Arachidonic Acid (AA)

Arachidonic acid (AA, sometimes ARA) is an omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil, In chemical structure, 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 that is present in the phospholipids (especially phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositides) of membranes of the body's cells, and is abundant in the brain and muscles.