Oxidative metabolites cyclooxygenase

Besides the design of synthetic molecules, several papers reported the presence of specific enzymatic reactions able to produce also in the cells compounds able to act as reversible FAAH inhibitors (Maccarrone and Finazzi-Agro, 2004a). In particular, it has been found that oxidative metabolites of AEA generated by various lipoxygenases, i.e. the hydroxyanandamides (HAEAs see 12-OH-AEA in Table 4.1), are powerful inhibitors of FAAH (van der Stelt et al., 2002). Instead, derivatives of AEA generated by cyclooxygenase-2, and termed prosta-mides, have been recently shown to be inelfective on FAAH activity (Matias et al., 2004). 

While comparatively few dihydrodiols have been observed in the metabolism of phenyl-containing drugs, the examples above are far from unique. Thus, oxazepam incubated in rat, mouse, and human microsomes did yield a dihydrodiol besides the para-phenol [82], A more-recent example is that of rofecoxib (10.22), a potent and selective cyclooxygenase-2 (COX-2) inhibitor. In rats and dogs, phenyl oxidation produced 4 -hydroxyrofecoxib and rof-ecoxib-3, 4 -dihydrodiol as urinary metabolites of intermediate quantitative importance [83]. 

In neuronal function ROS play a role of metabolites immediately participating in the excitation process. In the intracellular space there are both enzymic (cyclooxygenases, monoamine oxidases) and non-enzymic (spontaneous oxidation of biogenic amines) reactions where they are formed. Mitochondrial respiratory chain also provides ROS production in a cell under conditions of changeable oxygen pressure [29,30]. 

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