Hepoxilin

Hepoxilin A3

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Names
IUPAC name (5E,9E)-8-hydroxy-10-[3-[(E)-oct-2-enyl] -2-oxiranyl]deca-5,9-dienoic acid
Other names HXA3
Identifiers
CAS Number	94161-11-2 Y
Jmol 3D model	Interactive image
PubChem	5353666
SMILES CCCCCC=CCC1C(O1)C=CC(CC=CCCCC(=O)O)O
Properties
Chemical formula	C20H32O4
Molar mass	336.47 g/mol
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Hepoxilins (HxA3 and HxB3) are nonclassic eicosanoid hormones involved in inflammation.

History

Hepoxilins were identified and named in Canada in 1984 by CR Pace-Asciak and JM Martin.

Biochemistry

They derive from arachidonic acid via oxidation by the enzyme 12-lipoxygenase. Hepoxilins are differentiated from closely related eicosanoids, the leukotrienes and the lipoxins, in that hepoxilins have no conjugated double bonds. Corresponding trioxlins A4 and B4 are formed by the same pathway from EPA Two, more recently described hepoxins, 11(S)-hydroxy-14(S),15(S)-epoxy-5(Z),8(Z),12(E)-eicosatrienoic acid and 13(R)-hydroxy-14(S),15(S)-epoxy-5(Z),8(Z),11(Z)-eicosatrienoic acid, termed respectively 14,15-HXA₃ and 14,15-HXB₃ are made by 15-lipoxygenase-1 with 15(S)-hydroperoxy-eicosatetraenoic acid as an intermediate; 14,15-HXA₃ may then be further metabolized by glutathione transferases to 11(S),15(S)-dihydroxy-14(R)-glutathionyl-(5Z),8(Z),12(E)eicosatrienoic acid (14,15-HXA₃C) which is then further metabolized to 11(S),15(S)-dihydroxy-14(R)-cysteinyl-glycyl-(5Z),8(Z),12(E)eicosatrienoic acid (14,15-HXA₃D). The latter two hepoxilins are analogous to eoxins and leukotrienes and presumed to share the same glutatione transferase and peptidase pathways in their formation (see 15-Hydroxyicosatetraenoic acid).

Physiological effect

In the skin, Hx are pro-inflammatory, but in neutrophils they are anti-inflammatory. Hx are potent insulin secretagogues. One hepoxilin, HepA3, mediates neutrophil migration across the intestines. Hepoxilins are also produced in the brain. Cells under oxidative stress secrete HX₃, which in turn upregulates peroxidase, decreasing oxidative stress. This is proposed to constitute a compensatory defense response to protect the vitality and functionality of the cell.