). In Europe and the United States, ginkgo supplements are among the best-selling herbal medications and it consistently ranks as a top medicine prescribed in France and Germany.

Ginkgo has been used in traditional medicine to treat circulatory disorders and enhance memory. Scientific studies throughout the years lend support to these traditional uses. Emerging evidence suggests that GBE may be particularly effective in treating ailments associated with decreased blood flow to the brain, particularly in elderly individuals. Laboratory studies have shown that GBE improves blood circulation by dilating blood vessels and reducing the stickiness of blood platelets.

Ginkgo leaves also contain two types of chemicals (flavonoids and terpenoids) believed to have potent antioxidant properties. Antioxidants are substances that scavenge free radicals -- damaging compounds in the body that alter cell membranes, tamper with DNA, and even cause cell death. Free radicals occur naturally in the body, but environmental toxins (including ultraviolet light, radiation, cigarette smoking, and air pollution) can also increase the number of these damaging particles. Free radicals are believed to contribute to a number of health problems including heart disease and cancer as well as Alzheimer's disease and other forms of dementia. Antioxidants such as those found in ginkgo can neutralize free radicals and may reduce or even help prevent some of the damage they cause.

Plant Description:

Ginkgo biloba is the oldest living tree species. A single tree can live as long as 1,000 years and grow to a height of 120 feet. It has short branches with fan-shaped leaves and inedible fruits that produce a strong odor. The fruit contains an inner seed, and there has been a report of a human poisoning from ingesting the seed.

Although Chinese herbal medicine has used both the ginkgo leaf and seed for centuries, modern research has focused on the standardized Ginkgo biloba extract (GBE), which is prepared from the dried green leaves. This standardized extract is highly concentrated and seems to be clinically more effective in treating health problems (particularly circulatory ailments) than the non-standardized leaf alone.

What's It Made Of?:

More than 40 components isolated from the ginkgo tree have been identified, but only two are believed to be responsible for the herb's beneficial effects in humans -- flavonoids and terpenoids. Flavonoids (such as quercetin and rutin) have potent antioxidant effects. Laboratory and animal studies have shown that flavonoids protect the nerves, heart muscle, blood vessels, and retina from damage. Terpenoids (such as ginkgolides) improve blood flow by dilating blood vessels and reducing the stickiness of platelets.

Medicinal Uses and Indications:

Based on studies conducted in laboratories, animals, and humans, many health care professionals may recommend ginkgo for the following health problems:

Dementia and Alzheimer's Disease

Ginkgo is widely used in Europe for treating dementia. It use is primarily due to its ability to improve blood flow to the brain and because of its antioxidant properties. The evidence that ginkgo may improve thinking, learning, and memory in people with Alzheimer's disease (AD) has been highly promising.

Clinical studies suggest that ginkgo may provide the following benefits for people with AD:

  • Improvement in thinking, learning, and memory (cognitive function)
  • Improvement in activities of daily living
  • Improvement in social behavior
  • Fewer feelings of depression

Several studies have found that ginkgo may be as effective as leading AD medications in delaying the symptoms of dementia in people with this debilitating condition. In addition, ginkgo is sometimes used preventively because it may delay the onset of AD in someone who is at risk for this type of dementia (for example, family history).

Eye problems

The flavonoids found in ginkgo may help halt or lessen some retinal problems (that is, problems to the back part of the eye). Retinal damage has a number of potential causes, including diabetes and macular degeneration. Macular degeneration (often called age-related macular degeneration or ARMD) is a progressive, degenerative eye disease that tends to affect older adults and is the number one cause of blindness in the United States. Studies suggest that gingko may help preserve vision in those with ARMD.

Intermittent Claudication

Because ginkgo is reported to improve blood flow, this herb has been studied in people with intermittent claudication (pain caused by inadequate blood flow to the legs). People with intermittent claudication have difficulty walking without suffering extreme pain. An analysis of eight published studies revealed that people taking ginkgo tend to walk roughly 34 meters farther than those taking placebo. In fact, ginkgo has been shown to be as effective as a leading medication in improving pain-free walking distance. However, regular walking exercises are more beneficial than ginkgo in improving walking distance.

Memory Impairment

Ginkgo is widely touted as a "brain herb." Researchers recently reviewed all of the high-quality published studies on ginkgo and mild memory impairment (in other words, people without Alzheimer's or other form of dementia), and concluded that ginkgo was significantly more effective than placebo in enhancing memory and cognitive function. Ginkgo is commonly added to nutrition bars, soft drinks, and fruit smoothies to boost memory and enhance cognitive performance, although there is debate over whether the small amounts of ginkgo found in these products are effective.

Tinnitus

Given that nerve damage and certain blood vessel disorders can lead to tinnitus (the perception of ringing, hissing, or other sound in the ears or head when no external sound is present), some researchers have investigated whether ginkgo relieves symptoms of this hearing disorder. Although the quality of most studies was poor, the reviewers concluded that ginkgo moderately relieves the loudness of the tinnitus sound. However, a well-designed study including 1,121 people with tinnitus found that ginkgo (given 3 times daily for 3 months) was no more effective than placebo in relieving symptoms of tinnitus. Given these conflicting findings, the therapeutic value of ginkgo for tinnitus remains uncertain. In general, tinnitus is a very difficult problem to treat.

Other uses

In addition to these health problems, health care professionals may also recommend ginkgo for a variety of other ailments, including altitude sickness, asthma, depression, disorientation, headaches, high blood pressure, erectile dysfunction, and vertigo.

  • A clinical study found that a standardized ginkgo extract may reduce the side effects of menopause as well as risk factors for osteoporosis and cardiovascular disease. Women are becoming more reluctant to use pharmaceutical hormone replacement therapy (HRT) due to its undesirable side effects, such as irregular bleeding and an increased risk of breast cancer. Several human studies have reported that a standardized ginkgo extract has estrogenic activity and might be suitable as an alternative to HRT.
  • A standardized ginkgo extract was reported to significantly improve functional measures (such as coordination, energy level, strength, mental performance, mood, and sensation) in 22 individuals with multiple sclerosis (MS).

Available Forms:

  • Standardized extracts containing 24 - 32% flavonoids (also known as flavone glycosides or heterosides) and 6 - 12% terpenoids (triterpene lactones)
  • Capsules
  • Tablets
  • Liquid extracts (tinctures, fluid extracts, glycerites)
  • Dried leaf for teas

How to Take It:

Pediatric

Ginkgo is not routinely used in children by the medical community. Therefore, it is not currently recommended to use ginkgo in children under 12.

Adult

Initial results often take 4 - 6 weeks, but should continue to accumulate beyond that period.

Memory impairment and cardiovascular function: Generally, 120 mg daily in divided doses, standardized to contain 24 - 32% flavone glycosides (flavonoids or heterosides) and 6 - 12% triterpene lactones (terpenoids). If more serious dementia or Alzheimer's disease is present, up to 240 mg daily, in 2 or 3 divided doses, may be necessary.

Precautions:

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain components that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider qualified in the field of botanical medicine.

GBE is considered to be safe, and side effects are rare. In a few cases, gastrointestinal upset, headaches, skin reactions, and dizziness were reported.

Because gingko decreases platelet aggregation (stickiness), there is some concern that it may increase risk of intracranial (brain) hemorrhage. In fact, there have been several reports of bleeding complications associated with ginkgo use. However, it is not clear whether ginkgo or another factor (such as the combination of ginkgo and blood-thinning medications including aspirin and non-steroidal anti-inflammatory agents such as ibuprofen) caused the bleeding complications. One human study found that a ginkgo extract significantly prolonged bleeding time when given along with cilostazol (Pletal), a commonly used medication that inhibits platelet aggregation.

Pregnant and breastfeeding women should avoid using ginkgo preparations. In addition, ginkgo use should be discontinued at least 36 hours prior to surgery due to the risk of bleeding complications.

Do not ingest Ginkgo biloba fruit or seed.

Possible Interactions:

Ginkgo may alter the metabolism and effectiveness of some prescription and non-prescription medications. If you are being treated with any of the following medications, you should not use ginkgo without first talking to your health care provider:

Anticonvulsant medications -- High doses of ginkgo could decrease the effectiveness of anticonvulsant therapy, such as carbamazepine (Tegretol) or valproic acid (Depakote), in controlling seizures.

Antidepressant medications -- Taking ginkgo along with selective serotonin reuptake inhibitor (SSRIs) antidepressants -- including fluoxetin (Prozac), sertraline (Zoloft), paroxetine (Paxil), and escitalopram (Lexapro) -- may cause serotonin syndrome. This condition is characterized by rigidity, tachycardia (fast heart rate), hyperthermia (low body temperature), restlessness, and diaphoresis (sweating). Ginkgo may enhance the effects (both good and bad) of antidepressant medications known as MAOIs, such as phenelzine (Nardil).

Antihypertensive medications -- Ginkgo may decrease blood pressure, so use of ginkgo along with prescription antihypertensive medications should be monitored by a health care provider. There has been a report of an interaction between ginkgo and nifedipine (Procardia), a calcium channel blocking drug used for blood pressure and arrhythmias.

Blood-thinning medications -- Ginkgo has blood-thinning properties and therefore should not be used if you are taking anticoagulant (blood-thinning) medications, such as aspirin, clopidogrel (Plavix), dipyridamole (Persantine), heparin, ticlopidine (Ticlid), or warfarin (Coumadin). There has been bleeding in the brain reported when using a ginkgo product and ibuprofen (Advil), a non-steroidal antiinflammatory drug (NSAID).

Blood sugar lowering medications -- Ginkgo was reported to increase insulin levels in healthy subjects and to decrease insulin levels in diabetic patients. Use ginkgo supplements under the supervision of a health care provider if you are diabetic and taking insulin or oral blood sugar lowering drugs.

Cylosporine -- Ginkgo biloba may help protect the cells of the body during treatment with the immunosuppressive (decreases immunity) drug cyclosporine.

Thiazide diuretics -- Although there has been one literature report of increased blood pressure associated with the use of ginkgo during treatment with thiazide diuretics, this interaction has not been verified by clinical trials. Nevertheless, you should consult with your health care provider before using ginkgo if you are taking thiazide diuretics.

Trazodone -- There has been a report of an adverse interaction between ginkgo and trazodone (Desyrel), an antidepressant medication that resulted in an elderly patient going into a coma.

Alternative Names:

Fossil tree; Kew tree; Maiden hair tree

  • Reviewed last on: 1/26/2007
  • Ernest B. Hawkins, MS, BSPharm, RPh, Health Education Resources; and Steven D. Ehrlich, N.M.D., private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.

Supporting Research

Adams LL, Gatchel RJ, Gentry C. Complementary and alternative medicine: applications and implications for cognitive functioning in elderly populations. Altern Ther HealthMed. 2001;7(2):52-61.

Aruna D, Naidu MU.Pharmacodynamic interaction studies of Ginkgo biloba with cilostazol and clopidogrel in healthy human subjects. Br J Clin Pharmacol. 2006 Sep 29; [Epub ahead of print].

Ashton, A. K., Ahrens, K., Gupta, S., and Masand, P. S. Antidepressant-induced sexual dysfunction and Ginkgo Biloba. Am J Psychiatry. 2000;157(5):836-837.

Barrett B, Kiefer D, Rabago D. Assessing the risks and benefits of herbal medicine: an overview of scientific evidence. Altern Ther Health Med. 1999;5(4):40-49.

Barth SA, Inselmann G, Engemann R, Heidemann HT. Influences of Ginkgo biloba on cyclosporin A induced lipid peroxidation in human liver microsomes in comparison to vitamin E, glutathione and N-Acetylcysteine. Biochem Pharmacol. 1991;41(10):1521-1526.

Benjamin J, Muir T, Briggs K, Pentland B. A case of cerebral haemorrhage-can Ginkgo biloba be implicated? Postgrad Med J. 2001;77(904):112-113.

Birks, J., Grimley, E. V., and Van Dongen, M. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database.Syst Rev. 2003;(4):CD003120.

Blumenthal M, Busse WR, Goldberg A, et al., ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, Mass: Integrative Medicine Communications; 1998.

Bridi, R., Crossetti, F. P., Steffen, V. M., and Henriques, A. T. The antioxidant activity of standardized extract of Ginkgo biloba (EGb 761) in rats. Phytother Res 2001;15(5):449-451.

Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, Ore: Eclectic Medical; 1998:76-77.

Cheuvront, S. N. and Carter, R., III. Ginkgo and memory. JAMA. 2-5-2003;289(5):547-548.

Christen Y. Oxidative stress and Alzheimer's disease. Am J Clin Nutr. 2000;71(suppl):621S-629S.

Cieza, A., Maier, P., and Poppel, E. Effects of Ginkgo biloba on mental functioning in healthy volunteers. Arch Med Res. 2003;34(5):373-381.

Clostre F. Ginkgo biloba extract (EGb 761). State of knowledge in the dawn of the year 2000. Ann Pharm Fr. 1999;57(Suppl 1):1S8-88.

Cupp MJ. Herbal remedies: adverse effects and drug interactions. Am Fam Physician. 1999;59(5):1239–1244.

Davydov L and Stirling AL. Stevens-Johnson syndrome with Ginkgo biloba. J Herbal Pharmacother. 2001;1(3):65-69.

Diamond BJ, Shiflett SC, Feiwel N, et al. Ginkgo biloba extract: mechanisms and clinical indications. Arch Phys Med Rehabil. 2000;81:669-678.

Drew S, Davies E. Effectiveness of Ginkgo biloba in treating tinnitus: double blind, placebo controlled trial. BMJ. 2001;322(7278):73.

Engelsen, J., Nielsen, J. D., and Hansen, K. F. [Effect of Coenzyme Q10 and Ginkgo biloba on warfarin dosage in patients on long-term warfarin treatment. A randomized, double-blind, placebo-controlled cross-over trial]. Ugeskr.Laeger. 4-28-2003;165(18):1868-1871.

Ernst E. The risk-benefit profile of commonly used herbal therapies: ginkgo, St. John's wort, ginseng, echinacea, saw palmetto, and kava. Ann Intern Med. 2002;136:42-53.

Ernst E, Pittler MH. Ginkgo biloba for dementia: a systematic review of double-blind, placebo-controlled trials. Clin Drug Invest. 1999;17:301-308.

Ernst E, Stevinson C. Ginkgo biloba for tinnitus: a review. Clin Otolaryngol. 1999;24(3):164-167.

Fong, K. C. and Kinnear, P. E. Retrobulbar haemorrhage associated with chronic Gingko biloba ingestion. Postgrad.Med.J. 2003;79(935):531-532.

Galluzzi S, Zanetti O, Binetti G, Trabucchi M, Frisoni GB. Coma in a patient with Alzheimer's disease taking low dose trazodone and Ginkgo biloba. J Neurol Neurosurg Psychiatry. 2000;68:679-683.

Hartley, D. E., Elsabagh, S., and File, S. E. Gincosan (a combination of Ginkgo biloba and Panax ginseng): the effects on mood and cognition of 6 and 12 weeks' treatment in post-menopausal women. Nutr Neurosci. 2004;7(5-6):325-333.

Hilton, M. and Stuart, E. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev. 2004;(2):CD003852.

Horsch, S. and Walther, C. Ginkgo biloba special extract EGb 761 in the treatment of peripheral arterial occlusive disease (PAOD)--a review based on randomized, controlled studies. Int.J Clin Pharmacol Ther. 2004;42(2):63-72.

Huang, S. Y., Jeng, C., Kao, S. C., Yu, J. J., and Liu, D. Z. Improved haemorrheological properties by Ginkgo biloba extract (Egb 761) in type 2 diabetes mellitus complicated with retinopathy. Clin.Nutr. 2004;23(4):615-621.

Johnson SK, Diamond BJ, Rausch S, Kaufman M, Shiflett SC, Graves L. The effect of Ginkgo biloba on functional measures in multiple sclerosis: a pilot randomized controlled trial. Explore (NY). 2006;2(1):19-24.

Kidd PM. A review of nutrients and botanicals in the integrative management of cognitive dysfunction. Alt Med Rev. 1999;4(3):144-161.

Kampman, K., Majewska, M. D., Tourian, K., et al., A pilot trial of piracetam and ginkgo biloba for the treatment of cocaine dependence. Addict Behav. 2003;28(3):437-448.

Kenney C, Norman M, Jacobson M, and et al. A double-blind, placebo-controlled, modified crossover pilot study of the effects of Ginkgo biloba on cognitive and functional abilities in multiple sclerosis. American Academy of Neurology 54th Annual Meeting. April 13-20 2002;P06.081.

Kim YS, Pyo MK, Park KM, et al. Antiplatelet and antithrombotic effects of a combination of ticlopidine and Ginkgo biloba ext (EGb 761). Thromb Res. 1998;91:33-38.

Kleijnen J, Knipschild P. Ginkgo biloba for cerebral insufficiency. [Review]. Br J Clin Pharmacol. 1992;34(4):352-358.

Kohler, S., Funk, P., and Kieser, M. Influence of a 7-day treatment with Ginkgo biloba special extract EGb 761 on bleeding time and coagulation: a randomized, placebo-controlled, double-blind study in healthy volunteers. Blood Coagul.Fibrinolysis. 2004;15(4):303-309.

LaValle JB, Krinsky DL, Hawkins EB, et al. Natural Therapeutics Pocket Guide. Hudson, OH: LexiComp; 2000:441-442.

Le Bars PL, Katz MM, Berman N, Itil TM, Freedman AM, Schatzberg AF. A placebo-controlled, double-blind, randomized trial of an extract of Ginkgo biloba for dementia. JAMA. 1997;278:1327–1332.

Le Bars PL, Kieser M, Itil KZ. A 26-week analysis of a double-blind, placebo-controlled trial of the Ginkgo biloba extract EGb761 in dementia. Dement Geriatr Cogn Disord. 2000;11:230-237.

Manocha A, Pillai KK, Husain SZ. Influence of Ginkgo biloba on the effect of anticonvulsants. Indian J Pharmacol. 1996;28:84-87.

Mantle D, Pickering AT, Perry AK. Medicinal plant extracts for the treatment of dementia: a review of their pharmacology, efficacy and tolerability. CNS Drugs. 2000;13:201-213.

Mashour NH, Lin GI, Frishman WH. Herbal medicine for the treatment of cardiovascular disease. Arch Intern Med. 1998;158(9):2225–2234.

Matthews MK. Association of Ginkgo biloba with intracerebral hemorrhage [letter]. Neurol. 1998;50(6):1933-1934.

Mauro, V. F., Mauro, L. S., Kleshinski, J. F., Khuder, S. A., Wang, Y., and Erhardt, P. W. Impact of ginkgo biloba on the pharmacokinetics of digoxin. Am.J Ther 2003;10(4):247-251.

Mazza M, Capuano A, Bria P, Mazza S. Ginkgo biloba and donepezil: a comparison in the treatment of Alzheimer's dementia in a randomized placebo-controlled double-blind study. Eur J Neurol. 2006;13(9):981-5.

Meisel, C., Johne, A., and Roots, I. Fatal intracerebral mass bleeding associated with Ginkgo biloba and ibuprofen. Atherosclerosis. 2003;167(2):367.

Miller LC. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med. 1998;158(9):2200–2211.

Mix JA, Crews WD. An examination of the efficacy of Ginkgo biloba extract Egb 761 on the neuropsychiatric functioning of cognitively intact older adults. J Alt Comp Med. 000;6(3):219-229.

Moher D, Pham B, Ausejo M, Saenz A, Hood S, Barber GG. Pharmacological management of intermittent claudication: a meta-analysis of randomised trials. Drugs. 2000;59(5):1057-1070.

Nathan, P. J., Harrison, B. J., and Bartholomeusz, C. Ginkgo and memory. JAMA. 2-5-2003;289(5):546-548.

Oh SM, Chung KH. Antiestrogenic activities of Ginkgo biloba extracts. J Steroid Biochem Mol Biol. 2006;100(4-5):167-76.

Oken BS, Storzbach DM, Kaye JA. The efficacy of Ginkgo biloba on cognitive function in Alzheimer disease. Arch Neurol. 1998;55:1409-1415.

Persson, J., Bringlov, E., Nilsson, L. G., and Nyberg, L. The memory-enhancing effects of Ginseng and Ginkgo biloba in healthy volunteers. Psychopharmacology (Berl) 2004;172(4):430-434.

Peters H, Kieser M, Holscher U. Demonstration of the efficacy of Ginkgo biloba special extract Egb 761 on intermittent claudication a placebo-controlled, double-blind trial. Vasa. 1998;27:105–110.

Pittler MH, Ernst E. Ginkgo biloba extract for the treatment of intermittent claudication: a meta-analysis of randomized trials. Am J Med. 2000;108(4):276-281.

Rai GS, Shovlin C, Wesnes KA. A double-blind, placebo controlled study of Ginkgo biloba extract ('tanakan') in elderly outpatients with mild to moderate memory impairment. Curr Med Res Opin 1991;12(6):350-355.

Rosenblatt M, Mindel J. Spontaneous hyphema associated with ingestion of Ginkgo biloba extract. N Engl J Med. 1997;336:1108.

Rowin J, Lewis SL. Spontaneous bilateral subdural hematomas associated with chronic ginkgo. Neurol. 1996;46:1775–1776.

Schneider LS, DeKosky ST, Farlow MR, Tariot PN, Hoerr R, Kieser M. A randomized, double-blind, placebo-controlled trial of two doses of Ginkgo biloba extract in dementia of the Alzheimer's type. Curr Alzheimer Res. 2005;2(5):541-51.

Sikora R, Sohn M, Deutz F-J, et al. Ginkgo biloba extract in the therapy of erectile dysfunction. J Urol. 1989;141:188A.

Trick, L., Boyle, J., and Hindmarch, I. The effects of Ginkgo biloba extract (LI 1370) supplementation and discontinuation on activities of daily living and mood in free living older volunteers. Phytother Res. 2004;18(7):531-537.

Van Dongen, M., van Rossum, E., Kessels, A., Sielhorst, H., and Knipschild, P. Ginkgo for elderly people with dementia and age-associated memory impairment: a randomized clinical trial. J Clin Epidemiol. 2003;56(4):367-376.

Vellas, B., and Grandjean, H. Association of Alzheimer's disease onset with ginkgo biloba and other symptomatic cognitive treatments in a population of women aged 75 years and older from the EPIDOS study. J Gerontol A Biol.Sci.Med Sci. 2003;58(4):372-377.

Source - http://www.umm.edu

Organic Ginkgo Biloba

No comments:

Post a Comment