A voice for
herbal medicine

We share traditional, scientific and practical insights written by experienced herbalists and health experts from the world of herbal medicine and natural health

A very modern herbal medicine - can we generate a new tradition?

Ginkgo

Ginkgo biloba Ginkgoaceae

Ginkgo is a deciduous tree, referred to by Darwin as a living fossil, that has survived unchanged from the time of the dinosaurs. However there is no tradition for using the leaf in medicine and all its recommended therapeutic uses so far relate to research on a 50:1 proprietary extract with very high flavonoid levels. There is still very little modern evidence for the use of ginkgo leaves themselves. Given its popularity among herbal practitioners there is an opportunity to develop a new herbal story for this plant.

  • How does it feel?

    The overwhelming taste of ginkgo leaf is bitterness. It is immediate, direct and persists for a long time in the mouth. However, without a history of use it is difficult to link this to any traditional therapeutic quality.

  • What can I use it for?

    Concentrated ginkgo extracts can be used to improve blood flow, tissue oxygenation and nutrition, and to protect nervous tissue. They enhance memory and cognitive function, especially in the elderly and have also been used in some cases of tinnitus, dizziness and headaches. Some symptoms of atherosclerosis such as intermittent claudication (pain in the lower legs on walking even short distances) may also be relieved. Ginkgo extract has been taken as a supplement to reduce the risk of cardiovascular disease, to improve retinal blood flow and as a remedy to manage glaucoma and age-related macular degeneration.

    The extract has also been shown to reduce the impact of a range of stressors and to reduce anxiety and depression.

    However given what is known about a) about the widespread adulteration of commercial ginkgo extracts, b) the threat of allergenic constituents in these extracts, and c) the lack of evidence for ginkgo leaf itself, one should choose either an EGb761 extract or one with similar constituents and quality assurances.

    The use of other preparations of ginkgo has become widespread among herbal practitioners and it will be important to generate a new evidence base to support its continuing use. This will become an interesting future project.

  • Into the heart of Ginkgo

    While ginkgo nuts are used in traditional Chinese medicine (for lung and kidney ailments), the modern use of the green leaf is entirely due to scientific discovery. In the 1960s a group of German scientists set out to investigate the effects of novel herbs on circulation. In traditional German healthcare circulatory disturbances have been default explanations for a wide range of illnesses, including ageing and cognitive decline. Perhaps attracted by the heart-shaped leaves (Herz is the key circulatory metaphor in German culture) they investigated further and developed a concentrated ginkgo extract. This was standardised for flavonoid content and patented soon after.

    The original therapeutic focus was improving peripheral circulation to the brain. This fits in with another concept popular in Germany of ‘cerebral insufficiency’ with symptoms including difficulties in concentration and memory, absentmindedness, confusion, lack of energy, tiredness, decreased physical performance, depressive mood, anxiety, dizziness, tinnitus and headaches. These symptoms have also been associated with the early stages of dementia. The assumption is that anything that improves circulation to the brain would help in these conditions. Ginkgo was also prescribed for tinnitus, and in reducing clotting in cardiovascular diseases. Cerebral insufficiency is not much recognised outside continental Europe and the use of ginkgo as a prescription medicine is largely confined to these countries. The idea is however consistent with herbal therapeutics and the ginkgo story opens the door to other similar approaches.

    Wider acceptance of ginkgo has followed recognition of its potential neuroprotective effects and EGb761 is emerging as an important phytomedicine treatment for dementia and Alzheimer’s disease. To support the latter benefit there is laboratory evidence for a reduction in platelet-activating factor (PAF), especially by the terpenes (ginkgolides) which could justify the use of ginkgo extract also in asthma, allergic and immunological reactions. Laboratory evidence also points to a significant effect in protecting mitochondria and other intracellular functions against oxidative stress.

  • Research

    Almost all the clinical research evidence relates to the patented 50:1 extract EGb761 – containing 24% flavone glycosides and 6% terpenoids) at a daily dose typically corresponding to 4 to 16 g of leaf. There is a considerable body of this evidence, with over 400 clinical trials published in the scientific literature.

    Much of this work has focused on the potential effects of ginkgo extracts on cognitive decline and dementia, and on various measures of cognitive performance in healthy subjects, such as memory.

    Other benefits of the extract have been demonstrated, including reduced stress responses.

    There is very little published evidence for any effects of other ginkgo leaf preparations. One exception is in the case of a 3-5:1 fresh-leaf extract (at 90 mg/day equating to 300-400mg of fresh leaf) in a German-language publication.

  • Did you know?

    For many years EGb761 was the most frequently used medicine in Germany, routinely prescribed by doctors for their elderly patients, with as usual for medical prescriptions there, the costs largely met by the state. This support was withdrawn in the 1990’s and prescription levels initially fell. However they recovered significantly afterwards, even without reimbursement.

    Ironically in most of the English-speaking world ginkgo is classified as a food or dietary supplement.

Additional information

  • Safety

    There is very little record of problems associated with the use of ginkgo extracts. There is a theoretical risk of a bleeding event or interaction with blood thinning drugs because of its PAF activity but this is neither supported by controlled clinical trials nor by mandatory adverse reporting schemes in Germany and other parts of Europe. Given the very widespread prescription of ginkgo in medical practice there this is a significant assurance of safety.

    Because of potential allergic reactions to ginkgolic acids (specified to be less than 5 parts per million in assured extracts), the use of normal tinctures or fluid extracts is not recommended without assurance on this front. Most commercial ginkgo products other than EGb761 have been shown to contain seriously high levels of these allergens.

  • Dosage

    The daily dose of the 50:1 standardised extract (EGb761) is 120 to 240 mg. This corresponds to 4 to 16 g of leaf, depending on the quality of original leaf.

  • Constituents

    The European Pharmacopoeia definitive monograph on dried ginkgo leaf requires a minimum 0.5% flavonoids, calculated as flavone glycosides.

    By contrast EGb761 is standardized to 24% ginkgo-flavone glycosides and 6% terpenoids (eg, bilobalide, ginkgolides A, B, C, and J).

    Ginkgo leaf also contains ginkgolic acid. This is a strong allergen and in assured extracts levels are specified to be less than 5 parts per million.

    Other constituents include procyanidins.

Aromatic
An ‘aromatic’ remedy, high in volatile essential oils, was most often associated with calming and sometimes ‘warming’ the digestion. Most kitchen spices and herbs have this quality: they were used both as flavouring and to ease the digestion of sometimes challenging pre-industrial foods. Many aromatics are classed as ‘carminatives’ and are used to reduce colic, bloating and agitated digestion. They also often feature in respiratory remedies for colds, chest and other airway infections. They are also classic calming inhalants and massage oils, and are the basis of aromatherapy for their mental benefits.
Astringent taste
The puckering taste you get with many plants (the most familiar is black tea after being stewed too long, or some red wines) is produced by complex polyphenols such as tannins. Tannins are used in concentrated form (eg from oak bark) to make leather from animal skins. The process of ‘tanning’ involves the coagulation of relatively fluid proteins in living tissues into tight clotted fibres (similar to the process of boiling an egg). Tannins in effect turn exposed surfaces on the body into leather. In the case of the lining of mouth and upper digestive tract this is only temporary as new mucosa are replenished, but in the meantime can calm inflamed or irritated surfaces. In the case of open wounds tannins can be a life-saver – when strong (as in the bark of broadleaved trees) they can seal a damaged surface. One group of tannins, the reddish-brown ‘condensed tannins’ are procyanidins, which can reduce inflammation and oxidative damage.
Bitter
Bitters are a very complex group of phytochemicals that stimulate the bitter receptors in the mouth. They were some of the most valuable remedies in ancient medicine. They were experienced as stimulating appetite and switching on a wide range of key digestive functions, including increasing bile clearance from the liver (as bile is a key factor in bowel health this can be translated into improving bowel functions and the microbiome). Many of these reputations are being supported by new research on the role of bitter receptors in the mouth and elsewhere round the body. Bitters were also seen as ‘cooling’ reducing the intensity of some fevers and inflammatory diseases.
Blue-purple colouring
Any fruits with a blue-purple colouring contain high levels of the polyphenols known as anthocyanins. These work 1) on the walls of small blood vessels, helping to maintain capillary structure to reduce a key stage in inflammation, and improving the microcirculation to the tissues; 2) to improve retinal function and vision; 3) to support connective tissue repair around the body.
Cooling
Traditional ‘cold’ or cooling’ remedies often contain bitter phytonutrients such a iridoids (gentian), sesiquterpenes (chamomile), anthraquinones (rhubarb root), mucilages (marshmallow), some alkaloids and flavonoids. They tend to influence the digestive system, liver and kidneys. Cooling herbs do just that; they diffuse, drain and clear heat from areas of inflammation, redness and irritation. Sweet, bitter and astringent herbs tend to be cooling.
Hot
Traditional ‘hot’ or ‘heating’ remedies, often containing spice ingredients like capsaicin, the gingerols (ginger), piperine (black or long pepper), curcumin (turmeric) or the sulfurous isothiocyanates from mustard, horseradich or wasabi, generate warmth when taken. In modern times this might translate as thermogenic and circulatory stimulant effects. There is evidence of improved tissue blood flow with such remedies: this would lead to a reduction in build-up of metabolites and tissue damage. Heating remedies were used to counter the impact of cold, reducing any symptoms made worse in the cold. .
Mucilaginous
Mucilages are complex carbohydrate based plant constituents with a slimy or ‘unctuous’ feel especially when chewed or macerated in water. Their effect is due simply to their physical coating exposed surfaces. From prehistory they were most often used as wound remedies for their soothing and healing effects on damaged tissues. Nowadays they are used more for these effects on the digestive lining, from the throat to the stomach, where they can relieve irritation and inflammation such as pharyngitis and gastritis. Some of the prominent mucilaginous remedies like slippery elm, aloe vera and the seaweeds can be used as physical buffers to reduce the harm and pain caused by reflux of excess stomach acid. Mucilages are also widely used to reduce dry coughing. Here the effect seems to be by reflex through embryonic nerve connections: reduced signals from the upper digestive wall appear to translate as reduced activity of airway muscles and increased activity of airway mucus cells. Some seed mucilages, such as in psyllium seed, flaxseed (linseed) or guar bean survive digestion to provide bulking laxative effects in the bowel. These can also reduce rate of absorption of sugar and cholesterol. .
New-mown hay aroma
The familiar country odour of haymaking, of drying grass and other plants, is largely produced by coumarins (originally isolated from tonka beans – in French coumarou) and widely used in perfumery. They are chemically categorised as benzopyrone lactones and are important phytochemicals, with strong antioxidant activity in the laboratory and likely effects in modulating inflammation. They were most often associated with the calming effect linked to their use in stuffing mattresses and pillows and plants, high In coumarins were commonly used for these properties.
Resinous
Resins are most familiar as tacky discharges from pine trees (and as the substance in amber, and rosin for violin bows). They were most valued however as the basis of ancient commodities like frankincense and myrrh (two of the three gifts of the Three Wise Men to the baby Jesus) and getting access to their source was one benefit to Solomon for marrying the Queen of Sheba (now Ethiopia). Resins were the original antiseptic remedies, ground and applied as powders or pastes to wounds or inflamed tissues, and were also used for mummification. With alcohol distillation it was found that they could be dissolved in 90% alcohol and in this form they remain a most powerful mouthwash and gargle, for infected sore throats and gum disease. They never attracted much early research interest because they permanently coat expensive glassware! For use in the mouth, gums and throat hey are best combined with concentrated licorice extracts to keep the resins in suspension and add extra soothing properties. It appears that they work both as local antiseptics and by stimulating white blood cell activity under the mucosal surface. They feel extremely effective!
Salty
The salty flavour is immediately distinctive. A grain dropped onto the tongue is instantly moistening and a sprinkle on food enkindles digestion. This easily recognisable flavour has its receptors right at the front of the tongue. The salty flavor creates moisture and heat, a sinking and heavy effect which is very grounding for the nervous system and encourages stability. People who are solid and reliable become known as ‘the salt of the earth'.
Sharpness
The sharp taste of some fruits, and almost all unripe fruits, as well as vinegar and fermented foods, is produced by weak acids (the taste is generated by H+ ions from acids stimulating the sour taste buds). Sour taste buds are hard-wired to generate immediate reflex responses elsewhere in the body. Anyone who likes the refreshing taste of lemon or other citrus in the morning will know that one reflex effect is increased saliva production. Other effects are subjective rather than confirmed by research but there is a consistent view that they include increased digestive activity and contraction of the gallbladder.
Sweet
In the days when most people never tasted sugar, ‘sweetness’ was associated with the taste of basic foods: that of cooked vegetables, cereals and meat. In other words sweet was the quality of nourishment, and ‘tonic’ remedies. Describing a remedy as sweet generally led to that remedy being used in convalescence or recovery from illness. Interestingly, the plant constituents most often found in classic tonics like licorice, ginseng are plant steroids including saponins, which also have a sweet taste.

Sign up to our Newsletter

Sign up to our newsletter to receive the very latest in herbal insights.

Sign up to our newsletter