Willow (Salix spp.)

SALICACEAE, Willow Family

The history of medicine has been enriched by thousands of plant species, but one plant--the willow--has probably been used and prescribed more than any other powdered drug. Willow is the original source of aspirin. Even today, when aspirin substitutes are available, up to 80 million tablets of aspirin are used each day in North America, and up to 50 million pounds each year are swallowed throughout the world. Now aspirin can be easily made by reacting phenol and carbon dioxide.

Hippocrates of Cos (460-377 B.C.) noted that chewing leaves of willow (Salix) reduced pain, and he prescribed this remedy for women in labor. Hippocrates certainly did not discover this drug, which was used for centuries earlier in European folk medicine. [We should be cautious in crediting Hippocrates with everything because researchers have suggested that the extensive collection of medical writings found in Alexandria, formerly ascribed to Hippocrates, may have been written by several people, the most influential of whom was Hippocrates.] Subsequent ancient Greek physicians recommended willow for alleviating pain and reducing fever and inflammation. In North America, probably even before the Greeks, the Alabama, Chickasaw, and Montagnai Indians used willow to relieve fevers, aches, and pains, and the beneficial effects were also known to the Hottentots of southern Africa.

Advocates of the Doctrine of Signatures described how willow worked to reduce inflammation of joints because the "weeping" branches were very flexible, like human limbs. As late as 1763, an English clergyman named Edward Stone (also known as Edmund Stone) wrote that willow is useful for lowering fever because both willow and fever thrive in damp regions.

In the 1820s, European chemists, eagerly studying the chemistry of plants, were able to isolate from willow a glycoside, which was named salicin, after the genus. Salicin was also discovered in poplars and aspens (also Salicaceae). In the laboratory, Karl L÷wig (1839) treated salicin with acid--as salicin is acted on in the human stomach--to make salicylic acid, and about that time salicylic acid was also discovered occurring naturally in a European species of Spiraea (dropwort). Salicylic acid had major medicinal uses and soon became a panacea. A related compound being used at that time was methyl salicylate, found in an oil from birch bark (Betula lenta) and oil of wintergreen (Gaultheria procumbens), long used to relieve aches. In this century, oil of wintergreen was formerly used in "analgesics" (rubefacients) for athletes.

The problem with salicylic acid was that, for many, it caused nausea and great gastric discomfort. A different compound was synthesized in 1853 by Carl von Gerhardt by putting an acetyl group on salicylic acid, making acetylsalicylic acid, which is a chemical salt (solid). Nonetheless, no one was aware of the more gentle properties of this compound until 1893, when Felix Hoffman, an employee of Friedrich Bayer and Company, found an easier way to make this salt and then tested it on his father, who had arthritis. In 1899, Bayer, which started in 1863 as a dye production company, marketed this medicine as "aspirin"--coming from the words 'acetyl' and Spiraea. The price of aspirin initially was expensive until Bayer learned how to mass produce tablets. Aspirin was thus the first major medicine in the world to be sold in tablet form.

As the ancients already knew, aspirin is a remarkable painkiller, i.e., an analgesic. Research indicates that painkilling results from the depressant action of aspirin on the central nervous tissue, somehow by reducing mild to moderate pain messages from reaching the brain. A very important use of aspirin is as an antipyretic, i.e., to lower body temperature (fever), via the dissipation of heat through effects on the hypothalamus, increasing sweating. The third major use of aspirin is as an anti-inflammatory agent (reduce swelling), as for victims of arthritis and "rheumatism."

American consumers spend $700,000,000 to 800,000,000 per year on painkillers (excluding opiates), especially aspirin and acetaminophen, the very common alternative that is marketed under names such as Tylenol, Datril, and Liquiprin. Both chemicals allay pain, but there are important differences. Aspirin, which is significantly cheaper, has the additional anti-inflammatory effects and therefore is critical for arthritis patients (much cheaper than the competing drugs). However, as arthritis pain intensifies, aspirin dosages must also be made stronger, and high dosages are potentially more dangerous. Maximum aspirin daily dosage should be 60 grains per 24 hours. Ibuprofen (Advil and Motrin) is similar as a painkiller but is especially widely used to reduced swelling of joints, particularly for athletes, where narcotics often cannot be administered for pain, and ketoprofen (Orutis KT) is substituted for ibuprofen, when ibuprofen is not effective. About 40 nonsteroidal anti-inflammatory drugs (NSAIDs) are currently available.

Medical studies on the effect of aspirin on breaking up blood clots (an antithrombotic drug) are now fairly conclusive, and many physicians prescribe daily aspirin after heart attacks or even as a preventative program because aspirin inhibits release of prostaglandin and thereby platelet agglutination. There are more effective, but not cheaper, antithrombotic drugs, e.g., sulfinpyrazone.

There are over 500 aspirin deaths in this country every year, from large accidental (child) or mostly suicidal (adult) overdoses or, rarely, from allergic reactions. [In 1989, there were 1.28 million ingestion poisonings, of which 5889 were of aspirin, and ten times more of acetaminophen.] Actually, in the United States, children aspirin deaths have declined from 40 to just 2 within the last 20 years. The dangerous side effect of aspirin is gastrointestinal irritation and stomach bleeding, which contribute to stomach ulcers (caused by bacteria). For treating simple aches and pains, painkilling pills that combine aspirin with acetaminophen do not appear to be any more useful than a single chemical.

Perhaps a piece of judiciary history is needed here. Aspirin was a patented name by Bayer, but this German company had conflicts with France and Great Britain, who fought against Germany in World War I and did not acknowledge that patent. Australia also began its own production when aspirin could not be supplied there. A legal battle ensued when Monsanto in the United States began its own production in 1917, and this eventually reached the U.S. Supreme Court, which ruled that "aspirin" had become so widely advertised and common that Bayer no longer owned the name. Hence, aspirin is now a vernacular name, which is why large companies of other products now aggressively take anyone to court when a popular product name is unlawfully used.