Isoprostane

The isoprostanes are prostaglandin-like compounds formed "in vivo" from the free radical-catalyzed peroxidationof essential fatty acids (primarily arachidonic acid) without the direct action of cyclooxygenase (COX) enzyme. [COX activity produces H₂O₂ which may non-enzymatically produce isoprostanes.] ] These nonclassical eicosanoids possess potent biological activity as inflammatory mediators that augment the perception of pain.] These compounds are accurate markers of lipid peroxidation in both animal and human models of oxidative stress.
The increased levels of isoprostane is one of the underlying mechanisms contributing to increased risk of heart attack in patients taking Coxibs.

Abundance

Cquote| Polyunsaturated fatty acids other than arachidonic acid are also vulnerable to reactive oxygen species and produce isoprostanes. For example, in addition to the four classes of F2-isoprostanes that can arise from arachidonic acid, peroxidation of eicosapentaenoic acid (EPA) is predicted to lead to the generation of six classes of F3 isoprostanes, α-linolenic and γ-linolenic acids to two classes of E1- and F1-isoprostanes, and docosahexaenoic acid to eight classes of D4-isoprostanes and eight classes of E4-isoprostanes. Each of the classes comprise up to eight racemic isomers, leading to an astounding number of isoprostane molecules!|40px|40px|LJ Janssencite journal
author=Janssen LJ
title=Isoprostanes: an overview and putative roles in pulmonary pathophysiology
journal=Am. J. Physiol. Lung Cell Mol. Physiol.
volume=280
issue=6
url=http://ajplung.physiology.org/cgi/reprint/280/6/L1067
pages=L1067–82
year=2001
pmid=11350785
doi=
accessdate=2007-11-02]

References