Chem Pharm Bull (Tokyo) 2000 Oct;48(10):1410-2

A new gluco indole alkaloid, 3, 4-dehydro-5-carboxystrictosidine, from Peruvian Una de Gato (Uncaria tomentosa).

Kitajima M, Hashimoto K, Yokoya M, Takayama H, Aimi N, Sakai SI.

Faculty of Pharmaceutical Sciences, Chiba University, Japan.

A new gluco indole alkaloid, 3,4-dehydro-5-carboxystrictosidine, was obtained from Peruvian Una de Gato (Cat's Claw, original plant: Uncaria tomentosa) together with two known gluco indole alkaloids. This compound was the first example of isolation of a gluco monoterpenoid indole alkaloid having a 3,4-dihydro-beta-carboline ring system from nature. A characteristic feature of the compound was the quick replacement of the methylene hydrogens on C-14 with deuterium that was observed when it was dissolved in CD3OD. We demonstrated a similar proton-deuterium exchange on a model compound, 1-methyl-3,4-dihydro-gamma-carboline, in CD3OD solution.