The great economic and social damage caused by unusual explosion of jellyfish population has attracted the attention of researchers. A chemical study on the bioactive components of the giant jellyfish Nemopilema nomurai led to the isolation of two new (1 and 2) and three known alkoxyglycerols (3 - 5), along with known monoglycerides (6 - 7) and fatty acids. Based on NMR and MS data, the structures of compounds 1 and 2 were elucidated as 1-O-[(Z)-tetradec-3-enyl]-sn-glycerol and 1-O-[(Z)-octadec-10-enyl]-sn-glycerol, respectively. The absolute configurations of compounds 1 - 7 were determined by comparison of specific optical rotation values with those reported. The isolated compounds were evaluated for suppressive effect on the proinflammatory mediators (NO, IL-6, and TNF-${alpha}$) in murine macrophage cells. However, they were found inactive upto the concentration of 100 ${mu}M$.