GINKGO BILOBA

BACKGROUND

Ingredient Type:  Botanical, Extract

Also Known As: Ginkgo, Braun’s stonewort, Common ginkgo, Maidenhair tree

Ginkgo is one of the oldest living tree species on earth (1).  It consists of short branches with fan-shaped leaves and foul-smelling fruits.  Ginkgo biloba is derived from the leaves of the ginkgo tree, which is predominantly grown in China, South Korea, and Japan.  Ginkgo is available as a liquid extract, in capsule or tablet form or as a tea.  The nuts, which are contained within the seeds of the ginkgo tree, may be consumed and are a common ingredient in Asian cuisine.

Ginkgo biloba has been used for centuries in traditional Chinese medicine.  Its seeds were used as part of traditional Chinese medicine about 2000 years ago, but more recent medicinal applications typically involve using leaf extracts (2).    

TRADITIONAL USES

Ginkgo leaf has been used frequently to treat dementia and other conditions associated with cerebral vascular insufficiency, especially in the elderly, including memory loss, headache, tinnitus, vertigo, dizziness, difficulty concentrating, mood disturbances, and hearing disorders.  Ginkgo is believed to also improve cognitive behavior and sleep patterns in patients with depression, chronic fatigue syndrome (CFS), schizophrenia, and for the prevention of winter depression.

Like many other natural ingredients it has also been used for a variety of other conditions including: ischemic stroke, peripheral arterial disease (PAD), arteriosclerosis, angina pectoris, and cardiac reperfusion injury, macular degeneration and glaucoma; attention deficit-hyperactivity disorder (ADHD); autism; thrombosis; heart disease; hypercholesterolemia; premenstrual syndrome (PMS); dysentery and filariasis; asthma, allergies and bronchitis; and diabetic retinopathy.  Ginkgo leaf is also purportedly useful for preventing acute mountain sickness and aging, regulating gastric acidity, improving liver and gallbladder function, controlling blood pressure, and treating Raynaud’s disease (3).

WHAT DOES SCIENCE TELL US?

Laboratory studies have shown that ginkgo dilates blood vessels and makes blood platelets less sticky, thereby improving blood flow (23).  An analysis of eight studies reported in the March 2000 issue of “The American Journal of Medicine” found that people who took ginkgo walked 34 meters farther than those who took a placebo (23).

Ginkgo improves blood circulation and may help treat blood-related conditions, such as blood vessel disorders, high blood pressure, and blood clots.  In addition to improvements in blood flow, ginkgo may also be beneficial for eye health (24).

SAFETY

Standardized ginkgo leaf extracts have been used safely in trials lasting for several weeks up to 6 years (4).

It has a few potential safety issues.  Ginkgo should not be used by people who have bleeding disorders because it could make the condition worse.  Stop taking ginkgo prior to surgery or dental work, because there is the danger of bleeding too much.  People with seizure disorders may experience more seizures after using this supplement.

Ginkgo leaf extract is generally well tolerated when taken orally and at typical doses.  It can cause mild gastrointestinal (GI) upset, headache, dizziness, palpitations, constipation, and allergic skin reactions in some people.  Large doses can cause restlessness, diarrhea, nausea, vomiting, lack of muscle tone, and weakness.  Spontaneous bleeding is one of the most concerning potential side effects associated with ginkgo, although several large-scale clinical trials and a meta-analysis show that the incidence of bleeding in patients taking ginkgo is not significantly higher than in those taking a placebo.

Interactions:

Ginkgo should not be taken with blood thinning drugs, including heparin, warfarin (which is often sold as Coumadin) and aspirin; or with anti-seizure or antidepressant medications.

Theoretically, concomitant use of ginkgo with other herbs and supplements that affect platelet aggregation could increase the risk of bleeding.

Theoretically, patients taking supplements that also lower the seizure threshold might be at greater risk for increased seizures.

REFERENCES

1. Singh B, Kaur P, Singh GRD, Ahuja PS. Biology and chemistry of Ginkgo biloba. Fitoterapia 2008;79(6):401-18
2. Briskin DP. Medicinal plants and phytomedicines. Linking plant biochemistry and physiology to human health. Plant Physiol 2000;124(2):507-14.
3. WebMD
4. Mix JA, Crews WD Jr. An examination of the efficacy of Ginkgo biloba extract EGb761 on the neuropsychologic functioning of cognitively intact older adults. J Altern Complement Med 2000;6:219-29
5. Victoire C, Haag-Berrurier M, Lobstein-Guth A, and et al. Isolation of flavonoid glycosides from Ginkgo biloba leaves. Planta Med 1988;54:245-247.
6. Oken BS, Storzbach DM, Kaye JA. The efficacy of Ginkgo biloba on cognitive function in Alzheimer disease. Arch Neurol 1998;55:1409-15.
7. http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/TR578_508.pdf
8. Zhang, S., Chen, B., Wu, W., Bao, L., and Qi, R. Ginkgolide B reduces inflammatory protein expression in oxidized low-density lipoprotein-stimulated human vascular endothelial cells. J Cardiovasc.Pharmacol 2011;57(6):721-727
9. Brautigam MR, Blommaert FA, Verleye G, et al. Treatment of age-related memory complaints with Ginkgo biloba extract: a randomized double blind placebo-controlled study. Phytomedicine 1998;5:425-3
10. Kudolo G. Ingestion of Ginkgo biloba extract significantly inhibits collagen-induced platelet aggregation and thromboxane A2 synthesis. Alt Ther 2001;7:105
11. 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 Coagul Fibrinolysis 2004;15:303–9.
12. Aruna D, Naidu MU. Pharmacodynamic interaction studies of Ginkgo biloba with cilostazol and clopidogrel in healthy human subjects. Br J Clin Pharmacol 2007;63:333-8
13. Kellermann AJ, Kloft C. Is there a risk of bleeding associated with standardized ginkgo biloba extract therapy? A systematic review and meta-analysis. Pharmacotherapy 2011;31:490-502.
14. Zhang, S., Chen, B., Wu, W., Bao, L., and Qi, R. Ginkgolide B reduces inflammatory protein expression in oxidized low-density lipoprotein-stimulated human vascular endothelial cells. J Cardiovasc.Pharmacol 2011;57(6):721-727
15. Brautigam MR, Blommaert FA, Verleye G, et al. Treatment of age-related memory complaints with Ginkgo biloba extract: a randomized double blind placebo-controlled study. Phytomedicine 1998;5:425-34
16. Oken BS, Storzbach DM, Kaye JA. The efficacy of Ginkgo biloba on cognitive function in Alzheimer disease. Arch Neurol 1998;55:1409-15
17. Logani S, Chen MC, Tran T, et al. Actions of Ginkgo Biloba related to potential utility for the treatment of conditions involving cerebral hypoxia. Life Sci 2000;67:1389-96.
18. Campos-Toimil M, Lugnier C, Droy-Lefaix M, et al. Inhibition of type 4 phosphodiesterase by rolipram and Ginkgo biloba extract (EGb 761) decreases agonist-induced rises in internal calcium in human endothelial cells. Arterioscler Thromb Vasc Biol 2000;20:e34-e40
19. Paick J, Lee J. An experimental study of the effect of ginkgo biloba extract on the human and rabbit corpus cavernosum tissue. J Urol 1996;156:1876-80
20. Campos-Toimil M, Lugnier C, Droy-Lefaix M, et al. Inhibition of type 4 phosphodiesterase by rolipram and Ginkgo biloba extract (EGb 761) decreases agonist-induced rises in internal calcium in human endothelial cells. Arterioscler Thromb Vasc Biol 2000;20:e34-e40.
21. Deng, Y. K., Wei, F., and An, B. Q. [Effect of ginkgo biloba extract on plasma vascular endothelial growth factor during peri-operative period of cardiac surgery]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2009;29(1):40-42
22. Guillon, J. M., Rochette, L., and Baranes, J. [Effects of Ginkgo biloba extract on 2 models of experimental myocardial ischemia]. Presse Med 9-25-1986;15(31):1516-1519
23. University of Maryland Medical Center
24. Mayo Clinic internist Brent A. Bauer

See the Mayo Clinic entry for ginkgo, the National Center for Complementary and Integrative Health entry for ginkgo, the Penn State Hershey Health Information Library entry for Ginkgo biloba, the European Medicines Agency public summary for Ginkgo folium, Michigan Medicine Health Library entry for ginkgo, the Examine.com entry for Ginkgo biloba, or the RXList entry for ginkgo for more information.