Studies on in vivo antitussive activity of Leucas lavandulaefolia using a cough model induced by sulfur dioxide gas in mice.

The methanol extract of Leucas lavandulaefolia was investigated for its effects on a cough model induced by sulfur dioxide gas in mice. It exhibited significant antitussive activity when compared with control in a dose-dependent manner. The antitussive activity of the extract was comparable to that of codeine phosphate (10 mg/kg), a prototype antitussive agent. The Leucas lavandulaefolia extract at 100, 200, and 400 mg/kg. p.o. showed inhibition of cough by 35.0, 51.9, and 56.5% within 1 h of performing the experiment.