Effects of stilbene derivatives on arachidonate metabolism in leukocytes.

The effects of various alpha-phenylcinnamic acid derivatives (i.e., alpha-(3,4-dihydroxyphenyl)cinnamic acid, alpha-(3,4-dihydroxyphenyl)-3-hydroxycinnamic acid, alpha-(3,4-dihydroxyphenyl)-4-hydroxycinnamic acid and alpha-(3,4-dihydroxyphenyl)-3, 4-dihydroxycinnamic acid) synthesized from 3,4-dihydroxyphenyl acetic acid and hydroxy-benzaldehyde, and 3,3',4-trihydroxystilbene obtained by decarboxylation of alpha-(3,4-dihydroxyphenyl)-3-hydroxycinnamic acid on rat peritoneal polymorphonuclear leukocyte lipoxygenase and cyclooxygenase activities were studied. 3,3',4-Trihydroxystilbene was found to inhibit the 5-lipoxygenase product, 5-hydroperoxy-6,8,11,14-eicosatetraenoic acid (5-HETE), and cyclooxygenase products, 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and thromboxane B2; its concentrations for 50% inhibition (IC50) were 0.885 +/- 0.016 microM for the leukocyte lipoxygenase product, 5-HETE, 7.70 +/- 0.104 microM for the formations of HHT and 7.96 +/- 0.143 microM for the formation of thromboxane B2. Alpha-(3,4-Dihydroxyphenyl)cinnamic acid, alpha-(3,4-dihydroxyphenyl)-3-hydroxycinnamic acid and alpha-(3,4-dihydroxyphenyl)-3,4-dihydroxycinnamic acid also inhibited the formations of 5-HETE, HHT and thromboxane B2, although less strongly. Their IC50 values were, respectively, 91.3 +/- 3.62 microM, 947.5 +/- 28.7 microM, 453.3 +/- 229.3 microM and 148.8 +/- 50.6 microM for the formation of 5-HETE, 894.0 +/- 5.57 microM, 792.5 +/- 15.9 microM, greater than 1000 microM and 925.0 +/- 7.64 microM for the formation of HHT and 941.0 +/- 18.0 microM, 825 +/- 14.4 microM, greater than 1000 microM and 932.7 +/- 3.93 microM for the formation of thromboxane B2.