In vitro effects of synthetic dyes on the syntheses of prostaglandin E2 (PGE2) and 5-hydroxyeicosatetraenoic acid (5-HETE).

The effects of thirty-one synthetic dyes (tar dyes in Japan), which are permitted in cosmetics, on three different enzymes were evaluated as an initial step in developing in vitro safety screens. The activities of the prostaglandin (PG)-synthetase from rabbit renal medulla and the lipoxygenases from potato tubers and guinea pig peritoneal polymorphonuclear leukocytes (PMN) were determined based on the biosyntheses of PGE2 and 5-hydroxyeicosatetraenoic acid (5-HETE), respectively. Xanthene dyes with halogen substituents exhibited marked inhibition on the PG-synthetase. Among the dyes which are permitted for any pharmaceutics and cosmetics, only the xanthene dyes exhibited inhibitory effects on the PG-synthetase at 2.5 mM. The xanthene dyes also showed inhibition and stimulation of potato lipoxygenase and PMN lipoxygenase, respectively.