Toxicity of Puffer Fish Next morning after tasting opuffer fish soup. Awaking and realizing you're really still aliue. Buson (old famous Japanese poet)
Favor by puffer flsh Goshun, a painter, was a pupil of Buson, a famous poet. At one time Gashun was so very poor because he had never sold any pictures that he decided toselecta way to die. Then the idea flashed across his mind to dare to eat a dangerous but supposedly very tasty puffer fwh, He felt elated a t the thought of dying just after tasting a puffer fish, something that had been his long-cherished desire. He did so, and the puffer fish was so delicious that he felt it was certainly worth eating even a t the risk of his own life. Goshun went to bed feeling some paralysis in his h d y . However, the next day, he awoke from his sleep and cried out: "I did not die. No! I was revived from death. Oh! Let me live and work on! I shall never be defeated by anything." This is a story of a new start of the great painter Goshun.
Even if this anecdote is so, puffer fish toxin is dangerous I t was a long time ago that the Japanese discovered how tasty the puffer fish is. From old tombs in the Yamato era (3rd to 6th century), a great number of puffer fish bones have been excavated. Dishes of puffer fish appear in Basho's famous poems and in Ekiken's hook (both in Edo era, 17th century) However, unless the secret of oreoaration is known. the ouffer fish is ooisonous. Even now. anoroximatelv . . .. . 200 ~. e .o ~ l e suffer h m puffer f ~ po8aoning h every year. and about 100among them die. However, you can safely eat puffer lish that is prepared by a propcrly trained cook, since the toxin isonly located in theeggs and liver ofthe lish.
Japan has done advanced research on puffer fish toxin Because of Japanese interest in the puffer fish, research to elucidate the toxic substance started in the Meiji era (end of 19th century) far ahead of other countries. Many chemists became enthusiastic about isolating the pure toxin, called tetradotoxin, because it is violently poisonous. At last, in 1964, chemists in Japan as well as the United States succeeded a t task. This was certainly almost the same time in determining the chemical structure of the toxin, which proved to be a difficult one of the brilliant achievements of organic chemistry of that time. The toxin molecule was found to he eomwsed of carbon.. hvdroeen. ,. . nitroeen. ,. . and axveen. d l of which are verv common elemenu, and no special umic atoms are in\,ulved. Why then, dwa the molecule eahihit sued a toxic character? A mystery of the horrible pinon was concealed in the spatial structure of the torin molecule which is shown in the illustratam above. The great progress of modern organic chemistry led to successful efforts by a group of young Japanese chemists to synthesize the same tetrdotoxin that is present in natural puffer fish toxin by building up the molecule from individual atoms through a long synthetic pathway.
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Why does the puffer flsh not die by his own toxin? Very interestingly, the same compound, tetrodotoxin, which had been believed to be unique to puffer fish, was recently found to exist in the California newt, Taricha torosa, and a toxic wtopus, Hapalo chlaena meulosa, neither of them fishes. The lethal toxic dose of tetrodotoxin for animals is 0.5 mg per body weight of 50 kg, that is, an amount about the size of a tiny poppy seed. I t is an exceptionally strong poison. Nevertheless, it is said that a poison can serve as a drug depending on how much is used. This is the case for tetrodoxin which is actually used clinically in very small doses as a good antineuralgic. By the way, why does a puffer fish not die by his own tetrodotoxin? Nobody knows the reason yet. When one door to the mystery of nature is opened, a more solid door to a deeper place awaits us. Chemists are continuing to challenge each new target, attracted by the mystery of nature. Someday in the future, a method to counteract the poison of puffer fish may be discovered. When that happens we will he able to enjoy the wonderful taste of puffer fish without our present anxiety. This article is translated from a bwk "Chemistry, a la carte," which Uw authm wrote fm Japanese citizens who were interested in how chemistry affects their daily lives. "Chemistry, a la carte" was published by the Society of Kinki Chemical Indushy. Japan. which has given its permission for reprinting this excerpt.
Tetsuo Shiba Osaka University Toyanaka. Osaka, 560 Japan
Volume 59
Number 10
October 1982
833
