This elegant-looking tree , GINKGO BILOBA, GINKGOACEAE,is considered a « living fossil ».
Geology tells us that very similar plants lived in the primary (Permian) era, peaked in the Secondary (Jurassic) era, and lasted significantly until the end of the tertiary.
Ginkgo biloba is the only surviving species of this ancient botanical genus.
Currently « wild » ginkgo are only found in the Far East in very limited areas.
The organization of this tree recalls that of the cherry tree, the leaves are born in a bouquet on short secondary branches.
The leaves are generally bilobed, show a dichotomous venation which would be the signature of its archaic character.
During autumn, the leaves turn a bright yellow, then fall, sometimes within one or two weeks.
The ginkgo is dioecious, the male plants are more numerous than the females, but it is necessary to wait 15 years to know its sex.
The fruit is a naked ovum, fertilization by ciliated gametes recalling that of the most « simple » plants (algae, mosses, ferns).
The ginkgo is of Far Eastern origin, the Buddhist priests maintained it around the pagodas.
It was introduced in Europe in the 18th century.
It is now grown for its leaves in Korea, China, France and the USA.
CHEMICAL COMPOSITION AND PROPERTIES
Found in the leaf:
-sugars, sterols and ketones,
-organic acids
especially flavonoids and terpenoids which are the support of pharmacological activity.
About twenty flavonoids (let us quote bilobétol, ginkgétol) and proanthocyanidols.
Diterpenes are known as ginkgolides and have a special hexacyclic structure.
Some ginkgolides are inhibitors of the platelet aggregation factor (very important in triggering the inflammatory reaction).
Flavonoids are antioxidants that trap free radicals.
In total the leaf extract is considered to be:
- a veinotonic,
- vasculoprotective (increased resistance of blood capillaries),
- and anti-inflammatory.
- It would improve the blood supply to tissues (especially the brain),
- and activate cell metabolism by increasing the uptake of glucose and oxygen, especially in the cells of the cerebral cortex.
USES
GINGKO EXTRACTS are interesting:
To prevent and attenuate VASCULAR DISORDERS WITH ANTI-INFLAMMATORY REACTION:
- chronic arteritis and arterial disease, intermittent claudication, hemorrhoidal crisis, phlebitis, incidents of perfusion, following venous sclerosis,
- to relieve venolymphatic insufficiency,
- to « improve » circulation and cerebral oxygenation: intellectual deficit in the elderly, disorders of the inner ear (dizziness, tinnitus, hearing disorders).
- Gingko extracts are also currently used to slow the progression of Alzheimer’s disease and « senile dementia » secondary to very poor cerebral blood circulation associted with many small cerebral infarctions.
- Permanent anxiety can also be improved by gingko extracts.
- Some therapists have obtained good results in patients suffering from schizophrenia in treatment associated with anti-psychotics in particular to attenuate their side effects.
So these are very modern indications for such an ancient plant.
EXAMPLES OF DOSAGE
- There is an homeopathic tincture but to obtain an effect it is necessary to maintain a high dosage: 100 to 150 drops for 1 to 3 months, in repeated treatment.
- It is preferable to use concentrated and standardized extracts of ginkgo leaves in flavonoids and terpenoids. like « tanakan » or « EGb 761 ».
There is no international standard but we can advise extracts which are close to 25% flavonoids and 5 to 7% terpenoids and less than 5 ppm of ginkgolic acid which can cause an allergic reaction.
It is best to start treatment with low dosage, 40 to 60 mg per day for one to two weeks and then double in the absence of side effects to 120 mg which is the standard dosage.
If the treatment is well supported, it is possible to increase the daily dosage up to 240 mg per day.
The treatment must last at least 2 to 3 months, sometimes in repeated cures with intervals without treatment of 2 to 3 weeks.
One can associate gingko with other vasculoprotective phytomedicines, it presents few undesirable effects, some rare digestive or cutaneous disorders.
CAUTION: People who are under anticoagulant treatment should avoid gingko extracts which themselves are slightly anticoagulant or adapt the anticoagulant treatment (reduce the dose by monitoring the coagulation parameters)
OTHER USES
Gingko fruits are sometimes eaten in traditional dishes in the Far East, especially in Japan, but you have to be careful:
- because the seed (the nucleus) of gingko is covered with a « flesh » containing a smelly substance which can cause a major allergic reaction on contact.
- the seed contains a slightly toxic substance, ginkgotoxin, which disturbs the metabolism of vitamin B6 (pyridoxine) (antivitamin action).
Significant and repeated consumption of ginkgo seeds can lead, especially in children, to nervous disorders resembling epilepsy or convulsions.
The antidote is vitamin B6.
This antivitamin B6 substance exists only in very small quantities in the leaves.
GINGKO CULTIVATION
The gingko is propagated by cuttings or by germinating fertilized ova (seeds), it is suitable for temperate countries even with harsh winter.
It is an extremely resistant tree, with long longevity and which has an important capacity of regeneration (see the gingko present at the very place of the atomic explosion of Hiroshima).
It is also resistant to diseases and insects.
It survives in flowerpots in the form of « bonsai » or grows in the open ground to reach 20 to 30 m with well spread out branches.
The majority of gingko trees planted in town are male trees, to avoid the fall of smelly and allergenic fruits from the female trees
RESUME
A living but very modern fossil
Ginkgo as a genus is native to the Far East and contemporary with dinosaurs.
Ginkgo biloba is cultivated for its beautiful appearance and its leaves containing pharmacological substances which protect blood vessels and promote blood circulation.
It is used to improve oxygenation of the brain in the elderly and to treat varicose veins, hemorrhoids and muscle pain due to insufficient arterial circulation.
Copyright 2020 : Dr Jean-Michel Hurtel
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