The ethanolic extract from Erythrina mulungu Benth. flowers attenuates allergic airway inflammation and hyperresponsiveness in a murine model of asthma

Abstract

Ethnopharmacological relevanceErythrina mulungu Benth. (“mulungu”, Fabaceae) is a Brazilian native species with ethnopharmacological use for respiratory diseases. However, the effects of E. mulungu on the respiratory were never studied. Aims of the studyTo evaluate the effects of an ethanolic extract from flowers of E. mulungu in ovalbumin (OVA)-induced asthma in mice, and to study the mechanisms involved. Materials and methodsOVA-sensitized mice were intraperitoneally (i.p.) treated with four doses (200, 400, 600, and 800 mg/kg) of the E. mulungu extract or dexamethasone (DEXA, 2 mg/kg) during seven consecutive days and simultaneously challenged with intranasal OVA. Bronchial hyperresponsiveness was evaluated in vivo, 24 h after the last OVA challenge. Bronchoalveolar lavage (BAL) was collected for counting the number of total and differential inflammatory cells. Blood was collected for measurement of anti-OVA IgE levels. Levels of cytokines interleukin (IL)− 4, IL-5, IL-10, IL-13, and interferon (INF)-γ were measured in pulmonary homogenate by ELISA. The recruitment of inflammatory cells to the lung tissue was determined using hematoxylin and eosin staining (H&E). The extract's chromatographic profile was evaluated by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). ResultsThe treatment with E. mulungu extract significantly reduced bronchial hyperresponsiveness, significantly reduced the number of leukocytes, eosinophils, and lymphocytes in BAL, and significantly decreased the levels of IL-4 and IL-5, while increased levels of IL-13 and INF-γ. In addition, E. mulungu significantly decreased the cellular inflammatory infiltration in the lung tissue. Erysotrine, erysotrine-N-oxide, and hypaphorine were the major constituents identified in the extract. ConclusionCollectively, these results confirm the potential of E. mulungu for asthma treatment, through modulation of inflammatory response, supporting its ethnopharmacological use for respiratory diseases.