Anti-asthmatic activity of standardized hydro-ethanolic and aqueous extracts of Stachytarpheta cayennensis (Rich.) Vahl in a murine model.

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE Stachytarpheta cayennensis (Verbenaceae) has been used in Brazilian traditional medicine to treat asthma and other respiratory diseases. AIMS OF THE STUDY To investigate the effects of different doses of standardized hydro-ethanolic (SCH) and aqueous (SCA) extracts of aerial parts of S. cayennensis using a murine ovalbumin (OVA)-induced asthma model. MATERIALS AND METHODS: The major constituents of the plant extracts were identified and standardized by ultra-performance liquid chromatography coupled with mass spectrometry. Balb/c mice were challenged with OVA solution and treated concomitantly by intraperitoneal injection of standardized SCH or SCA extracts at 50, 100, and 200 mg/kg concentrations. OVA-challenged control animals were treated with either dexamethasone (OVA-DEX) or saline solution (OVA-SAL). After challenge, we assessed in vivo bronchial hyperresponsiveness, airway inflammation (number of cells), peribronchial inflammation (histological analysis) and production of OVA-specific IgE and interleukin (IL)-4, IL-5, and IL-13 (ELISA). RESULTS: Acteoside, isoacteoside, and ipolamiide were the major constituents of SCH and SCA. The respective concentrations of acteoside in SCH and SCA were 78 and 98 µg/mL, while those of ipolamiide were 30 and 19 µg/mL. Treatment with 200 mg/kg of SCH or SCA decreased IL-4, IL-5, and IL-13 in lung homogenates. These reductions were accompanied by a lower influx of inflammatory cells (eosinophils, lymphocytes, and macrophages) to the airways and lungs. In addition to the anti-inflammatory effects, administration of SCA, but not SCH, ameliorated the parameters of bronchial hyperresponsiveness and decreased levels of circulating OVA-specific IgE. CONCLUSION: The results presented herein demonstrate for the first time the anti-asthmatic activity of S. cayennensis extracts in a murine model, thereby supporting the ethnopharmacological uses of the plant.