RESUMEN
The antimicrobial property of the ethanol leaf extract of Hymenocardia acida (H. acida) on some opportunistic respiratory pathogens was evaluated in this study. We also assessed the activity of the extract on tracheal mucociliary activity using murine tracheal mucus exudation and mucociliary motility in pigeons as experimental models. Phytochemical screening of the extract was done; and acute toxicity of the extract in mice was carried out using Lorke's method for estimation of its median lethal dose. Results show the presence of carbohydrates, saponins, tannins, flavonoids, alkaloids, resins, and balsams in the extract and the absence of anthraquinones, terpenes, and sterols. Results of the acute toxicity test showed that the extract was slightly toxic, with an estimated median lethal dose of 1,767.77 mg/kg body weight. At 50, 100, and 200 mg/kg body weight of H. acida, tracheal mucus exudation was increased by 14.29, 19.24, and 33.82%, respectively. The effect on mucociliary velocity was dose-dependent as 50, 100, and 200 mg/kg body weight of the extract led to increased ciliary activity by 7.69, 61.5, and 81.6%, respectively. The effects of the extract (200 mg/kg body weight) on mucus exudation and clearance were significant (p < .05) and higher than the effect of ammonium chloride. Although the extract did not inhibit the growth of C. albicans and K. pneumoniae, it exhibited moderate antimicrobial activity against Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Staphylococcus aureus. These findings show the mucociliary activity and antimicrobial properties of H. acida ethanol extract, and justify its use in the treatment of airway disorders.