MedicalResearch.com Interview with:
Prof. Daniel F. Klessig
Boyce Thompson Institute for Plant Research,
Department of Plant Pathology and Plant-Microbe Biology
Cornell University, Ithaca, New York
MedicalResearch: What is the background for this study?
Prof. Klessig: Acetyl salicylic acid, commonly called aspirin, has been the most widely used drug worldwide for more than a century. Currently, 80 million pounds of aspirin are produced worldwide every year and almost 30 billion tablets are consumed annually in the US alone. Long before German pharmacologist Johann Buchner identified the salicylic acid derivative salicin in 1828 as the ingredient in willow bark that is responsible for its therapeutic effects, different cultures throughout the world were, and many still are, using a variety of plants rich in salicylic acid derivatives, such as willow, wintergreen, and meadowsweet, to treat pain, fever, swelling, and other maladies. Aspirin also is used to reduce the risk of heart attack, stroke, and certain cancers.
One might expect that aspirin’s mechanisms of action would be well understood, given its extraordinarily widespread use and the fact that it was first synthesized by the Bayer chemist Felix Hoffmann over 100 years ago. The prevailing view in the biomedical community has been that aspirin works primarily, if not exclusively, by irreversibly inhibiting the enzymatic activities of cyclooxygenases 1 and 2 (COX1 and COX2), thereby disrupting the synthesis of inflammation-inducing prostaglandins. However,
this assumption ignores two important facts.
- First, aspirin is rapidly converted to salicylic acid (SA) in the body. Indeed, almost all aspirin is metabolized to SA within an hour after ingestion.
- Second, SA and many of its natural plant derivatives are rather poor inhibitors of COX1 and COX2 as compared to aspirin, yet SA and aspirin have nearly the same beneficial pharmacological effects. Thus, there must be additional targets through which aspirin/SA exerts its many effects. Over the past two decades, a number of proteins whose activities are altered by aspirin/SA have been identified; however, their relevance as aspirin/SA targets has been called into question due to the very high, non-physiological levels of aspirin/SA required to alter their activities.
In light of our unexpected discovery that SA mediates its physiological effects in plants via many targets, and given that SA is a key hormone produced by all plants, we hypothesized that there might be multiple targets through which SA acts in animals, regardless of whether it is obtained in low to moderate levels via the diet or in moderate to high doses through herbal-based medicines or aspirin usage.
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