Analgesic effect of the methanol extract of Erica arborea (L.) in mice using formalin test

Background and the purpose of the study: Erica arborea L. (Ericaceae) has been used inTurkey folk medicine as a diuretic, urinary antiseptic and laxative. However, its otherpharmacological effects have not been yet elucidated clearly. The aim of this study was toinvestigate analgesic effects of its methanolic (MeOH) extract in mice using formalin test,as a model of tonic inflammatory pain.Methods: The MeOH extract of aerial parts and its fractions (20, 40, 60, 80 and 100%MeOH in water) were prepared by maceration and solid phase extraction methodrespectively. Effects of the MeOH extract (10, 20 and 30 mg/kg, i.p.) and different fractions(5 mg/kg, i.p.) were compared with analgesic effects of the morphine (10 mg/kg, i.p.) andindomethacine (5 mg/kg, i.p.) as standard analgesic drugs.Results and major conclusion: Results showed that the MeOH extract of E. arborea (10mg/kg, i.p.) similar to the morphine (10 mg/kg, i.p.) and indomethacen (5 mg/kg, i.p.)decreased formalin-induced paw licking time,. Among the prepared-fractions of the MeOHextract, only fraction of 20% (5 mg/kg, i.p.) caused significant decrease in paw lickingbehavior. Moreover, the MeOH extract (10 mg/kg, i.p.) did not produce any motor deficiteffects in rotarod test. From the results it may be concluded that the MeOH extract andfaction of 20% of E. arborea have a good analgesic effects in formalin test.