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.
Pangamic acid and interstate shipment of pangamic acid on the grounds that pangamic acid and pangamic acid products are unsafe for use and have no known nutritional properties. Pangamic acid's distribution in Canada has been prohibited by the then-named Canadian Food and Drug Directorate. Pangamic acid Pangamic acid, also called pangamate, is the name given to the chemical compound described as "-gluconodimethylamino acetic acid", initially promoted by Ernst T. Krebs, Sr. and his son Ernst T. Krebs, Jr. as a medicinal compound for use in treatment of a wide range of diseases. They also termed this chemical "Vitamin B", though it is