Role of hypaphorine in the toxicity of Astragalus lusitanicus.

Hypaphorine, an alpha-N,N,N-trimethyltryptophan betaine, was isolated, for the first time, from Astragalus lusitanicus Lam. (Fabaceae), a plant highly toxic for lambs and goats. This alkaloid was characterized by NMR and MS analysis. Hypaphorine was previously reported to be a convulsive poison. To confirm the toxicity, it was synthesized and tested in goats. Hypaphorine was shown to be non-toxic for goats even at a high dose of 2 g kg(-1) by oral administration.