Hydroethanolic extract from Echinodorus scaber Rataj leaves inhibits inflammation in ovalbumin-induced allergic asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Echinodorus scaber, Alismataceae, is popularly known in Brazil as "chapéu-de-couro". The plant leaves are used by the population as decoction, infusion, or maceration in bottled spirits, to treat inflammatory respiratory diseases. AIM OF THE STUDY: To investigate the anti-inflammatory mechanism of the hydroethanolic extract of leaves of Echinodorus scaber (HEEs) in allergic asthma. A phytochemical analysis of the extract was performed as well. MATERIALS AND METHODS: The leaves of Echinodorus scaber were prepared by maceration in 75% ethanol. Preliminary phytochemical analysis was carried out using basic classical methods, and the secondary metabolites detected in HEEs were analyzed and confirmed by high-performance liquid chromatography (HPLC). The in vivo anti-inflammatory activity of HEEs was evaluated in Swiss male albino mice sensitized and challenged by OVA. The HEEs (1, 5 and 30mg/kg, p.o.) was administered to mice twice a day, 1h before the challenge, from days 19 through 24. The mechanism of action of HEEs was studied by evaluating the levels of TH2 cytokines (IL-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) and IgE production in blood plasma. Histopathological changes triggered by OVA-sensitization/challenge in the lung tissue were also investigated. RESULTS: HEEs reduced total leukocyte, eosinophil, neutrophil, and mononuclear cell counts at all doses tested, with maximum effect at 30mg/kg (73.9%, 75.9%, 75.5%, and 65.2% reduction, p<0.001, respectively). Increases in TH2 cytokine secretion (IL-4, IL-5 and IL-13) and in IgE levels were also attenuated by HEEs. Preliminary phytochemical screening seems to indicated the presence of phenolic compounds, flavonoids and alkaloids. HPLC analyses evidenced the presence of phenolic compounds, such as gallic acid, rutin and vitexin. CONCLUSION: Our findings provided pharmacological preclinical evidence for the popular use of the leaves of Echinodorus scaber in allergic inflammation. Its anti-inflammatory effect was dependent on the decrease in migratory inflammatory cells, and both TH2 cytokines and IgE levels. It is suggested that vitexin, gallic acid and rutin, known anti-inflammatory compounds, may participate in the anti-asthamtic effect of the HEEs, by acting jointly along with other components present in the extract.

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

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.