Uña de gato, or Cat's claw, is the popular name for an herb scientifically
called Uncaria tomentosa Willd. This is a woody vine, technically a member
of the Rubiaceae family. It grows in the high Amazonian basin region of Peru
at elevations of 700 to 2500 meters, in the valleys of the Perene and the
Paucartambo rivers. Typically, the vine grows to two to three inches or more
in diameter. A related plant, Uncaria guianensis, which grows at lower
elevations, is also called Cat's claw in Peru and employed for the same purposes.
The bark of this vine is widely used as a medicine in Amazonian regions.
Either the bark itself is powdered or else it is made into a concentrated
extract. (The liquid that drains from the stem when it is cut is also used
locally as a medicine.) Since time immemorial it has been used a traditional
medicine among the Ashaninka Indians. Its applications are many: arthritis,
rheumatism, gastritis, and ulcers are commonly treated by cat's claw.
In 1974, cat's claw was "discovered" or rather rediscovered by the Austrian
scientist, Klaus Keplinger of Innsbruck University. It was British scientists
who first correctly identified the plant as Uncaria tomentosa. It was soon
found that injections of some of the active compounds derived from this thick
bark increased T-4 lymphocyte count, thereby reinforcing the immune system,
and having anti-inflammatory properties.
Cat's claw is also said to neutralize stomach ulcers, to work as a diuretic
and to regenerate cells. Dr. Keplinger's first experiments were done in
veterinary problems: a rare kind of "crown" virus that affects cats as well
as the "Maed visna" virus that afflicts lambs. Keplinger then went on to
treat herpes infections in humans.In 1986, he started to work with HIV-infected
people.
According to some Peruvian accounts, after 20 days, people with AIDS showed
beneficial effects on their immune systems and in 30 days their lymphatic
glands showed improvement.
Subsequent research in Germany and Austria has shown that a water (aqueous)
extract of the bark has an enhancing effect on the process by which white
blood cells engulf and digest microbes, phagocytosis. It is said to have
remarkable effects in the treatment of neurobronchitis and allergies as well
as any disease related to the immune system.
COMPOSITION
Dr. Keplinger has found that the bark contains various oxindole alkaloids,
as well as alloisopteropodine (the so-called isomer A), which he is working
on to develop into an anti-AIDS drug. Italian scientists have also discovered
quinovic acid glycosides in the bark, which also possesses antiviral activity.
Scientists at Naples University, for instance, have shown the presence of
anti-inflammatory beta-sitosterols, which would lend credence to the traditional
claims of anti-inflammatory properties.
Italian scientists have also shown how non-toxic the herb really is. Given
to mice orally at a high dose of 5 grams per kilogram of body weight (or
into the peritoneal cavity at 2 g/kg body weight), as well as similar doses
of the raw alkaloid, they produced no observable changes in behavior over
14 days of observation.
The herb-derived compounds did have a significant antioxidant and antimutagenic
effect (which is usually a sign of anti-cancer activity, as well.) Nevertheless,
the herb is not recommended for women intending to become pregnant, because
of its mild contraceptive effect.
According to news reports coming out of Peru, Dr. Keplinger has had great
success in fighting AIDS with this medicinal herb. "The new product has been
administered for the last six years to patients with AIDS....the clinical
symptoms disappeared" (El Comercio, 11/28/88 and 7/17/93). According to the
same article, early investigations done in Austria suggest that cat's claw
may be useful when used in conjunction with conventional chemotherapy and
radiation, in order to minimize the side effects of such treatments, such
as nausea.
There is a natural tendency on the part of some to deny such unsubstantiated
reports and to see the whole topic of cat's claw as yet another health fad.
I think that would be a tragic mistake. Needless to say, all such reports
need to be taken with a grain of salt, and should be subjected to controlled
studies for confirmation.
However, before NCI runs off and starts testing "unnatural" derivatives
[as its director, Dr. Klausner, suggests], it should carry out a patient,
respectful and sympathetic study of the South American and European experience
with the herb. Sit at the feet of the healers and shamans, as well as
the most advanced scientists who have spent decades researching this topic.
In that way, we all might learn how cat's claw can be added to the growing
international medicine bag of herbal treatments useful against cancer.
