CURARE
(Chondrodendron tomentosum - Menispermaceae)

From Arrow Poison to Surgical Muscle Relaxant

It was from Sir Walter Raleigh’s expedition up the Orinoco, Venezuela in 1595 that curare first gained its fearful reputation. The trip’s historian described in detail the horrific manner of death that resulted and the plant was also named as a poisonous herb in a book written by one of the party. La Condamine, the French explorer (and mathematician) was the first to collect it in the late 18th century. He recognised that it was the vine that was of prime importance and that it would kill in less than a minute only if it entered the bloodstream, but not otherwise. There was no danger in eating the animals afterwards however.

Shortly after, in about 1800, at Esmerelda in Venezuela, Von Humboldt, the Prussian naturalist and explorer, observed a brujo pounding the vine fibres into a yellow runny mush to which he added water. The substance was allowed to stand so as to evaporate the liquid. Adding the juice of another plant resulted in a black, sticky molasses type material and this was the substance they stuck to their arrows. It could be tasted though without danger, being only dangerous in the blood stream. But he was unable to make a botanical identification.

In the early 1800’s, the entertaining and eccentric English squire, Charles Waterton, who gained fame by riding a captured alligator, had observed the Maconsis making curare. In England, together with a doctor, Ben Collins Brodie, he administered it to a donkey, which collapsed and stopped breathing within minutes. Swiftly Brodie cut the donkey’s windpipe and they inserted a bellows and pumped. The donkey sat up. Two hours were spent like this until the poison wore off and the donkey recovered. After its experience, it was put to pasture for services to medicine.

By 1938, explorers had decided that the genus of vine ‘chondrodendron’ was the probable source. At that time, there existed only two species of this vine. A British chemist had isolated the active ingredient in 1935 and he named it d-tubocurarinechloride, ‘tubo’ referring to bamboo tube and indicating that it was the curare kept in one. Around this time an American Richard Gill and his wife Ruth bought a ranch in Ecuador and learnt the Quichua language, friendship with the locals being the result. A small accident to his wife led him to try local methods of medicine, which left him thoughtful and so he noted carefully the plants used. Just before he was to return to the States, Gill suffered a fall from his horse. It was the beginning of an incomprehensible paralysis that was to last months. In the States, his doctor made a chance remark about the possible power of curare to help him and it dawned on Gill, that his friends in Ecuador would know about the plant. It was the motivation needed and Gill made the most extreme efforts to recover.

He returned to Ecuador, mounted an expedition and by barter and persuasion collected about 75 different specimens. By comparing ingredients used by several brujos, he identified the one recurring plant, ‘tonispa pala ango’, a very thick woody vine that wound through many trees. The New York Botanic Garden identified it as ‘chondodendron’ of the moonseed family Menispermaceae.
Frustratingly, curare could relax limbs that had been crabbed and frozen for years but only worked temporarily. Side effects were so dangerous that they could suffocate a patient. However, an enthusiastic supporter of Gill, Abram Bennett, tried it as a treatment for schizophrenia and in so doing, established that at least it could be used without causing harm to patients.

In 1942, curare finally found its place in medicine – as a muscle relaxant during surgery. It was particularly suitable during abdominal surgery, where the muscles were difficult to relax. A Canadian doctor and anaesthesiologist first took the calculated risk of administering it to an appendicitis patient - without either the doctor or patient’s knowledge. Curare was to become an important part of anaesthesia and a molecule on which other anaesthetics were to be based. After Gills efforts to sell curare to the drug companies had been rebuffed and scientists and governments had sidelined him, he spent the rest of his life trying to turn curare into a cure that he could administer to himself. He finally died in 1958 either of a typical multiple sclerosis or of amyotrophic lateral sclerosis.