New and Uncommon Indole- and Imidazole-Alkylamines in Skins of Amphibians from Australia and Papua New Guinea

Abstract

Extracts of the skin of some amphibians from Australia and Papua New Guinea contained, in addition to the usual 5-hydroxyindolealkylamines and histamine, 2 new indolealkylamines, i.e., O-sulfate of bufotenidine and 2-(3-indolyl)ethyltrimethylammonium, a quaternary ammonium base of tryptamine. The rare O-sulfate of bufotenine was also present, the occurrence of which was previously demonstrated only in the skin of some South American toads; a series of uncommon imidazolealkylamines, such as N''-acetylhistamine, N''-methylhistamine, N'',N''-dimethylhistamine, spinaceamine and 6-methylspinaceamine. Amphibian skin continues to be an exceptionally rich source of aromatic amines.