The metabolites of arachidonic acid form a very large class of biologically active lipid substances generated within cells by several different oxygenase reactions. The prostaglandins (PG) 1 are derived from the cyclooxygenase reaction mediated by PGH synthase and the leukotrienes (LT) formed by the 5-lipoxygenase enzyme, while the epoxyeicosatrienoic acids are formed by the action of various cytochrome P450s. The name “eicosanoids” comes from the Greek term eicosa, meaning 20, since these compounds are derived from a 20-carbon acid, arachidonic acid (5, 8, 11, 14 (Z, Z, Z, Z)-eicosatetraenoic acid). The biosynthetic pathways are often referred to as cascades since a complex sequence of reactions (Scheme 1) occurs during biosynthesis such as the case for prostaglandins [1, 2]. The general pathways involve a critical oxygenase, which incorporates molecular oxygen into the arachidonic acid structure, to form a reactive intermediate. For the cyclooxygenase pathway, this intermediate is prostaglandin H2 (PGH2) and for the leukotriene pathway this intermediate is leukotriene A4 (LTA4). These chemically reactive intermediates are then processed by secondary enzymes to form the biologically active lipid mediator. For example, PGH2 is converted into PGE2 by PGE2 synthase [3], and leukotriene B4