HeneicosapentaenoicAcid (HPA) is a 21:5 ω-3 fatty acid present in trace amounts in the green alga B. pennata and in fish oils. Its chemical composition is similar to eicosapentaenoicacid (EPA) except elongated with one carbon on the carboxyl end, placing the first double bond in the δ6 position. HPA can be used to study the significance of the position of the double bonds in ω-3 fatty acids. It incorporates into phospholipids and into triacylglycerol in vivo with the same efficiency as EPA and docosahexaenoic acid and exhibits strong inhibition of arachidonic acid synthesis from linoleic acid. HPA is a poor substrate for prostaglandin H synthase (PGHS) (cyclooxygenase) and for 5-lipoxygenase but retains the ability to rapidly inactivate PGHS.
Eicosapentaenoicacid methyl ester is a degradation product derived from monogalactosyl diacylglycerol, which is an apoptosis-inducing anticancer compound.
HeneicosapentaenoicAcid (HPA), a 21:5 ω-3 fatty acid, is found in minute quantities in green algae and fish oils, resembling eicosapentaenoicacid (EPA) but with an added carbon on the carboxyl end, positioning the initial double bond at the Δ6 location. HPA serves as a tool for examining the impact of double bond positions within n-3 fatty acids, as it is incorporated into phospholipids and triacylglycerol in vivo as efficiently as EPA and docosahexaenoic acid (DHA), while significantly inhibiting the synthesis of arachidonic acid from linoleic acid. Moreover, the ethyl ester variant of heneicosapentaenoicacid offers a more lipophilic and stable alternative to the free acid form.
HeneicosapentaenoicAcid (HPA) is a fatty acid found in small amounts in Bryopsis pennata Lamouroux green algae and fish oils, with a structure similar to eicosapentaenoicacid (EPA), but with an additional carbon at the carboxyl end, resulting in the first double bond being in the Δ6 position. HPA is important for researching the impact of double bond positions in n-3 fatty acids, as it integrates into phospholipids and triacylglycerol in vivo as effectively as EPA and docosahexaenoic acid (DHA), while strongly inhibiting the synthesis of arachidonic acid from linoleic acid. Despite being a poor substrate for prostaglandin H (PGH) synthase and 5-lipoxygenase, HPA can rapidly deactivate PGH synthase. HPA methyl ester, in certain formulations, acts as a prodrug to enhance cellular uptake of HPA before being converted into free acid by esterases, and serves as a useful reference standard.
Resolvin E2 (RvE2) is a member of the specialized pro-resolving mediator (SPM) family of bioactive lipids.1It is produced from eicosapentaenoicacidviaan 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 eicosapentaenoicacid 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)
Resolvins are a family of potent lipid mediators derived from both eicosapentaenoicacid and docosahexaenoic acid.[1] In addition to being anti-inflammatory, resolvins promote the resolution of the inflammatory response back to a non-inflamed state.[2] Resolvin D1 is produced physiologically from the sequential oxygenation of DHA by 15- and 5-lipoxygenase.[1] 17(R)-RvD1 is an aspirin-triggered epimer of RvD1 that reduces human polymorphonuclear leukocyte (PMN) transendothelial migration, the earliest event in acute inflammation, with equipotency to RvD1 (EC50 = ~30 nM).[3] 17(R)-RvD1 exhibits a dose-dependent reduction in leukocyte infiltration in a mouse model of peritonitis with maximal inhibition of ~35% at a 100 ng dose.[3] In contrast to RvD1, the aspirin-triggered form resists rapid inactivation by eicosanoid oxidoreductases. Analytical and biological comparisons of synthetic 17(R)-RvD1 with endogenously derived 17(R)-RvD1 have confirmed its identity as matching the natural product.[4]
17R(18S)-EpETE is an oxylipin and a cytochrome P450 metabolite of eicosapentaenoicacid .1,217R(18S)-EpETE is an activator of large-conductance calcium-activated potassium (BKCa) channels, increasing the potassium current amplitude by 15-fold in isolated rat cerebral artery vascular smooth muscle cells (VSMCs) at +60 mV when used at a concentration of 50 nM.2It has negative chronotropic effects in isolated neonatal rat cardiomyocytes (NRCMs; EC50= ~1-2 nM) and prevents calcium-induced increases in the spontaneous beating of NRCMs.3,4 1.Schwarz, D., Kisselev, P., Ericksen, S.S., et al.Arachidonic and eicosapentaenoicacid metabolism by human CYP1A1: Highly steroselective formation of 17(R), 18(S)-epoxyeicosatetraenoic acidBiochem. Pharmacol.67(8)1445-1457(2004) 2.Lauterbach, B., Barbosa-Sicard, E., Wang, M.H., et al.Cytochrome P450-dependent eicosapentaenoicacid metabolites are novel BK channel activatorsHypertension39(2 Pt. 2)609-613(2002) 3.Falck, J.R., Wallukat, G., Puli, N., et al.17(R),18(S)-Epoxyeicosatetraenoic acid, a potent eicosapentaenoicacid (EPA) derived regulator of cardiomyocyte contraction: Structure-activity relationships and stable analoguesJ. Med. Chem.54(12)4109-4118(2011) 4.Arnold, C., Markovic, M., Blossey, K., et al.Arachidonic acid-metabolizing cytochrome P450 enzymes are targets of omega-3 fatty acidsJ. Biol. Chem.285(43)32720-32733(2010)
Leukotriene B5 (LTB5) is a leukotriene with diverse biological activities. It is a metabolite of eicosapentaenoicacid formed through the 5-lipoxygenase (5-LO) pathway. LTB5 increases contraction of bullfrog lung strips ex vivo in a concentration-dependent manner. In vivo, LTB5 (100 nM) reduces tumor volume in mice injected with Tm1 murine melanoma cells. LTB5 also elicits chemokinesis and lysosomal enzyme release from polymorphonuclear leukocytes (PMNLs) 20- to 30-fold less, and induces platelet aggregation 8-fold less, potently than LTB4 .
Monoacylglycerols (MAGs) of ω-3 polyunsaturated fatty acids have diverse physiological and health effects. In particular, MAGs containing docosahexaenoic acid or eicosapentaenoicacid have anti-proliferative properties against colon and lung cancer cell lines. Eicosapentaenoyl 1-propanol-2-amide is an EPA-containing MAG amide analog that inhibits the growth of human lung carcinoma A549 cells, producing 98.4% growth inhibition when applied at 3 μM. It is an analog of eicosapentaenoyl ethanolamide , a natural N-acylethanolamide that impacts aging and inflammation.
20-HEPE is a metabolite of eicosapentaenoicacid that is formed via ω-oxidation of EPA by cytochrome P450 (CYP) ω-oxidases, including human CYP4F3B. It activates peroxisome proliferator-activated receptor α (PPARα) in COS-7 cells expressing a luciferase reporter when used at a concentration of 10 μM. 20-HEPE also activates murine transient receptor potential vanilloid receptor 1 (mTRPV1) in vitro but lacks antinociceptive activity in rats.
1,3-Dipalmitoyl-2-eicosapentaenoyl-rac-glycerol is a triacylglycerol that contains palmitic acid at the sn-1 and sn-3 positions and eicosapentaenoicacid at the sn-2 position. Dietary administration of 1,3-dipalmitoyl-2-eicosapentaenoyl-rac-glycerol decreases hepatic triacylglycerol levels in mice.
(±)8,9-DiHETE is a major metabolite of the 20:5 ω-3 fatty acideicosapentaenoicacid .[1] It is produced in rat liver microsomes, but not renal microsomes, by the generation of the unstable intermediate 8,9-epoxy eicosatetraenoic acid from EPA by cytochrome P450 monooxygenases. Dietary EPA supplementation in humans results in substantial urinary excretion of vicinal diols, including 8,9, 11,12, and 14,15 forms.[2]
EDHF (endothelium-derived hyperpolarizing factor) is an unidentified mediator released from vascular endothelial cells in response to acetylcholine and bradykinin which is distinct from the NOS- (nitric oxide) and COX-derived (prostacyclin) vasodilators.[1],[2]Cytochrome P450 (CYP450) metabolism of polyunsaturated fatty acids produces epoxides such as (±)14(15)-EET which are prime candidates for the actual active mediator.[3] However, the CYP450 metabolites of eicosapentaenoicacid and docosahexaenoic acid have been little studied relative to arachidonate epoxygenase metabolites. (±)16(17)-EpDPA is the DHA homolog of (±)14(15)-EpETrE, derived via epoxidation of the 16,17-double bond of DHA. The EDHF activity of (±)16(17)-EpDPA has not yet been determined. The epoxygenase metabolites of DHA have also been detected in a mouse inflammation model.[4]
Eicosapentaenoicacid is an ω-3 fatty acid abundantly available in marine organisms. (±)17(18)-DiHETE is one of the major metabolites produced when eicosapentaenoicacid (EPA) is incubated with various rat tissue homogenates or cynomolgus monkey seminal vesicles. The route of production of (±)17(18)-DiHETE likely proceeds through cytochrome P450-catalyzed epoxidation at the ω-3 double bond followed by conversion to the vicinal diols by epoxide hydrolase. EPA is also metabolized preferentially by Gaeumannomyces graminis to (±)17(18)-DiHETE.
EDHF (endothelium-derived hyperpolarizing factor) is an unidentified mediator released from vascular endothelial cells in response to acetylcholine and bradykinin which is distinct from the NOS- (nitric oxide) and COX-derived (prostacyclin) vasodilators. Cytochrome P450 (CYP450) metabolism of polyunsaturated fatty acids produces epoxides such as (±)14(15)-EpETrE which are prime candidates for the actual active mediator. However, the CYP450 metabolites of eicosapentaenoicacid and docosahexaenoic acid have been little studied relative to arachidonate epoxygenase metabolites. (±)19(20)-EpDPA is a DHA epoxygenase metabolite, derived via epoxidation of the ω-3 double bond of DHA. The EDHF activity of (±)19(20)-EpDPA has not yet been determined. The epoxygenase metabolites of DHA have also been detected in a mouse inflammation model.
Eicosapentaenoicacid is an ω-3 polyunsaturated fatty acid that is abundant in marine organisms and fish oils. EPA is metabolized, in part, through cytochrome P450-catalyzed epoxidation followed by conversion to the vicinal diols by epoxide hydrolases. (±)5(6)-DiHETE is a possible metabolite produced from EPA following epoxidation of the α-5 double bond. The biological activity of (±)5(6)-DiHETE has not been documented.
Eicosapentaenoicacid is metabolized, in part, through cytochrome P450-catalyzed epoxidation followed by conversion to the vicinal diols by epoxide hydrolases. (±)5(6)-DiHETE is a possible metabolite produced from EPA following epoxidation of the α-5 double bond. (±)5(6)-DiHETE lactone is a 1,5 cyclic ester derived from (±)5(6)-DiHETE. While its biological activity is unknown, the selective capacity of (±)5(6)-DiHETE to form this lactone can be utilized to specifically quantify (±)5(6)-DiHETE in biological samples.