Investigation of antitussive and toxicological activity of Ballota limbata in mice

Abstract

Context: Ballota limbata Benth. (Lamiaceae) (syn, Otostegia limbata Hook.f.) is a species grown in the North West Frontier Province and the lower hills of West Punjab, Pakistan. Ballota species are renowned for their antispasmodic, antiulcer, diuretic, vermifuge, and especially sedative effects. However, little is known about the biological activity of B. limbata.

Objective: Evaluation of antitussive activity and safety profile of dried B. limbata extract.

Materials and methods: Whole air-dried plants were partitioned with various solvents and the butanol fraction was subjected to antitussive evaluation using a sulfur dioxide (SO₂)-induced cough model in mice. Codeine and dextromethorphan were used as positive control. Safety profile of the testing material was established using standard toxicity tests.

Results: B. limbata extract inhibited cough provoked by SO₂ gas in mice in a dose-dependent manner. The extract exhibited maximum protection against SO₂-induced cough after 60 min of administration. B. limbata offered maximum cough suppressive effects, that is, number of coughs during 60 min was 11.66 ± 1.2 (mean ± SEM), after s.c. administration of 800 mg/kg, as compared with codeine 10 mg/kg, s.c., dextromethorphan 10 mg/kg, s.c., and saline showing a frequency of cough of 11.75 ± 1.18, 12.25 ± 0.83, and 46.25 ± 1.52, respectively. LD₅₀ value of B. limbata was greater than 5000 mg/kg. No sign of neural impairment was observed at antitussive doses and the extract has been well-tolerated at higher doses.

Discussion and conclusion: This study demonstrates that the extract of B. limbata has shown strong cough suppressive effect in mice without yielding any notable toxicity.

Keywords::

• Cough
• antitussive
• Ballota limbata
• Otostegia limbata
• codeine
• dextromethorphan
• sulfur dioxide

Acknowledgements

This work was accomplished by an institutional grant from Department of Pharmacology, University of Karachi, Pakistan and an exceptional assistance from Mr. Muhammad Liaquat Raza, Mr. Shamsher Ali, and Mr. Afsar Khan. We are grateful to Marlene L. Anderson for helpful comments on the manuscript.

Declaration of interest

We declare that we have no conflict of interest with any organization or person.