Cat’ Claw

cat's claw leafs

Other common names: Uña de gato
Latin name: Uncaria tomentosa (Willd.) DC. [Rubiaceae]
Plant part: Root


Cat’s claw, or uña de gato, is a South American vine that has been
used widely as a folk remedy. Claims have been made for its effectiveness
against viral infections, including human immunodeficiency
virus (HIV), as well as cancer, arthritis, and a long list of largely incurable
diseases. Following clues from the Asháninka Indians in the
Central Peruvian rain forest, it was discovered that there are two
chemotypes of U. tomentosa. One contains predominately pentacyclic
oxindole alkaloids (pteropodine, isopteropodine, isomitraphylline,
etc.), which are reported to have immunostimulatory activity. The
other chemotype contains primarily tetracyclic oxindole alkaloids
(rhynochophylline and isorynchophylline), which are thought to oppose
the actions of the pentacyclic oxindole alkaloids. Because these
two chemotypes are identical in appearance, commercial cat’s claw is
usually a mixture of the two. Thus, it is suggested that cat’s claw
products taken for their immunostimulatory action have no more than
0.02 percent tetracyclic oxindole alkaloids (Schulz, Hänsel, and Tyler,
2001; Reinhard, 1999).

Saventaro® (Krallendorn®) capsules contain 20 mg root extract,
which is standardized to 1.3 percent pentacyclic oxindole alkaloids
and free of tetracyclic oxindole alkaloids. Saventaro is manufactured
by IMMODAL Pharmaka GmbH in Austria and under license in the
United States by Enzymatic Therapy, Green Bay, Wisconsin.

Rheumatoid Arthritis
Saventaro (three 20 mg capsules daily) was given to patients with
rheumatoid arthritis stage II and III in a double-blind, placebo-controlled
trial that included 40 subjects. After six months, there was a
significant reduction in pain but no effect on joint swelling or laboratory
indicators of inflammation compared to placebo (Clinical Examinations
of Krallendorn Products, 1999). Our reviewer, Dr. John
Trimmer Hicks, commented that although significant pain relief was
documented, a much larger sample size is needed to prove significant
differences in trials on disease-modifying agents for rheumatoid arthritis
due to large placebo effects usually seen in these trials.