Uncaria tomentosa, commonly known as cat's claw, is a woody vine native to the tropical jungles of South and Central America. Renowned for its hook-like thorns that resemble a cat’s claws, this vine climbs on other plants or trees to reach sunlight. Cat's claw is valued for its bark and root, which have been used in traditional medicine for centuries due to their purported health benefits.

Botanical Classification

Kingdom: Plantae
Clade: Angiosperms
Class: Eudicots
Order: Gentianales
Family: Rubiaceae
Genus: Uncaria
Species: U. tomentosa

Plant Characteristics

Uncaria tomentosa can grow up to 30 meters in height as it climbs using its thorns. The leaves are simple and oval, with a glossy green appearance. It produces small, yellowish flowers. The plant's most distinctive features are its claw-shaped thorns, which it uses to hook onto other vegetation.

Chemical Composition and Structure

It is rich in various bioactive compounds, including alkaloids, terpenoids, flavonoids, and tannins. The most notable alkaloids in cat's claw are isopteropodine and mitraphylline, which are believed to contribute to its immune-boosting and anti-inflammatory properties.

Cultivating Uncaria tomentosa involves the following considerations:

1. Soil: Prefers well-drained, fertile soil, typically found in its natural rainforest habitat.
2. Light: Requires partial shade; too much sunlight can inhibit its growth.
3. Water: Needs abundant moisture, consistent with the high humidity of tropical rainforests.
4. Temperature: Thrives in warm, humid environments and is not frost-tolerant.

Uses and Benefits

Traditionally, cat's claw has been used by indigenous cultures for its potential therapeutic effects, including boosting the immune system, reducing inflammation, and aiding in the recovery from health conditions such as arthritis and digestive system disorders. Modern research has focused on its potential anti-inflammatory, antioxidant, and immune-modulating properties.

Applications

• Medicinal: Used in supplement form for various health benefits, including immune support and inflammation reduction.
• Herbal Teas: Often consumed as a tea for its health-promoting properties.
• Research: The focus of scientific studies investigating its potential in treating a range of ailments from autoimmune diseases to cancer.

Environmental and Safety Considerations

The harvesting of Uncaria tomentosa must be conducted sustainably to prevent overexploitation. The plant is sometimes harvested destructively in the wild, which can threaten local ecosystems. Sustainable cultivation practices are essential for preserving this species. While generally considered safe for consumption, it is recommended to use cat's claw under the guidance of a healthcare provider, as it can interact with various medications and is not recommended for pregnant women or individuals with autoimmune diseases.

References__________________________________________________________________________

Keplinger K, Laus G, Wurm M, Dierich MP, Teppner H. Uncaria tomentosa (Willd.) DC.--ethnomedicinal use and new pharmacological, toxicological and botanical results. J Ethnopharmacol. 1999 Jan;64(1):23-34. doi: 10.1016/s0378-8741(98)00096-8. 

Abstract. The medicinal system of the Asháninka Indians in Perú is portrayed. Three categories of medical disorders and healers are recognized. A human is viewed to consist of a physical and a spiritual being who communicate with each other by means of a regulating element. The significance of Uncaria tomentosa (Willd.) DC. (Rubiaceae), locally known as unã de gato, in traditional medicine is emphasized by its exclusive use by priests to influence this regulation. Pharmacological and toxicological results obtained with extracts or isolated compounds are summarized. Pentacyclic oxindole alkaloids stimulate endothelial cells in vitro to produce a lymphocyte-proliferation-regulating factor. Tetracyclic oxindole alkaloids act as antagonists. A significant normalization of lymphocyte percentage was observed in vivo although total leucocyte numbers did not change.

Della Valle V. Uncaria tomentosa. G Ital Dermatol Venereol. 2017 Dec;152(6):651-657. doi: 10.23736/S0392-0488.17.05712-1. 

Abstract. Uncaria tomentosa (U. tomentosa) or uña de gato, a species of vine of Rubiaceae family, was used from centuries in various medical conditions. Although there are no randomized controlled trials or published human outcome studies, some conditions reportedly improved by U. tomentosa include osteoarthritis, rheumatoid arthritis, prostatitis, viral illnesses and cancer (acting as a non-specific immunomodulantign agent) and it may also have potential as an immunomodulating adaptogen in cellular aging. The understanding of some specific mechanisms of molecular action leads to the demonstration of various anti-inflammatory, immunostimulating and protective effects. These results bring the strong hypothesis that U. tomentosa could be effective in the topical treatment of dermatological manifestation, namely rosacea.

Araujo LCC, Feitosa KB, Murata GM, Furigo IC, Teixeira SA, Lucena CF, Ribeiro LM, Muscará MN, Costa SKP, Donato J Jr, Bordin S, Curi R, Carvalho CRO. Uncaria tomentosa improves insulin sensitivity and inflammation in experimental NAFLD. Sci Rep. 2018 Jul 20;8(1):11013. doi: 10.1038/s41598-018-29044-y. 

Abstract. We investigated the effect of the crude herbal extract from Uncaria tomentosa (UT) on non-alcoholic fatty liver disease (NAFLD) in two models of obesity: high fat diet (HFD) and genetically obese (ob/ob) mice. Both obese mouse models were insulin resistant and exhibited an abundance of lipid droplets in the hepatocytes and inflammatory cell infiltration in the liver, while only the HFD group had collagen deposition in the perivascular space of the liver. UT treatment significantly reduced liver steatosis and inflammation in both obese mouse models. Furthermore, serine phosphorylation of IRS-1 was reduced by 25% in the HFD mice treated with UT. Overall, UT treated animals exhibited higher insulin sensitivity as compared to vehicle administration. In conclusion, Uncaria tomentosa extract improved glucose homeostasis and reverted NAFLD to a benign hepatic steatosis condition and these effects were associated with the attenuation of liver inflammation in obese mice.

Yepes-Pérez AF, Herrera-Calderon O, Quintero-Saumeth J. 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 modeling. J Biomol Struct Dyn. 2022 Mar;40(5):2227-2243. doi: 10.1080/07391102.2020.1837676. 

Abstract. COVID-19 is a novel severe acute respiratory syndrome coronavirus. Currently, there is no effective treatment and vaccines seem to be the solution in the future. Virtual screening of potential drugs against the S protein of severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) has provided small molecular compounds with a high binding affinity. Unfortunately, most of these drugs do not attach with the binding interface of the receptor-binding domain (RBD)-angiotensin-converting enzyme-2 (ACE-2) complex in host cells. Molecular modeling was carried out to evaluate the potential antiviral properties of the components of the medicinal herb Uncaria tomentosa (cat's claw) focusing on the binding interface of the RBD-ACE-2 and the viral spike protein. The in silico approach starts with protein-ligand docking of 26 Cat's claw key components followed by molecular dynamics simulations and re-docked calculations. Finally, we carried out drug-likeness calculations for the most qualified cat's claw components. The structural bioinformatics approaches led to the identification of several bioactive compounds of U. tomentosa with potential therapeutic effect by dual strong interaction with interface of the RBD-ACE-2 and the ACE-2 binding site on SARS-CoV-2 RBD viral spike. In addition, in silico drug-likeness indices for these components were calculated and showed good predicted therapeutic profiles of these phytochemicals found in U. tomentosa (cat's claw). Our findings suggest the potential effectiveness of cat's claw as complementary and/or alternative medicine for COVID-19 treatment.

Zari A, Alfarteesh H, Buckner C, Lafrenie R. Treatment with Uncaria tomentosa Promotes Apoptosis in B16-BL6 Mouse Melanoma Cells and Inhibits the Growth of B16-BL6 Tumours. Molecules. 2021 Feb 18;26(4):1066. doi: 10.3390/molecules26041066. 

Abstract. Uncaria tomentosa is a medicinal plant native to Peru that has been traditionally used in the treatment of various inflammatory disorders. In this study, the effectiveness of U. tomentosa as an anti-cancer agent was assessed using the growth and survival of B16-BL6 mouse melanoma cells. B16-BL6 cell cultures treated with both ethanol and phosphate-buffered saline (PBS) extracts of U. tomentosa displayed up to 80% lower levels of growth and increased apoptosis compared to vehicle controls. Treatment with ethanolic extracts of Uncaria tomentosa were much more effective than treatment with aqueous extracts. U. tomentosa was also shown to inhibit B16-BL6 cell growth in C57/bl mice in vivo. Mice injected with both the ethanolic and aqueous extracts of U. tomentosa showed a 59 ± 13% decrease in B16-BL6 tumour weight and a 40 ± 9% decrease in tumour size. Histochemical analysis of the B16-BL6 tumours showed a strong reduction in the Ki-67 cell proliferation marker in U. tomentosa-treated mice and a small, but insignificant increase in terminal transferase dUTP nick labelling (TUNEL) staining. Furthermore, U. tomentosa extracts reduced angiogenic markers and reduced the infiltration of T cells into the tumours. Collectively, the results in this study concluded that U. tomentosa has potent anti-cancer activity that significantly inhibited cancer cells in vitro and in vivo.