5-hepe

(±)5-HEPE is produced by non-enzymatic oxidation of EPA. It 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, namely 5-HEPE, 5-oxoEPE, and LTB5, have significantly decreased biological effects compared to the arachidonic acid-derived metabolites.

5(S)-HEPE, an active metabolite of eicosapentaenoic acid (EPA), is produced via the action of 5-lipoxygenase (5-LO). This compound functions as an agonist for G protein-coupled receptor 119 (GPR119), promoting cAMP accumulation in CHO-K1 cells expressing human GPR119 at 10 µM concentration. Additionally, 5(S)-HEPE enhances glucose-stimulated insulin secretion from MING6 insulinoma pancreatic islets and glucagon-like peptide 1 (GLP-1) secretion from HuTu 80 adenocarcinoma cells at the same concentration. Notably, serum levels of 5(S)-HEPE are increased in hyperlipidemia patients.

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.

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.

5(S)-HpEPE is a monohydroperoxy polyunsaturated fatty acid produced by the action of 5-LO on EPA. It is metabolized to LTA5, a key intermediate in the formation of the 5-series leukotrienes. Alternatively, 5(S)-HpEPE is reduced to 5(S)-HEPE by peroxidases.

(±)8-HEPE is produced by non-enzymatic oxidation of EPA. It contains 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] Reference：[1]. Shing, T.K.M., Gibson, K.H., Wiley, J.R., et al. First total synthesis of a barnacle hatching factor 8(R)-hydroxy-eicosa-5(Z),9(E),11(Z)-pentaenoic acid. Tetrahedron Letters 35, 1067-1070 (1994).[2]. Hill, E.M., and Holland, D.L. Identification and egg hatching activity of monohydroxy fatty acid eicosanoids in the barnacle Balanus balanoides. Proceedings of the Royal Society of London Series B.Biological Sciences 247, 41-46 (1991).

Resolvin E2 (RvE2) is a member of the specialized pro-resolving mediator (SPM) family of bioactive lipids.1It is produced from eicosapentaenoic acidviaan 18-HEPE intermediate, which is formed by aspirin-acetylated COX-2-mediated oxidation of EPA, by 5-lipoxygenase (5-LO) in human polymorphonuclear (PMN) neutrophils.2,3RvE2 (20 ng/animal) inhibits increases in inflammatory exudate neutrophil infiltration in a mouse model of peritonitis induced by zymosan A .3Hepatic RvE2 levels are increased in mice fed normal chow, as well as in a mouse model of high-fat diet-induced non-alcoholic fatty liver disease (NAFLD), by dietary supplementation with EPA.4Plasma levels of RvE2 are increased by dietary supplementation with fish oil containing ω-3 polyunsaturated fatty acids (PUFAs) in patients with peripheral artery disease or chronic kidney disease.1,5,6 1.Chiang, N., and Serhan, C.N.Specialized pro-resolving mediator network: An update on production and actionsEssays Biochem.64(3)443-462(2020) 2.Tjonahen, E., Oh, S.F., Siegelman, J., et al.Resolvin E2: Identification and anti-inflammatory actions: Pivotal role of human 5-lipoxygenase in resolvin E series biosynthesisChemistry & Biology131193-1202(2006) 3.Sungwhan, F.O., Pillai, P.S., Recchiuti, A., et al.Pro-resolving actions and stereoselective biosynthesis of 18S E-series resolvins in human leukocytes and murine inflammationJ. Clin. Invest.121(2)569-581(2011) 4.Echeverría, F., Valenzuela, R., Espinosa, A., et al.Reduction of high-fat diet-induced liver proinflammatory state by eicosapentaenoic acid plus hydroxytyrosol supplementation: Involvement of resolvins RvE1/2 and RvD1/2J. Nutr. Biochem.6335-43(2019) 5.Ramirez, J.L., Gasper, W.J., Khetani, S.A., et al.Fish oil increases specialized pro-resolving lipid mediators in PAD (the OMEGA-PAD II trial)J. Surg. Res.238164-174(2019) 6.Barden, A.E., Shinde, S., Burke, V., et al.The effect of n-3 fatty acids and coenzyme Q10 supplementation on neutrophil leukotrienes, mediators of inflammation resolution and myeloperoxidase in chronic kidney diseaseProstaglandins Other Lipid Mediat.1361-8(2018)