Study Title:

Quercetin Reduces Airway Allergy

Study Abstract

The aqueous extract of Kalanchoe pinnata (Kp) has been shown to down regulate TH2 responses and inhibit mast cell degranulation and histamine release. Kp has been demonstrated to be effective in murine models of leishmania infections and anaphylactic shock. In the present study we investigated the effect of Kp and its flavonoid quercetin (QE) in a murine model of allergic airway inflammation and hyperresponsiveness.

BALB/c mice were sensitized to ovalbumin (OVA) by 2 intraperitoneal injections with 20 mg OVA in phosphate buffered saline (PBS) on days 0 and 14. Mice were challenged on days 28, 29 and 30, using nebulised OVA (1% in PBS). Oral treatments with 400 mg/Kg of Kp or 20 mg/Kg of QE started on day 27 and was performed once daily for 4 days. On day 31 airway reactivity was assessed in anaesthetized, intubated and mechanically ventilated mice. After assessment of airway function, bronchoalveolar lavage fluid (BAL) was obtained for cytokines measurements by ELISA. Lung tissue sections were prepared for histology analysis. OVA-specific IgE titers in serum were determined by ELISA.

Oral treatment with Kp or QE resulted in a significant reduction of airway reactivity to methacholine in sensitized and challenged animals. Furthermore, in sensitized and challenged animals treated with Kp or QE decreased numbers of eosinophils and lymphocytes and levels of TNF-a, IL-13 and IL-5 were detectable in BAL fluid compared to sham treated controls. In addition the numbers of peribronchial and perivascular inflammatory cells were reduced by treatment with Kp or QE.

These findings show that treatment with Kp reduces airway reactivity and airway inflammation in a murine model of allergic airway disease. Similar effects were observed using the quercetin flavonoid, suggesting that QE is a critical component of this protective effect of Kp extract.

Study Information

E.A. Cruz, MS, S. Reuter, PhD, H. Martin, MS, N. Dehzad, MS, M.F. Muzitano, PhD, S.S. COSTA, PhD, B.R. Bergmann, PhD, R. Buhl, MD, C. Taube, MD
American Thoracic Society May 2010 annual International Conference in New Orleans
2010 May
Rio De Janeiro/BR

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