Suppressive effect of Petasites japonicas extract on TPA-induced ear edema in mouse model

Inflammation is a beneficial host response to foreign pathogens or tissue injury, and it eventually leads to the restoration of normal tissue structure and function. Petasites japonicas (Pj) is known as an herb for treating asthma, oxidant stress and gastric ulcer in traditional Oriental medicine. In this study, we evaluated the anti-inflammatory effects of Pj extract on 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ear edema in mouse model. The Pj extract (10, 30, 50 mg) was acquired from whole plants of Petasites japonicas using butanol. After the PJ extract was administered to mice via gavage consecutively for 5 days, an edema was induced on the ear by topical application of 2.5 μg/ear of TPA dissolved in 10 μl of acetone. Ear thickness was measured using a Digimatic Micrometer (Mitsutoyo Co., Tokyo, Japan) before TPA application and 4 h after. ELISA was performed to determine the expression levels of cytokines. The levels of ear thickness were not significant between normal group and experimental...