The Contribution of Water and Lipid Soluble Substances in the Relaxant Effects of Nigella sativa Extract on Guinea Pig Tracheal Smooth Muscle (in vitro)

Objective In previous studies, the relaxant, anticholinergic (functional antagonism), antihistaminic and its stimulatory effects on b-adrenoceptors of Nigella sativa have been demonstrated on guinea pig tracheal chains. In the present study, the relaxant effects of hydro-ethanolic, macerated aqueous (MA) and lipid-free macerated aqueous (LFMA) extract of Nigella sativa on tracheal chains of guinea pigs were examined. Materials and Methods The relaxant effects of four cumulative concentrations of each extract (0.8, 1.2, 1.6 and 2.0 g%) was compared with saline as negative control and four cumulative concentrations of theophylline (0.2, 0.4, 0.6 and 0.8 mM) on precontracted tracheal smooth muscle of guinea pig (60 mM KCl in group 1 and 10 µM methacholine in group 2, n=6 for each group).  Results In group 1 all concentrations of theophylline, the last two concentrations of MA and the last three concentrations of  LFMA extracts showed significant relaxant effects compared to that of saline (p