12hepe

12(S)-HEPE is a monohydroxy fatty acid synthesized from EPA by the action of 12-LO. Unstimulated neutrophils metabolize 12(S)-HEPE to 12(S),20-diHEPE, whereas stimulated neutrophils produce 5(S),12(S)-HEPE via the 5-lipoxygenase pathway. The competitive action of 12(S)-HEPE with arachidonic acid as a substrate for 5-LO in the formation of leukotrienes may provide a basis for the anti-inflammatory potential of ω-3 fatty acids.

(±)12-HEPE is produced by non-enzymatic oxidation of EPA. It contains equal amounts of 12(S)-HEPE and 12(R)-HEPE. The biological activity of (±)12-HEPE is likely mediated by one of the individual isomers, most commonly the 12(S) isomer in mammalian systems. 12-HEPE inhibits platelet aggregation with the same potency as 12-HETE, exhibiting IC50 values of 24 and 25 µM, respectively. [1] These compounds are also equipotent as inhibitors of U46619-induced contraction of rat aorta (IC50s = 8.6-8.8 µM).[2]