(±)14(15)-EET is a metabolite of arachidonic acid that is formed via epoxidation of arachidonic acid by cytochrome P450.[1],[2] It prevents increases in leukotriene B4, ICAM-1, and chemokine (C-C motif) ligand 1 (CCL2) induced by oxidized LDL in primary rat pulmonary artery endothelial cells (RPAECs) when used at a concentration of 1 μM.[3] (±)14(15)-EET induces dilation of preconstricted isolated canine coronary arterioles (EC50 = 0.2 pM).[4] It reduces myocardial infarct size as a percentage of the area at risk in a canine model of ischemia-reperfusion injury induced by left anterior descending coronary artery (LAD) occlusion when administered at a dose of 0.128 mg kg prior to occlusion or reperfusion.[5] Reference:[1]. Chacos, N., Falck, J.R., Wixtrom, C., et al. Novel epoxides formed during the liver cytochrome P-450 oxidation of arachidonic acid. Biochem. Biophys. Res. Commun. 104(3), 916-922 (1982).[2]. Oliw, E.H., Guengerich, F.P., and Oates, J.A. Oxygenation of arachidonic acid by hepatic monooxygenases. Isolation and metabolism of four epoxide intermediates. J. Biol. Chem. 257(7), 3771-3781 (1982).[3]. Jiang, J.-X., Zhang, S.-J., Xiong, Y.-K., et al. EETs attenuate ox-LDL-induced LTB4 production and activity by inhibiting p38 MAPK phosphorylation and 5-LO BLT1 receptor expression in rat pulmonary arterial endothelial cells. PLoS One 10(6), e0128278 (2015).[4]. Oltman, C.L., Weintraub, N.L., VanRollins, M., et al. Epoxyeicosatrienoic acids and dihydroxyeicosatrienoic acids are potent vasodilators in the canine coronary microcirculation. Circ. Res. 83(9), 932-939 (1998).[5]. Nithipatikom, K., Moore, J.M., Isbell, M.A., et al. Epoxyeicosatrienoic acids in cardioprotection: Ischemic versus reperfusion injury. Am. J. Physiol. Heart Circ. Physiol. 291(2), H537-H542 (2006).
Arachidonic acid is metabolized in the vascular endothelium to epoxytrienoic acids (EETs or EpETrEs) by cytochrome P450 enzymes. The EETs are released in response to acetylcholine, bradykinin, arachidonic acid, or cyclic stretch. (±)14(15)-EET-SI is the methyl sulfonamide analog of 14(15)-EET. This substitution results in a metabolically more stable compound because it is not sensitive to β-oxidation or membrane esterification. (±)14(15)-EET-SI is equipotent to 14(15)-EET in vascular agonist activity as measured by relaxation of precontracted bovine coronary arteries. In addition, 14(15)-EET and the methyl sulfonamide analog both stimulate tyrosine phosphorylation and induce mitogenesis in renal epithelial cells.
5(6)-EET is a fully racemic version of the enantiomeric forms biosynthesized from arachidonic acid by cytochrome P450 enzymes. In solution, 5(6)-EET degrades into 5,6-DiHET and 5(6)-δ-lactone, which can be converted to 5(6)-DiHET and quantified by GC-MS. In neuroendocrine cells, such as the anterior pituitary and pancreatic islets, 5(6)-EET has been implicated in the mobilization of calcium and hormone secretion. 5(6)-EET is an inhibitor of T-type voltage-gated calcium channels (Cav3) that inhibits isoforms Cav3.1, Cav3.2 (IC50 = 0.54 μM), and Cav3.3 and decreases nifedipine-resistant phenylephrine-induced vasoconstriction in isolated mouse mesenteric arteries via Cav3.2 blockade when used at a concentration of 3 μM. In addition, it is a substrate of COX-1 and COX-2, as measured by oxygen consumption and product formation assays when used at a concentration of 50 μM. (±)5(6)-EET is provided as a mixture of the free acid and lactone.
14S(15R)-EET is an oxylipin and a cytochrome P450 metabolite of arachidonic acid .114S(15R)-EET binds to isolated guinea pig monocytes with a Kivalue of 612.5 nM in a competitive binding assay using [3H]14(15)-EET.2It induces dilation of precontracted isolated canine epicardial arterioles (EC50= 4 pM) and denuded porcine subepicardial arterioles (EC50= 3 pM).3Unlike 14R(15S)-EET, 14S(15R)-EET does not inhibit COX in enzyme assays or isolated platelets.4 1.Daikh, B.E., Lasker, J.M., Raucy, J.L., et al.Regio- and stereoselective epoxidation of arachidonic acid by human cytochromes P450 2C8 and 2C91J. Pharmacol. Exp. Ther.271(3)1427-1433(1994) 2.Wong, P.Y.-K., Lai, P.-S., and Falck, J.R.Mechanism and signal transduction of 14 (R), 15 (S)-epoxyeicosatrienoic acid (14,15-EET) binding in guinea pig monocytesProstaglandins Other Lipid Mediat.62(4)321-333(2000) 3.Zhang, Y., Oltman, C.L., Lu, T., et al.EET homologs potently dilate coronary microvessels and activate BKCa channelsAm. J. Physiol. Heart Circ. Physiol.280(6)H2430-H2440(2001) 4.Fitzpatrick, F.A., Ennis, M.D., Baze, M.E., et al.Inhibition of cyclooxygenase activity and platelet aggregation by epoxyeicosatrienoic acidsJ. Biol. Chem.261(2)15334-15338(1986)
14S(15R)-EET methyl ester, an oxylipin derived from arachidonic acid through cytochrome P450 metabolism, demonstrates specific biological activities. It exhibits affinity for isolated guinea pig monocytes, evidenced by a competitive binding assay with a Ki value of 612.5 nM using [3H]14(15)-EET. This compound notably enhances the dilation of precontracted isolated canine epicardial arterioles (EC50= 4 pM) and denuded porcine subepicardial arterioles (EC50= 3 pM), indicating potent vasodilatory effects. Unlike its isomer 14R(15S)-EET, 14S(15R)-EET methyl ester does not inhibit COX activity in enzyme assays or affect isolated platelets, highlighting its distinct functional profile.
(±)11(12)-EET is a fully racemic version of the R S enantiomeric forms biosynthesized from arachidonic acid by cytochrome P450 enzymes.[1][2][3[]A higher proportion of 11(R),12(S)-EET is produced by the CYP450 isoforms CYP2C23 and CYP2C24 while CYP2B2 produces a higher proportion of 11(S),12(R)-EET.[3]11(12)-EET has been shown, along with 8(9)-EET to play a role in the recovery of depleted calcium pools in cultured smooth muscle cells[4] It also inhibits basolateral 18-pS potassium channels in the renal cortical collecting duct when used at a concentration of 100 nM.[5]11(12)-EET (50 μg kg per day) increases adhesion of isolated peripheral blood leukocytes in a chamber coated with P-selectin and ICAM-1 but does not affect choroidal neovascularization size following laser photocoagulation[6] It also has anti-inflammatory, angiogenic, and cardioprotective properties[7]