According to this Herb Wisdom article on Cat’s Claw:
The primary mechanism for Cat’s claw anti-inflammatory actions appears to be immunomodulation via suppression of TNF-alpha synthesis.
Cat’s Claw may help create support for the intestinal and immune systems of the body, and may also create intestinal support with its ability to cleanse the entire intestinal tract. This cleansing helps create support for people experiencing different stomach and bowel disorders, including: colitis, Crohn’s disease, irritable bowel syndrome, and leaky bowel syndrome.
Crohn’s Disease wasn’t an ailment common to South America before the Spanish arrived, butto the indigenous peoples of Peru did use Cat’s Claw to treat gastritis and other digestive disorders for its anti-inflammatory properties.
Extra resources about Cat’s Claw / Uña de Gato and Crohn’s Disease: