Medicinal extracts from the Asian Ginkgo tree were considered some years as “natural miracle cures” against a variety of ailments. In particular, the touted positive influence in neurodegenerative diseases and declining cognitive performance caused quite a stir. However, new findings cast doubt on the natural remedy’s actual efficacy.
Occurrence and cultivation of ginkgo
Reportedly, ginkgo was the first tree species to recover and spread after the Hiroshima nuclear disaster. Ginkgo (ginkgo biloba) is a tree species native to China and Japan. Due to its increasing use as a medicinal plant and its valued function as a robust ornamental tree in parks, the ginkgo has been increasingly planted in other parts of the world. In 1750, the German physician Engelbert Kaempfer brought the ginkgo to Europe. Ginkgo trees belong to the group of the seed plants (Ginkgoaceae), one of the oldest plant species at all, whose development-historical roots go back approximately 300 million years. The ginkgo is therefore – as the last existing representative of this species – often referred to as a “living fossil”. Fossil findings indicate that the ginkgo was once naturally widespread in other parts of the world before its habitat was concentrated in Asia. Ginkgo trees are characterized by strong resistance to external environmental stimuli, thus they are adaptable to different climatic conditions and can live for several hundred years. Reportedly, the ginkgo was the first tree species to recover and spread after the Hiroshima nuclear disaster. Their longevity, robustness and imposing appearance led to the veneration and cultivation of ginkgo trees as “temple trees” in the Far East. They are also unusual plants from a botanical point of view: visually, deciduous ginkgo trees, with their fan-like, finely notched leaves, tend to resemble deciduous trees or ferns, but due to other botanical characteristics they actually belong to the conifers.
Effect and application
For centuries, ginkgo has been used as a medicinal plant in China, Japan and Indonesia. Through the spread of Far Eastern medicine in the context of modern holistic medicine approaches, the medicinal plant also found its way into Western countries. The seeds, leaves and bark of the tree are used medicinally. Applications of the extracts obtained include infections and chronic diseases of the respiratory tract (bronchitis, asthma), skin diseases and the promotion of blood circulation and circulation. Today, ginkgo is mainly known as a phyto-therapeutic agent for symptoms of declining cognitive performance – especially for concentration and memory disorders, including dementia syndrome. Extracts from the leaves of the tree, produced in a complex process, are used. These contain the effective ingredients of the plant (especially so-called terpenoids, flavonoids and ginkgolides) in concentrated form, while at the same time potentially harmful substances (ginkgolic acids) are eliminated in the manufacturing process. Ginkgolic acids are suspected of causing allergies and possibly altering genetic material. The ingredients of the ginkgo are said to have circulation-promoting and cell-protecting properties. Due to their complex structure, the active substances of ginkgo have not yet been completely imitated synthetically. In particular, blood circulation in small blood vessels (microcirculation) is said to be improved by the vasodilatory effect of ginkgo. Among other things, this circulation-enhancing effect is said to have a positive impact on non-specific symptoms that are difficult to treat, such as dizziness, balance disorders and tinnitus. In addition, the plant extract is said to have antioxidant effects and thus offers protection against free radicals, inhibits the degradation of nerve cells and promotes their performance. Also a positive influence of signal transmitter materials in the brain, which are important for cognitive abilities, is assumed. In this way Ginkgo is to counteract the age-conditioned dismantling of thinking and memory ability and to support also with young humans generally the learning ability. Also a positive influence with depressive moods is discussed.
Significance for health, prevention and treatment
The effectiveness of ginkgo extracts has already been tested in numerous studies – with sometimes very contradictory results.Critical studies questioning promising results of earlier scientific tests are becoming more frequent. Large-scale placebo-controlled studies deny promises of efficacy made by drug manufacturers, but are in turn challenged by the pharmaceutical industry, which criticizes methodological weaknesses in the studies. The welfare effects of the Ginkgos – after all one of the Phytotherapeutika at all strongest in terms of sales – can be considered after today’s state of knowledge thus neither as scientifically secured nor as clearly disproved. Advocates of the Ginkgo therapy refer frequently to the tradition of the nature welfare means. Century-long, traditional applications suggest indeed at least a certain effectiveness of Ginkgo extracts. Due to the relative side effect poverty and the many positive empiric reports of Ginkgo consumers a self-experiment with the freely saleable preparations can be considered. Ginkgo extracts are available as tablets, capsules and drops. Tea preparations from ginkgo leaves, on the other hand, are not recommended because the active ingredient density in aqueous extracts is insufficient and the potentially harmful ginkgolic acids are also dissolved out of the leaves. Which dosage form and active ingredient concentration is most appropriate in each individual case should be discussed with the doctor or pharmacist. Treatment is usually administered as a course of several weeks to months, as the effect can only be felt after a longer period of use. Patients suffering from coagulation disorders or who have to take prophylactic blood-thinning medication must consult their doctor before starting treatment. Some study findings point to interactions with blood thinners and the associated increased bleeding tendency and increased risk of heart attack. Apart from this, only minor and rarely occurring side effects have been recorded – including mild gastrointestinal discomfort and headache. Because data are still insufficient, ginkgo preparations should not be taken during pregnancy or lactation.
