Ginkgo biloba is used widely through out the world as a medicinal herbal for the improvement of a number of conditions. It has been used traditionally by Chinese physicians for thousands of years. It is reported to be the most popular prescription drug in Germany and France. Millions of prescriptions are filled every year. Ginkgo biloba has an excellent adverse effect record. Looking at a compellation of a number of studies with a total of almost 10.000 patient, only 21 had minor gastrointestinal upset, 7 complained of headache and 6 sited dizziness.(1) Ginkgo is a tree in the oldest of tree species. The two most active ingredients in it’s leaves are glycoside and terpenes. In numerous trials it has been shown that the total leaf extract is exponentially more potent than the individual parts.(1) Products containing Ginkgo biloba leaf extract (GBE) are those that are closest to the supplements that are used in the clinical trials. The plant chemicals are about 50 times more concentrated than in dried ginkgo leaf. Ginkgo has been found to have a significant effect on platelet activity in the blood, on circulation, and on oxygen delivery. Ginkgo affects blood platelets as it is an inhibitor of platelet-activating factor or PAF (2), circulation as it increases vascular permeability and dilates blood vessels by prompting the release of prostacyclin (3,4,5), a vasodilating hormone-like substance, oxygenation as it is reported to counter constriction and spasm of the bronchial tubes, and as an anti inflammatory for general inflammation as well as allergic symptoms. It can improve the blood supply to the body overall and particularly cerebral blood flow in the brain, and can increase oxygen availability at the tissue level. The primary use for Ginkgo biloba is to enhance memory both in people who have memory deficits such as in Altzhiemer’s disease and other dementias and in healthy people as they age or are under a lot of stress. It is also used in circulatory maladies such as intermittent claudication and Raynaud’s syndrome which cause painful symptoms in the extremities because of constrictions of the blood vessels. It has been used in the complications of diabetes from the impaired circulation that causes neuropathies and neuropathic pain. It can be an adjunctive aid for asthmatics who have mild disease. It has been shown to decrease vertigo. It is used in Europe for glaucoma, macular degeneration, and retinal nerve damage for circulatory reasons. Some men feel it helps with impotence that is caused by impaired blood vessels. It increases the efficacy and reduces the side effects of some of the psychotropic medications like phenothiazines and the atypical antipsychotic drugs. It probably does not help altitude sickness. An 80mg capsule of GBE should have the flavonol glycosides (sometimes called heteosides) at between 19 – 20mg and the terpene lactones between 4 - 5 mg or 24% and 6% respectively. The specific flavonol glycosides and terpene lactones should ideally be standardized at minimums of 9.5% for quercetin, 10.5% for kaempferol 2% for isorhamnetin, 2.8% for ginkolides A,B &C, and 2.6% for bilobalide, according to ConsumerLab scientists. Suggested doses vary form 40 mg twice a day to 240mg a day in divided doses. The European standard is 80mg 3 x a day for healthy people. Studies of those with Altzheimer’s disease showed improvement in memory function with higher doses. There is a potential for drug interactions with Ginkgo because of it’s “blood thinning” effect. It would be prudent to avoid combined use with drug blood thinners known as anticoagulants, such as warfarin (Coumadin) although one study found no interaction between Ginkgo biloba and Coumadin (6). Other blood thinning drugs include heparin, aspirin, Plavix (clopidogrel), Ticlid (ticlopidine), and Trental (pentoxifylline). These other drugs were prohibited from combined use with Ginkgo in most trials. Natural blood thinners such as garlic, policosanol and high dose Vitamin E might be enhanced if used together with Ginkgo biloba.
1. Funfgeld, EW (ed): Rokan. Ginkgo biloba. Recent Results in Pharmacology and Clinical Applications. Springer-Verlag , New York , 1988. 2. Chung, KF, Dent, G, McCusker, M, et al. Effect of a ginkgolide mixture (BN 52063) in antagonizing skin and platelet response to platelet activating factor in man. Lancet. 1087;1:248,251. 3. Kohler, S, Funk, P, 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 Coagulation Fibrinolysis. 2004;15:303-309. 4. Kudolo, GB, Dorsey, S, Blodgett, J. Effect of the ingestion of Ginkgo biloba extract on platelet aggregation and urinary prostanoid excretion in healthy and Diabetes type 2 subjects. Thromb Res. 2002; 108:151-160. 5. Bal Dit Sollier, C, Caplain, H, Drouet, L. No alteration in platelet function or coagulation induced by EGb 761 in a controlled study. Clinical Laboratory Hematology. 2003; 25:251-253. 6. Engelstein, J, Nielsen, JD, Winther, K. Effect of CoEnzyme Q10 and Ginkgo biloba on warfarin dosage in stable, long term warfarin-treated outpatients. A randomized, double-blind, placebo-crossover trial. Thromb Haemost. 2002;87:1075-1076.
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