title: Analgesic effect of the aqueous and ethanolic extracts of clove.
abstract: OBJECTIVE
  The beneficial effects of clove on toothache have been well documented. We have also previously shown the analgesic effects of clove essential oil. The present work was done to investigate the analgesic effects of the aqueous extract of clove using hot plate test. The possible role of opioid receptors in the analgesic effects of clove was also investigated using naloxone.
  
  
  METHODS
  Ninety male mice were divided into nine groups: (1) Saline, (2-4) Aaqueous (Aq 50, Aq 100, and Aq 200) groups which were treated with 50, 100, and 200 mg/kg of aqueous extract of clove, respectively, (5-7) Ethanolic (Eth 50, Eth 100, and Eth 200) groups which were treated with 50, 100, and 200 mg/kg of ethanolic extract of clove, respectively, and (8-9) Aq 100- Naloxone and Aq 200- Naloxone which were pretreated with 4 mg/kg of naloxone before injection of 100 or 200 mg/kg of the aqueous extract. The hot plate test was performed as a base record 10 min before injection of drugs and consequently repeated every 10 minutes after the injection.
  
  
  RESULTS
  The maximal percent effect (MPE) in the animal groups treated with 50, 100, and 200 mg/kg of aqueous extract was significantly higher than the control group. Pretreatment with naloxone reduced the analgesic effects of both 100 and 200 mg/kg of the aqueous extract. Administration of all three doses of the ethanloic extract also non-significantly increased the MPE.
  
  
  CONCLUSIONS
  The results of the present study showed that aqueous extract of clove has analgesic effect in mice demonstrated by hot plate test which is reversible by naloxone. The role of opioid system in the analgesic effect of clove might be suggested. However, more investigations are needed to elucidate the exact mechanism(s).
authors: Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, I. R. Iran.
authors: Mina
authors: M
authors: Kamkar Asl
authors: Department of Physiology, School of Medicine, Zabol University of Medical Sciences, Zabol, I. R. Iran.
authors: Ashraf
authors: A
authors: Nazariborun
authors: Neuroscience Research Center and Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad I. R. Iran.
authors: Mahmoud
authors: M
authors: Hosseini
keywords: Analgesia; Clove; Extract; Hot Plate; Mice; Naloxone