Medicinal chemistry, in its crudest sense, has been practiced for several thousand years. Man has searched for cures of illnesses by chewing herbs, berries roots, and barks. Some of these early clinical trials were quite successful, however, not until the last 100 year has knowledge of the active constituents of these natural sources been known. The earliest written records of the Chinese, Indian, South American, and Mediterranean cultures described the therapeutic effects of various plant concoctions. If the approach to drug discovery continued as in ancient times, few diseases would be treatable today.
Natural products make up a small percentage of drugs on the current market.
Typically, when a natural product is found to be active, it is chemically modified in order to improve its properties. As a result of advances made in synthesis and separation methods and biochemical techniques since the late 1940s, a more rational approach to drug discovery has been possible, namely, one which involves the element of design. Basic Considerations of Drug Activity. Analgesics and Anti-Inflammatory Agents. Cholinergic Drugs Part 1.