5-Lipoxygenase-derived oxylipins from the red alga Rhodymenia pertusa

The lipid extract of the temperate red alga Rhodymenia pertusa has yielded four eicosanoid metabolites, three of which are new natural products. Using principally NMR and MS techniques, their structures were deduced as 5R,6S- dihydroxy-7(E),9(E),11(Z),14(Z)-eicosatetraenoic acid (5R,6S-diHETE), 5R*,6 S*-dihydroxy-7(E),9(E),11(Z),14(Z),17(Z)-eicosapentaenoic acid (5R*,6S*-diH EPE), 5-hydroxy-6(E),8(Z),11(Z),14(Z)-eicosatetraeonic acid (5-HETE), 5-hyd roxy-6(E),8(Z),11(Z),14(Z),17(Z)-eicosapentaenoic acid (5-HEPE). The co-occ urrence of these metabolites strongly suggests that R. pertusa contains a u nique 5R-lipoxygenase system acting on both arachidonic and eicosapentaenoi c acids. (C) 2000 Elsevier Science Ltd. All rights reserved.