Biodiversity of alkaloids in amphibian skin: A dietary arthropod source

Abstract

Over four hundred alkaloids in amphibian skin have been detected and structures from twenty different classes have been elucidated. These include batrachotoxins, histrionicotoxins, pumiliotoxins, epibatidine, pyrrolidines, piperidines, decahydroquinolines, pyrrolizidines, indolizidines, quinolizidines and tricyclic gephyrotoxins, pyrrolizidine oximes, pseudophrynamines, coccinellines and cyclopentaquinolizidines. The alkaloids of amphibian skin are not synthesized by the amphibians, but instead are accumulated unchanged from dietary sources. Pyrrolidines, piperidines, decahydroquinolines, pyrrolizidines, indolizidines, and quinolizidines appear likely to be derived from ants, the coccinellines from beetles, and the pyrrolizidine oximes from millipedes. The origins of the batrachotoxins, histrionicotoxins, pumiliotoxins and epibatidine are of particular interest in view of their remarkable biological activity