Docosapentaenoic acid designates any straight chain 22:5 fatty acid.
- See essential fatty acid#nomenclature for nomenclature.
Two isomers are of particular interest
- all-cis-7,10,13,16,19-docosapentaenoic acid is an ω-3 fatty acid with the trivial name clupanodonic acid, commonly called DPA. It is an intermediary between eicosapentaenoic acid (EPA, 20:5 ω-3) and docosahexaenoic acid (DHA, 22:6 ω-3). Seal oil is a rich source.
- all-cis-4,7,10,13,16-docosapentaenoic acid is an ω-6 fatty acid with the trivial name Osbond acid. It is formed by an elongation and desaturation of arachidonic acid 20:4 ω-6. In mammals, clupanodonic acid deficiency is accompanied by an increase of this isomer; the Osbond/DHA ratio is thus a marker of dietary DHA sufficiency. However, this usage has been questioned.