Health care Research in Europe

Cat’s claw, also known by its Spanish name Uña de Gato, is sometimes referred to as the “life giving vine of Peru.” Its name is derived from the hook-like thorns that resemble the claws of a cat. It should not be confused with cat’s claw acacia, which contains a potentially poisonous cyanide compound.

Cat’s claw (Uncaria tomentosa) is a woody vine native to the Amazon and Central American rainforests. Cat’s claw bark and root, often made into a tea, have been used for centuries by South Americans as a remedy for a wide range of ailments, including stomach ulcers and fevers. Most of these uses are unsupported by scientific evidence or only have early evidence supporting their use.

“the commercially available root bark powders can have nearly the same alkaloid content and profile as the more expensive pharmaceutical grade extracts, depending on the purity of the crude extract and the content of the alkaloids therein”

Components of Cat’s Claws:

– Constituents: Most commercial preparations of cat’s claw contain the plant species Uncaria tomentosa. Cat’s claw is found in nature in two different chemotypes producing different alkaloidal constituents. Pentacyclic oxindoles are found in the roots of one type, while the tetracyclic oxindoles are present in the second type. Uncarine C and uncarine E are two stereoisomers of the pentacyclic oxindoles. Other alkaloids of the tetracyclic oxindoles found in cat’s claw include mitraphylline, rhynchophylline, and isorhynchophylline.

Cat’s claw also contains 3,4-dehydro-5-carboxystrictosidine and seven quinovic acid glycosides.

Cat’s claw bark has been found to contain ursolic acid, oleanolic acid, beta-sitosterol, stigmasterol, campesterol, and three polyhydroxylated triterpenes. The C-8-(S) isomer of deoxyloganic acid (7-deoxyloganic acid), together with beta-sitosteryl glucoside, five known stereoisomeric pentacyclic oxindole alkaloids, and the tetracyclic oxindole isorhyncophylline, have been isolated from the inner bark of Uncaria tomentosa.

Rotundifoline and isorotundifolune, quinovic acid glycoside 1-7, flavonoids, and coumarins have all been isolated from Uncaria tomentosa.

Cat’s claw vine accumulates nearly 80% palmitoleic acid (16:1Delta9) plus cisvaccenic acid (18:1Delta11) in its seed oil. Acyl-acyl carrier protein (acyl-ACP) desaturases were isolated from developing cat’s claw seeds. Upon expression in Escherichia coli, the cat’s claw polypeptide functioned as a Delta9 acyl-ACP desaturase and displayed distinct substrate specificity for palmitate (16:0)-ACP.

Benefits of Cat’s Claws

Several identified properties of cat’s claw make it attractive to medical researchers. It has been shown to have immune-modulating, antioxidant, and anti-inflammatory effects and research is looking into its potential use for several concerns, including some types of arthritis, Lyme disease, and cancer.

May Boost Your Immune System Cat’s claw may support your immune system, possibly helping fight infections more effectively.

A small study in 27 men found that consuming 700 mg of cat’s claw extract for 2 months increased their number of white blood cells, which are involved in combating infection. Another small study in four men given cat’s claw extract for six weeks noted the same results.

Cat’s claw seems to work both by boosting your immune response and calming an overactive immune system.

Its anti-inflammatory properties could be responsible for its immune benefits. Despite these promising results, more research is needed.


Cat’s claw contains a unique compound known as pentacyclic oxindolic alkaloid (POA) that is believed to have anti-inflammatory effects, which makes it attractive as a possible treatment for arthritis. POA appears to block the production of inflammatory substances such as tumor necrosis factor-alpha (TNF-a).

TNF-a helps regulate the immune response and, among other things, is responsible for inducing fever, inflammation, and apoptosis (programmed cell death) in old or damaged cells.

Lyme Disease

A special type of cat’s claw, known as samento, is believed to aid in the treatment of Lyme disease. Proponents claim that samento is able to “boost” the immune system more effectively than regular cat’s claw because it is devoid of a compound called tetracyclic oxindole alkaloid (TOA), which is believed to inhibit POA.


Some early test tube studies have suggested that the POA found in cat’s claw may have antitumor properties. It is believed that POA is toxic in specific cancers cells and may have less impact on the healthy cells that are typically damaged by chemotherapy.

Dosage and Preparation

Cat’s claw supplements are generally sold in capsule and tincture formulations. The herb is also available in tea bags or purchased as loose “wild-crafted” powders and bark chips. There is no official guidance as to the appropriate use of cat’s claw. Dosing recommendations vary by manufacturer and are guided more by current practices than by hard evidence. Capsule formulations are generally considered safe at doses of up to 350 milligrams (mg) daily. The dosing of cat’s claw tinctures can vary by the strength of the formulation, but 1 to 4 millilitres (ml) daily is the most commonly recommended dose. As a rule of thumb, never take more than is recommended on the product label.

How to Make Cat’s Claw Tea

The indigenous people of Peru boil traditionally boil 20 to 30 grams (g) of the inner bark or root in a litter of water for 30 to 60 minutes.

For home use, you can steep one tablespoon (2 g) of dried cat’s claw powder in one cup of hot water for five to 10 minutes.

The flavour of the tea, unsurprisingly, is bitter and woody. Some people like to mix it with rooibos tea, honey, and lemon to make it more palatable.

However, WHO says that an average daily dose is 20–350 mg of dried stem bark for extracts or 300–500 mg for capsules, taken in 2–3 separate doses throughout the day.

Studies have used daily doses of 60 and 100 mg of cat’s claw extract for treating rheumatoid arthritis and osteoarthritis of the knee, respectively.

One potential risk is that many herbal supplements — including cat’s claw — are not tightly regulated by the FDA. Therefore, it’s best to purchase cat’s claw from a reputable supplier to reduce the risk of contamination

Possible Side Effects

Cat’s claw may cause side effects in some people, including:11

–          Nausea

–          Headache

–          Dizziness

–          Diarrhea

–          Vomiting

–          Low blood pressure

Most side effects resolve on their own once the treatment is stopped. Cat’s claw can also slow blood clotting, leading to easy bruising and bleeding (particularly in people on anticoagulants). Because of this, you should stop taking cat’s claw at least two weeks before surgery to avoid excessive bleeding.

It is generally advised that the following groups of people should avoid or limit cat’s claw:

–          Pregnant or breastfeeding women. Cat’s claw is not considered safe to take during pregnancy or breastfeeding due to a lack of safety information.

–          People with certain medical conditions. Those with bleeding disorders, autoimmune disease, kidney disease, leukemia, problems with blood pressure, or who are awaiting surgery should avoid cat’s claw.

–          People taking certain medications. As cat’s claw may interfere with some drugs, such as those for blood pressure, cholesterol, cancer, and blood clotting, you should speak to your doctor before taking it.

The lack of safety evidence means that you should always use cat’s claw with caution.

Recent Studies

SARS-CoV-2 contains four structural proteins, namely the spike (S), membrane (M), envelope (E) and nucleocapsid (N) proteins. The S protein is responsible for the host  attachment and fusion of the viral and host-cell membranes (Wu et al., 2020). Otherwise, the angiotensin-converting enzyme 2 receptor (ACE-2r) is the host cellular receptor with a higher affinity to SARS-CoV-2 (Jamwal et al., 2020). This process is triggered when the S1 subunit of S protein binds to a host-cell receptor (Han & Král, 2020). To engage a host-cell receptor, the receptor-binding domain (RBD) of S1 undergoes transient hinge-like conformational motions (receptor-accessible or receptor-inaccessible states). U. tomentosa’s constituents could block the virus from binding to human cell receptors and disrupt the virus cycle helping to prevent the protein maturation of SARS-CoV-2 and limit its infection spread (Li et al., 2020).

Several molecular targets have been identified as the main druggable key of SARS-Cov-2 for new antiviral discovery. Moreover, its X-ray structure has been recently released, hence allowing possible computational analysis. In fact, several computational studies have already been undertaken on this system including a long 20 μs molecular dynamics (MD) study and virtual screening of several databases (Huang et al., 2020).


Cat’s claw is a popular herbal supplement derived from a tropical vine. While research to support many of its supposed health benefits is limited, some evidence suggests that cat’s claw may help boost your immune system and ease symptoms of osteoarthritis and rheumatoid arthritis.

Because safety and dosage guidelines have not been established, it may be best to consult with your doctor before taking cat’s claw.