EFFECTS OF PHENOLS ON EICOSANOID SYNTHESIS IN A23187-STIMULATED HUMAN WHOLE-BLOOD

We have previously demonstrated that catecholamines have opposite effects on leukotriene (LT) and prostanoid synthesis. The aim of the present study was to test the effects of phenols (catechol, hydroquinone, phenol and resorcinol) on LTB4, LTE4 and thromboxane (TX)B2 synthesis in A23187-stimulated human whole blood. All tested compounds inhibited LTB4 and LTE4 synthesis. The IC50-values for catechol were 3 muM, 6 muM; for hydroquinone 4 muM, 3 muM; for phenol-285 muM, 226 muM and for resorcinol 180 muM, 902 muM. The compounds did not stimulate TXB2 synthesis but only inhibited it. The IC50 value for catechol was 3 muM, for hydroquinone 7 muM, for phenol 18 muM and for resorcinol 25 muM. Catechol and hydroquinone had hardly any effect on the LT/TX ratio. Phenol and resorcinol even increased the LT/TX ratio. The positions of hydroxyl groups of phenolic compounds are thus important for their actions on the LT/TX ratio.