ANTIINFLAMMATORY EFFECT OF UNCARIA TOMENTOSA
("CAT'S CLAW")

(From the May 15, 1995 Bulletin of the National Institute of Traditional Medicine, Peru's Ministry of Health. English translation by Laura León)

Inflammation is a non-specific defensive response of the tissues to local aggression. In acute inflammation, blood vessel dilatation, liquid and plasmatic protein exudation, and leukocytarian emigration are prevalent . Chronic inflammation is characterized by the presence of lymphocytes and macrophagues, as well as the proliferation of blood vessels and conjunctive tissue. In both cases, edema, blush, an increase in local temperature, and pain are present.

The Medicinal Plant

For "bone aches" and other inflammations, the medicine men or "curanderos" of the Peruvian rainforest ashaninka community use Uncaria tomentosa (Willd.) DC; an 18 to 19 meter long vine that grows in high forest with abundant sunlight at 700-800 meters above sea level. This climbing rubiaceous is covered by pink-colored bark and clings to other trees using small hooks that resemble cat's claws. The "curanderos" boil the stem's bark in water for 1 hour and have their patients drink the extract during the day. The usual dose is a litre a day until the symptoms dissapear. The medicinal applications of cat's claw comprise innumerable clinical cases, the antiinflamatory, antitumoral, and contraceptive uses being the better known ones (Cabieses, 1994; Jones, 1994; Steimberg, 1994).

The main compounds identified in U. tomentosa are listed in Ffigure 1 (Lock de Ugaz, 1994). The alcaloids (Keplinger, 1982) and the glycosides (Aquino et al; 1991) show systematic antiinflammatory action. There are also preliminary evidences of an antiinflammatory effect from the sterolic fraction (Senatore et al; 1989), attributed mainly to ß-sitosterol (Scheda Informative, 1994).

Figura 1 Componentes de la Uncaria Tomentosa

Alcaloides oxindólicos Glicósidos del ácido quinóvico Triterpenos polihidroxilados Acetil derivados de esteroles Polifenoles

Experimental Model

For the evaluation of U. tomentosa's antiinflammatory action, researchers have made use of an experimental model that consists of inducing inflammation in a rat's hind paw with a shot of Carragenian solution and measuring the induced edema using a plethysmograph. Rats treated with U. tomentosa before, during, or after edema induction are compared to control rats that do not recieve drugs or recieve conventional antiinflamatory drugs.

Antiinflamatory Efficiency

A statistically significant reduction of the edema after the use of U. tomentosa alcaloids was reported in research carried out in Austria (Keplinger, 1982). Antiinflammatory efficiency (AE) is computed as a percentage (the volume of the edema induced in experimental rats as a percent of that of control rats). For example, Figure 2 shows the edema evolution both in rats treated with glycoside 7 of U. tomentosa quinovic acid and in rats that were not treated. (Delta is the volume difference before and after the Carragenian shot). At the highest point of the edema (hour 3), the treated rats exhibited a volume that was 33% less than the volume of those with no treatment.

In Italy, Aquino et al. (1991) observed an antiinflamatory effect of U. tomentosa that was comparable to that of indomethacine. This finding has been extended in Peru (Peralta and Zambrano, 1992). Table 1 compares the AE of an U. tomentosa extract (9:1 chloroform methanol, 0.16 mg/kg). The values are averages of AEs measured every half hour until reaching the fifth hour. The U. tomentosa extract had a significantly higher antiinflammatory effect than that of the conventional drugs.

 

Table 1 Antiinflammatory Efficiency averaged over 5 hours (Adapted from Peralta and Zambrano, 1992, Table III)
U. TOMENTOSA 87.2%	INDOMNETHACINE 77.0%	PIROXICAM 72.5%	DEXAMETHASONE 72.0%

Synergies

Aquino et al. (1991) pointed out the possible antiinflammatory synergy of U. tomentosa compounds. First, they obtained 5 extracts and evaluated their antiinflammatory efficiency. Then they isolated 5 fractions of the most efficient extract (AE = 69.2%), none of which were as efficient as the extract; and several fractions were inactive. In the most efficient fraction (AE = 46.89%), they isolated 9 compounds, none of wich were as efficient as the fraction; and several compounds were inactive. The authors proposed the hypothesis that some compounds (e. g; glycoside 7) have an intrinsec antiinflammatory effect of the fractions and extracts on activating in the combination. The additive and mutually reinforced effect of alcaloids, glycosides, and sterols of U. tomentosa are the subjects of current research.

Possible Action Mechanisms

The U. tomentosa's alcaloids stimulate the inmunological system, promoting blood neutrophils' and macrophages' phagocytosis, as well as phagocytosis by tissue macrophagues of the reticularendotelial system (Wagner et al; 1985). The macrophagues activated by U. tomentosa probably eliminate, by phagocytosis, the immunizing complexes that cause inflammation. In their turn, glycosides have an antioxidant action that protects cells from degenerative processes (Rizzi et al; 1933).

Clinical Experiences

Dr. K. Keplinger, from the Immodal Pharmaka laboratory at Innsbruck, offers cat's claw capsules under the brand name of KALLENDORN. Summarized clinical histories that illustrate its therapeutical effects appear in Figure 3. In Naples, Dr. F. P. laccarino uses tablets and an oral spray of cat's claw extract produced by the Italian-Peruvian Laboratory of Homeopathic Research. He states that in all cases of inflammatory processes, even in those where solid bodies are deposited, there has been an improvement of health. No side-effects have been observed, even after continued tablet intake. In Cusco, homeopaths from the Peruvian Iinstitute of Andean Phytotherapeutic Research have exported excellent U. tomentosa action concerning rheumatologic cases, with no side effects. The recent popularity of industrial products of this medicinal plant in Peru have brought up abundant testimonies of relief from patients that suffer chronic inflammatory processes.

Figure 3 Austrian clinical cases

Female, 64 years old. Chronic polyarthrosis In knees during 12 years...After 14 days (of treatment with U. tomentosa) there has been a favorable change... Movement has improved and pain has disappeared. Female, 36 years old...suffers rheumatoid arthritis. After 4 weeks of applying U. tomentosa, pain was considerably reduced... Female, 42 years old...suffers from rheumatoid arthritis...She used U. tomentosa..Pain in joints has disappeared almost completely.

Comment

Conventional antiinflammatory drugs rely on diverse action mechanisms, yet share severe gastrointestinal side effects. U. tomentosa is a more efficient antiinflammatory and does not appear to bring undesirable side effects. Nevertheless, close monitoring of hepatic and renal safety variables still is lacking, and rigorous long-term clinical follow-ups are needed.

Comparing the antiinflammatory efficiency of U. tomentosa to that of Uncaria Guianensis, a more abundant cat's claw variety of the Peruvian rainforest, would be useful.

References