Lipid extracts of several collections of the tropical red marine alga Murrayella periclados were found to be rich sources of eicosanoids more commonly associated with mammalian systems, including 12S-hydroxyeicosapentaenoic acid, 12S-hydroxyeicosatetraenoic acid, (6E)-leukotriene B4, and erythro and threo diastereomers of hepoxilins B3 and B4. This is the first report of leukotriene or hepoxilin B sub(4) natural products from a plant, and several spectroscopic features of these molecules are reported herein for the first time. Two conjugated triene-containing acids recently reported from another red alga, 5Z,7E,9E,14Z,17Z-eicosapentaenoic acid and 5E,7E,9E,14Z,17Z-eicosapentaenoic acid, were also found in the algal extract. A 12-lipoxygenase initiated biosynthetic origin is proposed for most of these Murrayella oxylipins. |
