any octadeca-9,11,13,15-tetraenoic acid; two isomers are found in
Parinarium laurinum, namely the (9
Z,11
E,13
E,15
Z)-isomer (α- or
cis-parinaric acid) and the (9
E,11
E,13
E,15
Z)-isomer (β- or
trans-parinaric acid). Both are useful as probes in membrane studies,
trans-parinaric acid especially, as it partitions preferentially into the less fluid regions of membrane lipids with increased quantum yield. They inhibit neutrophil elastase.