General Information
Common Name:
Ginkgo Biloba
Latin Name:
Ginkgo Biloba
Family:
gingkoaceae
Other Names:
Maidenhair tree.
Indications & Historical Uses
Ginkgo biloba is one of the world’s oldest living tree species. It is considered a sacred tree in China, and has been used in oriental medicine since ancient times, mainly to improve brain function, and for respiratory ailments. Currently, its main indications are:
- Macular degeneration of retina;
- Allergies;
- Asthma;
- Cerebral vascular insufficiency, vertigo, headaches, tinnitus;
- Senility, memory loss, Alzheimer’s disease, dementia;
- Peripheral vascular (arterial) disease;
- Raynaud’s Syndrome, numbness, tingling;
- Ischaemia, edema, hypoxia;
- Impotence and erectile dysfunction;
- Migraine.
Contraindications & Precautions
Contraindications:
None Known. See Caution.
Precautions:
Rare cases of gastric upset or headaches. Ginkgo seeds and fruit pulp are toxic if ingested. Contact with ginkgo fruit may lead to a allergic skin reaction,. similar to poison ivy, with possible redness ,itching and blistering.There may actually be a cross-reactivity between gingko fruit and poison ivy, oak and sumac .Children in Asia who have ingested as many as sixty gingko seeds have suffered seizures and loss of consciousness. See Caution.
Adverse Side Effects:
Relatively uncommon. Minor gastrointestinal disturbances, headache, allergic sun reactions in 4% of individuals.
Drug Interactions:
See Caution. Ginkgo can have anticoagulant activity, and can therefore potentiate the effects of anticoagulant and antithrombotic drugs like ASA, anti-inflammatories and warfarin or coumadin. Patients on these drugs should watch for bleeding.
Dosage Information
How Supplied:
60 mg capsules.
Dosage:
120mg daily. (One 60 mg. capsule twice daily with meals).
Pharmacology
The therapeutic effects of ginkgo biloba are attributed to a mixture of the active ingredients, especially the flavo glycosides, which have free radical and anti-oxidant properties; and the terpenes, which have anti-inflammatory properties. A principal effect is by inhibition of the platelet activating factor (PAF). PAF, produced by many tissues, is associated with aggregation of platelets, as well as causing broncho constriction, vasoconstriction, chemotaxis of phagocytes, hypotension, and the release of inflammatory compounds of phagocytes. By inhibiting PAF, ginkgo blocks all these effects, and therefore reduces clotting, bronchospasm and other allergic responses. Bilobalide acts in concert with the ginkgolides to enhance cerebral circulation and increase oxygen flow to the brain tissue and hence the cognitive benefits. The Journal of the American Medical Association reported the results of the first controlled study of Ginkgo in the US. This showed that 33% of Alzheimer’s patients showed a modest improvement in cognitive performance and social behaviour. The researchers claim that this is approximately equivalent to a six month delay in the progression of the disease. Federal health authorities in Germany have declared GBE (Gingko biloba extract ) to be an effective treatment for cerebral circulatory disturbances resulting in reduced functional capacity and vigilance. These authorities have also found the extract useful for the treatment of certain other types of circulatory diseases, particularly Intermittent Claudication. When Ginkgo leaf extract was given to diabetic patients, peripheral blood flow increased 40 to 50 %. In addition, patients with arterial disease of the lower limbs who receive Ginkgo extract have shown a clinically and statistically significant improvement in pain-free walking distance, maximum walking distance and in circulation measurements. Other Circulatory Benefits are noted in patients with hearing problems due to poor circulation in the ear. It is reported that about 40 % of these patients have improved hearing after six months of treatment with Ginkgo extract. Two other important benefits of gingko are in the areas of sexual dysfunction and asthma control.
Sexual function benefits: Ginkgo has also been found to improve sexual dysfunction caused by SSRI medications such as Prozac, Luvox, Paxil, and Zoloft. It was accidentally noted that a patient taking SSRI medication experienced improvement in sexual function when he began taking Ginkgo to improve cognitive function. Studies to date are very encouraging, and show that about 80% of SSRI patients show a positive response to Ginkgo biloba extract.
Asthma control benefits are due to gingkos anti allergic properties. The gingkolides appear to inhibit a key chemical mediator ( in asthma , allergies and inflammation ) -platelet activating factor-apparently preventing it from latching on to its membrane receptor. In so doing ,gingko can limit the allergic response .This was demonstrated in a study of asthma patients who were given a standardized mixture of mixed gingkolides [60mg three times a day] and a final 120mg dose before the challenge test ,or a placebo. They were then challenged with a substance they were allergic to and which normally caused a response. The findings suggest that gingkolides may help in both the early and the late phases of the airway hyper-reactivty. It is very important that the use of gingko for asthma is directed and supervised by a physcian .Gingko is not a bronchodilator and cannot be used as a quick-relief medication.
Active Ingredients:
The two main classes of chemicals in Gingko Biloba are Flavanoids and terpenoids.
Flavanoids:
- Flavonol and Flavone Glycosides, principally Quercetin and Kaempferol Glycosides;
- Rutin.
Terpenoids:
- Ginkgolides A, B, C, & M;
- Bilobalide.
Enhancing Agents:
- Duis autem vel eum;
- Vel illum dolore;
- Feugiat nulla facilisis.
Origin
Gingko biloba is one of the World’s oldest living tree species, to have survived for more than 200 million years in China, and has since become popular as a stately ornamental tree in parks,gardens and city streets around the World. Gingko trees are tall, hardy trees , highly resistant to insects and disease. Both the male and female versions have leathery, fan shaped leaves that turn golden in autumn; female type bears an inedible foul-smelling fruit . Gingko biloba is now found all over the World.
Processing
Green leaves are harvested in the fall, and air-dried. They are then extracted in a water and acetone mixture, filtered and concentrated to a standardized potency of 24%flavone glycosides and 6%terpenes.
Scientific References
Bauer, U. (1984) 6 Month double-blind randomized clinical trial of Ginkgo Biloba extract versus placebo in two parallel groups of patients suffering from peripheral arterial insufficiency. Arzneim-Forsch. /Drug Res. 34:716.
Brown, D. (1992) Ginkgo Biloba-Old and New: Part I. Let’s Live 60(4): 46. Chung, K. F. et al. (1987) Effect of a ginkgolide mixture (BN 52063) in antagonizing skin and platelet responses to platelet activating factor in man. Lancet, Jan 31.
Hindmarch, I. (1986) Activite de l’extrait de Ginkgo biloba sure la memoire a court terme/ Activity of Ginkgo Biloba extract on short term memory. Presse Medicale. 15:1592.
Kleijnen, J. and Knipschild, P. (1992) Ginkgo biloba. Lancet 340(7): 1136.
Mowrey, D. (1988) Guaranteed Potency Herbs. Next Generation Herbal Medicine. Lehi, UT: Cormorant Books.
Sikora, R. et al. (1989) Ginkgo biloba extract in the therapy of erectile dysfunction.
J. Urol. 141: 188A.
Vorberg, G. (1985) GBE: long term study concerning the major symptoms of age-related cerebral disorders. Clin. Trials. J. 22:149.
Weiner, M. (1990) Weiner’s Herbal. Mill Valley: Quantum Books.
Bradberry, J.C.: “Chapter 18” in Pharmacotherapy: A Pathophysiologic Approach, J.T. DiPiro, R.L. Talbert, P.E. Hayes, G.C. Yee, and L.M. Posey, eds., Elsevier, New York, 1989, p. 280.
Tyler, V.E.: Nutrition Forum 8:23 (1991).
Del Tredici, P.: Arnoldia 51: 2-15 (1991)
Hansel, R.: Phytopharmaka, 2nd ed., Springer-Verlag, Berlin, 1991, pp. 59-72.
Brestel, E.P. and Van Dyke, K.: “Chapter 42” in Modern Pharmacology, 3rd ed., C.R. Craig and R.E. Stitzel, eds., Little, Brown, Boston, 1991, pp. 567-569.
Weiss, R.F.: Herbal Medicine, AB Arcanum, Gothenburg, Sweden, 1988, pp. 185-186.
Prescriber’s letter– Therapeutic uses of Herbs. Oct.1998.
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