The anti-inflammatory and anti-nociceptive effects of ethyl acetate fraction of cynanchi paniculati radix.

The anti-inflammatory and anti-nociceptive effects and sedative activities of the ethyl acetate fraction of Cynanchum paniculatum (EACP) were evaluated in mice and rats by acetic acid-induced vascular permeability, arachidonic acid-induced paw edema, cotton pellet-induced granuloma formation, formalin-induced licking time, acetic acid-induced writhing response, and pentobarbital-induced sleeping time. EACP at a dose of 40 mg/kg significantly exhibited anti-inflammatory activities on acetic acid-induced vascular permeability, arachidonic acid-induced paw edema, and the late phase of formalin-induced licking time. Moreover, it showed anti-nociceptive effects on acetic acid-induced writhing responses and significant sedative effects on pentobarbital-induced sleeping time. The results demonstrated that the anti-nociceptive effects are apparently related to the sedative effects of EACP. These results support the use of Cynanchum paniculatum in relieving inflammatory pain.