The anti-inflammatory effects of phlorotannins from Eisenia arborea on mouse ear edema by inflammatory inducers

The anti-allergic and anti-inflammatory effects of phlorotannins (seaweed polyphenols) from the brown alga Eisenia arborea using in vitro experiments has already been reported. Therefore, in this study, these effects were examined in vivo using mice. When ear edema was induced in ICR mice by three sensitizers (arachidonic acid (AA), 12-O-tetradecanoylphorbol-13-acetate (TPA) and oxazolone (OXA)), four phlorotannins tested (eckol, 8,8'-bieckol, phlorofucofuroeckol (PFF)-A and PFF-B) inhibited the ear edema after spreading of 0.01 or 0.1 mg onto the mouse ear. The effects of the phlorotannins on the ear edema after AA and OXA treatments tended to be stronger than after TPA treatment, and the inhibitory effects against each sensitizer were similar to epigallocatechin gallate, a typical inhibitor. This is the first report that phlorotannins exhibit anti-allergic and anti-inflammatory effects in in vivo experiments, and inhibit OXA-induced delayed-type (type IV) allergic reactions.