Fishes and frogs in the flow
Even the oceans have contributed chemical substances that directly, or indirectly, can be used to improve the health of humans. One example is the puffer fish of the genus Tetraodon. The toxin has been named tetrodotoxin and exists primarily in the fish’s liver and genitals
Another interesting poison is froth from certain South American frogs. The Indians of South America have long known that when the small, colourful frogs are under stress, they exude poisonous froth through their skins.
Arrows that have been treated with the froth kill animals very efficiently and so the frogs are called poison dart frogs (e.g., the genera Phyllobates and Dendrobates). When chemists managed to refine the poisonous substances from the frogs and the puffer fish, pharmacologists found that they were very strong neurotoxins.
Pharmacologists and neurologists have since used these toxins as pharmacological tools to examine how the human nervous system works. Also other poisons, from various snakes, have been used to increase the understanding of how our bodies work. Substances from nature do not need to be used as drugs; they can also be used to learn more about how the body functions. When you understand how various reactions take place in the body, you can isolate substances from nature or produce synthetic substances for developing drugs for specific purposes. Thus you maximise the medicinal effect and minimise the side effects.
Modern studies have shown that the South American poison dart frog contains a substance that has an effect approximately 200 times stronger in relieving pain than morphine.
Bradley, D. Frog Venom Cocktail Yields A One-Handed Painkiller. Science 261: 1117, 1993.