Tuesday, February 28, 2017

Discovery of salicylic acid by Edward Stone

About 3500 years ago Ebers papyrus recommended a decoction of dried leaves of myrtle to cure rheumatic pains.

Hippocrates favored the juices of the popular tree against eye diseases and those of Willow bark in case of pain in childbirth and against fever. The active ingredient of both these remedies is salicylic acid - aspirin’s active ingredient.

One summer day in 1758, an English clergyman named Edward Stone was walking along a brook near Chipping Norton, past some willow trees. For reasons that are not recorded, he put a strip of the bark to his lips and noticed that it tasted bitter.

He knew that the bitter tasting bark of the South American cinchona tree was used as a treatment for malaria, and argued that willow bark might have similar curative properties.

On June 2, 1763, he read a paper to the Royal Society of London entitles “An Account of the Success of the Bark of the Willow the cure of Agues.” By ague, Stone was referring to what now call malaria, but his use of the word cure was optimistic; what his extract of willow bark actually did was to reduce the feverish symptom of the disease.

He described chewing dried bark from Willow trees: “…Which I have found by experience to be powerful astringent and very efficacious in curing anguish and intermitting disorders.”

The substance was named salicylic acid. But when people suffering from pain took the salicylic acid, it caused severe stomach and mouth irritation. In 1899 German chemist working for Bayer, then a dye company found that acetyl salicylic acid was much convenient to take.
Discovery of salicylic acid by Edward Stone

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