Health care Research in Europe

Written by Alejandro Andión


Cat’s claw is a climbing plant of the Rubiaceae family native to Paraguay, Ecuador, Colombia, Perú and Bolivia. (1)
It has a woody, thin and climbing stem, which can exceed 40 meters in length and reach 20 meters in height. The leaves are elliptic with a smooth edge, and grow in opposing pairs. (1)
In addition, along the stem it has curved, and reflex spines directed in the opposite direction to the growth of the stem – which serve to anchor, its name comes from these hook-shaped spines, which resemble the claws of a cat. (1)
It grows in the Amazon, along the eastern flank of the Andes Mountain range, and develops best at altitudes between 200 and 800 meters above sea level. (1)
Its scientific discovery dates to 1830, the year in which it was first described as a species. However, it was not until the 1950s that the German naturalist Arturo Brell carried out the first systematic studies of the species from plants collected in the central Peruvian jungle. (1)
There are two species of cat’s claw commonly used in North America and Europe, Uncaria tomentosa and Uncaria guianensis, having different properties and uses. The two are frequently confused but U. tomentosa is the more commonly used in traditional medicine. (2)
Cat’s claw has been used as a traditional medicine in South American countries over centuries for its supposed health benefits. The part used medicinally is the bark of the vine or root. (2)


Main constituents of cat’s claw extracts include:
– Oxindole alkaloids (isopteropodine, pteropodine, rhynchophylline, mytraphylline, speciophylline, uncarine F, uncarine E) (3)
– Indole alkaloidal glucosides (cadambine, 3-dihydrocadambine, and 3-isodihydrocadambine) (3)
– Polyhydroxylated triterpenes (uncaric acid, floridic acid, PHT-1) (4)
– Quinovic acid glycosides (QAG-1, QAG-2, QAG-3, QAG-4, QAG-5, QAG) (4)
– Proanthocyanidins ( Proanthocyanidin C1, Epiafzelechin-4Beta-8, Proanthocyanidin B4, Proanthocyanidin B2, Epicatechin, Chlorogenic acid) (4)
– Tannins, polyphenols, catechins and beta sitosterol. (3)


SARS-CoV-2 (5)
Published: 2021 Feb 24.
Study title: The Hydroalcoholic Extract of Uncaria tomentosa (Cat’s Claw) Inhibits the Infection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) In Vitro
Autors: Andres F Yepes-Perez , Oscar Herrera-Calderón , Cristian A Oliveros, Lizdany Flórez-Álvarez , María I Zapata-Cardona , Lina Yepes 4, Wbeimar Aguilar-Jimenez , María T Rugeles , Wildeman Zapata
Study conclusion:
In this study, the antiviral potential of the hydroalcoholic extract of the stem bark of Uncaria tomentosa from Peru against SARS-CoV-2 in vitro was investigated. The results showed that U. tomentosa, known as cat’s claw, has an antiviral effect against SARS-CoV-2, which was observed as a reduction in viral titer and CPE (cytopathic effect) after 48 h of treatment on Vero E6 cells. Therefore, it is hypothesized that the stem cortex of U. tomentosa could be promising in the development of new therapeutic strategies against SARS-CoV-2.

Published: 2019 Jan 24.
Study title: The Amazon rain forest plant Uncaria tomentosa (cat’s claw) and its specific proanthocyanidin constituents are potent inhibitors and reducers of both brain plaques and tangles
Autors: Snow AD, Castillo GM, Nguyen BP, Choi PY, Cummings JA, Cam J, Hu Q, Lake T, Pan W, Kastin AJ, Kirschner DA, Wood SG, Rockenstein E, Masliah E, Lorimer S, Tanzi RE, Larsen L.
Study conclusion:
This study found that specific phytochemicals in Cat’s claw (proanthocyanidins) had an inhibitory effect on the formation of both beta-amyloid plaques and tau protein “tangles”. The accumulation of beta-amyloid plaques and tau protein tangles have been posited as a primary cause of Alzheimer’s Disease. This finding led the authors to conclude: “The discovery of a natural plant extract from the Amazon rain forest plant (Uncaria tomentosa or cat’s claw) as both a potent “plaque and tangle” inhibitor and disaggregator is postulated to represent a potential breakthrough for the natural treatment of both normal brain aging and Alzheimer’s disease.”

Published: 2021 Oct 27.
Study title: Comparison of the chemical constituents and anti-Alzheimer’s disease effects of Uncaria rhynchophylla and Uncaria tomentosa
Authors: Xu, Qing-Qing; Shaw, Pang Chui; Hu, Zhen; Yang, Wen; Ip, Siu-Po; Xian, Yan-Fang; Lin, Zhi-Xiu
Study conclusion:
This study has found a significant improvement in cognitive function following the administration of Cat’s claw extract, albeit exclusively in rats. This 2021 study published in Chinese Medicine found that rats with Streptozotocin-induced Alzheimer’s Disease showed improved memory function after being given a large, highly concentrated dose of Cat’s claw extract. Again, the authors concluded that their findings “amply implicate that both of UTE (Uncaria tomentosa) and URE (Uncaria rhynchophylla) are worthy of being developed clinically into pharmaceutical treatment for AD (Alzheimer’s Disease).


Cat’s claw has soared in popularity as an herbal supplement due to its alleged health benefits — though only the claims below are backed up by sufficient research.
May boost your immune system
Studies suggest that cat’s claw may support your immune system, possibly helping fight infections more effectively.
Its anti-inflammatory properties could be responsible for its immune benefits.
Despite these promising results, more research is needed.
May relieve symptoms of osteoarthritis
In this case, in an eight-week study, a supplement of cat’s claw and maca root reduced pain and stiffness in people with osteoarthritis. In addition, participants needed pain medication less frequently.
Another trial tested a daily mineral supplement alongside 100 mg of cat’s claw extract in people with osteoporosis. After 1–2 weeks, joint pain and function improved compared to those not taking the supplements.
However, after eight weeks, the benefits were not sustained.
It should also be noted that it can be difficult to determine the specific actions of cat’s claw in studies that test multiple supplements at once.
Scientists believe that cat’s claw may ease osteoarthritis symptoms due to its anti-inflammatory properties.
Keep in mind that more research is needed on cat’s claw and osteoarthritis.
May relieve symptoms of rheumatoid arthritis
Some studies suggest that cat’s claw can help relieve its symptoms.
For example, a study in 40 people with rheumatoid arthritis determined that 60 mg of cat’s claw extract per day alongside regular medication resulted in a 29% reduction in the number of painful joints compared to a control group.
As with osteoarthritis, cat’s claw is thought to reduce inflammation in your body, easing rheumatoid arthritis symptoms as a result.
Although these results are promising. Larger, better-quality studies are needed to confirm these benefits.


– 1 cup of water
– Freshly squeezed lemon juice, a few drops
– 1-2 teaspoons Cat’s claw ground powder (or 1-2 average-sized pieces bark)
– Honey or spices to improve the taste (Optional)

The process is developed in four simple steps:
– Step1: Pour boiling water into a cup and add a few drops of lemon juice. The acid from the lemon juice will release the tannins in the tea.
– Step2: Add the cat’s claw to the cup. If your cat’s claw is ground, use 1 to 2 teaspoons in a typical tea strainer. If you are using cat’s claw bark, add one to two average-sized pieces. (For proper use, consult the dosage information section).
– Step 3: Let the cat’s claw steep for five to 10 minutes. Remove the strainer from the cup. If you are using bark, remove the bark with a spoon.
– Step 4: Sweeten the tea to taste. Cat’s claw tea does not have a very good natural flavour. Consider adding honey or spices to improve the taste. (Optional).


The dosage guidelines have not been established.
However, WHO (World Health Organization) 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.


While side effects of cat’s claw are rarely reported, available information to determine its overall safety is currently insufficient.
The high levels of tannins in cat’s claw may cause some side effects, including nausea, stomach upset, and diarrhea, if consumed in large amounts.
Case reports and test-tube studies support other possible side effects, including low blood pressure, increased risk of bleeding, nerve damage, anti-estrogen effects, and adverse effects on kidney function.
That said, these symptoms are rare.

1. Wikipedia in Spanish. (June 20, 2022). Uncaria Tomentosa
2. Wikipedia in English. (May 17, 2022). Uncaria Tomentosa
3. National Library of Medicine, National Center for biotechnology information. (February 18, 2019). Cat’s Claw.
4. Andres F. Yepes-Pérez, Oscar Herrera-Calderon, and Jorge Quintero-Saumeth (October 29, 2020). Uncaria tomentosa (cat’s claw): a promising herbal medicine against SARS-CoV-2/ACE-2 junction and SARS-CoV-2 spike protein based on molecular modelling.
5. Andres F Yepes-Perez , Oscar Herrera-Calderón , Cristian A Oliveros, Lizdany Flórez-Álvarez , María I Zapata-Cardona , Lina Yepes 4, Wbeimar Aguilar-Jimenez , María T Rugeles , Wildeman Zapata. (February 24, 2021). The Hydroalcoholic Extract of Uncaria tomentosa (Cat’s Claw) Inhibits the Infection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) In Vitro.
6. Mary Jane Brown, PhD, RD (UK). (January 31, 2019). Cat’s Claw: Benefits, Side Effects, and Dosage.
7. Michael Long. How to Make Cat’s Claw Tea.