ACTIONS OF GALLIC ESTERS ON THE ARACHIDONIC-ACID METABOLISM OF HUMAN POLYMORPHONUCLEAR LEUKOCYTES

Gallic esters with a varying chain length of its alcohol moiety produc ed strong inhibition of the conversion of [1-C-14]-arachidonic acid to 5S-hydroxy-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-HETE) by isolated h uman polymorphonuclear leukocytes. Octyl gallate and decyl gallate wer e the most powerful inhibitors with a concentration of half-inhibition of about 1-mu-mol.1-1. Additionally these compounds caused however at 10-mu-mol.1-1 a complete inhibition of the incorporation of arachidon ic acid in triacylglycerols and phospholipids which is assumed to be a consequence of the damage to the energy metabolism of the cells. In c ontrast, the other gallic esters enhance the incorporation of arachido nic acid in the ester lipids in addition to moderate inhibition of the 5-lipoxygenase pathway.