Mohammad Hossein Boskabady, Akram Moghaddas ,
Volume 8, Issue 3 (7-2004)
Abstract
In a previous study, the relaxant and anticholinergic (functional antagonism) effects of Bunium persicum (B. persicum ) have been demonstrated on guinea pig tracheal chains. To elucidate the other mechanisms responsible for this relaxant effect, the inhibitory effect of this plant on histamine H1 receptors was examined in this study. The antihistaminic effects of aqueous and macerated extracts, essential oil, 20 nM chlorpheniramine, and saline were tested by performing the cumulative log concentration-response curves of histamine induced contraction of isolated guinea pig tracheal chains incubated with three different conditions including: 1) 1.4 µM indomethacin, 2) 1.4 µM indomethacin, 1 µM propranolol, and 10 nM atropine, and 3) 1.4 µM indomethacin and 1 µM propranolol (for each group n = 8). The results showed clear parallel rightward shifts in histamine-response curves obtained in the presence of macerated extract in group 2, aqueous extract in group 3, and essential oil in group 2 and 3 experiments compared with the curves obtained in the presence of saline. The EC50 (effective concentration of histamine causing 50% of maximum response) obtained in the presence of essential oil, extracts, and chlorpheniramine in all three sets of experiments were significantly higher than that of saline (p<0.05 to p<0.001), but maximum response to histamine obtained in the presence of essential oil and extracts were lower (p<0.01 to p<0.001). However, the maximum response obtained in the presence of aqueous extract in group 3 compared to group 1 and that of macerated extract in group 2 compared to the other two sets of experiments were improved. These results indicated a competitive antagonistic effect of B. persicum at histamine H1 receptors
Mohammad Hossein Boskabady, Mohammad Reza Aslani,
Volume 9, Issue 3 (7-2005)
Abstract
In the previous studies the relaxant, anti-cholinergic (functional antagonism) and anti-histaminic effects of Nigella sativa have been demonstrated on guinea pig tracheal chains. To elucidate the main substance responsible for the relaxant effect of this plant, the effect of thymoquinone, one of the main constituent of Nigella sativa was examined in this study. The bronchodilatory effects of three cumulative concentrations (40, 80, and 120 µM) of thymoquinone were examined by their relaxant effects on precontracted tracheal chains of guinea pigs using (1) 10 µM methacholine and (2) 60 mM KCl. The results were compared with the effects of saline, theophylline, and extracts (macerated and aqueous) of Nigella sativa (n = 5 for each group). The results showed significant relaxant effects of theophylline and extracts from Nigella sativa as compared to saline in group 1 experiments (P<0.05 and P<0.005). There were no significant differences between the effects of two higher concentrations of extracts with those of theophylline. However, none of the three thymoquinone concentrations showed any relaxant effect in both groups. There were also significant differences between the relaxant effect of theophylline and extracts with those of thymoquinone concentrations (P<0.05 and P<0.001). In group 2, only theophylline showed a significant relaxant effect (P<0.05 and P<0.001). The effects of two higher concentrations of both extracts and thymoquinone were significantly lower than those of theophylline in group 2 (P<0.05 to P<0.001). These results indicated that the relaxant effect of Nigella sativa is not due to its constituent thymoquinone
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