Identification of eicosanoids in the red algae, Gracilaria asiatica, using high-performance liquid chromatography and electrospray ionization mass spectrometry.

Identification of eicosanoids which are metabolites of arachidonic acid in red algae Gracilaria asiatica, one of the popular seaweeds in Japan, was carried out using high-performance liquid chromatography (HPLC) interfaced with electrospray ionization mass spectrometry. Prostaglandin (PG) E2, 15-keto-PGE2, and 8-hydroxyeicosatetraenoic acid (HETE) were detected as major eicosanoids and PGA2, leukotriene B4 as minor ones in G. asiatica. 8- and 12-HETE had the same retention time in HPLC analysis, but using this analytical method, we were able to identify them.