Inhibition of icosanoid production in MC/9 mouse mast cells by n-3 polyunsaturated fatty acids isolated from edible marine algae.

The effects of two polyunsaturated fatty acids, 18:4n-3 and 16:4n-3 purified from the marine algae, Undaria pinnatifida and Ulva pertusa, on icosanoid production in MC/9 mouse mast cells were assessed. Both fatty acids suppressed the production of leukotriene B4 (LTB4), leukotriene C4 (LTC4), and 5-hydroxyeicosatetraenoic acid (5-HETE). The order of the suppressive activity for the two marine algae-derived fatty acids and three other common polyunsaturated fatty acids was as follows; 22:6n-3 = 18:4n-3 = 18:3n-3 > 20:5n-3 = 16:4n-3 for LTB4; 22:6n-3 = 18:4n-3 = 18:3n-3 > 16:4n-3 > 20:5n-3 (no suppression) for LTC4; 22:6n-3 = 18:4n-3 > 18:3n-3 > 20:5n-3 = 16:4n-3 for 5-HETE.