The sharp nails of Uncaria tomentosa: POA’s and TOA’s

Abstract. Uncaria tomentosa (Willd. ex Schult.) DC. or Cat’s claw is not only known for its therapeutic effects, such as inflammatory action and immune system enhancement, but also because of the controversy surrounding some of its constituents: the POAs and the TOAs. One would be “bad”, the other “good”. This has led to the sale of highly varied products and confusion among therapists and consumers.

Maaike van Kregten
Nederlands Tijdschrift voor Fytotherapie 2017 (30) nr 2: pag 19-20. (Original Dutch article).

This article argues that the effects of Cat’s claw cannot be fully explained by means of the activity of the alkaloids. It takes into account the traditional way of preparing, namely a water decoction and the poor solubility of oxindole alkaloids in water. They are therefore likely to be less present in traditional (water) extracts. They are also prone to isomerization, for which not only the extraction fluid, but also the duration of heating is important. Isomerization causes the alkaloids to possibly have a different effect in isolated form compared to alkaloids as part of an extract.

Studies show that water decoction provides the same effects as studies with ethanol extracts, such as reduced inflammation and strengthening of the immune system. Moreover, studies with non-alkaloid constituents of Cat’s claw also show the same results. Therefore, it seems important to study the alkaloid’s possible additive and synergistic actions. Based on these findings, it is plausible that the importance of POAs and TOAs is exaggerated, or at least different as initially expected.