Melia azedarach L. reduces pulmonary inflammation and mucus hypersecretion on a murine model of ovalbumin exposed asthma

Ethnopharmacological relevance: Melia azedarach L. is a traditional medicinal plant used to control pain, pyrexia, inflammation and bacterial infections that possesses several pharmacological activities, including antiinflammatory and antioxidant activities. Particularly, the root of M. azedarach was used as expectorant and anti-cough and asthma treatment. Based its properties, M. azedarach is expected to have a potential to treat allergic asthma, chronic inflammatory respiratory disease. However, there is no study on anti-asthmatic effects of M. azedarach and its mechanism of action until now. Aim of the study: We investigated the active ingredient of M. azedarach fruit extract (MAE) using highperformance liquid chromatography (HPLC) and explored the therapeutic effects of MAE on pulmonary inflammation and mucus hypersecretion using a murine model of ovalbumin (OVA) exposed asthma. Materials and methods: The ingredients of MAE were analyzed using HPLC. To develop allergic asthma model, the animals were sensitized (days 1 and 14) and the airway was challenged (from day 21-23) using OVA. MAE was administered by oral gavage once a day from day 18-23 at doses of 30 and 100 mg/kg. Results: HPLC analysis revealed the presence of toosendanin in MAE. In asthmatic mice, MAE administration effectively suppressed the inflammatory cell counts in bronchoalveolar lavage fluid (BALF) along with a reduction in airway hyperresponsiveness. Moreover, MAE administration inhibited the production of proinflammatory cytokines and immunoglobulin E in BALF and serum of asthmatic mice, respectively. These results were similar to the results of histological examination showing a reduction in pulmonary inflammation and mucus hypersecretion. MAE elevated the expression of nuclear factor erythroid 2-related factor 2, heme oxygenase-1, and superoxide dismutase 2, which in turn resulted in the suppression of matrix metallopeptidase-9 expression in lung tissue of asthmatic mice. Conclusions: Altogether, MAE successfully inhibited allergic asthma in OVA-exposed mice. Thus, MAE could be a potential therapeutic remedy for treating allergic asthma.