Biosynthesis and function of secondary metabolites

Natural products have long been used by humans owing to their beneficial effects. Indulgences such as coffee and tea, with their moderate stimulatory properties, have a long cultural tradition and are today some of the most important agricultural products worldwide. Other drugs have much stronger impacts on the central nervous system. For example, coca was originally used by the Inca civilisation because of its strong stimulatory effects, which result in feelings of happiness and euphoria. Opium was used by many ancient cultures as an efficient analgesic, but this also illustrates one of the first examples of drug abuse as it was used by warriors as an anxiolytic when girding their loins. Besides their pleasant traits these highly active drugs have adverse side effects, including most importantly an extremely high potential to cause addiction in combination with physical and mental prostration upon long-term abuse. Therefore, the production, importation, trading, and possession of these drugs are today under strict control by public authorities. Another historically interesting example of drug misuse is given by the death penalty imposed on Socrates in 399 B.C., carried out by the forced ingestion of the proverbial cup of hemlock.