Pseudophryne genus

The European fire salamander (Salamandra salamandra) and the alpine salamander (Salamandra atra) are the only amphibians known to contain samandarine alkaloids. These are the only two species in this genus. The proposal that extracts of the brilliant black and yellow Australian myobatrachid frog Pseudophryne corroboree contained samandarine alkaloids (52) has proved to be incorrect, and this and other frogs of the genus Pseudophryne instead contain pumiliotoxins and pseudophrynamines (see Sections III,C and VII, A). The major alkaloids of Salamandra salamandra are samandarine, samandarone, and 0-acetylsamandarine. There do not... 

A major class of amphibian alkaloids was recently discovered in frogs of the myobatrachid genus Pseudophryne (86,119). These represent the unidentified indolic compounds first noted by Erspamer and co-workers in 1976 (169). Isolation of two of these indole alkaloids from partially purified extracts of Pseudophryne coriacea allowed structure elucidation of pseudophrynaminol (XIV) and pseudophrynamine A (XV) by nuclear magnetic resonance spectral analysis (119). Methoxide cleavage of pseudophrynamine A yielded pseudophrynaminol and a methyl ester... 

The structures of other alkaloids of the pseudophrynamine class (3a-prenylpyrrolo[2,3-6]indoles) were deduced from mass spectral analysis (86). The pseudophrynamines are tabulated below. In addition to the listed pseudophrynamines, other trace analogs of pseudophrynamine A (XV) with molecular ions at miz 526,540, and 542 were detected. The structures of the alkaloids of the pseudophrynamine class from frogs of the genus Pseudophryne are shown in Fig. 22. 

The pseudophrynamines have not been detected elsewhere in Nature. In myobatrachid frogs of the genus Pseudophryne, they occur in varying amounts in all species examined (56). The pair of dimeric indole alkaloids, chimonanthine/calycanthine, have been detected in amphibians only in the dendrobatid frog Phyllobates terribilis and, tentatively, as a trace alkaloid in Phyllobates bicolor (14). 

Scheme 16. Pseudophrynamines from frogs of the genus Pseudophryne.

The pseudophrynamines are only known from seven species of the genus Pseudophryne in the family Myobatrachidae (205). However, almost all Pseudophryne species investigated also contained the well known dendrobatid alkaloids pumilotoxins in some populations they could not be detected. Pseudophrynamines were the dominant alkaloids in two species (P. guentheri and P. occidentalis) from Western Australia, while all five eastern species contained significant amounts of pumilotoxins as well. It is interesting to note that the pseudophrynamines vary like the bryozoan alkaloids and that they were the main alkaloids only in some populations of the same species. 

However, it looks as if some other frogs can, indeed, make their own alkaloids. Australian myobatrachid frogs of the genus Pseudophryne contain two types of alkaloids in their skin extracts, some of which they get from their diets of formicine ants, but some they synthesis themselves. 

The skins of Australian myobatrachid frogs of the genus Pseudophryne contain pseudophrynamines (l,2,3,3a,8,8a-hexahydropyrrolo[2,3-l)]indole alkaloids), which appear to be biosynthesized by the animals themselves, and also varying quantities of pumifrotoxins sequestered from dietary... 

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