LAUSR

ETHNOPHARMACOLOGICAL RELEVANCE Calycophyllum spruceanum (Benth.) Hook. F. ex K. Schum. is widely distributed in the Amazonian region of Brazil, where it is popularly known as "mulateiro", "pau-mulato", "pau-mulato-de-várzea", "escorrega-macaco" or "pau-marfim". Preparations of C. spruceanum barks are used in the form of tea, poultice or skin patches to treat stomach diseases, skin inflammation and uterus tumors. PURPOSE OF THE STUDY To investigate in vivo the antinociceptive and anti-inflammatory activities of the hydroalcoholic extract of Calycophyllum spruceanum barks (HECSb) in order to validate its popular usage in inflammatory conditions. MATERIALS AND METHODS Chemical analysis of HECSb was performed using the UHPLC-MS system. Mice were treated per oral with HECSb (5-5000 mg/kg) and evaluated for acute toxicity (during 15 days); motor activity (Rota rod test); body weight (up to 72 h); antinociceptive activity: writhes induced by 0.8% acetic acid; paw licking induced by 2.5% formalin; paw withdrawal (von Frey test) induced by carrageenan (300 μg) or PGE2 (100 ng); anti-inflammatory (paw edema model). For histopathological analysis subplantar tissue fragments were collected 1 h after paw edema induction. RESULTS HECSb chemical analysis revealed the presence of caffeoylquinic derivatives, small organic acids, and phenolic compounds. HECSb showed antinociceptive effect, reducing the number of acetic acid-induced writhes by 72% at 120 mg/kg, paw licking (phase 2- Formalin test) by 33% at 60 mg/kg and 49% at 120 mg/kg; and paw withdrawal elicited by carrageenan (53% at 120 mg/kg) and PGE2 (120 mg/kg) at 0.5 h (48%) and 1 h (45%). HECSb (120 mg/kg) also inhibited the paw edema elicited both by carrageenan (48%) and PGE2 (92%). Histopathological analysis (leukocyte infiltration, edema, focal areas of hemorrhage, vascular congestion) of HECSb treatment at 120 mg/kg demonstrated normal morphology [median 0 (0,1)] compared to PGE2, showing severe alterations [median 3 (2,3); p = 0,0035]. HECSb did not induce acute toxicity nor altered body mass or motor coordination. CONCLUSIONS HECSb shows antinociceptive and anti-inflammatory effect in mice without inducing apparent acute toxicity.