What is Cat’s Claw?
Cat’s claw (Uncaria tomentosa) is a medicinal plant that grows in the Amazonian rainforest and other tropical areas in Central and South America. The use of the herb dates back to the Inca civilization. Indigenous cultures of South America used cat’s claw for inflammation, cancer, viral infections, ulcers, and to stimulate the immune system [1, 2].
It gets its name from its thorns, which resemble the claws of cats.
Most commercial preparations such teas, tablets, and capsules contain U. tomentosa .
There are two different types of cat’s claw, and they contain different active compounds and have different medicinal properties. One contains more pentacyclic oxindole alkaloids (POAs) and the other more tetracyclic oxindole alkaloids (TOAs) [3, 4].
TOAs act on the central nervous system (brain and spinal cord), whereas POAs affect the immune system .
TOAs cancel out the effects of POAs. Therefore it is important when purchasing and consuming cat’s claw extracts to be sure that they have been tested for TOA and POA levels .
Differences between the two types are conveyed in the chemical structure. Pentacyclic alkaloids are found in the vine bark while tetracyclic alkaloids are found in the leaves and stem of the plant [6, 7].
Main Beneficial Compounds of Cat’s Claw
Cat’s claw is rich in three major groups of chemical compounds: alkaloids, terpenoids, and flavonoids .
Specific compounds found in cat’s claw include:
- Mitraphylline is an alkaloid usually found in older leaves and has anticancer effects, causing cell death in sarcoma and breast cancer cells [4, 8].
- Rhynchophylline is an alkaloid isolated from the bark, which helps with convulsions, lightheadedness, numbness, and hypertension [9, 10].
- Isopteropodine is an alkaloid isolated from the leaves and has antimicrobial properties against (Gram-positive) bacteria [9, 11].
- Uncarine (C, D, and E) are a family of alkaloids found in the leaves, which have anti-cancer properties, inducing cell death in leukemia cells [4, 12].
- Hirsutine is an alkaloid found in the young leaves, which has antihypertensive properties, relaxing blood vessels and reducing overall blood pressure [4, 13].
- Uncaric acid is a triterpene extracted from the bark and is effective against Mycobacterium tuberculosis (H37Rv strain) [14, 15].
- Quinovic acid is an acid triterpene compound extracted from the bark that reduces heart rate [16, 17].
- Quinic acid has antioxidant properties, enhances DNA repair, and has neuroprotective effects in the brain [18, 19, 20].
- Procyanidins is a flavonoid (phenolic compounds found in the leaves, stems, bark, and wood of U. tomentosa), which has antioxidant, anti-inflammatory, and anticancer properties [21, 22].
Mechanisms of Action
- Decreases inflammatory molecules TNF-α and NF-κB [23, 24, 25, 23].
- Blocks the release of iNos, an enzyme that creates free radicals as part of the immune response .
- Blocks the release of COX-1 and COX-2, enzymes that play crucial roles in inflammation and pain [27, 28].
Health Benefits of Cat’s Claw
1) Cat’s Claw Can Help with Chemotherapy
In rats who received chemotherapy, cat’s claw increased white blood cell count and helped repair damaged DNA .
In a study (DB-RCT) of 40 breast cancer patients undergoing chemotherapy, 300 mg cat’s claw extract prevented a decrease in white blood cells (neutropenia) and repaired DNA damage .
However, in another study (DB-RCT) of 43 colorectal cancer patients undergoing chemotherapy, 300 mg of cat’s claw extract did not affect white or red blood cell counts .
Cat’s claw also stimulates the growth of progenitor cells in mice, which can replace damaged cells and reduce the damaging effects of chemotherapy .
2) Cat’s Claw Helps Treat Arthritis
Cat’s claw’s anti-inflammatory effects have been commonly used to treat both rheumatoid arthritis and osteoarthritis. The different compounds in cat’s claw act together to achieve these effects .
In one study (DB-RCT) of 40 rheumatoid arthritis patients, cat’s claw combined with conventional arthritis treatments (sulfasalazine/hydroxychloroquine) reduced tender and painful joints .
In another study (DB-RCT) of 45 patients with osteoarthritis, one week of cat’s claw reduced pain associated with activity compared to placebo .
3) Cat’s Claw Helps with Stomach and Gut Inflammation
Cat’s claw can cleanse the digestive tract and may help treat inflammatory gut disorders including :
- Crohn’s disease
- Stomach ulcers
- Leaky gut
Cat’s claw protected against stomach inflammation in rats and prevented TNF-α production and cell death .
Inflammation of the gut is also caused by toxic free radicals (peroxynitrite). Cat’s claw not only acts as a powerful antioxidant against free radicals but also reduces cell death caused by gut bacterial toxins .
4) Cat’s Claw May Help with High Blood Pressure
Cat’s claw inhibits platelet aggregation and blood clot formation, decreasing overall blood pressure and increasing circulation. It also inhibits the formation of plaques and blood clots in the heart, brain, and blood vessels .
Hirsutine acts as a calcium channel blocker in the heart and blood vessels, which slows down heart rate and relaxes the blood vessels .
5) Cat’s Claw Fights the Herpes Virus
Cat’s claw prevented immune cells from being infected with Dengue Virus and reduced inflammatory cytokines TNF-alpha and IFN-alpha .
The extracts prevented the spread of the herpes virus by preventing it from attaching to cells .
In a study (DB-RCT) of 31 volunteers with cold sores (herpes labialis), cat’s claw was more effective in reducing symptoms such as swelling, skin reddening, and pain compared to prescription antiviral drug Acyclovir .
6) Cat’s Claw Can Protect Against Type 1 Diabetes
Cat’s claw has positive effects in the treatment of diabetes .
Type 1 diabetes is a chronic autoimmune disorder, where the immune system destroys the cells in the pancreas that make insulin .
7) Cat’s Claw May Help Fight Cancer
Cat’s claw directly inhibited the growth of human breast cancer cells .
Cat’s claw extracts inhibited the growth of and increased programmed cell death in leukemia cells .
8) Cat’s Claw Boosts the Immune System
9) Cat’s Claw Protects Red Blood Cells
Cat’s claw protected red blood cells (RBCs) from damage due to toxins and reduced oxidative stress .
10) Cat’s Claw is Anti-inflammatory
Procyanidins and other polyphenols in cat’s claw scavenge and remove oxidative radicals in cell studies .
Cat’s claw also prevented the production of the inflammatory cytokine TNF-α and prevented programmed cell death in cell studies .
Side Effects and Precautions
Cat’s claw is generally considered safe and effective as a complement to chemotherapy .
Pregnant women should avoid using cat’s claw because of the herb’s potential to cause abortion .
When cat’s claw was used in combination with some HIV treatments like protease inhibitors (atazanavir, ritonavir, and saquinavir), it increased their toxicity .
Common side effects include :
- Upset stomach
- Skin rash
1) Cat’s Claw May Worsen Autoimmune Diseases
Cat’s claw enhances the immune response by increasing the activities of immune cells .
2) Cat’s Claw May Increase Bleeding
Clotting is essential for preventing blood loss and allowing tissue repair .
This may increase the risk of bruising or bleeding .
Few high-quality clinical trials with cat’s claw have been conducted in humans and more studies are needed to confirm its health benefits .
Clinical trials have used between 80 – 350 mg of cat’s claw extract. These extracts usually contain a certain amount of pentacyclic oxindole alkaloids, rather than tetracyclic oxindole alkaloids.
Experiences with Cat’s Claw
According to one doctor, “In my experience on approximately 150 patients during the last four years…I have seen Uncaria tomentosa break through severe intestinal derangements that no other available products can touch.”
One user noted that cat’s claw increased the severity of their headache and fatigue, which they linked to a die-off effect.