Angelic acid

Angelic acid is a monocarboxylic unsaturated organic acid. It is found in garden angelica (Angelica archangelica), Umbelliferae, and many other plants. It was also isolated from the defensive secretion of certain carabid beetles.

Properties and uses
Angelic acid has a double bond between the second and third carbons of the chain. Together with tiglic acid form a pair of cis-trans isomers. Angelic acid is a volatile body, of biting acid taste and pungent sour odour. It crystallizes in colorless monoclinic prisms. Angelic acid was formerly used therapeutically as a sedative.

Name and discovery
Angelic acid gets its name from the plant garden angelica (Angelica archangelica) from whose roots it was first obtained in 1842 by L. A. Buchner.