Contrary to popular belief, aspirin is not found in nature, it is not found in willow. But there is a connection. Aspirin, or acetyl salicylic acid, was first produced commercially by the Bayer Company from a synthesis by Felix Hoffmann, a chemist working in 1897 for the Bayer Company in Germany. Although Hoffmann synthesized the first commercial sample of acetylsalicylic acid, he was certainly not the first to produce the substance in the laboratory. That honor goes to Karl Friedrich Gerhardt, who in 1853 at the University of Montpelier in France made an impure version with the aim of improving the effects of salicylic acid, a commonly used pain reliever. Salicylic acid was then extracted from the leaves of the meadowsweet plant and used to treat fever and pain, especially of the arthritic variety. But it had to be taken in large quantities, had a bitter taste and often caused stomach irritation. Gerhardt identified the molecular structure of salicylic acid and thought he could modify it and produce a better product. He abandoned the project when he could not reliably produce the “acetylated” version.
How did salicylic acid come to be used as a pain reliever in the first place? It is a long and endearing story. It all starts with a recommendation in the famous 3500-year-old Egyptian Ebers papyrus about treating an inflamed wound with a mixture made from the leaves of the white willow. This makes sense considering that willow leaves and bark contain a substance known as salicin, which can be converted to salicylic acid in the body. Of course, not all of the Ebers papyrus inflammation prescriptions turned out to be so scientifically convincing. A poultice made from chopped bat or a potion of wasp dung in fresh milk have not stood the test of time. But plants that contain salicylate do. Hippocrates advocated the use of willow bark for labor pain and the Roman physician Celsius described the treatment of inflammation, characterized by redness, heat, pain and swelling, with willow leaves. The ancient Chinese, as well as the American Indians, knew the special properties of plants such as meadowsweet.
The true scientific era of salicylates began in 1763 when the Reverend Edward Stone presented a report to the Royal Society of England on the use of willow bark in the treatment of fever. Stone was a believer in the rather curious Doctrine of Signatures which held that cures could be found in the same places that produced disease. Since fevers were often associated with swamps, probably due to infectious agents transmitted by mosquitoes, it was here that Stone sought cures. He tasted a branch of willow and was surprised by its bitterness. It was exciting though, because he knew that quinine, an equally bitter substance, was useful in the treatment of malarial fever. So he decided to try willow bark. Stone dried and powdered the substance and tested it on fifty patients with rheumatic symptoms. The bark worked!
Now the search began to discover the active ingredient. In 1828, salicin, named after Salix alba vulgaris, the botanical name for willow, was isolated and shown to have a medicinal effect. In addition, it could be converted in the laboratory to salicylic acid, which was even more potent as a drug. It was around this time that Gerhardt became interested in solving the problem of bitterness and gastric complications, a problem that was finally solved by Felix Hoffmann some fifty years later. Hoffmann’s father had been taking salicylic acid for arthritis for some time, but he could no longer take it without vomiting. The chemist searched the literature for alternative forms of salicylates and found Gerhardt’s work. By this time chemical techniques had been perfected to the point where it was possible to make acetylsalicylic acid in pure form and the age of aspirin was underway. The name was chosen by combining “spiric acid,” as salicylic acid was originally known, with “a” for “acetyl.” The rest, as they say, is history.
It should be obvious from the above that aspirin itself is not found in nature, but similar and less effective substances are. Willow extracts sold in health food stores cannot compare to the proven effectiveness of aspirin; in fact, aspirin emerged as an improvement on natural salicylates. In addition, the anticoagulant effect of aspirin can be attributed to the acetyl part of the molecule that is responsible for inactivating an enzyme that leads to the formation of blood clots. So there’s really no point in chewing willow bark to prevent a heart attack. But carrying a 325 mg aspirin tablet and chewing it if a heart attack is pending is a good idea.
@JoeSchwarcz