Capsaicin
Capsaicin ( (INN); 8-methyl-N-vanillyl-6-nonenamide) is an active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact. Capsaicin and several related compounds are called capsaicinoids and are produced as secondary metabolites by chili peppers, probably as deterrents against certain mammals and fungi. Pure capsaicin is a volatile, hydrophobic, colorless, odorless, crystalline to waxy compound.
History
The compound was first extracted in impure form in 1816 by Christian Friedrich Bucholz (1770–1818). He called it "capsicin", after the genus Capsicum from which it was extracted. John Clough Thresh (1850–1932), who had isolated capsaicin in almost pure form, gave it the name "capsaicin" in 1876. Karl Micko isolated capsaicin in its pure form in 1898. Capsaicin's chemical composition was first determined by E. K. Nelson in 1919, who also partially elucidated capsaicin's chemical structure. Capsaicin was first synthesized in 1930 by Ernst Spath and Stephen F. Darling. In 1961, similar substances were isolated from chili peppers by the Japanese chemists S. Kosuge and Y. Inagaki, who named them capsaicinoids.