Mandevilla longiflora (Desf.) Pichon improves airway inflammation in a murine model of allergic asthma

Abstract

Ethnopharmacological relevance: Mandevilla longiflora, popularly known as "velame" in central Brazil, is a subshrub widely distributed in South America. Its xylopodium is used in the form of a decoction or infusion to treat inflammation and other ailments.

Aim of the study: This study aimed to evaluate the anti-inflammatory potential of M. longiflora in an in vivo model of ovalbumin-induced immediate hypersensitivity, identifying its effects on leukocyte infiltration, IgE and LTB₄ levels, and Th2 cytokine production. In addition, HPLC fingerprint of the extract was performed.

Material and methods: The hydroethanolic extract 70% of M. longiflora (HEMI) was obtained by maceration of the plant xylopodium. Swiss mice were sensitized by i.p. injection OVA-aluminium hydroxide on days 1 and 10. Nine days after the last sensitisation animals were challenged for 6 consecutive days with OVA solution for 20min daily in a closed chamber under continuous flow of aerosol. The animals were treated with HEMl (20, 50 and 200mg/kg p.o.), 2 times per day, and euthanized 24h later. Animals treated with vehicle (2% Tween-20) or dexamethasone were used as negative and positive controls, respectively. The recruitment of inflammatory cells into the pulmonary cavity was evaluated by counting cells present in broncho-alveolar lavage fluid (BALF). Lung tissue was also collected for histopathology and infiltration analysis. Quantification of IL-4, IL-5 and IL-13 from the BALF, and IgE, and LTB₄ from plasma, were conducted by immunoassay.

Results and conclusions: The HEMl attenuated leukocyte migration into the airways, which was evidenced by a decrease in eosinophils, neutrophils and mononuclear cells, both in BALF quantification and by histopathological analysis, as well as decreasing the concentrations of IL-4, IL-5, IL-13, IgE and LTB₄. All of these events are typical of air-mucosa inflammatory disease. These findings scientifically evidence for the first time the ethnopharmacological use of M. longiflora to treat chronic inflammatory events, such as asthma, and suggest a potential therapeutic use or complementary therapy for this plant extract.

Keywords: Asthma; Inflammation; Mandevilla longiflora.