(±)5hepe

(±)5-HEPE is produced by non-enzymatic oxidation of EPA and contains equal amounts of 5(S)-HEPE and 5(R)-HEPE. The biological activity of (±)5-HEPE is likely mediated by one of the individual isomers, most commonly the 5(S) isomer in mammalian systems. EPA can be metabolized to 5-HEPE in human and bovine neutrophils, and human eosinophils, which is further metabolized to 5-oxoEPE and LTB5. The 5-series metabolites of EPA, including 5-HEPE, 5-oxoEPE, and LTB5, have significantly decreased biological effects compared to the arachidonic acid-derived metabolites.

15(S)-HEPE is a monohydroxy fatty acid synthesized from EPA by the action of 15-LO. The biosynthesis of 15-HEPE from EPA in guinea pig epidermal enzyme preparations has been documented. 15(S)-HEPE generated by soybean lipoxygenation of EPA inhibits RBL-1 cell 5-LO with an IC50 value of 28 μM.

(±)8-HEPE is produced by the non-enzymatic oxidation of EPA, containing equal amounts of 8(S)-HEPE and 8(R)-HEPE. The ability of (±)8-HEPE to induce hatching of E. modestus and B. balanoides eggs is probably due to the presence of the 8(R) isomer within the racemic mixture.[1][2]

(±)18-HEPE is produced by non-enzymatic oxidation of EPA. It contains equal amounts of 18(S)-HEPE and 18(R)-HEPE. Specific biological activity attributed to (±)18-HEPE has not been documented.

9(S)-HEPE is a monohydroxy fatty acid derived from EPA. The biological activity of 9(S)-HEPE has not been documented.

(±)9-HEPE is produced by non-enzymatic oxidation of EPA. It contains equal amounts of 9(S)-HEPE and 9(R)-HEPE. The biological activity of (±)9-HEPE has not been clearly documented.

8(S)-HEPE is a monohydroxy fatty acid produced by lipoxygenase oxidation of EPA. While it promotes barnacle egg hatching at 10 nM, its role as the natural egg hatching factor is not definitively established.

11(R)-HEPE is produced by the oxidation of EPA by 11(R)-LO. This enzymatic activity and the resulting 11(R)-hydroxy acid have been isolated from the sea urchin S. purpuratus.

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, while 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 leukotriene formation may underlie the anti-inflammatory potential of ω-3 fatty acids.