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Ginkgo
biloba
Common name:
Maidenhair tree
Botanical name: Ginkgo
biloba
Ginkgo biloba is the world’s
oldest living species of tree. Individual trees live as
long as 1,000 years. Ginkgo grows most predominantly in
the southern and eastern United States, southern France,
China, and Korea. The leaves of the tree are used in
modern herbal medicine.
Historical
or traditional use
Medicinal use of ginkgo can be traced
back almost 5,000 years in Chinese herbal medicine. The
nuts of the tree were most commonly recommended and used
to treat respiratory tract ailments. The use of the
leaves is a modern development originating in
Europe.
Active
constituents
The
medical benefits of Ginkgo biloba extract are
attributed primarily to two groups of active
constituents: the ginkgo flavone glycosides and the
terpene lactones. Ginkgo flavone glycosides, which
typically make up approximately 24% of the extract, are
primarily responsible for ginkgo’s antioxidant activity
and may mildly inhibit platelet aggregation
(stickiness). These two actions may help ginkgo prevent
circulatory diseases, such as atherosclerosis, and
support the brain and central nervous system. In
addition to the cardiovascular system, ginkgo’s
antioxidant action may also extend to the brain and
retina of the eye. Preliminary trials have suggested
potential benefit for people with macular degeneration
and diabetic retinopathy. The terpene lactones found in
ginkgo extracts, known as ginkgolides and bilobalide,
typically make up approximately 6% of the extract. They
are associated with increasing circulation to the brain
and other parts of the body and may exert a protective
action on nerve cells. ginkgo regulates the tone and
elasticity of blood vessels, making circulation more
efficient.
Ginkgo is also well-known for its effect
on memory and thinking (cognitive function). It may
enhance cognitive performance in healthy older adults,
in people with age-related cognitive decline, and in
people with Alzheimer’s
disease.
How much is
usually taken?
Most
clinical trials have used between 120 and 240 mg of
ginkgo (standardized to contain 6% terpene lactones and
24% flavone glycosides) per day, generally divided into
two or three portions.The higher amount (240 mg per day)
has been used in some people with mild-to-moderate
Alzheimer’s disease, age-related cognitive decline,
intermittent claudication, and resistant depression.
Ginkgo may need to be taken for eight to twelve weeks
before desired actions such as cognitive improvement are
noticed. Although nonstandardized Ginkgo biloba
leaf and tinctures are available, there is no
well-established amount or use for these
forms.
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