zetekitoxin-ab and chiriquitoxin

Bioactive marine natural products occur only rarely in nonmarine sources. The converse also is true. Divergent evolutionary pathways for the biosynthesis of bioactive secondary metabolites seem to be the rule. Marine biosynthetic pathways lead to a wide variety of different structural classes, among which polyethers, macrolides, terpenes, unusual amino acids/peptides, and alkaloids are notable. Nonmarine biosynthetic pathways also lead to a similar wide variety of structural classes. However, the structures are usually quite different from the marine analogues. The alkaloids of plants are notable, but again there appears little convergence between the marine and nonmarine alkaloids. However, tetrodotoxin, a remarkable, highly polar, marine alkaloid, does occur in various amphibians. The occurrence and possible origin of tetrodotoxin and congeners, including chiriquitoxin, and of the saxitoxin analogue zetekitoxin in amphibians are reviewed.

Topics: Alkaloids; Amphibian Venoms; Animals; Fish Venoms; Marine Toxins; Molecular Structure; Quinazolines; Saxitoxin; Tetrodotoxin; Toxins, Biological

Major toxins from skin extracts of 18 specimens of six Atelopus toad species collected in Panama were analyzed. Chiriquitoxin was identified using (1)H NMR in A. limosus and A. glyphus for the first time. Zetekitoxin in A. zeteki and tetrodotoxin in A. varius, A. chiriquiensis and A. zeteki were identified again. Furthermore, A. certus was suggested to contain a water-soluble toxin other than tetrodotoxin.

Topics: Animals; Biological Assay; Bufonidae; Chromatography, Liquid; Complex Mixtures; Lethal Dose 50; Magnetic Resonance Spectroscopy; Male; Mice; Panama; Saxitoxin; Skin; Species Specificity; Spectrometry, Fluorescence; Spectrometry, Mass, Electrospray Ionization; Tetrodotoxin; Toxins, Biological