Ginkgo biloba extract
Ginkgo (Ginkgo biloba; in Chinese and Japanese 銀杏, pinyin romanization: yín xìng, Hepburn romanization: ichō or ginnan), also spelled gingko and known as the maidenhair tree, is a unique species of tree with no close living relatives. The ginkgo is a living fossil, recognisably similar to fossils dating back 270 million years. Native to China,the tree is widely cultivated and was introduced early to human history. It has various uses in traditional medicine and as a food.
Ginkgo biloba extract (GBE, species Ginkgo biloba) has been used for centuries as part of the ancient Chinese pharmacopoeia in the treatment of respiratory ailments, cognitive impairment, and circulatory disorders. In recent years, Ginkgo has gained great worldwide acceptance for treatment of a number of medical conditions including tinnitus, cognitive decline in dementia, intermittent claudication, asthma, macular degeneration and, most recently, antidepressant induced sexual dysfunction.
The oldest tree species in the world, dating from the time of the dinosaurs, Ginkgo biloba (bi-loba, two sided leaf) is the last remaining species of the Ginkgoales order. Fossil records show the species was once widespread in Asia and North America, and it is speculated that it was saved from extinction by monks in the far east who cultivated it secretly as a sacred tree. Each tree can live for more than a thousand years, immune to bugs, disease and pollution. The tree grows to 100 feet tall and has fan-like leaves and yellow-green fetid smelling fruits. If you are lucky enough to have access to a mature tree, take advantage of the fresh leaves, which contain the broadest spectrum of medicinal properties.
Case reports have confirmed GBE’s beneficial effect on ASD. An open clinical trial of Ginkgo biloba extract with 63 patients was found to be effective in 84% of patients with ASD. All phases of the sexual response cycle were improved (desire, excitement, orgasm and resolution). Minimal side effects were reported which included gastrointestinal upset, headache, CNS stimulation and easy bruisability. There were no serious adverse events. A double blind placebo-controlled trial of a GBE compound has just been completed and the results are currently under review.
Possible mechanisms of action may include improved circulation and prostaglandin agonist effects, as well as neurotransmitter and nitric oxide second messenger modulation. Although Ginkgo biloba is relatively safe, it also works as a potent inhibitor of platelet activating factor. Therefore, patients taking aspirin, nonsteroidal anti-inflammatory agents, and anti-coagulants, or patients with a coagulopathy should consult a physician and exercise caution when considering adding GBE to their existing regimen. Dose ranges of GBE 50:1 extract are 60 milligram tablets twice a day; this can be advanced to 120 mg twice a day after two weeks.
The use of the ginkgo leaf is recent, and has been studied for its cardiovascular benefits. Today ginkgo biloba is one of the most commonly prescribed herbs and is a great example of a tonic herb – one that balances whatever is going on in your system; if you are tired it can energize you, if you are stressed it will relax you.
The bilobalides, ginkgolides, flavonoids, and other substances unique to the tree restore better blood flow to all parts of the body but particularly to the brain, allowing improved use of oxygen. Ginkgo’s antioxidant actions also stabilize the structure of brain and nerve cells and protect them from oxidative attacks from free radicals. Research indicates ginkgo action of supporting healthier circulation in the eyes, make it an herb of choice for natural treatment eye health and macular degeneration.
There is an significant body of scientific and clinical evidence supporting the safety and efficacy of ginkgo extract for both cognitive function and improved circulation, said Mark Blumenthal, the founder and executive director of ABC
. Ginkgo’s hallmark effect is increased circulation, which is important in maintaining our energy level and one of the factors in stopping early hair loss. Increasing genital blood flow heightens responsiveness, making for higher libido in both men and women. Good circulation means getting the full benefit from the foods we eat and the vitamins and herbal supplements we take.
Allergies and asthma also improve with ginkgo. The herb contains a dozen different anti-inflammatory chemicals and seven natural antihistamines. 1
- Medicinal Uses: * Allergies * Alopecia * Asthma * Bronchitis * Circulation * Eyes/Vision * Libido * Longevity Tonics * Memory/Focus * Varicose Veins
- Properties: * Anti-inflammatory * AntiCancer * Antioxidant * Antitussive * Astringent * Cardiac tonic Cordial * Tonic * Vasodilator * Vermifuge
- Parts Used: Leaves and Nuts
- Constituents: gibberellin, cytokinin-like substances, ginkgolic acid, bilobol, ginnol, aspartine, calcium
EGb 761 [Ginkgo biloba extract EGb 761, Rökan, Tanakan, Tebonin] is a standardised extract of Ginkgo biloba leaves and has antioxidant properties as a free radical scavenger. A standardised extract of Ginkgo biloba leaves is a well defined product and contains approximately 24% flavone glycosides (primarily quercetin, kaempferol and isorhamnetin) and 6% terpene lactones (2.8-3.4% ginkgolides A, B and C, and 2.6-3.2% bilobalide). Ginkgolide B and bilobalide account for about 0.8% and 3% of the total extract, respectively. Other constituents include proanthocyanadins, glucose, rhamnose, organic acids, D-glucaric and ginkgolic acids. EGb 761 promotes vasodilation and improves blood flow through arteries, veins and capillaries. It inhibits platelet aggregation and prolongs bleeding time. EGb 761, which was originated by Dr Willmar Schwabe Pharmaceuticals (Dr Willmar Schwabe Group), has been available in Europe as a herbal extract since the early 1990s. However, products containing EGb 761 are not approved for use by the US FDA. As a dietary supplement, Nature’s Way in the US distributes and markets a standardised extract of Ginkgo biloba leaves (the EGb 761 Formula) under the name Gingold Nature’s Way. The French company Beaufour-Ipsen and its German subsidiary Ipsen Pharma are co-developing EGb 761 with Dr Willmar Schwabe Group. Beaufour-Ipsen (France) is developing EGb 761 as Tanakan, Dr Willmar Schwabe Pharmaceuticals (Germany) as Tebonin and Ipsen Pharma (Germany) as Rökan. Intersan was formerly developing EGb 761 in Germany, but Intersan appears to have been merged into Ipsen Pharma. However, there has been no recent development for these indications. In the UK and other European countries, the cardioprotective effects of EGb 761 in myocardial ischaemia and reperfusion are being investigated in preclinical studies. The psychological and physiological benefits of ginkgo are said to be based on its primary action of regulating neurotransmitters and exerting neuroprotective effects in the brain, protecting against or retarding nerve cell degeneration. Ginkgo also benefits vascular microcirculation by improving blood flow in small vessels and has antioxidant activity. There has been conflicting evidence about the benefits of ginkgo, e.g. the ginkgo clinical trial published in August 2002 in JAMA concluded that a leading ginkgo supplement did not produce measurable benefits for memory in healthy adults over 60, although a month earlier, another study concluded that the same ginkgo extract is effective in helping normal healthy older adults in memory and concentration. However, in December 2002, the Cochrane Collaboration, the world’s most respected scientific reviewer of clinical trials in medicine, concluded that the published literature strongly supports the safety and potential benefits of ginkgo in treating memory loss and cognitive disorders associated with age- related dementia. A phase II study of EGb 761 in combination with fluorouracil is in progress in Germany in patients with pancreatic cancer. German researchers are investigating the potential of EGb 761 for the treatment of sudden deafness and tinnitus in clinical studies. EGb 761 was undergoing preclinical development for the potential treatment of diabetes in France, diabetic neuropathies in Russia, and cancer in Brazil. However, there has been no recent development for these indications. Beaufour-Ipsen has expressed the intention to license out its diabetes projects that may include EGb 761.
The first mentioned use of Ginkgo biloba appears in China. Ginkgo leaf is first mentioned in Lan Mao’s Dian Nan Ben Cao, published in 1436 during the Ming dynasty. Lan Mao notes external use to treat skin and head sores as well as freckles. Internal use of the leaves is first noted in Liu Wen-Tai’s Ben Cao Pin Hui Jing Yao , an imperial commissioned work recorded in 1505. Liu Wen Tai notes use of the leaves in the treatment of diarrhea. The leaves of ginkgo are known in Chinese medicine as bai-guo-ye. Recent clinical reports in modern China suggest that the leaves lower serum cholesterol levels and have some clinical value in angina pectoris.
In Traditional Chinese pharmacopeia the seeds (with fleshy rind removed) are considered more important than the leaves. The nut, called Pak Ko, is recommended to expel phlegm, stop wheezing and coughing, urinary incontinence and spermatorrhea. The raw seed is said to help bladder ailments, menorrhea, uterine fluxes, and cardiovascular ailments. The powdered leaf is inhaled for ear, nose, and throat disorders like bronchitis and chronic rhinitis. Locally applied boiled leaves are used for chilblains.. The seeds are used as an astringent for the lung, to stop asthma and enuresis.
Ginkgo leaves are a Chinese herb that has been used much more in the West than in its homeland. Over five hundred scientific studies on the chemistry, pharmacology and clinical effects of gingko leaves have been conducted by European researchers over the last 20 to 30 years. The majority of studies on ginkgo leaf extract have involved a product produced by a German/French consortium, referred to in the scientific literature as EGb761.
The extract utilized in medicine is standardized in a multi-step procedure designed to concentrate the desired active principles from the plant. These extracts contain approximately 24% flavone glycosides (primarily composed of quercetin, kaempferol, and isorhamnetin) and 6% terpene lactones (2.8-3.4% ginkgolides A, B, and C, and 2.6-3.2% bilobalide). Other constituents include proanthocyanadins, glucose, rhamnose, organic acids, D-glucaric acid and ginkgolic acid (at most 5 ppm ginkgolic acids). Biochemical studies have concentrated on the flavonoids: much of the curative properties of the ginkgo tree are due to the activities of these flavonoids. The complex extract itself, rather than a single isolated component, is believed to be responsible for Ginkgo’s biological activity.
Ginkgo leaf extracts have been shown to have a wide range of biological activities. The most well-known use is the ability to improve short term memory. Other important effects include a protective effect on the blood-brain barrier and an anti-radical (antioxidant) effect. The leaf extracts has also been shown to increase vasodilation and peripheral blood flow rate in capillary vessels and end-arteries in various circulatory disorders. Ginkgo leaf helps to maintain integrity and permeability of cell walls by inhibiting lipid peroxidation of membranes. Other studies have shown vascular-tone regulating effects, and help in modulating cerebral energy metabolism.
Ginkgo biloba extract (Gbe) and two ingredients, bilobalide and ginkgolide B, are presented to the CSWG as part of a review of botanicals being used as dietary supplements in the United States. ( 1 of 3 adults in the United States are now taking dietary supplements ). Sweeping deregulation of botanicals now permits GBE to be sold as a dietary supplement to a willing public eager to “improve brain functioning” or “promote radical scavenging activity.”. In the U.S, there are four primary distribution channels: drug stores, supermarkets, mass merchandisers, and specialty vitamin shops and nutrition centers. The Internet is also becoming an increasingly important distribution channel.
Gbe is a well defined product, and it or its active ingredients, the ginkgolides, especially ginkgolide B, and bilobalide, have clearly demonstrated biological activity. It can be consumed in rather large doses for an extended period of time. Under the Dietary Supplement Health and Education Act of 1994, Gbe can be sold legally if it is not labeled or accompanied by any therapeutic or health claims. Herbal remedies can be labeled with descriptions of their role in affecting physiological structure or function, but must be labeled with a disclaimer that the product has not been evaluated by the FDA for cure, prevention, or treatment of a disease.
GINKGO Biloba Extract (Gbe)
Trade Names: Egb 761, Ginkgold, Tebonin, LI 1370, rökan, Tanakan
Standardized ingredients of Gbe
The extract utilized in medicine is standardized in a multi-step procedure designed to concentrate the desired active principles from the plant. These extracts contain approximately 24% flavone glycosides (primarily composed of quercetin, kaempferol, and isorhamnetin) and 6% terpene lactones (2.8-3.4% ginkgolides A, B, and C, and 2.6-3.2% bilobalide). Ginkgolide B accounts for about 0.8% of the total extract, and bilobalide accounts for about 3% of the extract. Other constituents include proanthocyanadins, glucose, rhamnose, organic acids, D-glucaric acid and ginkgolic acid (at most 5 ppm ginkgolic acids).Much of the curative properties of Gbe are due to the activities of these flavonoids.
CAS Registry Number: 117-39-5
Molecular Formula: C15 H10 O7 Mol. wt.: 338.3
Chemical Abstracts Service Name: 4H-1-Benzopyran-4-one, 2-(3,4-dihydroxyphenyl)- 3,5,7-trihydroxy- (9CI)
CAS Registry Number: 520-18-3
Molecular Formula: C15 H10 O6 Mol. wt.: 286.2
Chemical Abstracts Service Name: 4H-1-Benzopyran-4-one, 3,5,7-trihydroxy-2-(4- hydroxyphenyl)- (9CI)
CAS Registry Number: 480-19-3
Chemical Abstracts Service Name: 4H-1-Benzopyran-4-one, 3,5,7-trihydroxy-2-(4- hydroxy-3-methoxyphenyl)- (9CI)
Molecular Formulat: C15 H12 O6 Mol. wt.: ~314
CAS Registry Number: 33570-04-6
Modern pharmacological research into the active constituents of ginkgo leaves began in the late 1950s. Spearheaded by the phytopharmaceutical company Dr. Willmar Schwabe GmbH, twenty years of research resulted in a standardized, concentrated extract of ginkgo leaves. The 27 step extraction process requires fifty pounds of leaves to yield one pound of extract and takes up to two weeks to complete. Most critical to the extraction process and final product is the standardization of ginkgo flavone glycosides and terpene lactones. The 24% ginkgo flavone glycosides content of GBE constitutes a carefully measured balance of quercetin, kaempferol, and isorhamnetin. The group of constituents unique to GBE, however, are the terpene lactones which constitute 6% of the final extract.
Human Exposure: There is potential for ingestion of Gbe to a widespread consumer population, since this product is readily available without prescription at a cost highly competitive with prescription medications. The recommended dose of Gbe is 120 to 160 mg daily for persons with intermittent claudication and 240 mg daily for cerebrovascular insufficiency, early stage Alzheimer’s disease, resistant depression, and impotence.