It was Charles Darwin that was reported to have called the ginkgo tree (Ginkgo biloba L.) a living fossil on account of its existence for more than 200 million years. But as Darwin stole most of his good ideas from other people, it is unclear to whom this thought should really be credited. The Gingko tree is old, being the oldest existing tree species on earth with evidence suggesting that it coexisted with the earliest dinosaurs. The 30 meter gingko tree is also incredibly long lived, with lifespans of around 1000 years, and is well adapted to polluted and adverse conditions, which may explain its long existence. The fruit of the tree is inedible, but the fruit does contain a seed that can be consumed. However, it is the fan-like leaves of the ginkgo tree that can be used medicinally, and increasingly the gingko tree is cultivated for its medicinal properties. In particular, an extract of gingko standardised for flavones and terpenoids has been studied for its health effects. Research to date supports the historical records from traditional Chinese medicine in terms of beneficial blood flow and cognitive effects for the herb.
Gingko has been studied for its protective effect on the ageing and diseased brain. In this regard standardised extracts of gingko has been used to successfully treat peripheral vascular disease, tinnitus, dementia and chronic cerebrovascular insufficiency (compromised venous drainage of central nervous system tissue). Gingko appear to be effective protective of these conditions because the phytochemicals contained within gingko leaves increase blood flow and improve the elasticity of vascular tissue. The active ingredients responsible for this action may include the diterpenes (ginkgolides A, B, C, J and M), a number of flavones (blobetin, sciadopitysin, ginkgetin and isoginkgetin) and the flavones (quercetin, isorhamnetin and kaempferol). The ginkgolides and flavonoids (flavones and flavonols) in ginkgo appear to be able to relax blood vessels in spasm and increase vascular tone in those which are over dilated. This may explain the traditional view that ginkgo is able to increase blood flow to peripheral areas, particularly those which are ischaemic.
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