Ginkgo biloba is a unique species of tree with no close living relatives. It is believed to be the oldest tree species to survive on earth, with a history dating back to over 200 million years. They can be found in many areas of China and Japan, especially at ancient temples, and have been commonly cultivated in North America for over 200 years. The name ginkgo originates from Chinese, meaning “silver apricot” because its seeds consist of a soft, fleshy shell and a hard core. Ginkgo biloba has been documented in Chinese medicine for nearly 500 years and in the recent 30 years, more than 300 studies have shown that ginkgo may prevent and benefit many problems in the entire body.
Extracts from ginkgo leaves contain flavone glycosides and terpene lactones – the two active constituents that give ginkgo its medical benefits. The flavone glycosides typically make up approximately 24% of the extract and are largely responsible for ginkgo’s antioxidant activity. The terpene lactones typically make up approximately 6% of the extract and are linked with promoting circulation to the brain and other parts of the body. Because of its ability to inhibit platelet aggregation (stickiness), the flavone glycosides allow ginkgo extract to prevent circulatory diseases, such as atherosclerosis, and support the brain and central nervous system. In addition, the antioxidant action of ginkgo extract may also extend to the brain and retina of the eye. Well-known for its effect on memory and thinking, ginkgo extract is often supplemented by older patients to enhance their cognitive performance and to prevent age-related cognitive decline and Alzheimer’s disease.
Most ginkgo extracts are standardized to contain a fixed ratio of the active constituents mentioned earlier. There is no recommended daily intake but doctors have prescribed 120 – 240 mg of ginkgo extract, taken 2 or 3 times daily, to those with mild to moderate Alzheimer’s disease or age-related cognitive decline.
References:
(1) http://www.florahealth.com/flora/home/canada/
products/1469.htm (2) http://en.wikipedia.org/wiki/Ginkgo_biloba
(3) http://www.puritan.com/pages/healthnotes.asp?
languri=eng&ContentID=2096000
