Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid. It is present in the phospholipids of cell membranes. It is also involved in cellular signaling as a lipid second messenger including PLC-γ, PLC-δ and PKC-α, -β and -γ isoforms. Arachidonic acid is a key inflammatory intermediate.  Leukotrienes are inflammatory mediators generated from arachidonic acid.