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Presentation   Morphology   History   Reproduction   Ornamentation   Medicine	GINKGO Biloba Extract (Gbe) Trade Names: Egb 761, Ginkgold, Tebonin, LI 1370, rökan, Tanakan

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.

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. 

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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.