Octadecatrienoic acid

An octadecatrienoic acid is a chemical compounds with formula C₁₈H₃₀O₂, a fatty acid with whose molecule has an 18-carbon unbranched backbone with three double bonds.

The name refers to many different structural and conformational isomers, that differ in the position of the double bonds along the backbone and on whether they are in cis ('Z') or trans ('E') conformation. Some isomers have considerable biological, pharmaceutical, or industrial importance, such as:

• α-Linolenic acid (9Z,12Z,15Z), found in many cooking oils
• γ-Linolenic acid (6Z,9Z,12Z), found in the evening primrose (Oenothera biennis)
• α-Eleostearic acid (9Z,11E,13E), the main component of tung oil.
• β-Eleostearic acid (9E,11E,13E)
• α-Calendic acid (8E,10E,12Z), found in the pot marigold (Calendula officinalis)
• 9,12,15-Octadecatrienoic acid, a cigarette additive.