cales) are known to contain structurally unique secondary metabolites, such as plastoquinones, chromanols, a cyclopentenone, and polysaccharides. These compounds show various biological activities due to their unique structure. We previously reported that the methanolic extract of the brown alga, Sargassum micracanthum (KUETZING) ENDLICHER, “Togemoku” in Japanese, showed strong antioxidant acti...