title: The Relaxant Effects of Different Methanolic Fractions of Nigella sativa on Guinea Pig Tracheal Chains.
abstract: OBJECTIVE
  In regard to the high incidence of asthma and the side-effects of the drugs used, finding novel treatments for this disease is necessary. Our previous studies demonstrated the preventive effect of Nigella sativa extract on ovalbumin-induced asthma. In addition, water-soluble substances of N. sativa extract and methanol fraction of this plant were responsible for the relaxant effect of this plant on tracheal chains of guinea pigs. Therefore, for the first time, in the present study, in order to identify main constituents of the methanolic extract, the relaxant effects of five different methanolic fractions (20%, 40%, 60%, 80%, and 100%) of N. sativa on tracheal chains of guinea pigs were examined.
  
  
  METHODS
  The relaxant effects of four cumulative concentrations of each fraction (0.8, 1.2, 1.6, and 2.0 g%) in comparison with saline as negative control and four cumulative concentrations of theophylline (0.2, 0.4, 0.6, and 0.8 mM) were examined by their relaxant effects on precontracted tracheal chains of guinea pig by 60 mM KCl (group 1) and 10 µM methacholine (group 2).
  
  
  RESULTS
  In group 1, all concentrations of only theophylline showed significant relaxant effects but all concentrations of these methanolic fractions showed significant contractile effects compared with that of saline (P<0.001 to P<0.05). However, in group 2, all concentrations of theophylline and these methanolic fractions showed significant relaxant effects compared with that of saline (P<0.001 to P<0.05).
  
  
  CONCLUSIONS
  These results showed a potent relaxant effect of 20% methanolic fractions from N. sativa on tracheal chains of guinea pigs that were higher than that of theophylline at the used concentrations.
authors.affiliation: Tuberculosis and Lung Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Rana
authors.initials: R
authors.lastname: Keyhanmanesh
authors.forename: Horeyeh
authors.initials: H
authors.lastname: Bagban
authors.forename: Hossein
authors.initials: H
authors.lastname: Nazemiyeh
authors.forename: Fariba
authors.initials: F
authors.lastname: Mirzaei Bavil
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Alipour
authors.forename: Mehdy
authors.initials: M
authors.lastname: Ahmady
keywords: Guinea Pig; Methanolic Fractions; Nigella sativa; Relaxant Effect; Tracheal Chain