Relaxant Effects of Limonia Acidissima Linn (pulp) on Guinea Pig Tracheal Chains and Its Possible Mechanism(s)

Objective: The study was done to evaluate the antiasthma activity of Macerated and Soxhlet extracts of (pulp) of plant Liomnia acidissima Linn on tracheal chains of guinea pigs. Methods: The (pulp) of fruits of plant Liomnia acidissima Linn was extracted with 95% ethanol at 55oC and evaluate for their antiasthma activity on tracheal chains of guinea pigs by using three cumulative concentrations of macerated and soxhlet extracts (0.5, 0.75, and 1.0 g %) in comparison with saline as negative control and 3 cumulative concentrations of theophylline (0.5, 0.75, and 1.0 mM) as positive control were examined on precontracted tracheal chains of three groups of 6, 6 and 4 guinea pigs by 60 mM KCl (group 1) and 10 μM methacholine (group 2) and tissues incubated with 1 μM propranolol contracted tracheal chains by 10 μM methacholine (group 3) [2] [3] [4] [5] [6]. Results: Decrease in contractile tone of tracheal chains was considered as relaxant effect. Theophylline exhibits potent antiasthmatic activity at (1.0 mM) after administration and in compare with (1.0 g %) soxhlet extracts of 95% ethanol. Whereas (1.0 g %) soxhlet extracts of 95% ethanol exhibits significant antiasthma activity. In Group 1 experiments (contracted by 60 mM KCl) only the higher two concentrations (0.75, and 1.0 mM) of theophylline and the highest concentration (1.0 g %) of Soxhlet extract showed significant relaxant effect compared to that of saline (P<0.001 and P<0.05 for theophylline and Soxhlet extract respectively). The effects of two higher concentrations (0.75, and 1.0 mM) of theophylline in this group were significantly greater than those of (0.75, and 1.0 g %) Soxhlet and Macerated extracts (P < 0.01). In group 2 (Contracted by 10 μM methacholine) theophylline and both Macerated and Soxhlet extract showed significant relaxant effects compared to that of saline (p<0.05 to p<0.001). In group 3 (Incubated with 1μM propranolol contracted by 10 μM methacholine) all concentrations of both Macerated and Soxhlet extract showed significant relaxant effects compared to that of saline (p<0.05 to p<0.001). The relaxant effects of Macerated and Soxhlet extracts in group 1 were significantly lower than those of groups 2 and 3. In group 3 experiment potent relaxant effect was observed. Conclusion: These results showed a potent relaxant effect (pulp) of fruits of plant of Liomnia acidissima on tracheal chains of guinea pigs which were lower than theophylline at concentrations used, but it was found that due to the presence of flavanoids, glycosides, saponins, tannins, alkaloids, polyphenol and sterols in ethanolic extracts of the plants Limonia acidissima (pulp) might be responsible bronchodilatory and antiasthmatic effect on tracheal chains of guinea pig.