Study of Antitussive Potential of Glycyrrhiza Glabra and Adhatoda Vasica Using a Cough Model Induced by Sulphur Dioxide Gas in Mice

Cough is the most common symptom of respiratory diseases. When cough becomes serious, opioids are effective, but they have side effects like sedation, constipation. Therefore, there is a need to have effective antitussive agent which do not have respiratory depressant activity. The present study was carried out to evaluate antitussive activity of Glycyrrhiza glabra and Adhatoda vasica using a cough model induced by sulphur dioxide gas in mice. The effect of the ethanol extracts of Glycyrrhiza glabra and Adhatoda vasica on SO2 gas induced cough in experimental animals have very significant effects at the level of p<0.01 in inhibiting the cough reflex at a dose of 800 mg/kg and 200 mg/kg body wt. p.o., in comparison with the control group. Mice showed an inhibition of 35.62%, in cough on treatment with Glycyrrhiza glabra and 43.02% inhibition on treatment with Adhatoda vasica within 60 min of the experiment. The antitussive activity of the extract was comparable to that of codeine sulphate (10, 15, 20 mg/kg body wt.), a standard anti-tussive agent. Codeine sulphate, as a standard drug for suppression of cough, produced 24.80%, 32.98%, and 45.73% inhibition in cough at a dose of 10 mg/kg, 15 mg/kg and 20 mg/kg respectively, whereas, codeine sulphate (20 mg/kg) showed maximum 45.73% (p<0.001) inhibition at 60 min of the experiment. INTRODUCTION: A cough (Latin: tussis) is a sudden and forceful expiration of air from the lungs caused by an involuntary contraction of the muscles controlling the process of breathing. It is a protective reflex that removes foreign material and secretions from the bronchi and bronchioles. The cough reflex consists of three phases: an inhalation, a forced exhalation against a closed glottis . Ayurveda (Ayur-life, Vedaknowledge), is the knowledge of healthy living and is not merely confined to the treatment of illness. Ayurvedic medicines are largely based on herbal and herbo-mineral preparations and have specific diagnostic and therapeutic principles . Glycyrrhiza glabra is one of the most commonly used medicine in Indian indigenous system of medicine. It is used as an energy tonic, particularly for the spleen and stomach, and the root is added to many formulae. It is also used for asthmatic coughs, as an antispasmodic and ulcer remedy, and to cool 'hot' conditions. Roots of Glycyrrhiza glabra being tonic, demulcent laxative emollient are used in genito-urinary diseases, coughs and sore throat . The antitussive activity of glycyrrhetinic acid and its derivatives has been evaluated .