Common Name Ginkgo, Maidenhair Tree

Latin Binomial Ginkgo biloba L. Family: Onagraceae

Part(s) Used Leaf

Pharmacopoeial & Other Monographs

AHP (15)
BHP 1996 (21)
BP 2007 (33)
Complete German Commission E 1998 (17)
Martindale 35th Edition (34)
Ph Eu 2007 (32)
US 29/NF24 (35)
WHO Volume 1 1999 (28)

Active Constituents

Terpene Trilactones
Ginkgolides A, B, C and J
Bilobalide

Flavonoids
Quercetin, Kaempferol and
Isorhamnetin (glycosides).

Therapeutic Effects Most clinical trials of Ginkgo have explored its effects in the treatment of cognitive deficiency or cerebral insufficiency. (61)(27) Ginkgo leaf extract is primarily used to treat symptoms arising from poor cerebral blood flow. Symptoms include: Poor memory, poor concentration, dizziness, tinnitus, anxiety, and disorientation. Ginkgo leaf extract is also used on patients who suffer from peripheral arterial occlusive disease. (62)(27)

Contra-indications In light of the pharmacological effects of Ginkgo, it is not suitable for self treatment. Ginkgo should not be used in patients with bleeding disorders. Read more

In light of the pharmacological effects of Ginkgo, it is not suitable for self treatment. Ginkgo should not be used in patients with bleeding disorders.

Drug Interactions
Ginkgo extract should be used with caution, and under the supervision of a doctor. Especially patients taking anticoagulants or anti-platelet agents. Inhibition of CYP2C9 has been documented.(63) Flavonoids are thought to inhibit CYP2CP, CYP1A2, CYP2E1, and CYP3A.

Pregnancy and lactation The use of Ginkgo leaf extracts should be avoided during pregnancy and lactation.

Pharmacological Action

The combined activity of several Ginkgo phytoconstituents is generally considered to be responsible for its effects.

Cardiovascular effects
Ginkgo extract is believed to inhibit human platelet aggregation elicited by substances such as thrombin and collagen. (55)

Platelet-activating factor (PAF) antagonism
Ginkgolides have been reported to competitively inhibit the binding of PAF to its membrane receptor. (56)(57)(58)

Antioxidant
Ginkgo leaf extract scavenges several oxygen species, including hydroxyl, superoxide, and peroxyl radicals. (59)

Other effects
Ginkgo leaf extract and the flavonoid constituents bind to both oestrogen receptors (ER), alpha- and beta- receptors. At certain concentrations, Ginkgo extract and flavonoid constituents induced the proliferation of ER-positive MCF-7 human breast cancer cells. (60)

Food Use Seeds may be eaten. (17)

Herbal Use/Indication Concentrated extracts from Ginkgo leaves are used to improve cognitive deficiency, relieve symptoms of peripheral arterial occlusive disease, vertigo, and tinnitus of vascular origin.

Dosage

120-240mg of dry leaf extract orally every day in two or three divided doses to treat cognitive deficiency. (17)

120-160mg of dry leaf extract orally every day in two or three divided doses to treat peripheral arterial occlusive disease, vertigo, and tinnitus. (17)

Therapeutic Effects Although available data indicate that standardized extracts of Ginkgo leaf are well tolerated when used at recommended doses, (61)(65) there are several case reports in the literature of bleeding associated with the ingestion of Ginkgo biloba extracts. (1)

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AHP

BHP 1996

BP 2007

Complete German Commission E 1998

Martindale 35th Edition

Ph Eu 2007

US 29/NF24

WHO Volume 1 1999

Kleijen J, Knipschild P. Ginkgo biloba for cerebral insufficiency. Br J Clin Pharmacol 1992; 34: 352-358.

Schulz V, Hansel R, Tyler V. Rational Phytotherapy. A Physicians' Guide to Herbal Medicine. Berlin: Springer-Verlag, 1998.

Pittler MK, Ernst E. Ginko biloba extract for the treatment of intermittent claudication: a meta-analysis of randomised trials. Am J Med 2000; 108: 276-281.

Refeudis FV. Ginkgo biloba. From Chemistry to Clinic. Wiesbaden, Germany: Ullstein Medical, 1998.

Braquet P. The ginkoglides: potent platelet-activating factor antagonists isolated form Ginkgo biloba L. Chemistry, pharmacology and clinical applications. Drugs of the Future 1987; 12: 643-699.

Anonymous. Extract of Ginkgo biloba. FEBS 200; 478: 123-126.

Hosford D, et al. Natural antagonists of platelet-activating factor. Phytother Res 1988; 2: 1-17.

Maitra I et al. Peroxyl radical scavenging activity of Ginkgo biloboa extract EGb-761. Biochem Pharmacol 1995; 49: 1649-1655.

Oh SM, Chung KH. Estrogenic activities of Ginkgo biloba extracts. Life Sci 2004; 74: 1325-1335.

De Smet PAGM et al., eds. Adverse Effects of Herbal Drugs, vol. 3. Berlin: Springer-Verlag, 1993.

Barnes J, Anderson LA, Phillipson DJ. Herbal Medicines. Third edition. Grayslake, Il Phrmaceutical Press; 2007. 710p.