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Uncaria tomentosa (Willd.) DC.
A plant used in traditional South American medicine

Uncaria tomentosa in its native rainforest habitat

Uncaria tomentosa in its native rainforest habitat

Uncaria tomentosa (Willd.) DC is one of the two species of the genus Uncaria indigenous to South America and is a member of the Rubiaceae family. It occurs in the tropical Amazonian rainforest in an area extending from northern Bolivia through Peru, Brazil, Ecuador, Colombia and Venezuela to Honduras and Belize.


When growing naturally, the stems of this huge woody climbing shrub frequently reach a length of up to one hundred metres with a diameter of over 20 cm. The plant climbs up the trunks of its supporting trees and spreads out into their crowns in the forest canopy. The roots grow out horizontally along the boundary layer between loose organic material and firm clay soil at a depth of a few centimetres below the surface.


In the sunlight the plant produces whip-like shoots on which the oval leaves are arranged in pairs at intervals of 10 – 15 cm. The leaf axils bear slightly curved, sickle-shaped thorns. During the blossoming period Uncaria tomentosa produces panicles of yellow flower heads approx. 2 cm in diameter in place of the thorns.


Due to the characteristic shape of the thorns, which resemble the claws of a cat, the plant is known in Spanish by the common name “Uña de gato” (English “cat’s claw”, German “Katzenkralle”).


However, the designation “Uña de gato” and its translations "cat’s claw" or "Katzenkralle" are not specific to Uncaria tomentosa: at least 18 other plants from the same region in South America are also known by this common name, as is the second representative of the genus Uncaria in South America, Uncaria guianensis (Aubl.) Gmel. As a result, these two Uncarias are frequently mistaken for one another, and are often wrongly taken to be the same plant. Although both plants share the same Spanish common name and differ only slightly in appearance, they should not in fact be seen as being closely related. They differ not only in terms of their habitus, but also with regard to their chromosome pattern and their chemical constituents.

Read more about chemical constituents of Uncaria tomentosa (Willd.) DC. ...

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