ABSTRACT
Arachidonic acid (AA, sometimes ARA): A polyunsaturated omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil. In chemical structures, arachidonic acid is a carboxylic acid with a 20-carbon chain and four cis-double bonds; the first double bond is located at the sixth carbon from the omega end. Some chemistry sources define “arachidonic acid” to designate any of the eicosatetraenoic acids. However, almost all writings in biology, medicine, and nutrition limit the term to all-cis-5,8,11,14-eicosatetraenoic acid. Arachidonic acid is a polyunsaturated fatty acid present in the phospholipids (especially phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositides) of membranes of the body’s cells, and is abundant in the brain, muscles, and liver. In addition to being involved in cellular signaling as a lipid second messenger involved in the regulation of signaling enzymes, such as PLC-γ, PLC-δ, and PKC-α, -β, and -γ isoforms, arachidonic acid is a key inflammatory intermediate and can also act as a vasodilator.
