6(S)--Lipoxin-A-4-

6(S)-LXA4 is one of the original four metabolites first identified by Serhan, Nicolaou, and Samuelsson. It was considered to be an artifact by these authors because it lacked the potency of the 5(S),6(R) isomer with respect to contraction of isolated guinea pig lung parenchymal strips. It has not been possible to isolate “natural” LXA4 from humans or other mammals in amounts sufficient for determination of absolute stereochemistry. Most authors refer to LXA4 as the 5(S),6(R), 11-cis isomer, but it is not clear that biological systems are aware of or agree with these conventions. Historically,...