Since ancient times our ancestors have used phytochemicals found in plants to curtail the inflammatory process. For example, the bark of the willow tree was used as an analgesic and antipyretic medication more than 2400 years ago by the Greeks and Romans. The discovery of aspirin in 1899 was based on this observation.
The emergence of today's pharmaceutical industry, in large part, has been based on natural products. Drugs such as digoxin, Taxol, artemisinin, and scores more have been developed from phytochemicals.[80,138] Not only have many medical breakthroughs been based on compounds of natural origin, but these also represent a large share of the drug market. In 1999, close to 50% of the 20 best-selling drugs were derived from natural products, and their sales amounted to approximately $16 billion.[80,92] According to a survey by the National Cancer Institute, 61% of the 877 small molecules, which are new chemical entities introduced as drugs worldwide from 1981 to 2002, were inspired by natural products. The following is a discussion of the most commonly used natural antiinflammatory agents and their mechanism of action.