Willow Bark
<p>The leaves and bark of the willow tree have been mentioned in ancient texts from <a href="http://en.wikipedia.org/wiki/Assyria" title="Assyria" >Assyria</a>,<a href="http://en.wikipedia.org/wiki/Sumer" title="Sumer" >Sumer</a> and <a href="http://en.wikipedia.org/wiki/Ancient_Egypt" title="Ancient Egypt" >Egypt</a><sup id="cite_ref-7" class="reference" ><a href="http://en.wikipedia.org/wiki/Willow#cite_note-7" >[8]</a></sup> as a remedy for aches and <a href="http://en.wikipedia.org/wiki/Fever" title="Fever" >fever</a>,<sup id="cite_ref-8" class="reference" ><a href="http://en.wikipedia.org/wiki/Willow#cite_note-8" >[9]</a></sup> and the <a href="http://en.wikipedia.org/wiki/Ancient_Greece" title="Ancient Greece" >Ancient Greek</a> physician<a href="http://en.wikipedia.org/wiki/Hippocrates" title="Hippocrates" >Hippocrates</a> wrote about its medicinal properties in the fifth century BC. <a href="http://en.wikipedia.org/wiki/Indigenous_peoples_of_the_Americas" title="Indigenous peoples of the Americas" >Native Americans</a> across the American continent relied on it as a staple of their medical treatments, because willows contain <a href="http://en.wikipedia.org/wiki/Salicin" title="Salicin" >salicin</a>, a substance that chemically resembles aspirin. It temporarily relieves headache, stomachache, and other body pain. Salicin is metabolized into <a href="http://en.wikipedia.org/wiki/Salicylic_acid" title="Salicylic acid" >salicylic acid</a> in the human body, which is a precursor of <a href="http://en.wikipedia.org/wiki/Aspirin" title="Aspirin" >aspirin</a>.<sup id="cite_ref-9" class="reference" ><a href="http://en.wikipedia.org/wiki/Willow#cite_note-9" >[10]</a></sup> In 1763, its medicinal properties were observed by the <a href="http://en.wikipedia.org/wiki/Reverend_Edward_Stone" title="Reverend Edward Stone" class="mw-redirect" >Reverend Edward Stone</a> in England. He notified the <a href="http://en.wikipedia.org/wiki/Royal_Society" title="Royal Society" >Royal Society</a>, who published his findings. The active extract of the bark, called salicin, was isolated to its crystalline form in 1828 by <a href="http://en.wikipedia.org/w/index.php?title=Henri_Leroux&action=edit&redlink=1" class="new" title="Henri Leroux (page does not exist)" >Henri Leroux</a>, a French pharmacist, and <a href="http://en.wikipedia.org/wiki/Raffaele_Piria" title="Raffaele Piria" >Raffaele Piria</a>, an Italian chemist, who then succeeded in separating out the compound in its pure state. In 1897, <a href="http://en.wikipedia.org/wiki/Felix_Hoffmann" title="Felix Hoffmann" >Felix Hoffmann</a> created a synthetically altered version of salicin (in his case derived from the <i ><a href="http://en.wikipedia.org/wiki/Spiraea" title="Spiraea" >Spiraea</a></i> plant), which caused less digestive upset than pure salicylic acid. The new drug, formally <a href="http://en.wikipedia.org/wiki/Acetylsalicylic_acid" title="Acetylsalicylic acid" class="mw-redirect" >acetylsalicylic acid</a>, was named <a href="http://en.wikipedia.org/wiki/Aspirin" title="Aspirin" >Aspirin</a> by Hoffmann's employer <a href="http://en.wikipedia.org/wiki/Bayer" title="Bayer" >Bayer AG</a>. This gave rise to the hugely important class of drugs known as nonsteroidal anti-inflammatory drugs (<a href="http://en.wikipedia.org/wiki/NSAID" title="NSAID" class="mw-redirect" >NSAIDs</a>).</p>