Lipoxins

Lipoxin B₄

Names
IUPAC name 5S,14R,15S-Trihydroxy-6E,8Z,10E,12E -eicosatetraenoic acid
Other names LXB4
Identifiers
CAS Number	92950-25-9 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:6499 Y
ChemSpider	4444430 Y
IUPHAR/BPS	5216
PubChem	5280915
InChI InChI=1S/C20H32O5/c1-2-3-8-14-18(22)19(23)15-10-7-5-4-6-9-12-17(21)13-11-16-20(24)25/h4-7,9-10,12,15,17-19,21-23H,2-3,8,11,13-14,16H2,1H3,(H,24,25)/b6-4-,7-5+,12-9+,15-10+/t17-,18+,19-/m1/s1 Y Key: UXVRTOKOJOMENI-WLPVFMORSA-N Y InChI=1/C20H32O5/c1-2-3-8-14-18(22)19(23)15-10-7-5-4-6-9-12-17(21)13-11-16-20(24)25/h4-7,9-10,12,15,17-19,21-23H,2-3,8,11,13-14,16H2,1H3,(H,24,25)/b6-4-,7-5+,12-9+,15-10+/t17-,18+,19-/m1/s1 Key: UXVRTOKOJOMENI-WLPVFMORBP
SMILES O=C(O)CCC[C@H](O)/C=C/C=C\C=C\C=C\[C@@H](O)[C@@H](O)CCCCC
Properties
Chemical formula	C20H32O5
Molar mass	352.46508 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Lipoxins (LXs or Lxs), an acronym for lipoxygenase interaction products, are bioactive autacoid metabolites of Arachidonic acid made by various cell types. They are categorized as nonclassic eicosanoids and members of the Specialized pro-resolving mediators (SPM) family of Polyunsaturated fatty acid (PUFA) metabolites. Like other SPM, LXs form during, and then act to resolve, inflammatory responses. Initially, two lipoxins were identified, lipoxin A₄ (LXA₄) and LXB₄, but more recent studies have identified epimers of these two LXs viz., the epi-lipoxins, 15-epi-LXA₄ and 15-epi-LXB₄, respectively.

LXA₄ and LXB₄ were first described by Serhan, Hamberg, and the Nobel laurate Samuelsson in 1984. They reported that human blood neutrophils, when stimulated, make these two lipoxins and that neutrophils, when stimulated by either of the LX's, mounted superoxide anion (O₂⁻) generation and degranulation responses. Both responses are considered to be pro-inflammatory in that, while aimed at neutralizing invading pathogens and digesting foreign material, can contribute to damaging host tissues and thereby prolonging and promoting further inflammation. Subsequent studies, however, found that these lipoxins as well as their epimers, epi-LXA₄ and LXB₄ act primarily to dampen and resolve inflammation, i.e. they are anti-inflammatory cell signaling agents.

Lipoxins are derived enzymatically from arachidonic acid, an ω-6 fatty acid. Structurally, they are defined as arachidonic acid metabolites that contain 3 hydroxyl residues (also termed hydroxy residues) and 4 double bonds. This structural definition distinguishes them from other SPMs such as the resolvins, neuroprotectins, and maresins which are metabolites of the omega 3 fatty acids, eicosapentaenoic acid or docosahexaenoic acid as well as a range of metabolites derived from other polyunsaturated fatty acids (see specialized pro-resolving mediators). All of these other SPMs have activities and functions similar although not necessarily identical to the lipoxins .