Natural product to modern discovery of their active ingredients and eventually to the development of new drugs. A large number of currently prescribed drugs have been either directly derived from or inspired by natural products. A few representative examples are listed below. Some of the oldest natural product based drugs are analgesics. The bark of the willow tree has been known from antiquity to have pain relieving properties. This is due to presence of the natural product salicin which in turn may be hydrolyzed into salicylic acid. A synthetic derivative acetylsalicylic acid better known as aspirin is a widely used pain reliever.
Obeticholic acid Obeticholic acid Obeticholic acid (abbreviated to OCA, trade name Ocaliva), is a semi-synthetic bile acid analogue which has the chemical structure 6α-ethyl-chenodeoxycholic acid. It is used as a drug to treat primary biliary cholangitis, and is undergoing development for several other liver diseases and related disorders. Intercept Pharmaceuticals Inc. hold the worldwide rights to develop OCA outside Japan and China, where it is licensed to Dainippon Sumitomo Pharma. The natural bile acid, chenodeoxycholic acid, was identified in 1999 as the most active physiological ligand for the farnesoid X receptor (FXR), which is involved in many physiological and pathological processes. A