PANAXYNOL, A POLYACETYLENE COMPOUND ISOLATED FROM ORIENTAL MEDICINES, INHIBITS MAMMALIAN LIPOXYGENASES

Panaxynol is a polyacetylene compound isolated from commonly used oriental medicines, and its effects on various cyclooxygenases and lipoxygenases were investigated. The compound had only a marginal effect on cyclooxygenase activities (IC50 values much greater than 100 mu M), but inhibited lipoxygenases; 5-lipoxygenase (IC50, 2 mu M), two isoforms of 12-lipoxygenase (leukocyte-type, 1 mu M; platelet-type, 67 mu M) and 15-lipoxygenase (4 mu M). Thus, panaxynol inhibited leukocyte-type 12-lipoxygenase much more effectively than platelet-type 12-lipoxygenase. Falcarindiol, an analogue of panaxynol, inhibited these lipoxygenases with higher IC50 values than panaxynol. These compounds could provide a clue to develop a selective inhibitor of one isoform of 12-lipoxygenase.