Ginko biloba

	Ginko biloba

Introduction 1

Ginko biloba, derived from the Ginko tree, is the best-selling phytomedicine on the European market with sales are in excess of 280 million dollars per year. Ginkgo is considered the oldest tree species to survive on earth dating back over 200 million years. Ginkgo species were once common in North America and Europe. Ginkgo biloba is the only surviving member of the ginkgo family. While its relatives became extinct in other parts of the world Ginkgo biloba survived in China. It has been reintroduced as a ornamental tree throughout the Western world. Now ginkgo trees are found in virtually every city in the United States. The species name "biloba" refers to the two distinct lobes, typical of the tree's leaves. They are long-lived trees, often growing over 100 feet tall, that demonstrate excellent resistance to disease, pests, fires and air pollution. The most common tree along Manhattan sidewalks is ginkgo. Its unique fan-shaped leaves with two lobes make it one of the easiest trees to identify once you become familiar with the unusual leaf shape. Despite the fact that the tree occurs in China, the leaves are not one of the famous classical herbal drugs of ancient China.

Ginkgo leaves are a Chinese herb that has been used much more in the West than in China. The majority of studies on ginkgo leaf extract have involved a product produced by a German/French consortium, referred to in the scientific literature as EGb761. Ginkgo products are standardized to contain 24% of the bioflavonoids which occur in the leaf, as well as ginkgolides and bilobilides, a complex group of compounds found only in the ginkgo tree. Since virtually all research on ginkgo has involved high standardized extracts calibrated to specific quantities of chemical components, it is not possible to apply information from studies on the standardized extracts to ginkgo leaf itself. The complex extract itself, rather than a single isolated component, is believed to be responsible for Ginkgo's biological activity.

Uses

Active ingredients in Ginkgo biloba extract demonstrate both antioxidant properties and inhibit platelets from sticking together. Platelets are involved in blood clotting. These are properties shared by aspirin and other prescription medications directed at inhibiting platelet clotting. Ginkgo has been touted to be helpful in a number of conditions including:

Publication of a study in the October 22, 1997, issue of the Journal of the American Medical Association has broadened interest in the herb as a possible treatment for Alzheimer's disease. This study concluded Ginkgo can modestly improve functioning in patients with Alzheimer's dementia. Dementia is the loss of various parts of memory such that a person may not recognize persons, events or surroundings that were previously familiar to them. In more advanced stages persons with dementia are unable to care for themselves. Dementia, particularly that of the Alzheimer's type, has been linked to decreased levels of the chemical acetylcholine (a neurotransmitter) a certain parts of the brain.

Randomized, double blind studies with a control and treatment group (the type of studies accepted as most scientifically valid) have not been conducted for most other conditions claimed to be helped by Ginko.

Efficacy appears to be similar to that of a group of prescription medications known as Cholinesterase inhibitors used improve dementia symptoms. These medications are thought to work by decreasing the breakdown of acetylcholine by the enzyme acetylcholinesterase. Currently, two cholinesterase inhibitors are available for use in treating Alzheimer's disease: tacrine (Cognex) and donepezil (Aricept). Several others, such as metrifonate and rivastigmine, are in the late stages of development and testing. Effects are modest at best: a good response to either drug will return the patient's function to the level that was present between six and 12 months before medication was started. 3

Ginko has not yet been shown to be beneficial in improving memory in healthy persons without dementia nor have studies been conducted to show whether long term use can prevent dementia.

Although Ginko is well tolerated by a vast majority of persons those taking it must be aware of the potential for lifethreatening bleeding. Cases of spontaneous bleeding into both the brain and eye have been reported in several previously healthy patients without other risk factors taking only ginkgo. Likewise, brain hemorrhage have been reported in several patients taking blood thinning medications who started taking Ginkgo.

Yes! Persons taking medications or products with antiplatelet or anticlotting effects should be very careful about taking Ginkgo. These products include:

Many neurologists, though, say the study is inconclusive at best. They note that the apparent effect ginkgo had was small. Use for persons with dementia should be considered in consultation with a physician. There is no treatment for dementia that works very well.

It may be effective in the prevention of certain vascular diseases as well (not yet proved). Whether Ginkgo is beneficial for healthy people is not clear. It is possible some of Ginko's positive benefits are due to antiplatlet activity.

Remember, a baby aspirin a day has demonstrated benefits in preventing both heart attack and stroke, is very inexpensive, has been extensively studied and has an excellent safety record.