Ethanol extract of Angelica gigas inhibits croton oil-induced inflammation by suppressing the cyclooxygenase - prostaglandin pathway

The anti-inflammatory effects of an ethanol extract of Angelica gigas (EAG) were investigated in vitro and in vivo using croton oil-induced inflammation models. Croton oil (20 microg/mL) up-regulated mRNA expression of cyclooxygenase (COX)-I and COX-II in the macrophage cell line, RAW 264.7, resulting in the release of high concentrations of prostaglandin E(2) (PGE(2)). EAG (1 approximately 10 microg/mL) markedly suppressed croton oil-induced COX-II mRNA expression and PGE(2) production. Application of croton oil (5% in acetone) to mouse ears caused severe local erythema, edema and vascular leakage, which were significantly attenuated by oral pre-treatment with EAG (50 approximately 500 mg/kg). Croton oil dramatically increased blood levels of interleukin (IL)-6 and PGE(2) without affecting tumor-necrosis factor (TNF)-alpha and nitric oxide (NO) levels. EAG pre-treatment remarkably lowered IL-6 and PGE(2), but did not alter TNF-alpha or NO concentrations. These results indicate that EAG attenuates inflammatory responses in part by blocking the COX - PGE(2) pathway. Therefore, EAG could be a promising candidate for the treatment of inflammatory diseases.