Poison frogs

The active principle of dart frog poisons is alkaloids. The study of the den-drobatid poisons led to the discovery of over 200 new alkaloids, including batrachotoxins Pig. 10.5), pumiliotoxins, histrionicotoxins, gephyrotoxins, and decahydroquinolines (Daly et al., 1994). The most common compounds have the basic structure of piperidine and include histrionotoxin. In Phyllobates, the synthesis of other alkaloids is suppressed in favor of batrachotoxins. These are... 

This work and parallel studies by another group5 have been used to assign the threo-configuration to the allylic diol group in the side chain of the frog poison pumiliotoxin B (5). 

Frog poison. Batrachotoxin (BTX) is a steroidal alkaloid from the skin of Phyllobates terribilis, a poisonous Colombian frog (source of the poison used on blowgun darts). In the presence of BTX, sodium channels in an excised patch stay persistently open when the membrane is depolarized. They close when the membrane is repolarized. Which transition is blocked by BTX ... 

Dendrobatidae frog poisons (hexacyclic systems with N- and N,0-heterocyclic fragments) 00CLY230. 

A Pemvian Mats s Indian collecting frogs to extract sapo frog poison used for medicinal and ritual purposes. 

Strychnicine. This alkaloid, isolated from nux-vomica leaves grown in. lava, forms needles, m.p. 240° dec.), and is characterised by the following colour reaction. When sodium hydroxide solution is added drop by drop to a solution of a salt of the alkaloid in water, the precipitate formed dissolves on addition of more alkali, forming an orange-coloured liquid which develops a violet colour on addition of hydrochloric acid. Strychnicine is scarcely poisonous, but is said to produce tetanus in frogs. 

A novel splropentanopyrrolmdine oxime has been isolated from skin extracts of the Panamanian poison frog. This alkaloid can besynthesized via the Michael addi don of cyclop en-tanecarboxaldehyde to nitroethene fScheme 10.19. ... 

The product of the reaction in Entry 8 was used in the synthesis of the alkaloid pseudotropine. The proper stereochemical orientation of the hydroxy group is determined by the structure of the oxazoline ring formed in the cycloaddition. Entry 9 portrays the early stages of synthesis of the biologically important molecule biotin. The reaction in Entry 10 was used to establish the carbocyclic skeleton and stereochemistry of a group of toxic indolizidine alkaloids found in dart poisons from frogs. Entry 11 involves generation of a nitrile oxide. Three other stereoisomers are possible. The observed isomer corresponds to approach from the less hindered convex face of the molecule. 

A predator eating a victim that has accumulated pesticides in its tissues may die from secondary pesticide poisoning. For example, newts died when they ate tadpoles poisoned by OCPs. Frogs may die as a result of eating poisoned caterpillars [85]. 

A retro-l,3-dipolar cycloaddition followed by an 1,3-dipolar cycloaddition was used for a highly efficient total synthesis of (-)-histrionicotoxin (4-354) (HTX) by Holmes and coworkers [123]. HTX is a spiropiperidine-containing alkaloid which was isolated by Doly, Witkop and coworkers [124] from the brightly colored poison-arrow frog Dendrobates histrionicus. It is of great pharmacological interest as a noncompetitive inhibitor of acetylcholine receptors. 

The decahydrocyclazine skeleton is also found in the alkaloid 395, currently known only by the designation 261C. This compound bears a passing resemblance to some of the myrmicarins (Section 16.6.5.2), but occurs in the skin of a totally different animal species, namely poisonous frogs of the genus Mantella <2003H(59)745>. 

Very rapid-acting paralytic neurotoxin that binds to sodium channels of nerve and muscle cells depolarizing neurons by increasing the sodium channel permeability. It is obtained from South American poison-dart frogs (Phyllobates aurotaenia, Phyllobates terribilis). It is insoluble in water but soluble in hydrocarbons and other nonpolar solvents. The dried toxin can remain active for at least a year. However, it is relatively nonpersistent in the environment. 

Ellison earned a master of science in chemistry from the University of California, Irvine. His graduate research involved methods to synthesize poisons extracted from Colombian poison dart frogs. He has a bachelor of science in chemistry from the Georgia Institute of Technology. He is a member of the American Chemical Society and Federation of American Scientists. In addition to his works on weapons of mass destruction, he is the author of a chapter on the hazardous properties of materials in the sixth edition of the Handbook on Hazardous Materials Management, a textbook published in 2002 by the Institute of Hazardous Materials Management. 

Newt, Triturus cristatus, adults, held in tank with a zinc-plated base South African clawed frog, Xenopus laevis 200 to 3000 overa 7-day period Zinc-poisoned newts were lethargic, ate poorly, and had skin darkening prior to death. Zinc residues were elevated in kidney, brain, liver, and intestine, when compared to controls. The hippocampus region of the brain of poisoned newts contained zinc-rich cells 82... 

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