In vivo anti-inflammatory activities of the essential oil from Radix Angelicae dahuricae

Although Radix Angelicae dahuricae (Angelica) has been traditionally used in patients with rheumatism arthralgia, its bioactive ingredients remain to be determined. In this study, the essential oil extract of Radix Angelicae dahuricae (EOAD) was assessed for its anti-inflammatory activities against xylene-induced acute ear swelling and carrageenan-induced acute paw edema in mice as well as its anti-inflammatory and immunomodulating properties in Freund’s complete adjuvant (FCA)-induced arthritis in rats. We found that EOAD at 100 mg/kg significantly alleviated xylene-induced ear swelling and carrageenan-induced paw edema in mice. Moreover, in the FCA-induced rat arthritis model, EOAD significantly improved hind paw swelling, lowered the adjuvant arthritis score, mitigated synovial hyperplasia, inflammatory cell infiltration, and cartilage destruction in the ankle joint, and reduced the serum levels of inflammatory mediators such as nitric oxide, tumor necrosis factor-α, and prostaglandin E₂ as well as serum nitric oxide synthase activity. These findings support the fact that the essential oil extract of Angelica contains important active constituents responsible for its anti-inflammatory activities and therefore help to understand the phytotherapeutic effects of Angelica in the treatment of aseptic inflammation.