Extraction and purification of arachidonic acid metabolites from cell cultures

The oxygenated, biologically active, metabolites of arachidonic acid (5,8,11,14-eicosatetraenoic acid), collectively called eicosanoids, include products formed via the cyclooxygenase enzyme complex (prostaglandins, thromboxanes) and via the lipoxygenases (leukotrienes and hydroxy fatty acids). These compounds can be synthesized in vitro by different types of cells in culture but their analysis for metabolic studies or their isolation for subsequent pharmacological studies require proper procedures of extraction and purification. This paper reviews the various techniques of extraction and emphasizes the major and new procedures. In this connection the use of reverse-phase chromatographic material is particularly stressed both for the extraction of the various classes of metabolites by the solid-phase extraction technique and for the purification of classes or individual compounds by high-performance liquid chromatography.