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Linné on line arrow Linnaeus and Pharmacy arrow Medicinal plants arrow A willow for a headache

A willow for a headache

Pussy willow, Salix caprea, from a classical book of flora by C. A. M. Lindman.

Another example of the importance of medicinal plants for medicine is the story of acetylsalicylic acid which is also known as aspirin. Here,  two plants played major roles in its development. Both have been used for thousands of years, since long before chemical substances were isolated from them. The two main role players were the white willow, Salix alba and meadowsweet, Filipendula ulmaria. A substance was successfully isolated from willow bark in 1830 and since the generic name for willows in Latin is Salix, it was named salicin. Eight years later it was discovered that it was a glycoside, i.e., it consisted of one part sugar and one part aglycon. The aglycon could be oxidised into an acid, which was called salicylic acid. Similar substances were also found in other plants, e.g., meadowsweet. The substance from meadowsweet was named spirin since the plant’s scientific name at that time was Spiraea ulmaria.

In 1876 it was discovered that salicylic acid was effective against rheumatic pain. A common side effect was stomach problems. A German chemist, Felix Hoffman, whose father suffered from both rheumatic pain and stomach problems which were associated with the salicylic acid, started to experiment. In 1897 he modified the substance chemically to acetylsalicylic acid whereupon his father’s stomach problems were eased. At the pharmaceutical company where Hoffman was employed, they tested the substance on animals and this is thought to be the first time that animal trials were used in the pharmaceutical industry. Later, when tests were carried out on human beings, they found that the substance was not only effective against rheumatic pain but also other kinds of pains, e.g., headaches. When it was time to launch the substance on the market they needed a good name for it. Aspirin was chosen. “A” from acetyl and spirin from spiraea.

Meadowsweet played one of the leading roles in the development of medicines against headaches.
Photo: Håkan Tunón.

Acetylsalicylic acid is one of today’s most common medicines against pain. In many products, the substance is combined with caffeine, which is another well-known plant substance. Caffeine has been refined from coffee since 1820. In recent years there has emerged an alternative use for acetylsalicylic acid. It is known to be an anticoagulant and, in low doses, it prevents blood clots.