Cat's Claw (Uncaria tomentosa)

cats claw bark

What is Cat's Claw?

Cat's claw is one of the best immune system herbs available, especially for stimulating T-Cell and neutrophil production. Its effects on the immune system also include anti-inflammatory activities.

One of the most important developments in cat's claw research is around the area of adjunct cancer therapy. It has several beneficial actions against the cancer growth itself, as well as activities that help manage the side effects of chemotherapy.

Featured Cat’s Claw Products

 

What is Cat's Claw Used For?

Adjunctive treatment for cancer, poor immune system, HIV infection, rheumatoid arthritis, Herpes zoster infection, Inflammatory bowel disease, Diverticulitis.

Traditional Uses of Cat's Claw

+ Traditional Amazonian Medicine

Cat’s claw has been used by various Amazonian Indigenous cultures including Aguaruna, Asháninka, Cashibo, Conibo, and Shipibo tribes for at least the past 2000 years [1, 28, 29, 30].

The Asháninka Indian tribe of Peru have the longest recorded history of use for this herb. They have used cat’s claw to treat asthma, urinary tract inflammation, arthritis, rheumatism, bone pain, recovery from childbirth, as a kidney cleanser, as a vulnerary for deep wounds, control general inflammation, gastric ulcers, and cancer. [1, 28].

Other Peruvian indigenous cultures used cat’s claw to treat tumors, Inflammation, rheumatism, diabetes, urinary tract cancer in females, hemorrhages, menstrual irregularities cirrhosis, fevers, abscesses, gastritis, rheumatism, gastritis, abscesses, tumors, gastric ulcers, viruses and to normalise the body. [1, 28, 30].

Cat claw has reportedly been used as a contraceptive but several different tribes in Peru. They used very concentrated and large doses to achieve this. The Asháninka for example would boil 5-6 kg (12 pounds) of the root in water until it has been reduced to around 250 ml (1 cup), and consumed by females during menstruation periods for 3 months. Supposedly this will cause sterility for 3 or 4 years. [1].

+ Traditional Chinese Medicine (TCM)

(Chinese species: Uncaria rhyncophylla)

Taste:

Sweet [35]

Energy:

Cold [35]

Channels:

Liver, pericardium [35]

Actions:

Clears heat, Expels wind, extinguishes internal wind, calms and anchors the shen, settles tremors, anchors the yang [35].

Indications:

Headaches, irritability, red eyes, vertigo, fever, dizziness, seizures. Acceptable to use during pregnancy. [35].

Dose:

6-15g decocted 10 mins [35]

In Chinese medicine, the related species Uncaria rhynchophylla is considered to act on the liver, and expell wind conditions. It is often used for central nervous system conditions such as tremor, seizure, and epilepsy [26].

 

Herb Details: Cat's Claw

Herbal Actions:

  • Immunomodulator
  • Antinflammatory
  • Antioxidant
  • Adaptogenic
  • Antiviral
  • Alterative
  • Antihypertensive

Weekly Dose

Part Used

  • Bark, roots, leaves

Family Name

  • Rubiaceae

Distribution

  • South America, Amazon Rainforest

Constituents of Interest

  • Oxindole alkaloids
  • Quinolivic acid glycosides
  • Catechins
  • Procyanidins

Common Names

  • Uña De gato
  • Paraguayo
  • Harbato
  • Garbato Casha
  • Samento
  • Toro
  • Tambor Huasca
  • Uña Huasca
  • Uña De Gavilan
  • Hawks Claw
  • Saventaro

CYP450

  • Unknown

Quality

  • Unknown

Pregnancy

  • No adverse reactions expected.

Taste

  • Unknown

Duration of Use

  • May be used long term.
cats-claw-flower.jpg

Botanical Information

Cat's claw is a woody vine native to the Amazon rainforest. It has characteristic hook-like thorns that curl over like a cats claw.

Cat's claw is contained within the Rubiaceae family of plants which also contains such popular herbs as coffee, Cinchona, and Psychotria.

Cat’s claw is a large woody vine found in the Amazon rainforest. Its characterizing feature are the curved hook like thorns found along the vine itself. These are shaped in a curved hook shape that resembles the claws of cats which is where it gets its common name.

Cat's claw grows up to 30m up into the Amazonian canopy.

There are 2 commonly used species, Uncaria tomentosa, and Uncaria guianensis. The 2 can be told apart by their flowers. Uncaria tomentosa sports small, yellowish-white flowers, and Uncaria guianensis has reddish-orange flowers and its thorns are generally more curved. Both are used interchangeably as medicine however.

It is important to note that there are a few other species of plants referred to commonly as Cat’s claw or Uña de Gato that are completely unrelated. In fact several of these plants have known toxic effects. This is why knowing the botanical name is important when using herbs as medicine, and why purchasing these herbs from a reliable and trustworthy herbalist is very important.

cats-claw-vine.jpg

Pharmacology & Medical Research

+ Alzheimer's Disease

Alzheimer's is a neurodegenerative disorder characterized by the accumulation of extracellular beta-amyloid plaques leading to the eventual death of the synapse. The symptoms of Alzheimer's include a progressive loss of learning, hearing, memory, and other forms of cognitive decline.

Current treatments of Alzheimer's include the use of acetylcholinesterase inhibitors and antagonists of N-Methyl-D-aspartate receptors in an attempt to slow down the progression of this debilitating disease.

In Chinese medicine, a related species of cat's claw (Uncaria rhychophylla) has been used to treat headaches, dizziness, tremors, and hypertension-induced convulsion [19-21]. These are all symptoms of Alzheimer's and other age-related cognitive disorders. Some recent studies on this plant have indicated that it's useful for the inhibition of beta-amyloid fibril formation, as well as the ability to disassemble current beta-amyloid fibrils [22]. It has also been shown to produce significant anti-acetylcholinesterase activity [23]. Cat's claw has been shown in mice models to reverse cognitive deficits induced by D-galactose, which is used as a model to study Alzheimer's [24].

A study investigating the compounds responsible for these known beneficial effects on Alzheimer's found that the main components responsible are rhynchophylline and isorhynchophylline [25]. The results showed that these two chemicals significantly decreased beta-amyloid-induced cell death, calcium overloading, and tau protein hyperphosphorylation in PC12 cells. [25]. PC12 cells are used as a model for studying Alzheimer's in vitro.

Some of the effects noted with cats claw, including its potent antioxidant and vasodilatory actions in the brain, may also be of significant benefit for treating or preventing Alzheimer's or other forms of dementia as well.

+ Cancer

Breast cancer is the most common neoplasm affecting women worldwide but is most prevalent in developed countries. [3]. Roughly 70% of breast cancers express estrogen or progesterone receptors [4].

Women with breast cancer have been shown to present with an increase in blood concentrations of oxidized substances, which may have derived from lipid peroxidation, proteins, and DNA [11,12]. Cat's claw does, in fact, contain a significant amount of antioxidant compounds [8], but this form of treatment towards cancer is controversial, as the performance of antioxidants in vivo depends on the type of free radicals formed. Additionally, it's possible that some antioxidants will protect the cells, but also possible that they will not do anything for that form of free radical damage [3].

A study done comparing the effectiveness of various extracts of cat's claw against Walker-256 tumor model found that the extract containing all fractions of chemicals had more significant effects than did the extracts containing much higher alkaloid content, and extracts containing more non-alkaloid content. These researchers suggested these effects are due to the additional antioxidant value of the non-alkaloid fractions in combination with the alkaloid content [18]. This data indicates that the antioxidant components of cat's claw are indeed active in the free radicals associated with at least some cancer cell lines.

Modern cancer treatment usually involves chemotherapy, which brings with it a wide range of adverse side effects such as leucopenia (low white blood cells), and neutropenia (low neutrophils). When these cells are low, our immune system will be significantly lowered with them. [3].

Some of the older research has shown that cat's claw treatment, along with more modern cancer treatments such as radiation and chemotherapy, have resulted in lower side effects [5], to this form of treatment, which may include hair loss, weight loss, nausea, and secondary infections. It has been suggested that this reduction in side effects is due to cat's claws' ability to support and repair cellular DNA damage [1, 6] and prevent cells from mutating. It also helps to prevent the loss of white blood cells, which is a typical result of chemotherapy. [1].

Cat's claw modulates various levels of the immune system, including the proliferation of both T and B lymphocytes, as well as various cytokines, including TNF-a [7]. It is also directly myelo-stimulating, which acts through myelopoiesis and colony-stimulating factors (G-CSF) to benefit neutropenia (low neutrophils) [6,9]. In chemotherapy, the cytotoxic effects are not limited to cancerous cells but kill other cells in the body. When neutrophil content is lowered below 500 cells/mm3, treatment is generally discontinued [10]. Therefore neutrophils tend to be the limiting factor in the success of chemotherapy, and preventing and managing neutropenia induced by chemotherapy should be considered a top priority [3]. A 300 mg dry extract of Cat's Claw is effective in reducing the incidence and severity of neutropenia in a recent clinical trial. In this study, it was noted that by the end of the treatment, patients treated with Cats claw extract has neutrophil count twice that of the control group [3].

This clear immunostimulating benefit offered by cat's claw may prove to be a beneficial adjunct treatment with advanced cancer therapy for its ability to improve the immune system in immunocompromised patients due to malnutrition, stress, and medication side effects.

+ Hypertension

Other alkaloids contained within cat's claw have been shown to produce antihypertensive effects. These alkaloids include rhynchophylline, hirsutine, and mitraphylline. These alkaloids have been shown to produce vasodilatory actions.

Rhynchophylline has been found to prevent blood clots in blood vessels, dilate peripheral blood vessels, lower heart rate, lower cholesterol [1].

+ Inflammation

Many of cat's claws anti-inflammatory actions can be attributed to its antioxidant compounds and plant sterols [1]. It has been demonstrated to offer anti-inflammatory benefits when it was shown to prevent or modulate lung damage induced by ozone in vivo [27]. The anti-inflammatory action is suggested to be through a variety of factors, including the modulation of TNF synthesis, via NF-kb inhibition [29, 31-33]. A study investigating the more specific effects that cats claw has on cystitis (inflammation of the urinary bladder), found it to be effective in reducing urethral damage, reducing visceral pain, and downregulating several inflammatory factors [34].

Various compounds contained in the plant called quinovic acid glycosides have also been shown to benefit inflammation. In fact, it is these compounds that have been suggested to be the most potent anti-inflammatories contained in the plant. These studies back up much of the traditional use for this plant or such conditions as arthritis, rheumatism, gastrointestinal inflammations such as irritable bowel syndrome and Crohn's disease. [1]. Most likely, however, based on the wide range of anti-inflammatory effects, and a higher amount of anti-inflammatory action noted in the whole plant extract, these actions are the result of synergy found throughout the entire plant, and should not as such be considered the result of just one isolated chemical or class of chemicals. If using cat's claw for inflammation, use the whole plant extract. [16, 17].

+ Antioxidant

The antioxidant effects of a cat's claw hydroalcoholic extract were noted to be most effective when compared to extracts containing mostly alkaloid components, and a separate extract containing mostly non-alkaloid components [18]. This suggests a strong synergy within the plant.

+ Ulcers

The quinovic acid glycosides have been shown to provide significant benefits in treating stomach ulcers in rats [1].

+ Immunomodulatory

Many of the alkaloids contained in cats claw, including the oxindole alkaloids, have been found to produce immunostimulating benefits [1].

+ Neurotransmitters

Pteropodine and isopteropodine have been suggested to provide positive modulatory benefits on brain neurotransmitters such as 5-HT(2) receptors. This suggests a mechanism of action for many of cats claws' uses for conditions such as depression, anxiety, eating disorders, chronic pain, and obesity. [1].

uncaria-tomentosa-powder.jpg

Phytochemistry

Cat's claw contains a group of chemicals referred to as oxindole alkaloids. This class of chemicals has been documented to produce immune-stimulant, antioxidant, antineoplastic, and anti-leukemic actions. [1, 13-15].

Some of the research conducted through the past 30 years on this plant have been market-funded and has resulted in some confusion regarding these oxindole alkaloids. It has been circulating that this plant contains both "good alkaloids" that stimulate the immune system, as well as "bad alkaloids" which have adverse effects on the immune system. The good ones were reportedly pentacyclic alkaloids, and the bad were suggested to be tetracyclic alkaloids. This has been proven to be wrong information, however, as both alkaloids are indeed contained in both species of cat's claw, and in different ratios, however, both alkaloids were shown to produce immunostimulating effects instead. On top of these, both alkaloids have been shown to provide anti-cancer benefits as well [1].

Cat's claw also contains a group of chemicals called quinovic acid glycosides which have well-documented anti-inflammatory and antiviral actions.

Also contained within cat's claw is a series of antioxidant chemicals such as tannins, catechins, and procyanidins. [1, 8].

Plant sterols contained within cat's claw include beta-sitosterol, stigmasterol, and campesterol.

Carboxyl alkyl esters contained within cat's claw provide some of the immuno-stimulant, anti-inflammatory, cell repairing, and anticancer benefits.

Cat's claw contains ajmalicine, akuammigine, campesterol, catechin, carboxyl alkyl esters, chlorogenic acid, cinchonain, corynantheine, corynoxeine, daucosterol, epicatechin, harman, hirsuteine, hirsutine, iso-pteropodine, loganic acid, lyaloside, mitraphylline, oleanolic acid, palmitoleic acid, procyanidins, pteropodine, quinovic acid glycosides, rhynchophylline, rutin, sitosterols, speciophylline, stigmasterol, strictosidines, uncarine A thru F, and vaccenic acid [1].

uncaria-tomentosa.jpg

Clinical Applications Of Cat's Claw:

Cat's claw is best used for conditions related to poor immune function. It has mild antiviral activity, antibacterial activity, and potent immunostimulatory activity. Although immunostimulating, it doesn't tend to worsen autoimmune conditions and is actually an effective treatment for autoimmune conditions like rheumatoid arthritis.

Cat's claw is a useful adjunctive treatment alongside chemotherapy for various cancer cell lines. Other areas of significant benefit with cat's claw include viral infection from HIV, HSV, and EBV.

 

Cautions & Safety Information:

Cat's claw has a high level of safety, and few reported side effects. Due to the immunostimulating activity, however, it is not wise to take cat's claw before or after an organ or bone marrow transplant.

Avoid using cat's claw in combination with Warfarin or other blood thinners.

Cat's claw is generally very safe to consume, however, due to its well documented immunostimulating effects, it is recommended not to consume this herb before or following a bone marrow, or organ transplant or a skin graft as this may increase the chances of rejection. Also, do not take this herb if you are on any immune-suppressing medications as cat's claw may counteract or reduce the effectiveness of these medications. This theory has not been proven but until it is proven otherwise should be assumed that this will happen.

Some of the traditional use of this plant suggest anti-fertility effects and therefore should not be consumed by anybody trying to conceive. This effect has not been proven, however, and very little scientific research has been conducted in this area. Do not rely on this herb to produce anti-fertility actions even in large doses.

Cat's claw contains anticoagulant effects as well and therefore should not be taken by those on blood thinners such as Coumadin, and discontinue use at least a week before any surgery.

Large doses (3-4g at a time) of cat's claw have been reported to produce some gastrointestinal discomfort. These effects tend to disappear after continued use; however, if they do not go away after 3-4 days, reduce the dose or discontinue use. 

 

Synergy

Cat's claw has been suggested to provide protection from non steroidal anti inflammatory drugs such as ibuprofen in the gastrointestinal wall.

 

Author

Justin Cooke, BHSc

The Sunlight Experiment

(Updated November 2018)

 

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References:

  1. Taylor, L. (2005). The healing power of rainforest herbs: A guide to understanding and using herbal medicinals. Garden City Park, NY: Square One Publishers.

  2. Sun, G., Zhang, X., Xu, X., Yang, J., Zhong, M., & Yuan, J. (2012). A new triterpene from Uncaria macrophylla and its antitumor activity. Molecules, 17(2), 1883-1889.

  3. Araújo, S., do Carmo, M., Farias, I. L., Gutierres, J., Dalmora, S. L., Flores, N., ... & Chitolina Schetinger, M. R. (2012). Uncaria tomentosa—adjuvant treatment for breast cancer: clinical trial. Evidence-Based Complementary and Alternative Medicine, 2012.

  4. Phillips, T., Murray, G., Wakamiya, K., Askaa, J., Huang, D., Welcher, R., ... & Allred, D. C. (2007). Development of standard estrogen and progesterone receptor immunohistochemical assays for selection of patients for antihormonal therapy. Applied Immunohistochemistry & Molecular Morphology, 15(3), 325-331.

  5. Riva, L., Coradini, D., Di, G. F., De, V. F., De, N. T., De, F. S., & Pizza, C. (2001). The antiproliferative effects of Uncaria tomentosa extracts and fractions on the growth of breast cancer cell line. Anticancer Research, 21(4A), 2457-2461.

  6. Sheng, Y., Pero, R. W., & Wagner, H. (2000). Treatment of chemotherapy-induced leukopenia in a rat model with aqueous extract from Uncaria tomentosa. Phytomedicine, 7(2), 137-143.

  7. Allen-Hall, L., Cano, P., Arnason, J. T., Rojas, R., Lock, O., & Lafrenie, R. M. (2007). Treatment of THP-1 cells with Uncaria tomentosa extracts differentially regulates the expression if IL-1β and TNF-α. Journal of ethnopharmacology, 109(2), 312-317.

  8. Pilarski, R., Zieliński, H., Ciesiołka, D., & Gulewicz, K. (2006). Antioxidant activity of ethanolic and aqueous extracts of Uncaria tomentosa (Willd.) DC. Journal of ethnopharmacology, 104(1-2), 18-23.

  9. Farias, I., do Carmo Araújo, M., Zimmermann, E. S., Dalmora, S. L., Benedetti, A. L., Alvarez-Silva, M., ... & Schetinger, M. R. C. (2011). Uncaria tomentosa stimulates the proliferation of myeloid progenitor cells. Journal of ethnopharmacology, 137(1), 856-863.

  10. National Cancer Institute (NCI), Common Terminology Criteria for Adverse Events v. 3.0 (CTCAE),

  11. Åkesson, C., Pero, R. W., & Ivars, F. (2003). C-Med 100®, a hot water extract of Uncaria tomentosa, prolongs lymphocyte survival in vivo. Phytomedicine, 10(1), 23-33.

  12. García Giménez, M. D., García Prado, E., Sáenz Rodríguez, M. T., Fernández Arche, M. D. L. Á., & Puerta Vázquez-Zafra, R. D. L. (2010). Cytotoxic effect of the pentacyclic oxindole alkaloid mitraphylline isolated from Uncaria tomentosa bark on human Ewing's sarcoma and breast cancer cell lines. Planta Medica, 76, 133-136.

  13. Paniagua‐Pérez, R., Madrigal‐Bujaidar, E., Molina‐Jasso, D., Reyes‐Cadena, S., Álvarez‐González, I., Sánchez‐Chapul, L., & Pérez‐Gallaga, J. (2009). Antigenotoxic, antioxidant and lymphocyte induction effects produced by pteropodine. Basic & clinical pharmacology & toxicology, 104(3), 222-227.

  14. Bacher, N., Tiefenthaler, M., Sturm, S., Stuppner, H., Ausserlechner, M. J., Kofler, R., & Konwalinka, G. (2006). Oxindole alkaloids from Uncaria tomentosa induce apoptosis in proliferating, G0/G1‐arrested and bcl‐2‐expressing acute lymphoblastic leukaemia cells. British journal of haematology, 132(5), 615-622.

  15. Prado, E. G., Gimenez, M. G., De la Puerta Vázquez, R., Sánchez, J. E., & Rodriguez, M. S. (2007). Antiproliferative effects of mitraphylline, a pentacyclic oxindole alkaloid of Uncaria tomentosa on human glioma and neuroblastoma cell lines. Phytomedicine, 14(4), 280-284.

  16. Reinhard, K. H. (1998). Uncaria tomentosa (Willd.) DC: cat's claw, una de gato, or saventaro. The Journal of Alternative and Complementary Medicine, 5(2), 143-151.

  17. Rizzi, R., Re, F., Bianchi, A., De Feo, V., de Simone, F., Bianchi, L., & Stivala, L. A. (1993). Mutagenic and antimutagenic activities of Uncaria tomentosa and its extracts. Journal of Ethnopharmacology, 38(1), 63-77.

  18. Dreifuss, A. A., Bastos-Pereira, A. L., Fabossi, I. A., dos Reis Lívero, F. A., Stolf, A. M., de Souza, C. E. A., ... & Teixeira, S. (2013). Uncaria tomentosa exerts extensive anti-neoplastic effects against the Walker-256 tumour by modulating oxidative stress and not by alkaloid activity. Plos one, 8(2), e54618.

  19. Hsieh, C. L., Chen, M. F., Li, T. C., Li, S. C., Tang, N. Y., Hsieh, C. T., ... & Lin, J. G. (1999). Anticonvulsant effect of Uncaria rhynchophylla (Miq) Jack. in rats with kainic acid-induced epileptic seizure. The American journal of Chinese medicine, 27(02), 257-264.

  20. Hsieh, C. L., Tang, N. Y., Chiang, S. Y., Hsieh, C. T., & Lin, J. G. (1999). Anticonvulsive and free radical scavenging actions of two herbs, Uncaria rhynchophylla (MIQ) Jack and Gastrodia elata Bl., in kainic acid-treated rats. Life Sciences, 65(20), 2071-2082.

  21. Endo, K., Oshima, Y., Kikuchi, H., Koshihara, Y., & Hikino, H. (1983). Hypotensive principles of Uncaria hooks. Planta medica, 49(11), 188-190.

  22. Fujiwara, H., Iwasaki, K., Furukawa, K., Seki, T., He, M., Maruyama, M., ... & Maeda, S. (2006). Uncaria rhynchophylla, a Chinese medicinal herb, has potent antiaggregation effects on Alzheimer's β‐amyloid proteins. Journal of Neuroscience Research, 84(2), 427-433.

  23. Lin, H. Q., Ho, M. T., Lau, L. S., Wong, K. K., Shaw, P. C., & Wan, D. C. (2008). Anti-acetylcholinesterase activities of traditional Chinese medicine for treating Alzheimer's disease. Chemico-Biological Interactions, 175(1-3), 352-354.

  24. Xian, Y. F., Lin, Z. X., Zhao, M., Mao, Q. Q., Ip, S. P., & Che, C. T. (2011). Uncaria rhynchophylla ameliorates cognitive deficits induced by D-galactose in mice. Planta medica, 77(18), 1977-1983.

  25. Xian, Y. F., Lin, Z. X., Mao, Q. Q., Hu, Z., Zhao, M., Che, C. T., & Ip, S. P. (2012). Bioassay-guided isolation of neuroprotective compounds from Uncaria rhynchophylla against beta-amyloid-induced neurotoxicity. Evidence-Based Complementary and Alternative Medicine, 2012.

  26. Shim, J. S., Kim, H. G., Ju, M. S., Choi, J. G., Jeong, S. Y., & Oh, M. S. (2009). Effects of the hook of Uncaria rhynchophylla on neurotoxicity in the 6-hydroxydopamine model of Parkinson's disease. Journal of Ethnopharmacology, 126(2), 361-365.

  27. Cisneros, F. J., Jayo, M., & Niedziela, L. (2005). An Uncaria tomentosa (cat's claw) extract protects mice against ozone-induced lung inflammation. Journal of ethnopharmacology, 96(3), 355-364.

  28. Keplinger, K., Laus, G., Wurm, M., Dierich, M. P., & Teppner, H. (1998). Uncaria tomentosa (Willd.) DC.—ethnomedicinal use and new pharmacological, toxicological and botanical results. Journal of ethnopharmacology, 64(1), 23-34.

  29. Sandoval, M., Okuhama, N. N., Zhang, X. J., Condezo, L. A., Lao, J., Angeles, F. M., ... & Miller, M. J. S. (2002). Anti-inflammatory and antioxidant activities of cat's claw (Uncaria tomentosa and Uncaria guianensis) are independent of their alkaloid content. Phytomedicine, 9(4), 325-337.

  30. Heitzman, M. E., Neto, C. C., Winiarz, E., Vaisberg, A. J., & Hammond, G. B. (2005). Ethnobotany, phytochemistry and pharmacology of Uncaria (Rubiaceae). Phytochemistry, 66(1), 5-29.

  31. Sandoval-Chacon, M., Thompson, J. H., Zhang, X. J., Liu, X., Mannick, E. E., Sadowska-Krowicka, H., ... & Miller, M. J. S. (1998). Antiinflammatory actions of cat's claw: the role of NF-kB. Alimentary Pharmacology and Therapeutics, 12(12), 1279-1290.

  32. Allen-Hall, L., Cano, P., Arnason, J. T., Rojas, R., Lock, O., & Lafrenie, R. M. (2007). Treatment of THP-1 cells with Uncaria tomentosa extracts differentially regulates the expression if IL-1β and TNF-α. Journal of ethnopharmacology, 109(2), 312-317.

  33. Allen-Hall, L., Arnason, J. T., Cano, P., & Lafrenie, R. M. (2010). Uncaria tomentosa acts as a potent TNF-α inhibitor through NF-κB. Journal of ethnopharmacology, 127(3), 685-693.

  34. Dietrich, F., Kaiser, S., Rockenbach, L., Figueiró, F., Bergamin, L. S., da Cunha, F. M., ... & Battastini, A. M. O. (2014). Quinovic acid glycosides purified fraction from Uncaria tomentosa induces cell death by apoptosis in the T24 human bladder cancer cell line. Food and chemical toxicology, 67, 222-229.

  35. Hempen, C. H., & Fischer, T. (2009). A materia medica for Chinese medicine: plants, minerals, and animal products. Elsevier Health Sciences.