Antinociceptive effect of leaf essential oil from Croton sonderianus in mice.
The leaf essential oil from Croton sonderianus (EOCS) was evaluated for antinociceptive activity in mice using chemical and thermal models of nociception. Given orally, the essential oil at doses of 50, 100 and 200 mg/kg produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin or capsaicin injections. However, it evidenced no efficacy against thermal nociception in hot-plate test. More prominent inhibition of acetic acid-induced writhing and capsaicin-induced hind-paw licking responses was observed at 100 and 200 mg/kg of EOCS. At similar doses, the paw licking behavior in formalin test was more potently suppressed during the late phase (20-25 min, inflammatory) than in early phase (0-5 min, neurogenic). The EOCS-induced antinociception in both capsaicin and formalin tests was insensitive to naloxone (1 mg/kg, s.c.), but was significantly antagonized by glibenclamide (2 mg/kg, i.p.). In mice, the essential oil (100 and 200 mg/kg) neither significantly enhanced the pentobarbital-sleeping time nor impaired the motor performance in rota-rod test, indicating that the observed antinociception is unlikely due to sedation or motor abnormality. These results suggest that EOCS produces antinociception possibly involving glibenclamide-sensitive KATP+ channels, which merit further studies on its efficacy in more specific models of hyperalgesia and neuropathic pain.
Department of Physiology, Federal University of Ceará, C.P. 3157, 60430-270 Fortaleza, CE, Brazil.
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Jeferson
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D019342:Acetic Acid / Q000008:administration & dosage; D000700:Analgesics / Q000627:therapeutic use*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002211:Capsaicin / Q000008:administration & dosage; D029802:Croton / Q000737:chemistry*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004336:Drug Antagonism; D005905:Glyburide / Q000494:pharmacology; D008297:Male; D051379:Mice; D009822:Oils, Volatile / Q000302:isolation & purification / Q000627:therapeutic use*; D010146:Pain / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D018515:Plant Leaves / Q000737:chemistry; D004856:Postural Balance / Q000187:drug effects; D026902:Potassium Channel Blockers; D012890:Sleep / Q000187:drug effects
D000700:Analgesics; D009822:Oils, Volatile; D026902:Potassium Channel Blockers; D019342:Acetic Acid; D002211:Capsaicin; D005905:Glyburide