The Anti-Inflammatory Effects of a Methanolic Extract from Radix Isatidis in Murine Macrophages and Mice

Radix Isatidis is the dried root of the plant Isatidis indigotica Fort (family Cruciferae) and traditionally used as an anti-viral, anti-bacterial, anti-endotoxic, and immune regulatory agent in the folk medicine of Korea and China. The aim of the present study was to determine the anti-inflammatory effects of methanolic extracts of Radix Isatidis (RIME) in lipopolysaccharide (LPS)-stimulated murine macrophages and in a TPA-induced ear edema animal model. Anti-inflammatory effects of RIME were examined in LPS-stimulated RAW 264.7 macrophages. In order to investigate the effects of RIME in vivo, activation of myeloperoxidase, and histological assessment were examined in the 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced mouse ear edema model. RIME significantly inhibited the release from macrophages of inflammatory mediators such as nitric oxide, prostaglandin E2, and pro-inflammatory cytokines. Topical administration of RIME at 1–5 mg/ear resulted in reduction of ear inflammation in mice. Thus, our results indicate that the anti-inflammatory effects of RIME involve decreased production of inflammatory mediators, which suggests that RIME may have therapeutic potential in a variety of inflammation-related diseases.