Acetyl group known as paracetamol), and acetylsalicylic acid (better known as aspirin). The introduction of an acetyl group into a molecule is called acetylation. In biological organisms, acetyl groups are commonly transferred from acetyl-CoA to other organic molecules. Acetyl-CoA is an intermediate both in the biological synthesis and in the breakdown of many organic molecules. Acetyl-CoA is also created during the second stage of cellular respiration, the Krebs Cycle, by the action of pyruvate dehydrogenase on pyruvic acid. Histones and other proteins are often modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of
History of aspirin preparations became a standard part of the "materia medica" of Western medicine beginning at least with the Greek physician Hippocrates in the fifth century BCE; he recommended chewing on willow bark to relieve pain or fever, and drinking tea made from it to relieve pain during childbirth. The Roman encyclopedist Celsus, in his "De Medicina" of ca. 30 AD, suggested willow leaf extract to treat the four signs of inflammation: redness, heat, swelling and pain. Willow treatments also appeared in Dioscorides's "De Materia Medica", and Pliny the Elder's "Natural History". By the time of Galen, willow bark was commonly used