Antinociceptive activities of 70% methanol extract of evodiae fructus (fruit of Evodia rutaecarpa var. bodinieri) and its alkaloidal components

Abstract

The effects of 70% methanol extract (EA-ext) from Evodiae Fructus (EA) consisting of dried fruits of Evodia rutaecarpa var. bodinieri (Rutaceae) on nociceptive responses were investigated. Oral administration of 50 or 200 mg/kg EA-ext had the same antinociceptive effect on writhing responses as induced by acetic acid. Its major alkaloidal constituents, evodiamine and rutaecarpine also had the antinociceptive effect. EA-ext significantly decreased the frequency of licking behavior within a unit of time at the late phase without affecting that of the early phase in the formalin test. EA-ext also increased nociceptive threshold of the inflamed paw without increasing that in the non-inflamed paw in the Randall-Selitto test. Although EA-ext inhibited the rise of vascular permeability induced by acetic acid and the increase of paw edema induced by carrageenin, it was ineffective on nociceptive response in the hot plate test and on locomotor activity. These results suggest that EA possesses antinociceptive effects and its mode of action may be mediated by anti-inflammatory action, and that the antinociceptive constituents are only partially attributable to alkaloidal components mentioned above.