Inhibitory Effect of Extracts from the Brown Alga, Ecklonia stolonifera, on Enzymes Responsible for Allergic Reactions and Degranulation in RBL-2H3 Cells

The anti-allergic effects of the edible brown alga, Ecklonia stolonifera, are known to affect both degranulation in KU812 cells and anti-inflammatory properties of RAW 264.7 cells. Additional anti-allergic effects of E. stolonifera extracts were therefore investigated by examining the inhibitory effects of algal extracts on enzymes associated with eicosanoid synthesis, the inflammation reaction, and anti-degranulation activity in rat basophilic leukemia (RBL) -2H3 cells. A methanol: chloroform (1:2, v/v) extract of the alga inhibited the enzyme activities and degranulation in stimulated RBL cells in a dose-dependent manner. When phenolic compounds were removed from the M/C extract by treatment with polyvinylpolypyrrolidone resin, the obtained residue did not exhibit the same inhibitory activities. These results imply that the active compounds present in the M/C extract may be phenolic compounds, such as phlorotannins. In addition, the novel anti-allergic effects of E. stolonifera that contributed to inhibiting the enzymatic activities were also clarified.