title: Antinociceptive effect of the Orbignya speciosa Mart. (Babassu) leaves: evidence for the involvement of apigenin.
abstract: OBJECTIVE
  Babassu is the common Brazilian name of Orbignya speciosa Mart. (Arecaceae). The fruits are used for several disorders. In the present study, the antinociceptive effects of the ethanol extract (EE) and dichloromethane fraction (DF) obtained from leaves were investigated, as well as apigenin using nociception models (acetic acid-induced abdominal writhing, formalin, and hot plate).
  
  
  METHODS
  Mice were treated with EE, DF (10, 30, and 100mg/kg, p.o.), apigenin (1mg/kg, p.o.), morphine (5mg/kg, s.c.), acetylsalicylic acid (100mg/kg, p.o.) or vehicle (0.1 ml, p.o.). The EE and DF reduced the contortions induced by acetic acid. Both also reduced the licking response in the formalin model. In the hot plate model, the antinociceptive effects were, at least, equal to that shown by morphine. To elucidate the antinociceptive mechanism of action of EE, DF, and apigenin the animals were pre-treated with atropine (nonselective muscarinic receptor antagonist, 1mg/kg, s.c.), naloxone (opioid receptor antagonist, 1mg/kg, s.c.), l-nitro arginine methyl ester (L-NAME, nitric oxide synthase inhibitor, 3mg/kg, s.c.) or mecamylamine (nicotinic receptor antagonist, 2mg/kg, s.c.) and evaluated in the hot plate model.
  
  
  RESULTS
  The antinociception produced by DF was abolished by atropine, naloxone or mecamylamine. The effect of apigenin was significantly blocked by atropine or naloxone.
  
  
  CONCLUSIONS
  The results obtained indicated that EE and DF have antinociceptive activity that is mediated, at least in part, by opioid and cholinergic systems. This effect can be attributed to the presence of apigenin, a flavonoid in the dichloromethane fraction.
authors: Universidade Federal do Rio de Janeiro, Instituto de Ciências Biomédicas, Laboratório de Farmacologia da Inflamação e do Óxido Nítrico, Cidade Universitária, Rio de Janeiro, Brasil.
authors: Mariana Martins Gomes
authors: MM
authors: Pinheiro
authors: Fábio
authors: F
authors: Boylan
authors: Patrícia Dias
authors: PD
authors: Fernandes
mesh_terms: D000700:Analgesics / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D047310:Apigenin / Q000302:isolation & purification / Q000494:pharmacology*; D028023:Arecaceae / Q000737:chemistry*; D001241:Aspirin / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D001938:Brazil; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D010146:Pain / Q000188:drug therapy* / Q000473:pathology; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves
chemical_list: D000700:Analgesics; D010936:Plant Extracts; D009270:Naloxone; D008464:Mecamylamine; D009020:Morphine; D001285:Atropine; D047310:Apigenin; D001241:Aspirin