General Description
Devil's claw is a perennial plant native to desert regions of southern
Africa and Madagascar. The common name of the plant, which is actually
a translation of the German Teufelskralle, is derived from the plant's
unusual fruits, which are covered with thorny, claw-like barbs.1
The plant lies dormant most of the year, awakening during times
of sporadic rainfall to bring forth lush green leaves and bright
red, trumpet-shaped blossoms. In order to store enough moisture
to survive in its desert habitat, devil's claw has developed a specialized
root system consisting of primary roots, which are roughly 1 meter
in length, and several secondary storage roots, or tubers, which
resemble potatoes. These tubers are harvested in autumn and dried
for medicinal use.
Health Applications
- Arthritis
- Low back pain
- Digestive aid
History and Traditional Use
Devil's claw has a long history of use in the traditional tribal
medicine of southern Africa, where it has been used to treat arthritis,
rheumatism, headaches, and fevers, and as a tonic for the digestive
system.2 It was also used by pregnant women
to alleviate pain during difficult deliveries.1
The herb has become popular throughout much of Europe and Canada
as a home remedy for arthritis relief.3
Chemical Composition
Pharmacological experiments conducted on devil's claw extracts
have shown analgesic and antiinflammatory activity.4
The constituents believed responsible are a group of compounds
known as iridoid glycosides, one of which, harpagoside, is widely
viewed to be the herb's main active component. Devil's claw extracts
are often standardized for harpagoside content, but some studies
using isolated harpagoside have shown no antiinflammatory effect,
indicating other compounds may be responsible for antiinflammatory
activity attributed to the herb.5
Contemporary Uses
Although most modern use of devil's claw has centered on its purported
antiinflammatory and analgesic properties, the herb is still used
by some as an appetite stimulant and digestive tonic. Germany's
Commission E lists devil's claw root as an approved herb for "loss
of appetite, dyspepsia," and "supportive therapy of degenerative
disorders of the locomotor system."6 Devil's
claw's usefulness as an analgesic and antiinflammatory remains
in question. Research indicates that devil's claw inhibits the
production of oxygen free radicals, which are components of the
inflammtory response.7 However, one study
conducted on laboratory rats found no antiiflammatory activity
for devil's claw, even when administered at doses over 100 times
those recommended for humans.8 Although devil's
claw is used widely as a folk remedy for osteoarthritis and rheumatoid
arthritis, evidence to support such use is mostly anecdotal.9
While there have been impressive results reported in small, poorly
controlled trials,10 well designed, placebo-controlled
trials are needed before the usefulness of devil's claw in arthritis
treatment can be determined. Three small studies found devil's
claw to be more effective than placebo in treatment of low back
pain,.11-13 but these results have yet to
be duplicated in large-scale trials.
Dosage/Toxicity
The daily dosage approved by Commission E is 4.5 grams of dried
root or equivalent preparations. There are no known side effects
at this dosage.6 Clinical trials have used
extracts providing the equivalent of 6 grams of dried root per
day with no apparent toxicity.12-13 Devil's
claw is not recommended for people with gastric or duodenal ulcers.6
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