New Hydroxycinnamic Acid Esters as Novel 5-Lipoxygenase Inhibitors That Affect Leukotriene Biosynthesis

Figure 5

The inhibitory effects of the test compounds of the biosynthesis of 5-LO products in stimulated whole blood (a) and the biosynthesis of 12-lipoxygenase products in platelets (b). (a) Whole blood was incubated in presence of various compounds (1 μM and 5 μM) or with their diluent (control, DMSO 0.5%) for 5 min, then stimulated with opsonized zymosan (5 mg/ml) for 30 min at 37°C. Blood was then centrifuged and plasma was collected and added to 3.5 volumes of MeOH:CH₃CN (1 : 1). Samples were processed for analysis by RP-HPLC for total 5-LO products quantification. Total 5-LO products measured represent the sum of LTB₄, its trans isomers, 20-COOH and 20-OH-LTB₄, and 5-hydroxyeicosatetraenoic acid. (b) Platelets were incubated for 5 min in presence of test compounds (1 μM and 3 μM) then biosynthesis of 12-HETE was initiated with the addition of 10 μM of calcium ionophore A23187. Reactions were stopped with the addition of two volumes of MeOH:MeCN (1 : 1 v/v). Samples were processed for analysis by RP-HPLC for 12-hydroxyeicosatetraenoic acid (12-HETE) quantification. Different from control as determined by one-way ANOVA with Dunnett’s multiple comparison test (). Data are expressed as means ± SEM of at least 3 independent experiments.

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