Ginkgo products come from the leaves of the only surviving member of the ginkgo family, a living fossil more than 200 million years old. Most commercial leaf production is from plantations in South Carolina, France, and China.
Ginkgo leaf is a relatively new herbal medicine, used in China only since the fifteenth century. The leaves were traditionally used for "benefiting the brain", treatment of lung disorders, relief of cough and asthma symptoms, and diarrhea. The leaf tea was applied externally to treat sores of the skin and remove freckles.
Ginkgo leaf extracts are among the better-selling herbal medicines in Europe. Most research has focused on the use of the complex extracts to increase circulation to the extremities as well as the brain, especially in the elderly. Clinical use is supported by more than 400 scientific studies conducted since the late 1950s. Ginkgo extract has also been studied for the treatment of ringing in the ears (tinnitus), male impotence, degenerative nerve conditions such as multiple sclerosis, and other diseases. It has shown potential to relieve difficulties with short-term memory, attention span, and mood in early stages of Alzheimer's disease by improving oxygen metabolism in the brain.
Ginkgo's effects have been attributed to compounds called flavone glycosides, as well as unique compounds - ginkgolides-which are potent inhibitors of a platelet-activating factor involved in the development of inflammatory, cardiovascular, and respiratory disorders. The ginkgolides' activity helps explain the herb's broad-spectrum biological effects.
Another important effect is strong antioxidant activity. With its ability to "scavenge" reactive oxygen forms known as free radicals, ginkgo leaf extract directs antioxidant effects to the brain, central nervous system, and cardiovascular system. This is one of the mechanisms that make it promising in treatment of age-related declines of brain function.
Ginkgo is one of the few herbs produced in very complex forms with predictable effects. Nearly all studies have been conducted on a highly concentrated ginkgo leaf extract standardized to 24 percent flavone glycosides, further calibrated for six percent ginkgolides, and with potentially toxic ginkgolic acid removed. The results of studies on the complex leaf extract do not apply to the dried leaf or leaf tea.
Some individuals have shown hypersensitivity to ginkgo leaf extracts including rare cases of gastrointestinal upset, headaches, or skin allergies. In such cases use of ginkgo should be discontinued.
Age-related memory loss