Validation of Safety and Efficacy of Antitussive Herbal Formulations

Abstract

Background: Cough is an important defensive pulmonary reflex that removes irritants, fluids or foreign materials from the airways. Frequently, cough is non-productive and requires suppression and opioid receptor agonists such as codeine are commonly used as antitussive agents. However, opioids produce side effects that include sedation, addiction potential and constipation. Novel cough suppressant therapies should maintain or improve upon the antitussive efficacy profile of opioids but with minimum or no side effects.

Objective: To evaluate antitussive activity of combination of herbal medicines as formulations in sulphur dioxide - induced cough model in rats.

Methodology: Wister rats of either sex, weighing 150 - 200 g, were divided into 7 groups (n = 6). Group 1 served as a control and received normal saline, groups 2 received codeine phosphate, group 3 and 4 received the coded market samples and groups 5, 6 and 7 received the test samples, respectively. Thirty or sixty minutes following administration, the rats were exposed to sulphur dioxide gas for 1 minute and then placed in an open chamber for counting of cough bouts.

Results: The formulations exhibited cough inhibitions of between 15 and 27%, and 14 and 38%, with respect to the control group, 30 and 60 minutes after sample administration respectively.

Conclusion: The herbal formulations demonstrated significant (p < 0.05) antitussive activity in sulphur dioxide induced cough model.

Key words: Antitussive activity; herbal formulations; sulphur dioxide; cough