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Ginkgo Leaves

Scientific name : Ginkgo Biloba

Common name : Ginkgo, Maidenhair Tree

The ginkgo is the world's oldest living tree ;, and it can be traced back more than 200 million 10 the fossils of the Permian period. It is the sole Ir of the family Ginkgoaceae. Individual trees may long as 1000 years. They grow to a height of about et and have fan-shaped leaves. The species is IUS; male trees more than 20 years old blossom in 'ng, Adult female trees produce a plum-like gray that falls in late autumn. Its fleshy pulp has a foul, e odor and causes contact dermatitis. The edible seed resembles an almond and is sold in oriental markets.

History

The ginkgo species was almost destroyed the ice age, The species survived in China, where cultivated as a sacred tree, and is still found ting Buddhist temples throughout Asia. Prepara­have been used for medicinal purposes for more a thousand years. Traditional Chinese physicians ginkgo leaves to treat asthma and chillblains, which swelling of the hands and feet from exposure to cold. The ancient Chinese and Japanese ate Id ginkgo seeds, and considered them a digestive d preventive for drunkenness. In the Western ginkgo has been used since the 1960s when ology made it possible to isolate its essential com­Is. The fIavonoids act as free radical scavengers, 1e terpenes (ginkgolides) inhibit platelet activating. Currently, oral and intravenous forms are avail­in Europe, where it is one of the most widely ribed medications. Neither form has been approved ledical use in the United States, although ginkgo is as a nutritional supplement.

Chemistry

There is a seasonal variation in the con­ of active compounds in leaves, with the highest unts present in autumn. Leaf constituents include '10 acid 6-hydroxykynurenic acid, flavonoids (dimeric lvones) such as bilobetin, ginkgetin, isoginkgetin, opitysin, and flavonols quercetin, kae[llpferol and glycosides,4,5 About 40 different flavonoids have m indentified so far. Some of these flavonoids are lechins, dehydrocatechins (proanthocyanidins), and 'ones (eg, ginkgetin, amentoflavune, bilobetin, sciado­sin).6 Also present in ginkgo leaves are terpenoids terpenes), such as bilobalide, and gingolides A, B, C, J d MS,6 Other leaf components include steroids (sito­rol, stigmasterol), polyprenols, organic acids (shikimic, vanillic, ascorbic, p-coumaric), benzoic acid derivatives, carbohydrates, straight chain hydrocarbons, alcohol, ke­tones and 2 hexeno!.

The seed portion of ginkgo contains carbohydate (38%), protein (4%) and fat « 2%). Alkaloids such as ginkgo­toxin, amino acids, cyanogenetic glycosides and phenols (long-chain, including anacaric acid, bilobol and cardanol) are also present. Ginkgolic acid and related alkylphenols from lipid fraction of the fruit pods has been reviewed? The foul-smelling odor of the fleshy portion of the seeds is caused by high concentrations of butanoic and hexanoic acids. 4-0-methylpyridoxine has also been isolated from the seeds. Biological standardization of ginkgo extracts has been reported.

Pharmacology

Pharmacokinetic parameter testing of ginkgo has been performed in animals,6,g and also in humans evaluating three ginkgo forms (capsules, drops and tablets).1o Behavior of ginkgo after IV and oral administration in humans has been documented.

Numerous studies on the pharmacological actions of ginkgo have been reported, including treatments for ce­rebral insufficiency, dementia, circulatory disorders and asthma. The plant is also known for its antioxidant and neuroprotective effects.

Cerebral insufficiency: Cerebral insufficiency may cause anxiety and stress, memory, concentration and mood impairment, and hearing disorders, all of which may benefit from ginkgo therapy. In man, intravenous injection of ginkgo biloba extract (GBE) increased cerebral blood flow in about 70% of the patients evaluated. This increase was age-related: Patients between the ages of 30 and 50 years had a 20% increase from baseline, compared with 70% in those 50 to 70 years old. Further, the time to reach peak blood flow was shorter in the elderly. Ginkgo leaf improves cerebral metabolism and protects against hy­poxic damage in animals with cerebral ischemia.5 Cere­bral insufficiency in 112 patients (average age 70.5 years) treated with ginkgo leaf extract (120 mg) for 1 year, resulted in reduced symptoms such as headache, dizziness, short-term memory, vigilance and disturbance.5 Electroencephalographic effects of different preparations.