RESUMO
Background: Dialium guineense is a medicinal plant used by some communities of Enugu-Ezike in Enugu State; Nigeria for treatment of fever; headache and other diverse ailments. Objectives: The present study evaluated the analgesic activity of the methanolic stem bark extract of the plant. Method: Acetic acid-induced abdominal constriction or writhing; tail immersion and hot plate analgesic models in albino Wistar mice were used for the study. Three test doses (250; 500; 1000 mg/kg body weight) of the extract were administered orally by gastric gavage. The activity was compared with a standard reference drug; acetylsalicylic acid (aspirin) (400 mg/kg) and negative control. The results were analysed by SPSS version 17 using ANOVA and Post Hoc Duncan. Result: In the acetic acid-induced writhing reflex model; D. guineense extract and the reference drug significantly (P =0.014 - 0.002) decreased the mean total number of abdominal constriction in the mice in a dose dependent fashion. The percentage inhibition of the abdominal constriction reflex was increased dose dependently from 0in the negative control group to 71at the highest dose of the extract (1000mg/kg). In the tail immersion model the extract at the dose of 1000 mg/kg significantly (P = 0. 048) increased the pain reaction time (PRT) while in hot plate model the extract and drug also significantly (P = 0.048 - 0.05) increased the mean PRT at the doses of 500 and 1000 mg/kg. The dose of 250 mg/kg showed no analgesic activity in tail immersion and hot plate models. Conclusion: Dialium guineense demonstrated significant analgesic activity that may be mediated through peripheral pain mechanism