The story of how aspirin arrived on the shelves of the chemist in the late 1800s mirrors the changes the microscope brought to medicine. It is commonly thought aspirin was derived from plants. While isolating a constituent called salicin from willow bark was the first step in bringing aspirin to market, it was not a plant that aspirin was eventually synthesized from 40 years later.
Willow has been used for thousands of years to ease pain. The ancient Egyptians used it. Hippocrates used it. Dioscorides, a first-century CE Greek doctor/herbalist, recommended pounding willow leaves into small pieces and adding them to wine along with a pinch of black pepper to help ease painful intestinal obstructions, childbirth and gout.
I have a particular fondness for Willow’s medicine. As a student studying Willow’s medicine, I had an AH HA moment about the dynamic time-tested relationship between plants and humans. Let me try to explain.
The study and practice of herbal medicine nurtures feelings of belonging to the Earth, being part of the Earth. Practicing plant medicine creates a confidence that you are woven into the great web of life alongside every daisy, bear, rain drop. The essence of herbal medicine is the interdependence of life with its constant shifting forms. The study of Willow’s medicine deeped my trust in the great weaving.
I had this AH HA while studying the phytoconstituent salicin.
The phytoconstituent Salicin is an alcohol wrapped in a sugar molecule (glucose).[1] The glucose is sort of like a box for the alcohol. Like a box, it contains the alcohol, reducing its volatility and toxicity, while facilitating either its movement through the plant’s tissues and to store it for later use. And just like boxes glucose facilitates the delivery of salicin to both plant and human tissues.
This is where I had my ah ha moment. Salicin does not ease the pain of inflammation. As salicin interacts with enzymes in the small intestine and then is further metabolized in the liver, it transforms into pain-relieving salicylic acid. It is the complex and ancient relationship between plants and animal bodies that creates the pain-relieving medicine in Willow and Poplar.
The salicin in Willow or Poplar does not thin blood or damage the lining of the stomach, because it does not become salicylic acid, the pain-relieving medicine, until it is released from the liver into the bloodstream. Did you just have an AH HA moment?
Willow and Poplar, like most plants, also makes salicylic acid. Salicylic acid is a plant hormone that regulate growth. Salicylic acid also acts like a cytokine to signal the presence of welcome bacteria, fungi or virus. Plants do not store salicylic acid. They make the secondary metabolite according to their needs.
For example, to support the release of salicin into nibbled leaves, plants release a volatile compound methyl-salicytic acid from miniscule pores on the underside of their leaves. The methyl salicylic acid then floats through the air and alerts nearby leaves and other plants to the presence of the grazer or forager.
Receiving the air borne methyl salicyltic acid leaves and plants quickly begin to make more and more salicin. Salicin has a bitter taste. As the levels of salicin rise in the plant they less palatable. The grazing animal moves on.
Meadowsweet (Filipendula ulmaria), not a particularly bitter tasting plant, creates abundant amounts of salicylic acid. This is one of the reasons Meadowsweet is useful in easing the pain that arrives with inflammation. The salicylic acid in Meadowsweet however does not disturb the digestive system’s mucosa. It is a great healer for the mucosa, particularly when there is ulceration.
Let’s go back to the time to the development of the over-the-counter drug aspirin. This will shine light on how the “anti” prefix became part of the herbal lexicon.
Salicin was first isolated from Willow in 1828. But chemists could not figure out how to use the isolated secondary metabolite for medicine.
Salicylic acid was initially isolated from Meadowsweet about ten years later in 1839. While Meadowsweet makes an abundance of salicylic acid, chemists overall found the plant an unreliable source. As any herbalist knows, a plant makes secondary metabolites in response to its environmental conditions and where it is in its growth cycle. To use Meadowsweet’s salicylic acid to manufacture large amounts of commercially available pain medicine, was not viable. There was no interested in getting to know the plant, just the salicylic acid.
Around the same time that salicylic acid was isolated from Meadowsweet, chemists discovered a method to make the pain relieving phytoconstituent from salicin. The chemists. like those who discover salicylic acid in Meadowsweet, were challenged to find a reliable source of salicin. The pursuit of a drug made solely from salicylic acid was put on the back burner.
Then in 1860, while exploring the creation of synthetic colour-fast dyes, German chemists discovered a process to make salicylic acid from coal tar. Twenty years later they cashed in on their discovery and aspirin hit the market. Unfortunately the relieving-pain drug caused ulcerations in the stomach’s lining. Just before the turn of the century an acytl was attached to salicylic acid and presto pain relief that mildly disturbed the stomach and small intestine. The abundance of coal tar paved the way for the industrialization of salicytlic acids pain relieving properties.
Aspirin was not marketed initially as an anti-inflammatory. It was advertised as said good for rheumatism and called a rheumatic.
[1] Salicin is classed as a phenolic glycoside.