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Ginkgo Biloba

Ginkgo biloba

Description

Ginkgo biloba, known as the maidenhair tree, is one of the oldest trees on Earth, once part of the flora of the Mesozoic period. The ginkgo tree is the only surviving species of the Ginkgoaceae family. This ancient deciduous tree may live for thousands of years. Ginkgo is indigenous to China, Japan, and Korea, but also thrived in North America and Europe prior to the Ice Age. This drastic climate change destroyed the wild ginkgo tree throughout much of the world. In China, ginkgo was cultivated in temple gardens as a sacred tree known as bai gou, thus assuring its survival there for more than 200 million years. Ginkgo fossils found from the Permian period are identical to the living tree, which is sometimes called a living fossil.

Ginkgo trees may grow to 122 ft (37.2 m) tall and measure 4 ft (1.2 m) in girth. The female trees have a somewhat pointed shape at the top, like a pyramid. The male trees are broader at the crown. The bark of the ornamental ginkgo tree is rough and fissured and may be ash to dark-brown in color. Distinctive, fan-shaped leaves with long stalks emerge from a sheath on the stem. Leaves are bright green in spring and summer, and turn to golden yellow in the fall. Ginkgo trees may take as long as 30 years to flower. Ginkgo is dioecious, with male and female flowers blooming on separate trees. Blossoms grow singly from the axils of the leaf. The female flowers appear at the end of a leafless branch. The yellow, plumshaped fruits develop an unpleasant scent as they ripen. They contain an edible inner seed that is available in Asian country marketplaces. Ginkgo's longevity may be due, in part, to its remarkable resistance to disease, pollution, and insect damage. Ginkgo trees are part of the landscape plan in many urban areas throughout the world. Millions of ginkgo trees, grown for harvest of the medicinal leaves, are raised on plantations in the United States, France, South Korea, and Japan, and are exported to Europe for pharmaceutical processing.

General use

Ginkgo leaves, fresh or dry, and seeds, separated from the outer layer of the fruit, are used medicinally. Ginkgo has remarkable healing virtues that have been recorded as far back as 2800 b.c. in the oldest Chinese materia medica. Ginkgo seeds were traditionally served to guests along with alcohol drinks in Japan. An enzyme present in the ginkgo seed has been shown in clinical research to speed up alcohol metabolism in the body, underscoring the wisdom of this folk custom. The leaf extract has been used in Asia for thousands of years to treat allergies, asthma , and bronchitis . It is also valued in Chinese medicine as a heart tonic, helpful in the treatment of cardiac arrhythmia. Ginkgo was first introduced to Europe in 1730, and to North America in 1784 where it was planted as an exotic garden ornamental near Philadelphia. Ginkgo medicinal extracts are the primary prescription medicines used in France and Germany.

Ginkgo acts to increase blood flow throughout the body, particularly cerebral blood flow. It acts as a circulatory system tonic, stimulating greater tone in the venous system. The herb is a useful and proven remedy for numerous diseases caused by restricted blood flow. European physicians prescribe the extract for treatment of Raynaud's disease, a condition of impaired circulation to the fingers. It is also recommended to treat intermittent claudication, a circulatory condition that results in painful cramping of the calf muscles in the leg that impairs the ability to walk. German herbalists recommend ingesting the extract for treatment of leg ulcers, and large doses are used to treat varicose veins . Ginkgo is widely recommended in Europe for the treatment of stroke . The dried leaf extract may also act to prevent hemmorrhagic stroke by strengthening the blood capillaries throughout the body. In studies of patients with atherosclerotic clogging of the penile artery, long-term therapy with ginkgo extract has provided significant improvement in erectile function. Ginkgo extract also acts to eliminate damaging free radicals in the body, and has been shown to be effective in treatment of premenstrual syndrome , relieving tender or painful breasts.

Ginkgo extract is believed to benefit the elderly. This ancient herb is believed by some to enhance oxygen utilization and thus improve memory, concentration, and other mental faculties. In 2002, studies suggested that although gingko does have positive effects on dementia , its effects on age-related memory loss and tinnitus (ringing in the ears) are not scientifically proven. The herbal extract has also been shown to improve long-distance vision and may reverse damage to the retina of the eye. Studies have also demonstrated its value in the treatment of depression in elderly persons. The ginkgo extract may provide relief for persons with headache , sinusitis, and vertigo.

The active constituents in the ginkgo tree, known as ginkgolides, interfere with a blood protein known as the platelet activating factor, or PAF. Other phytochemicals in ginkgo include flavonoids, bioflavonoids , proanthocyanidins, trilactonic diterpenes (including the ginkgolides A, B, C, and M), and bilabolide, a trilactonic sesquiterpene. The therapeutic effects of this herb have not been attributed to a single chemical constituent; rather, the medicinal benefits are due to the synergy between the various chemical constituents. The standardized extract of ginkgo must be taken consistently to be effective. A period of at least 12 weeks of use may be required before the beneficial results are evident.

Preparations

Ginkgo's active principles are diluted in the leaves. The herb must be processed to extract the active phytochemicals before it is medicinally useful. It would take an estimated 50 fresh ginkgo leaves to yield one standard dose of the extract. Dry extracts of the leaf, standardized to a potency of 24% flavone glycosides and 6% terpenes, are commercially available. A standard dose is 40 mg, three times daily, though dosages as high as 240 mg daily are sometimes indicated.

Ginkgo extracts are widely used in Europe where they are sold in prescription form or over the counter as an approved drug. This is not the case in the United States, where ginkgo extract is sold as a food supplement in tablet and capsule form.

Precautions

Ginkgo is generally safe and non-toxic in therapeutic dosages. Exceeding a daily dose of 240 mg of the dried extract may result in restlessness, diarrhea , and mild gastrointestinal disorders. Those on anticoagulants should have their doctor adjust their dose or should avoid ginkgo

in order to avoid over-thinning their blood and hemorrhaging. Ginkgo should be avoided two days before and one to two weeks after surgery to avoid bleeding complications. Pregnant women should avoid ginkgo supplements because scientists have discovered a compound called colchicine in the placental blood of women who took ginkgo biloba. A 2002 report cautioned that the compound could cause problems for the growing fetus.

In 2002, a case of ginkgo seed poisoning was reported in a toddler in Japan, but she had ingested 50 or more pieces of roasted ginkgo seeds. She experienced severe vomiting and seizures.

Side effects

Severe allergic skin reactions, similar to those caused by poison ivy, have been reported after contact with the fruit pulp of ginkgo. Eating even a small amount of the fruit has caused severe gastrointestinal irritation in some persons. People with persistent headaches should stop taking ginkgo. Some patients on medications for nervous system disease should avoid ginkgo. It can interact with some other medicines, but clinical information is still emerging.

Interactions

The chemically active ginkgolides present in the extract, specifically the ginkgolide B component, act to reduce the clotting time of blood and may interact with antithrombotic medicines, including aspirin.

Resources

BOOKS

Duke, James A., Ph.D. The Green Pharmacy. Emmaus, PA: Rodale Press, 1997.

Elias, Jason, and Shelagh Ryan Masline. The A to Z Guide to Healing Herbal Remedies. New York: Lynn Sonberg Book Associates, 1996.

Murray, Michael T. The Healing Power of Herbs. 2nd ed. Roseville, CA: Prima Publications, Inc., 1995.

Ody, Penelope. The Complete Medicinal Herbal. New York: DK Publishing, Inc., 1993.

PDR for Herbal Medicines. Montvale, NJ: Medical Economics Company, 1998.

Prevention's 200 Herbal Remedies. Emmaus, PA: Rodale Press, Inc., 1997.

Tyler, Varro E., Ph.D. Herbs Of Choice, The Therapeutic Use of Phytomedicinals. Binghamton, NY: Haworth Press, Inc., 1994.

Tyler, Varro E., Ph.D. The Honest Herbal. Binghamton, NY: Haworth Press, Inc., 1993.

Weiss, Gaea and Shandor. Growing & Using The Healing Herbs. New York: Random House Value Pub., Inc., 1992.

PERIODICALS

Ernst, Edzard."The Risk-Benefit Profile of Commonly Used Herbal Therapies: Ginkgo, St. John's Wort, Ginseng, Echinacea, Saw Palmetto, and Kava." Annals of Internal Medicine (January 1, 2002):42.

Roan, Shari."Prenatal: Forget Ginkgo Biloba. (Small Packages)." Fit Pregnancy (February March 2002):34.

Kajiyama, Yo, Kenichi Fujii, Hajime Takeuchi, Yutaka Manabe."Ginkgo Seed Poisoning." Pediatrics (February 2002):325.

Clare Hanrahan

Teresa G. Odle

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Ginkgo Biloba

Ginkgo Biloba

Definition

Ginkgo biloba, known as the maidenhair tree, is one of the oldest trees on Earth, once part of the flora of the Mesozoic period. The ginkgo tree is the only surviving species of the Ginkgoaceae family. This ancient deciduous tree may live for thousands of years. Ginkgo is indigenous to China, Japan, and Korea, but also thrived in North America and Europe prior to the Ice Age. This drastic climate change destroyed the wild ginkgo tree throughout much of the world. In China, ginkgo was cultivated in temple gardens as a sacred tree known as bai gou, thus assuring its survival there for over 200 million years. Ginkgo fossils found from the Permian period are identical to the living tree, which is sometimes called a living fossil.

Description

Ginkgo trees may grow to 122 ft (37.2 m) tall and measure 4 ft (1.2 m) in girth. The female trees have a somewhat pointed shape at the top, like a pyramid. The male trees are broader at the crown. The bark of the ornamental ginkgo tree is rough and fissured and may be an ash to dark-brown in color. Distinctive, fan-shaped leaves with long stalks emerge from a sheath on the stem. Leaves are bright green in spring and summer, and turn to golden yellow in the fall. Ginkgo trees may take as long as 30 years to flower. Ginkgo is dioecious, with male and female flowers blooming on separate trees. Blossoms grow singly from the axils of the leaf. The female flowers appear at the end of a leafless branch. The yellow, plum-shaped fruits develop an unpleasant scent as they ripen. They contain an edible inner seed that is available in Asian country marketplaces. Ginkgo's longevity may be due, in part, to its remarkable resistance to disease, pollution, and insect damage. Ginkgo trees are part of the landscape plan in many urban areas throughout the world. Millions of ginkgo trees, grown for harvest of the medicinal leaves, are raised on plantations in the United States, France, South Korea, and Japan, and are exported to Europe for pharmaceutical processing.

Purpose

Ginkgo leaves, fresh or dry, and seeds, separated from the outer layer of the fruit, are used medicinally. Ginkgo has remarkable healing virtues that have been recorded as far back as 2800 B.C. in the oldest Chinese materia medica. Ginkgo seeds were traditionally served to guests along with alcohol drinks in Japan. An enzyme present in the ginkgo seed has been shown in clinical research to speed up alcohol metabolism in the body, underscoring the wisdom of this folk custom. The leaf extract has been used in Asia for thousands of years to treat allergies, asthma, and bronchitis. It is also valued in Chinese medicine as a heart tonic, helpful in the treatment of cardiac arrhythmia. Ginkgo was first introduced to Europe in 1730, and to North America in 1784 where it was planted as an exotic garden ornamental near Philadelphia. Ginkgo medicinal extracts are the primary prescription medicines used in France and Germany.

Ginkgo acts to increase blood flow throughout the body, particularly cerebral blood flow. It acts as a circulatory system tonic, stimulating greater tone in the venous system. The herb is a useful and proven remedy for numerous diseases caused by restricted blood flow. European physicians prescribe the extract for treatment of Raynaud's disease, a condition of impaired circulation to the fingers. It is also recommended to treat intermittent claudication, a circulatory condition that results in painful cramping of the calf muscles in the leg and impairs the ability to walk. German herbalists recommend ingesting the extract for treatment of leg ulcers, and large doses are used to treat varicose veins. Ginkgo is widely recommended in Europe for the treatment of stroke. The dried leaf extract may also act to prevent hemmorrhagic stroke by strengthening the blood capillaries throughout the body. In studies of patients with atherosclerotic clogging of the penile artery, long-term therapy with ginkgo extract has provided significant improvement in erectile function. Ginkgo extract also acts to eliminate damaging free-radicals in the body, and has been shown to be effective in treatment of premenstrual syndrome, relieving tender or painful breasts.

Ginkgo extract has proven benefits to elderly persons. This ancient herb acts to enhance oxygen utilization and thus improves memory, concentration, and other mental faculties. The herbal extract is used to treat Alzheimer's disease. It has been shown to have beneficial effect on the hippocampus, an area of the brain affected by Alzheimer's disease. The herbal extract has also been shown to significantly improve long-distance vision and may reverse damage to the retina of the eye. Studies have also confirmed its value in the treatment of depression in elderly persons. The ginkgo extract may provide relief for persons with headache, sinusitis, and vertigo. It may also help relieve chronic ringing in the ears known as tinnitus.

The active constituents in the ginkgo tree, known as ginkgolides, interfere with a blood protein known as the platelet activating factor, or PAF. Other phytochemicals in ginkgo include flavonoids, biflavonoides, proanthocyanidins, trilactonic diterpenes (including the ginkgolides A, B, C, and M), and bilabolide, a trilactonic sesquiterpene. The therapeutic effects of this herb have not been attributed to a single chemical constituent; rather, the medicinal benefits are due to the synergy between the various chemical constituents. The standardized extract of ginkgo must be taken consistently to be effective. A period of at least 12 weeks of use may be required before the beneficial results are evident.

Preparations

Ginkgo's active principles are dilute in the leaves. The herb must be processed to extract the active phytochemicals before it is medicinally useful. It would take an estimated 50 fresh ginkgo leaves to yield one standard dose of the extract. Dry extracts of the leaf, standardized to a potency of 24% flavone glycosides and 6% terpenes, are commercially available. A standard dose is 40 mg, three times daily, though dosages as high as 240 mg daily are sometimes indicated.

Ginkgo extracts are widely used in Europe where they are sold in prescription form or over the counter as an approved drug. This is not the case in the United States, where ginkgo extract is sold as a food supplement in tablet and capsule form.

Precautions

Ginkgo is generally safe and non-toxic in therapeutic dosages. Exceeding a daily dose of 240 mg of the dried extract may result in restlessness, diarrhea, and mild gastrointestinal disorders. Those on anticoagulants should have their doctor adjust their dose or should avoid ginkgo in order to avoid over-thinning their blood and hemorrhaging. Ginkgo should be avoided two days before and one to two weeks after surgery to avoid bleeding complications.

Side effects

Severe allergic skin reactions, similar to those caused by poison ivy, have been reported after contact with the fruit pulp of ginkgo. Eating even a small amount of the fruit has caused severe gastrointestinal irritation in some persons. People with persistent headaches should stop taking ginkgo. Some patients on medications for nervous system disease should avoid ginkgo. It can interact with some other medicines, but clinical information is still emerging.

Interactions

The chemically active ginkgolides present in the extract, specifically the ginkgolide B component, act to reduce the clotting time of blood and may interact with antithrombotic medicines, including aspirin.

Resources

BOOKS

PDR for Herbal Medicines. Montvale, NJ: Medical Economics Company, 1998.

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Ginkgo biloba

Ginkgo biloba

Definition

Ginkgo biloba is an herbal remedy that has been utilized for thousands of years in China and elsewhere. It is obtained from the leaves and seeds of a plant that is commonly known as the maiden hair tree, believed to be the oldest living species of tree.

Purpose

Ginkgo preparations have been used to treat such conditions as asthma, inflammation, dizziness, memory problems, and circulatory problems throughout the brain and body. As of 2002, research has been concentrating on the possibility that Ginkgo biloba may be a helpful adjunct therapy for memory deficits occurring in Alzheimer's disease . Ginkgo is also being explored as a possible treatment for impotence and other circulatory disorders.

Description

Recent research into how Ginkgo biloba affects memory suggests that Ginkgo improves blood flow to the brain by preventing blockages in small blood vessels. These blockages can occur when platelets (blood components that aid in clotting) clump together. Ginkgo seems to decrease platelet stickiness, thus preventing clumping.

The active ingredients of Ginkgo biloba appear to include flavone glycosides and terpene lactones. Flavone glycosides have antioxidant properties. They prevent damage to the cells in the brain by chemicals called free radicals. Terpene lactones improve memory by improving the uptake of the neurotransmitter component choline in the nerve synapses. Terpene lactones also help guard against blood clots within the brain, and may provide some protection against metabolic injury. Improved bloodflow throughout the brain seems to help preserve/improve memory.

Ginkgo biloba is available in a variety of forms, including extracts, capsules, and tinctures.

Recommended dosage

As with other herbal supplements, standardization issues sometimes make it difficult to verify the actual dose being administered. In general, efficacious preparations appear to contain at least 24% gingko flavone glycosides and 6% terpene lactones. This is the standardized extract that is commonly used in research about this remedy.

Adults may take between 120 and 240 mg of Ginkgo biloba daily, divided into two or three doses.

Precautions

Because of Ginkgo's effects on platelets, there has been some concern regarding interactions between Ginkgo biloba and anticoagulant medicines, such as warfarin (Coumadin) and aspirin. Studies so far have indicated that Ginkgo does decrease platelet function occasionally. For patients taking Ginkgo, their physician can monitor their platelet function. Rare case reports exist of patients experiencing hemmorhage (including cerebral) while taking Ginkgo.

Side effects

Most reports on Ginkgo biloba suggest that side effects are relatively rare. However, some people may experience stomach upset, including nausea and/or diarrhea. Others who have taken Ginkgo biloba report headache, dizziness, and weakness.

Interactions

Ginkgo biloba may interact with more medications than are listed below. People should notify their health care team of all medications and herbals they take.

To avoid the possibility of increased bleeding, Ginkgo biloba preparations should not be used by patients who are also taking blood thinners (anticoagulants), such as aspirin, warfarin (Coumadin), clopidogrel, dipyridamole, heparin, or ticlopidine.

Ginkgo preparations may interfere with the efficacy of anticonvulsants, such as carbamazepine and valproic acid .

Caution should be used when taking Ginkgo with thiazide diuretics or with the antidepressant, trazodone .

Resources

BOOKS

Blumenthal, Mark, and others, eds. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin: American Botanical Council, 1998.

PERIODICALS

Zink, Therese and Jody Chaffin. "Herbal 'Health' Products: What Family Physicians Need to Know." American Family Physician October 1, 1998.

Rosalyn Carson-DeWitt, M.D.

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"Ginkgo biloba." Gale Encyclopedia of Mental Disorders. . Encyclopedia.com. 15 Sep. 2018 <http://www.encyclopedia.com>.

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Ginkgo Biloba

Ginkgo Biloba

Definition

Purpose

Description

Recommended dosage

Precautions

Side effects

Interactions

Resources

Definition

Ginkgo biloba is an herbal remedy that has been utilized for thousands of years in China and elsewhere. It is obtained from the leaves and seeds of a plant that is commonly known as the maiden hair tree, believed to be the oldest living species of tree.

Purpose

Ginkgo preparations have been used to treat such conditions as asthma, inflammation, dizziness, memory problems, and circulatory problems throughout the brain and body. As of 2002, research has been concentrating on the possibility that Ginkgo biloba may be a helpful adjunct therapy for memory deficits occurring in Alzheimer’s disease. Ginkgo is also being explored as a possible treatment for impotence and other circulatory disorders.

Description

Recent research into how Ginkgo biloba affects memory suggests that Ginkgo improves blood flow to the brain by preventing blockages in small blood vessels. These blockages can occur when platelets (blood components that aid in clotting) clump together. Ginkgo seems to decrease platelet stickiness, thus preventing clumping.

The active ingredients of Ginkgo biloba appear to include flavone glycosides and terpene lactones. Flavone glycosides have antioxidant properties. They prevent damage to the cells in the brain by chemicals called free radicals. Terpene lactones improve memory by improving the uptake of the neurotransmitter component choline in the nerve synapses. Terpene lactones also help guard against blood clots within the brain, and may provide some protection against metabolic injury. Improved bloodflow throughout the brain seems to help preserve/improve memory.

Ginkgo biloba is available in a variety of forms, including extracts, capsules, and tinctures.

Recommended dosage

As with other herbal supplements, standardization issues sometimes make it difficult to verify the actual dose being administered. In general, efficacious preparations appear to contain at least 24% gingko flavone glycosides and 6% terpene lactones. This is the standardized extract that is commonly used in research about this remedy.

Adults may take between 120 mg and 240 mg of Ginkgo biloba daily, divided into two or three doses.

Precautions

Because of Ginkgo’s effects on platelets, there has been some concern regarding interactions between Ginkgo biloba and anticoagulant medicines, such as

KEY TERMS

Alzheimer’s disease —An incurable dementia marked by the loss of cognitive ability and memory over a period of 10-15 years. Usually affects elderly people.

Anticoagulant —A medication (such as warfarin, Coumadin, or Heparin) that decreases the blood’s clotting ability preventing the formation of new clots. Although anticoagulants will not dissolve existing clots, they can stop them from getting larger. These drugs are commonly called blood thinners.

Thiazide diuretic —Also called water pill, helps the body get rid of excess fluids. Examples include diuril, hydrodiuril, and microzide.

warfarin (Coumadin) and aspirin. Studies so far have indicated that Ginkgo does decrease platelet function occasionally. For patients taking Ginkgo, their physician can monitor their platelet function. Rare case reports exist of patients experiencing hemmorhage (including cerebral) while taking Ginkgo.

Side effects

Most reports on Ginkgo biloba suggest that side effects are relatively rare. However, some people may experience stomach upset, including nausea and/or diarrhea. Others who have taken Ginkgo biloba report headache, dizziness, and weakness.

Interactions

To avoid the possibility of increased bleeding, Ginkgo biloba preparations should not be used by patients who are also taking blood thinners (anticoagulants), such as aspirin, warfarin (Coumadin), clopidogrel, dipyridamole, heparin, or ticlopidine.

Ginkgo preparations may interfere with the efficacy of anticonvulsants, such as carbamazepine and valproic acid.

Caution should be used when taking Ginkgo with thiazide diuretics or with the antidepressant, trazodone.

Resources

BOOKS

Blumenthal, Mark, and others, eds. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin: American Botanical Council, 1998.

PERIODICALS

Zink, Therese, and Jody Chaffin. “Herbal ‘Health’ Products: What Family Physicians Need to Know.” American Family Physician (October 1, 1998).

Rosalyn Carson-DeWitt, MD

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"Ginkgo Biloba." The Gale Encyclopedia of Mental Health. . Retrieved September 15, 2018 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/ginkgo-biloba-1

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Ginkgo biloba

Ginkgo biloba

Definition

Purpose

Description

Precautions

Interactions

Complications

Parental concerns

Resources

Definition

Ginkgo biloba is an herbal dietary supplement made from the leaves of the tree Gingko biloba.

Purpose

Ginkgo biloba, sometimes called bai guo, has been used in Traditional Chinese Medicine (TCM) for about 5,000 years to treat memory loss, mood, nerve, circulatory and many other health problems. Ginkgo biloba often is combined with ginseng to boost memory, improve the quality of life, and increase a sense of well being. The effectiveness of some TCM uses of gingko, such as relieving pain caused by clogged arteries in the leg (claudication), treating Alzheimer’s disease, and improving blood flow to the brain have been evaluated in well-designed studies and are generally accepted by practitioners of conventional medicine. Many other TCM uses of gingko biloba are currently being investigated.

Description

Gingko biloba is the last existing member of an ancient family of trees. The fossil record shows that gingko trees existed 200 million years ago. Gingko biloba is native to China, Japan, and Korea. The tree was introduced to North America in the 1700s. Ginkgo trees grow to a height of 65–115 ft (20–35 m). They are extremely resistant to disease and insect damage and can live for several hundred years. Female trees produce bad-smelling fruit-like bodies the size of an apricot that contains seeds. Herbal practitioners sometimes use the seeds in treatment. The much cleaner male ginkgo is a popular tree for urban landscaping

The fan-shaped leaves of the ginkgo are used for medicinal purposes. About twenty different compounds have been identified in ginkgo leaves, but the medically active ingredients appear to be flavenoids and terpe-noids. Flavenoids are antioxidants that help lower the level of free radicals in the body. Terpenoids are thought

KEY TERMS

Alternative medicine— A system of healing that rejects conventional, pharmaceutical-based medicine and replaces it with the use of dietary supplements and therapies such as herbs, vitamins, minerals, massage, and cleansing diets. Alternative medicine includes well-established treatment systems such as homeopathy, Traditional Chinese Medicine, and Ayurvedic medicine, as well as more-recent, fad-driven treatments.

Alzheimer’s disease— An incurable disease of older individuals that results in the destruction of nerve cells in the brain and causes gradual loss of mental and physical functions.

Antioxidant— A molecule that prevents oxidation. In the body antioxidants attach to other molecules called free radicals and prevent the free radicals from causing damage to cell walls, DNA, and other parts of the cell.

Claudication— Tiredness and pain in the leg muscles that occur when walking and disappear with rest. The cause is inadequate supply of oxygen to the muscle usually caused by clogged blood vessels.

Complementary medicine— Includes many of the same treatments used in alternative medicine, but uses them to supplement conventional drug and therapy treatments, rather than to replace conventional medicine.

Conventional medicine— Mainstream or Western pharmaceutical-based medicine practiced by medical doctors, doctors of osteopathy, and other licensed health care professionals.

Dietary supplement— A product, such as a vitamin, mineral, herb, amino acid, or enzyme, that is intended to be consumed in addition to an individual’s diet with the expectation that it will improve health.

Free radical— An unstable, highly reactive molecule that occurs naturally as a result of cellular metabolism, but can be increased by environmental toxins, ultraviolet and nuclear radiation. Free radicals damage cellular DNA and are thought to play a role in aging, cancer, and other diseases. Free radicals can be neutralized by antioxidants.

Traditional Chinese Medicine (TCM)— An ancient system of medicine based on maintaining a balance in vital energy or qi that controls emotions, spiritual, and physical well being. Diseases and disorders result from imbalances in qi, and treatments such as massage, exercise, acupuncture, nutritional and herbal therapy is designed to restore balance and harmony to the body.

to protect nerves from damage, reduce inflammation, and decrease blood clotting

In the United States, Gingko biloba is cultivated and the leaves are harvested and dried, then often used to make a standardized extract that contains 24–25% flavenoids and 6% terpenoids. U. S. law does not require the standardization of dietary supplements, so consumers should read all labels carefully. Ginkgo biloba is often sold as capsules and tablets. Dry and liquid ginkgo extract is added to other herbal remedies as well as teas, energy or health bars, and similar products. An injectable form of ginkgo biloba extract that was available in Europe has been withdrawn from the market because of adverse side effects. Most well-designed studies have been done using a total of 80– 240 mg of 50:1 standardized extract divided into 2 or 3 doses daily and taken by mouth.

Regulation of ginkgo biloba sales

Ginkgo biloba is one of the top selling herbal remedies in the United States and is even more popular in Europe. Under the 1994 Dietary Supplement Health and Education Act (DSHEA), the sale of ginkgo biloba is regulated by the U.S. Food and Drug Administration (FDA) as a dietary supplement. At the time the act was passed, legislators felt because many dietary supplements such as ginkgo biloba come from natural sources and have been used for hundreds of years by practitioners of complementary and alternative medicine (CAM), supplements did not need to be regulated as rigorously as prescription and over-the-counter drugs used in conventional medicine.

The DSHEA regulates gingko biloba in the same way that food is regulated. Like food manufacturers, manufacturers of herbal products containing gingko biloba do not have to prove that they are either safe or effective before they can be sold to the public. This differs from conventional pharmaceutical drugs, which must undergo extensive human testing to prove their safety and effectiveness before they can be marketed. Also unlike conventional drugs, the label for a dietary supplement such as gingko biloba does not have to contain any statements about possible side effects. All herbal supplements sold in the United States must show the scientific name of the herb on the label.

Health claims

Gingko biloba is one of the most promising traditional herbs investigated by Western medicine. The National Center for Complementary and Alternative Medicine (NCCAM), a government organization within the National Institutes of Health, is sponsoring clinical trials to determine safety and effectiveness of gingko biloba as a treatment for more than a dozen diseases and disorders. Individuals interested in participating in a clinical trial at no charge can find a list of open trials at <//www.clinicaltrials.gov>.

Some health claims for gingko biloba have already been evaluated in large, well-controlled studies that satisfy the proof of safety and effectiveness demanded by conventional medicine. There is good evidence that gingko biloba can cause short-term improvement in mental function in people with Alzheimer’s disease. In a well-designed study, ginkgo biloba was as effective as the prescription drug done-pezil (Aricept) in slowing the development of dementia in people with mild to moderate Alzheimer’s. Ginkgo biloba has also been shown to be effective in improving blood flow to the brain and in treating certain other dementias. The effect of ginkgo biloba on memory in healthy young adults and in people with age-related memory impairment is inconsistent, but strong enough to continue to study the effects of the herb in these populations.

In other rigorous studies, ginkgo biloba has improved symptoms of claudication. Claudication is leg pain that occurs during walking when insufficient oxygen reaches the leg muscles. It is usually caused by blocked arteries in the leg. Ginkgo biloba’s ability to reduce blood clotting (“thin the blood”) is thought to account for improving symptoms in people with claudication. However, exercise and prescription medication were more effective in reducing leg pain due to claudication than ginkgo biloba alone. Ginkgo biloba has also been used, especially in Europe, to treat Ray-naud’s disease. Raynaud’s disease causes the extremities of the body to feel cold in response to stress or cool temperatures. During an attack of Raynaud’s disease, the blood vessels to the affected area narrow and blood flow is reduced.

Several health claims for ginkgo biloba center on treating disorders of the eye, including glaucoma, age-related macular degeneration, and type 2 diabetes-related retinopathy. Ginkgo appears to increase blood flow to the eye, but additional studies need to be done to evaluate its effectiveness in helping to treat these disorders.

The terpenoids in ginkgo biloba are thought to help prevent nerve damage. Because of this, ginkgo has been suggested as a treatment for tinnitus (ringing of the ears), multiple sclerosis, cochlear deafness, and Huntingdon’s disease. Results of studies so far are inconsistent, and additional research is needed to determine the usefulness of ginkgo in nerve disorders.

Some researchers have suggested that ginkgo bilobais useful in treating depression, seasonal affective disorder, premenstrual syndrome, altitude sickness, vertigo (dizziness), premenstrual syndrome (PMS), gastric cancer, side effects of anti-cancer drugs, and pulmonary interstitial fibrosis, as well as generally improving quality of live and sense of well being. Further studies need to be done to evaluate these health claims.

Precautions

Ginkgo biloba seeds contain toxins that can cause vomiting, seizures, loss of consciousness, and death, especially in young children. Ginkgo biloba seeds are not safe and should be avoided.

Extracts of the leaf of Gingko biloba are generally safe and cause few side effects when taken at recommended doses for up to six months. People who are planning to have surgery should stop taking ginkgo biloba at least two days before their operation because of the risk of increased bleeding. The safety of gingko biloba in children and pregnant and breastfeeding women is still being studied.

Interactions

Ginkgo biloba has blood-thinning properties and is likely to increase the blood-thinning and anticoagulant effects of medicines such as warfarin (Coumadin), clopidogrel (Plavix), aspirin, and nonsteroidal anti-inflammatory drugs (e.g. Advil, Motrin). Individuals taking these drugs should not begin taking ginkgo biloba without consulting their health care provider.

Ginkgo biloba may also interact with mono-amine-oxidase (MAO) inhibitors used to treat certain kinds of depression and mental illness. Examples of MAOs include isocarboxazid (Marplan), phenelzine (Nardil) and tranylcypromine (Parnate). Individuals taking MAOs along with ginkgo biloba may experience increased effects from the MAO.

Some reports suggest that ginkgo biloba lowers blood sugar levels. Individuals who are taking insulin or other medications that also lower blood sugar, and those with type 2 diabetes, should consult their health care provider before starting to take ginkgo biloba.

Complications

Serious side effects of ginkgo biloba are rare. The most common mild side effects are headache, dizziness, nausea, diarrhea, increased restlessness, and racing heart. Increased bleeding may occur. Allergic reactions to gingko are possible, but uncommon. In severe rare cases, the skin blisters and sloughs off, a condition called Stevens-Johnson syndrome. People who are allergic to sumac, mango rind, cashews, poison oak, and poison ivy are at slightly higher risk to have an allergic reaction to ginkgo biloba.

Parental concerns

Parents should be aware that the safe dose of many herbal supplements has not been establsihed for children. Accidental overdose may occur if children are give adult herbal supplements.

Resources

BOOKS

Cass, Hyla and Jim English. Basic Health Publications User’s Guide to Ginkgo biloba. North Bergen, NJ: Basic Health Publications, 2002

Fragakis, Allison. The Health Professional’s Guide to Popular Dietary Supplements Chicago: American Dietetic Association, 2003

PDR for Herbal Medicines, 3rd ed. Montvale, NJ: Thompson Healthcare, 2004

Pierce, Andrea. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: William Morrow, 1999

Tracy, Timothy S. and Richard L. Kingston, eds. Herbal Products: Toxicology and Clinical Pharmacology. Totowa, NJ, Humana Press, 2007

Wildman, Robert E. C., ed. Handbook of Nutraceuticals and Functional Foods, 2nd ed. Boca Raton, FL: CRC/ Taylor & Francis, 2007.

PERIODICALS

Akhondzadeh, S. and S. H. Abbasi. “Herbal Medicine in the Treatment of Alzheimer’s Disease.” American Journal of Alzheimer’s Disease and Other Dementias 21, no. 2 (Mar-April 2006):113–8

Dugoua, J. J., et al. “Safety and Efficacy of Ginkgo (Ginkgo biloba) During Pregnancy and Lactation.” Canadian Journal of Clinical Pharmacology 13, no. 3 (Fall, 2006):e277–84. <http://www.cjcp.ca/pdf/CJCP05-037_e277e284F.pdf>

Mazza, M. et al, “Ginkgo Biloba and Donepezil: A Comparison in the Treatment of Alzheimer’s dementia in a Randomized Placebo-controlled Double-blind Study.” European Journal of Neurology 13, no. 9 (September 2006):981–5

Oh, S. M. and K. H. Chung. “Antiestrogenic Activities of Ginkgo Biloba Extracts.” Steroid Biochemistry and Molecular Biology 100, nos. 4–5 (August 2006):167-76

Sierpina, Victor S., Bernd Wollschlaeger, and Mark Blu-menthal. “Ginkgo Biloba.” American Academy of Family Physicians. 68, (September 1, 2003):923–6. <http://www.aafp.org/afp/20030901/932.html>.

ORGANIZATIONS

Alternative Medicine Foundation. P.O. Box 60016, Potomac, MD 20859. Telephone: (301) 340-1960. Fax: (301) 340-1936. Website: <http://www.amfoundation.org>

National Center for Complementary and Alternative Medicine Clearinghouse. P.O. Box 7923, Gathersburg, MD 20898. Telephone: (888) 644-6226. TTY: (866) 464-3615. Fax: (866) 464-3616. Website: <http://nccam.nih.gov>

Natural Standard. 245 First Street, 18th Floor, Cambridge, MA 02142. Telephone: (617) 444-8629. Fax: (617) 444-8642. Website: <http://www.naturalstandards.com>/ bibcit.composed>

Office of Dietary Supplements, National Institutes of

Health. 6100 Executive Blvd., Room 3B01, MSC 7517, Bethesda, MD 20892-7517 Telephone: (301) 435-2920. Fax: (301)480-1845. Website: <http://dietarysupplements.info.nih.gov>.

OTHER

Mayo Clinic Staff. “Gingko (Gingko biloba L.).” Mayo Clinic.com, May 1, 2006. <http://www.mayoclinic.com/health/gingko-bilboa/NS_patient-gingko>

Maryland Medical Center Programs Center for Integrative Medicine. “Gingko Biloba.” University of Maryland Medical Center, 2002. <http://www.umm.edu/altmed/ConsHerbs/GingkoBilobah.html>

Medline Plus. “Gingko (Gingko biloba L.).” U. S. National Library of Medicine, November 1, 2006. <http://www.nlm.nih/gov/medlineplus/druginfo/natural/patneingingko.html>

National Center for Complementary and Alternative Medicine. “Gingko.” National Center for Complementary and Alternative Medicine, January 23, 2007. <http://nccam.nih.gov>

HOPES Project for Education at Stanford. “Gingko Bibloba: Disease Mechanism IV: Free Radical Damage.” Stanford University, December 3, 2004. <http://www.stanford.edu/group/hopes/sttools/hopes.html>

Tish Davidson, A.M.

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Ginkgo Biloba

Ginkgo biloba

Description

Ginkgo biloba, known commonly as the maidenhair tree, is one of the oldest trees on Earth, once part of the flora of the Mesozoic period. The ginkgo tree is the only surviving species of the Ginkgoaceae family. This ancient deciduous tree may live for thousands of years. Ginkgo is indigenous to China, Japan, and Korea, but it also thrived in North America and Europe prior to the Ice Age. That drastic climate change destroyed the wild ginkgo tree throughout much of the world. In China, ginkgo was cultivated in temple gardens as a sacred tree known as bai gou, thus assuring its survival there for more than 200 million years. Ginkgo fossils found from the Permian period are identical to the living tree, which is sometimes called a living fossil.

Ginkgo trees may grow to 122 ft (37.2 m) tall and measure 4 ft (1.2 m) in diameter. The female trees have a somewhat pointed shape at the top, like a pyramid. The male trees are broader at the crown. The bark of the ornamental ginkgo tree is rough and fissured and may be ash to dark-brown in color. Distinctive, fan-shaped leaves with long stalks emerge from a sheath on the stem. Leaves are bright green in spring and summer and turn golden yellow in the fall. Ginkgo trees may take as long as 30 years to flower. Ginkgo is dioecious, with male and female flowers blooming on separate trees. Blossoms grow singly from the axils of the leaf. The female flowers appear at the end of a leafless branch. The yellow, plum-shaped fruits develop an unpleasant scent as they ripen. They contain an edible inner seed that is available in Asian country marketplaces. Ginkgo's longevity may be due, in part, to its remarkable resistance to disease, pollution, and insect damage. Ginkgo trees are part of the landscape plan in many urban areas throughout the world. Millions of ginkgo trees, grown for harvest of the medicinal leaves, are raised on plantations in the United States, France, South Korea, and Japan, and are exported to Europe for pharmaceutical processing.

General use

Ginkgo leaves, fresh or dry, and seeds, separated from the outer layer of the fruit, are used medicinally. Ginkgo has remarkable healing virtues that have been recorded as far back as 2800 b.c. in the oldest Chinese materia medica. Ginkgo seeds were traditionally served to guests along with alcohol drinks in Japan. An enzyme present in the ginkgo seed has been shown in clinical research to speed up alcohol metabolism in the body, underscoring the wisdom of this folk custom. The leaf extract has been used in Asia for thousands of years to treat allergies, asthma , and bronchitis . It is also valued in Chinese medicine as a heart tonic to aid in the treatment of cardiac arrhythmia. Ginkgo was first introduced to Europe in 1730 and to North America in 1784 where it was planted as an exotic garden ornamental near Philadelphia.

Ginkgo medicinal extracts are the primary prescription medicines used in France and Germany. Ginkgo acts to increase blood flow throughout the body, particularly cerebral blood flow. It acts as a circulatory system tonic, stimulating greater tone in the venous system. The herb is a useful and proven remedy for numerous diseases caused by restricted blood flow. European physicians prescribe the extract for treatment of Raynaud's disease, a condition of impaired circulation to the fingers. It is also recommended to treat intermittent claudication, a circulatory condition that results in painful cramping of the calf muscles in the leg that impairs the ability to walk. German herbalists recommend ingesting the extract for treatment of leg ulcers, and large doses are used to treat varicose veins . Ginkgo is widely recommended in Europe for the treatment of stroke . The dried leaf extract may also act to prevent hemorrhagic stroke by strengthening the blood capillaries throughout the body. In studies of patients with atherosclerotic clogging of the penile artery, long-term therapy with ginkgo extract has provided significant improvement in erectile function. Ginkgo extract also acts to eliminate damaging free radicals in the body and has been shown to be effective in treatment of premenstrual syndrome, relieving tender or painful breasts. Other demonstrated benefits include improved long-distance vision and possible action to reverse damage to the retina of the eye. In addition, the ginkgo extract may provide relief for persons with headache, sinusitis, and vertigo.

Alzheimer's disease linked ginkgo use to improvement on certain cognitive tests, and in a French study in 2003, researchers credited ginkgo supplements with long-term benefits that could aid in delaying or preventing the development of Alzheimer's disease. However, in a 2007 Tufts University study, reported in Tufts University Health and Nutrition Letter, researchers concluded that ginkgo supplements did not improve the mental performance of elderly persons who were not experiencing dementia. Researchers acknowledged that the “null findings” in the study might be due to the already high cognitive functioning of study participants.

The active constituents in the ginkgo tree, known as ginkgolides, interfere with a blood protein known as the platelet activating factor (PAF). Other phytochemicals in ginkgo include flavonoids, bioflavonoids, proanthocyanidins, trilactonic diterpenes (including the ginkgolides A, B, C, and M), and bilabolide, a trilactonic sesquiterpene. The therapeutic effects of this herb have not been attributed to a single chemical constituent; rather, the medicinal benefits are due to the synergy between the various chemical constituents. The standardized extract of ginkgo must be taken consistently to be effective. A period of at least 12 weeks of use may be required before the beneficial results are evident.

Preparations

Ginkgo's active principles are diluted in the leaves. The herb must be processed to extract the active phytochemicals before it is medicinally useful. It would take an estimated 50 fresh ginkgo leaves to yield one standard dose of the extract. Dry extracts of the leaf, standardized to a potency of 24% flavone glycosides and 6% terpenes, are commercially available. A standard dose is 40 mg, three times daily, though dosages as high as 240 mg daily are sometimes indicated.

Ginkgo extracts are widely used in Europe where they are sold in prescription form or over the counter as an approved drug. This is not the case in the United States, where ginkgo extract is sold as a food supplement in tablet and capsule form.

Precautions

Ginkgo is generally safe and non-toxic in therapeutic dosages. Exceeding a daily dose of 240 mg of the dried extract may result in restlessness, diarrhea , and mild gastrointestinal disorders. Those on anticoagulants should have their doctor adjust their dose or should avoid ginkgo in order to avoid over-thinning their blood and hemorrhaging. Ginkgo should be avoided two days before and one to two weeks after surgery to avoid bleeding complications. Pregnant women should avoid ginkgo supplements because scientists have discovered a compound called colchicine in the placental blood of women who took ginkgo biloba. A 2002 report cautioned that the compound could cause problems for the growing fetus.

In 2002, a case of ginkgo seed poisoning was reported in a toddler in Japan, but she had ingested 50 or more pieces of roasted ginkgo seeds. She experienced severe vomiting and seizures.

Side effects

Severe allergic skin reactions, similar to those caused by poison ivy, have been reported after contact with the fruit pulp of ginkgo. Eating even a small amount of the fruit has caused severe gastrointestinal irritation in some persons. People with persistent headaches should stop taking ginkgo. Some patients on medications for nervous system disease should avoid ginkgo. It can interact with some other medicines, but clinical information is still emerging.

Interactions

The chemically active ginkgolides present in the extract, specifically the ginkgolide B component, act to reduce the clotting time of blood and may interact with antithrombotic medicines, including aspirin .

A study reported in 2007 by Gregory Reed of the Kansas Medical Center examined the possible interactions of ginkgo and ginseng supplements with prescription or over-the-counter drugs with regard to how these drugs are metabolized and eliminated by the body. The scientists concluded that these herbal supplements are “unlikely to alter the pharmacokinetics of the majority of prescription or over-the counter drugs.”

Resources

PERIODICALS

Carlson, Joseph J., et al. “Safety and Efficacy of a Ginkgo Biloba-Containing Dietary Supplement on Cognitive Function, Quality of Life, and Platelet Function in Healthy, Cognitively Intact Older Adults.” Journal of the American Dietetic Association 107, no. 3 (March 2007): 422–432.

“Experimental Therapeutic: Recommended Doses of Ginseng, Ginkgo Biloba Do Not Interfere with Drug Absorption.” Drug Week (May 18, 2007).

Clare Hanrahan

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