Pseudocedrela kotschyi limits airway inflammation in ovalbumin-induced asthma in guinea pigs

Abstract

Asthma is a respiratory disorder characterized by chronic airway inflammation, bronchial hyper-responsiveness and airflow obstruction. Its prevalence and associated mortality is expected to rise in the coming years particularly in Sub-Saharan Africa. This, together with cost and access limitations to effective disease management has highlighted the need to explore potentially effective, indigenous therapeutic alternatives. Our study set out to evaluate the effect of Pseudocedrela. kotschyi bark extract (PKE), a traditionally used remedy, on airway hyper-responsiveness and airway inflammation associated with ovalbumin-induced asthma in guinea pigs. We focused on the protective effect of PKE treatment on antigen-provoked hyper-responsiveness, inflammatory cell proliferation and structural changes in lung tissue associated with chronic asthma. Our investigations showed that PKE at 50, 100 and 500 mg/kg delayed onset of peak respiratory distress in asthmatic guinea pigs by 38.46 ± 8.88%, 61.54 ± 14.73%, 69.23 ± 8.88% respectively, relative to saline-treated group. Bronchoalveolar lavage fluid (BALF) analysis revealed significant suppression of eosinophil and total leucocyte proliferation associated with ovalbumin-induced asthma, in PKE-treated guinea pigs. Lung sections of PKE-treated guinea pigs showed a markedly preserved architecture with less severe bronchial smooth muscle hypertrophy, peri‑bronchiolar and alveolar inflammatory cell infiltration compared with saline-treated guinea pigs. Our findings therefore demonstrate that P. kotschyi is effective in reducing key features of experimentally induced chronic asthma and support its traditional use in the management of asthma.