Alieh Jalali - M.sc Student in Biology (Animal Physiology), Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
Masoud Fereidoni - Professor, Rayan Center for Neuroscience and Behavior, Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
Ali Asadollahi - Assistant Professor, Rayan Center for Neuroscience and Behavior, Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran

Discovery of substances that cause pain relief with lower side-effects are of today’s research objectives. Our previous research showed that aqueous extract of Melia azedirach at dose of 200 mg/kg has analgesic effects on chemical pain, but was ineffective for the thermal pain. According to reports on analgesic effects of ethanol extract of similar species (Azadirach indica), the possible analgesic effect of hydro-alcoholic extract of Melia azedirach wouldn’t be unexpected. So in this study the analgesic effect of Melia azedirach leaves hydro-alcoholic extract at the dose of 200 mg/kg was compared to that of the same dose on aqueous extract.Male rats (200-250g) were divided into 5 groups: control, sham1 (i.p. aqueous extract solvent), sham2 (i.p. hydro-alcoholic extract solvent), i.p., 200 mg/kg aqueous extract and i.p., 200 mg/kg hydro-alcoholic extract. In order to evaluate the chemical pain formalin test was used and to investigate thermal pain tail flick test was performed. Comparison of aqueous and hydro-alcoholic extracts on dose 200 mg/kg showed that hydro-alcoholic extract has no significant effect in the first phase of formalin test but reduced pain in second plant.phase though it was The results indicate that aqueous extract act better than( .less than the same effect for aqueous extract (P<0.05 the plant hydro-alcoholic extract regard to chemical pain. Maybe, water is more effective to extract the substances with analgesic effects, from the plant

Formalin test, Melia azedirach, Rats, Hydro-alcoholic extract