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Cat's Claw

 

Cat’s Claw

(Uncaria tomentosa)

 

Alexander G. Schauss, PhD

Director, Life Sciences Division,
American Institute for Biosocial Research
Tacoma, Washington
Clinical Professor of Natural Products Research,
National College of Naturopathic Medicine,
Portland, Oregon

 

Introduction

The Latin name for this herb is Uncaria tomentosa. The Spanish call it “uña de gato”, which translated into English is “cat’s claw.” The reference to a cat’s claw comes from the appearance of small hook-like appendices at the junction of this vine’s leaves. The Latin word for hook is uncus. Every member of the genus Uncaria has this distinctive characteristic.

U. tomentosa (referred to as “Cat’s Claw” hereinafter) is a liana, or as we more commonly refer to it, a vine, that is an indigenous plant found in the eastern Andes mountains of Peru and Colombia, that has spread throughout tropical areas of Central and South America, including Panama, where it is considered a nuisance plant on many banana plantations. The vine is akin to a weed. It averages 25-30 feet in length, but can reach to lengths of over 200 feet when climbing up towering trees found in the forests of South America. The base of the vine can be as thick as a watermelon.

Proponents of Cat's Claw have claimed that this new darling among herbal dietary supplements treats everything from malignant tumors to arthritis. This has stimulated considerable interest in this herb and, unfortunately, a number of unsubstantiated and even false myths that need to be dispelled.

Claim: “It is illegal to export the root of Cat’s Claw from Peru.”

Fact: False. Peru has no law prohibiting the export of Cat’s Claw root or bark. It is legal to export from Peru and import into the United States and other countries the bark or the root of the plant. Claims that it is illegal to do so is an outgrowth of competition between a company promoting the sale of the bark to the exclusion of the root, possibly because they could not gain access to the root product. If the myth was true, those exporting the root from Peru would have been arrested whenver they left or returned from Peru. Instead, company representatives who market Cat’s Claw root in the United States and throughout the world make frequent trips to Peru to oversee the harvesting and milling of the herb. None have ever been arrested or charged with any illegal export activities. Since 1975, Peru has banned the exportation of whole live plants without government approval.

Cat’s Claw is quite abundant. Similar to a dandelion, if you don’t remove the whole root, it will grow back. For this reason, during harvesting of the root, a portion of the root is left behind. In addition, companies that supply Cat’s Claw root to dietary supplement manufacturers and also offer a brand line of Cat’s Claw products, such as Inmuno Vital (Miami, FL) are very conscious of the importance of maintaining and preserving this important wildcrafted herb.

Claim: If it is labeled "Cat’s Claw" you can be sure it is genuine Uncaria tomentosa.

Fact: False. Uncaria guianensis is an Uncaria species found in the Amazonian area of Brazil and the Andes Mountains of Peru and Colombia. Unfortunately it is also called by the same Spanish name, “uña de gato.” Other Spanish names for both species are “garabato” and “unganangi” or the Spanish word for “Hawk’s Claw.”

It is important to know that U. guianensis has a different alkaloid makeup than U. tomentosa. U. guianensis has been used by shamans in Brazil and Peru for the treatment of a variety of ailments.(1)(2)(3). Analytical studies have found that the bark of both U. guianensis and U. tomentosa contain non-alkaloid glycosides, including quinovic acids.(4)(3). However, little is known about the toxicity of U. guianensis, while its clinical efficacy has yet to be confirmed by clinical trials.

There is also a third herb called “Cat’s Claw” to adds additional potential confusion; but this one is potentially toxic. In 1995 the Corpus Christi Texas Caller-Times, reported that some Hispanics along the U.S./Mexican border were buying “Uña de Gato” ( or “Cat’s Claw”) at local flea markets and border stores.(5) An investigation by the Texas department of health found the “Cat’s Claw” was mislabeled and actually an unrelated plant,Acacia greggii, that grows in the deserts as a shrub in both Mexico and the United States. Acacia greggii contains a cyanide compound not fit for human consumption.

Buy Cat’s Claw (Uncaria tomentosa) root or bark from a reputable source.

Claim: The bark is “better” than the root.

Fact: False. Most of the research on Uncaria tomentosa has been done on the root, although there is an appreciable growing body of data on the bark. Both products have therapeutic value, but there is a different in the concentration of the alkaloids and even composition of each plant part. Recent studies by experienced laboratories in Europe have revealed that there is between 3 to 20 times the concentration of total alkaloids in the root compared to that found in the bark.

As a raw material, the bark sells for approximately one half or less of the cost of the root. However, if the root contains appreciably more alkaloids, then on a gram for gram basis the root will contain more alkaloids. Of course, there are always exceptions. The retail price of Cat’s Claw root may be higher than the bark, but remember, the customer needs to take less of the root powder than the bark powder to obtain equivalent amounts of the total alkaloids. This does not infer that the bark is less useful. It is just that the root can be a better buy.

Surprisingly, far less root is sold than bark, probably due to the lack of adequate information on the difference between the two, and the previous campasign that falsely claimed the root was illegal to export. If the customer desires to take the product for its anti-inflammatory properties, the root may be superior, since it contains a quinovic acid glycoside that is unique to the root. This glycoside has been demonstrated in animals to be one of the main anti-inflammatory agents in the herb.

Claim: “If the manufacturer shows you a certificate of analysis that the Cat’s Claw they are marketing is adequate in the oxindole alkaloid, isopterodine, you can be sure it is genuine Cat’s Claw.”

Fact: False. Simply testing for one of 14 alkaloids found in Cat’s Claw and using a Certificate of Analysis as evidence that it is the genuine product is, unfortunately, inadequate. There are over 40 species of Uncaria found throughout the world, including U. guianensis mentioned earlier. Most species of Uncaria are known to traditional healers in the regions they grow in. Each species contains the important oxindole and indole alkaloids that will be discussed later. As a result, it is possible to show a high level of isopterodine on a certificate of analysis and assume it means the Cat’s Claw is 100% Uncaria tomentosa. However, depending on the level of only one of 14 alkaloids would be akin to looking at a single ridge of your thumb’s fingerprint and claiming that ridge proves it is you. As you well understand, it takes a number of ridges and swirls to provide enough information to validate that in fact it is you. To be really sure you are getting genuine Cat's Claw, several oxindole alkaloids known to be found in Cat’s Claw need to be analytically identified by an independent laboratory. A list of the 14 alkaloids found in Uncaria tomentosa is shown in Table 1. The 8 alkaloids that can be tested for in a few laboratories around the world are indicated in bold letters.

Table 1.

List of Alkaloids Found In Cat's Claw (Uncaria tomentosa) (6)(1), (7) (8), (9), (10), (11), (12)(13)

carboxystrictosidine

dihydrocorynantheine

hirsuteine

hirsutine

isomitraphylline

isopteropodine

isorotundifoline

isorhynchophylline

mitraphylline

pteropodine

rotundifoline

rhynchophylline

speciophylline

uncarine F

 

Therapeutic Constituents of Cat’s Claw

Table 2 provides a list of the constituents found in Cat’s Claw, and their reported biological activity, potential therapeutic benefits, as adapted and expanded from a previous work on Cat’s Claw written by this author.(14)

 

Table 2

Some Biologically Active Chemicals Found In

Cat’s Claw (Uncaria tomentosa)

 

Compound Biological Activity

Beta-sitosterol (phytosterol) anti-inflammatory

Campesterol (phytosterol) anti-inflammatory

Catechins (tannins) anti-alcoholic, anti-arthritic, anti-cariogenic, anti-histaminic, anti-oxidant, anti- periodontal, anti-ulcer, cancer-preventive

Dihydrocorynantheine (alkaloid) adrenergic blocker, hypotensive

Glycosides metabolic regulation

Hirsuteine (alkaloid) anti-hypertensive

Hirsutine (alkaloid) myorelaxant, anti-hypertensive, hypotensive

Isorhynchophylline (alkaloid) anti-hypertensive, hypotensive

Mitraphylline (alkaloid) anti-hypertensive, hypotensive, myorelaxant, vasodilator

Quercetin (flavonoid) anti-allergic, anti-anaphylactic, anti- asthmatic, anti-cataract, anti-diabetic, anti- viral, antitumor, cancer-preventive, anti- oxidant

Quinovic acid glycoside Anti-viral, anti-inflammatory

Rhynchophylline (alkaloid) anti-hypertensive, hypotensive, sedative, anti-inflammatory, vasodilator

Rutin (flavonoid) anti-cataract, anti-dermatatic, anti-diabetic, anti-tumor, anti-viral, anti-oxidant

Stigmasterol (phytosterol) anti-inflammatory

 

 

By reviewing Table 2, we can begin to confirm the wisdom of traditional healers who have used this herb to treat a diverse range of diseases and conditions, including cancer, arthritis, gastritis, and even some epidemic diseases.

Cat’s Claw is sold as a dietary supplement in countries throughout the world. Since it is generally sold as a powder of the plant (root, bark, or root/bark), with all of its constituents intact, is gentle in its action. It tends to support the body’s own natural processes to restore balance. By comparison, a synthetic drug, by its very nature, forces a rapid change in metabolism which can and often does lead to some side effects.

 

Alkaloids in Cat’s Claw

Alkaloids are among the most biologically active substances found in the plant kingdom. Many alkaloids can be potent therapeutic agents, while some can be highly toxic. For this reason, it is important to characterize (identify) all of the alkaloids in a plant being used for medicinal or food use.

Alkaloids are usually classified according to their basic chemical structure. The most common classifications based on chemical structures are listed in Table 3. Some of the most important groups of alkaloids found in Cat’s Claw possessing therapeutic activities are shown in bold print.

 

Table 3.

Classification of Major Alkaloids

Imidazole

Indole

Isoquinoline

Oxindole

Piperidine

Purine

Pyridine

Quinoline

Steroidal structures

Tropane

 

There are well over 5,000 alkaloids found in plants. Although they are not always easy to define in terms of their biological properties, they generally contain one or more nitrogen atoms per molecule, usually in a heterocyclic ring system, and possess pharmacological action, and by international convention end with the letters “ine”, with few exceptions.

Caffeine, one of several xanthines (e.g. theobromide, theophylline) is a good example of an alkaloid most of us are familiar with. It is found in such foodstuffs as chocolate, tea and coffee. The xanthine, caffeine, is a purine alkaloid (2,6-dioxypurine) derived from the plant, Coffea arabica. Another example is quinine, a cinchona alkaloid that is an anti-malarial agent obtained from the bark of the Chinchona tree (Chinchona officinalis). A toxic alkaloid is strychnine, a plant alkaloid whose toxicity is well known. It is a modified corynane-type monoterpenoid indole alkaloid obtained from the dried, ripe seed of Strychnos nux-vomica, which in Latin means “a nut that causes vomiting.”

One of the most interesting group of alkaloids found in Cat’s Claw, are the indole alkaloids, which are only found in three plant families, Apocyanaceae, Loganiaceae, and Rubiaceae. Within the family Rubiaceae is the genera, Uncaria, of which Uncaria tomentosa is a specific species. Indole alkaloids are widely distributed in nature and include such familiar compounds as tryptophan and serotonin.

Plant species in the Rubiaceae family have a chemical in common, secolaganin, that is necessary for the production of two compounds, strictosidine and carboxystrictodine, required for the production of the indole and quinoline alkaloids.

A second way to classify alkaloids is based on the specific amino acids they are derived from. Subdivisions of alkaloids can be based on amino acid precursors involved in alkaloid biosynthesis. The principal amino acid precursors that can result in these alkaloids are: anthranilic acid, histidine, lysine, nicotinic acid, ornithine, tyrosine, and tryptophan. Simply, plant alkaloids are derived from amino acids.

In human metabolism, 20 different amino acids are commonly found in proteins, and each protein has a unique, genetically defined, amino acid sequence which determines its specific shape and function. They can serve as enzymes, hormones, immunoglobulins, and structural elements, in addition to being involved in oxygen transport, electron transport, muscle contractions, and numerous other activities. In plants they are involved in photosynthesis and a myriad of similar activities.

The alkaloid, mitraphylline, found in U. tomentosa, is a hypotensive agent that acts as a weak central nervous system depressant.(15) The concentration of mitraphylline can vary depending on the part of the plant analyzed.

Rhyncophylline is an alkaloid found in U. tomentosa that has been shown in mice, rats, and rabbits, to have inhibitory effects on platelet aggregation and thrombosis (thromboembolism).(16),(17) The formation of malondialdehyde (MDA) and the release of platelet factor 4 (PF4), suggest that this alkaloid has anti-thrombotic activity.

With the exception of mitraphylline and rhynchophylline, the alkaloids in U. tomentosa have been shown to cause a pronounced enhancement of phagocytosis, in vitro and in vivo.(8) This partially explains its immunostimulatory reputation.

But there are other important constituents in Cat’s Claw than alkaloids.

 

Flavonoids and Their Anti-oxidant Activity

Cat’s Claw contains natural phenolic compounds called flavonoids. Flavonoids have been found to be important compounds found in many plant foods and herbs with a wide range of biological properties. For example, flavonoids can promote anti-oxidant activity. Flavonoids can spare the vitamin, ascorbic acid. Flavonoids can affect carcinogen metabolism by inhibiting the activities of tumor promoters involved in the process of carcinogenesis, including the hyperproliferation of cancer cells.(18)(19) Flavonoids can inhibit peroxidation of fats by trapping free-radicals.(20) Flavonoids can scavenge harmful free radicals such as hydroxyl and superoxide radicals.(21) This helps explain the anti-oxidant activity claims made for Cat’s Claw.

Certainly one of the most provocative actions of Cat’s Claw is its ability to decrease the rate of cellular mutagenicity, a cancer-preventive property of the herb. In a previous work by this author, the case of two chronic smokers was used to illustrate how Cat’s Claw can dramatically decrease mutagenic activity within weeks of use. Nevertheless, further clinical studies are needed.

 

Condensed Polyphenolic Tannins and Their Anti-oxidant Activity

Cat’s Claw contains condensed tannins, represented by such compounds as oligomeric proanthocyanidins (condensed tannins), leucoanthocyanidins, and polyphenols. In recent years, these compounds have been found to possess antioxidant activity.(22) Green tea (Camellia sinensis) is a good example of a plant that contains condensed tannins, whose “polyphenolic” flavonoid compounds are believed responsible for a lower incidence of some cancers in certain Asian populations.

 

Anti-viral Activity

Claims that Cat’s Claw has anti-viral activity has attracted attention, particularly in relationship to some viral diseases. Glycosides in Cat's Claw have been shown to possess moderate anti-viral activity in vitro against the vesicular stomatitis virus and the rhinovirus type 1B (a flu virus).(9) However, the anti-viral effect occurred “at relatively high concentrations with respect to the toxic dose...” Whether the bark contains compounds which diminish the likelihood of side effects if taken at high doses is not known. (Adaptogens, such as Withenia somnifera, asphaltum, or Panax ginseng, are known to contain compounds which can reduce side effects.) This may explain why individuals taking the crude bark or root of Cat’s Claw powders have not reported nearly as many side effects as those subjects who have participated in drug efficacy trials involving isolated constituents.

 

Traditional History of Use of Cat’s Claw

U. tomentosa is used as a remedy for various ailments among indigenous populations living in Latin America, especially tribal groups living in eastern Peru, such as the Ashaninka, Cashibo and Campa Indians. Members of the Ashaninka Indian living group are even employed today to harvest Cat’s Claw.

Traditional Peruvian healers prepare decoctions of Cat’s Claw for the treatment of arthritis, intestinal infections, wound healing, some cancers and several epidemic diseases.(2) (23)(24) One of the earliest references to the use of Cat’s Claw in the English language was made by the botanist Millspaugh in 1892.(25)

 

How Should Cat's Claw by Prepared?

The recommended intake of U. tomentosa is between two to five, 150 milligram, capsules a day on an empty stomach. Individuals experiencing gastrointestinal disturbance following the ingestion of the capsules should consider removing the contents of the capsules and mixing it in a cup of cold water. Slowly heat the water in a small pan for about ten minutes until it reaches the boiling point. When cool it can be consumed. Be forewarned: the taste is bitter.

To prepare a “decoction” of Cat’s Claw, mix the fine powder with cold water and allow the mixture to simmer for 45 minutes on a stove at a temperature of 80 degrees Celsius. Decoctions are generally made in a strength of 30 grams (around one ounce) of powder to 800-850 milliliters (approximately one and one half pint) of water. Around 500 milliliters of simmered down liquid will be left. When cool the decoction is strained through filter paper. Like infusions, decoctions should be prepared fresh on a daily basis and kept in a tightly sealed bottle at room temperature.

The adult dose is approximately 60 milliliters (two ounces) of the decoction mixed with 60 milliliters of water on an empty stomach. For children ages three to six, the dosage should be 20 milliliters of the tea with 20 milliliters of hot water. For older children, adjust accordingly. The decoction or encapsulated powder is taken three times a day.

If side effects occur, such as diarrhea, reduce the frequency and dosage of the product. Generally, diarrhea is an indication that the dose is too high. However, the dose can be gradually increased over a two week period, use the bowel tolerance rule as an indicated of excessive intake.

 

 

References

1. Hemingway SR, Phillipson JD. Alkaloids from S. American species of Uncaria (Rubiaceae). Journal of Pharmacology and Pharmaceuticals 1974;26 (Suppl.):113.

2. Ostendorf FW. Nuttige planten en sierplanten in Suriname. Landbouw Proefstation in Suriname Bulletin 1962;79:199-200.

3. Yepez AM, De Ugaz OL, Alvarez CM, et al. Quinovic acid glycosides from Uncaria guianensis. Phytochemistry 1991:1635-1637.

4. Lavault M, Moretti C, Bruneton J. Alcaloides de I'Uncaria guianensis. Journal of Medicinal Plant Research 1983;47:244-245.

5. Press A. Popular herb thought to be poisonous. Austin (TX) Statesman 1995 September 5, 1995:B3.

6. de Matta SM, Monache DF, Ferrari F, Marini-Bettolo GB. Alkaloids and procyanidins of an Uncaria spp. from Peru. Farmaco-Scientifica 1975;31:527-535.

7. Laus G, Keplinger D. Separation of steroisomeric oxindole alkaloids from Uncaria tormentosa by high performance liquid chromatography. Journal of Chromotography A 1994;662:243-249.

8. Wagner H, Kreutzkamp B, Jurcic K. Die alkaloid von Uncaria tomentosa und ihre phagozytose-steigernde wirkung. (The alkaloids of Uncaria tomentosa and their phagocytosis-enhancing effect). Planta Medica 1985;47:419-423.

9. Aquino R, De Simone F, Pizza C. Plant metabolites. Structure and in vitro antiviral activity of quinovic acid glycosides from Uncaria tomentosa and Guettarda platypoda. Journal of Natural Products 1989;52:679-685.

10. Aquino R, De Simone F, Vincieri FF, Pizza C. New polyhydroxylated triterpenes from Uncaria tomentosa. Journal of Natural Products 1990;53:559-564.

11. Aquino R, De Feo V, De Simone F, Pizza C, Cirino G. Plant metabolites. New compounds and anti-inflammatory activity of Uncaria tomentosa. Journal of Natural Products 1991;54:453-459.

12. Stuppner H, Sturm S, Konwalinka G. HFLC analysis of the main oxindole alkaloids from Uncaria tormentosa. Chromatography 1992;31:597-600.

13. Stuppner H, Sturm S. Capillary electrophoretic analysis of oxindole alkaloids from Uncaria Tomentosa. Journal of Chromatography 1992:375-380.

14. Schauss AG. Cat's Claw. New Canaan, CT: Keats Publishing, 1996.

15. Harbone JB, Baxter H, eds. Phytochemical Dictionary: A Handbook of Bioactive Compounds from Plants. London: Taylor & Francis, 1993.

16. Jin RM, Chen CX, Li YK, Xu PK. Effect of rhynchophylline on platelet aggregation and experimental thrombosis. Acta Pharmacologica Sinica 1991;26:246-249.

17. Chang-Xun C, Ruo-Min J, Yi-Kui L, et al. Inhibitory effect of rhynchophylline on platelet aggregration and thrombosis. Acta Pharmacologica Sinica 1992;13:126-130.

18. Das A, Wang JH, Lien EJ. Carcinogenicity, mutagenicity and cancer preventing activities of flavonoids: A structural-system-activity relationship (SSAR) analysis. Progress in Drug Research 1994;42:133-166.

19. Dewick PM. Medicinal Natural Products: A Biosynthetic Approach. New York: John Wiley & Sons, 1998.

20. Khushbaktova ZA, Yusupova SM, Zamaraeva MV, et al. Interrelationships of the structures and antioxidant activities of some flavonoids from the plants of central asia. Chemistry of Natural Compounds 1996;32:338-343.

21. Larson RA. The antioxidants of higher plants. Phytochemistry 1988;27:969-978.

22. Ferreira D, Bekker R. Oligomeric proanthocyanidins: Naturally occurring O-heterocycles. Natural Products Report 1996;13:411-433.

23. Stuppner H, Sturm S, Geisen G, Zillian U, Konwalinka G. A differential sensitivity of oxindole alkaloids to normal and leukemic cell lines. Planta Med. 1993;Supplement Issue:A583.

24. Personal communication. , 1995.

25. Millspaugh CF. Medicinal Plants. Philadelphia: John C. Yorston & Company, 1892.

 

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