Suppression of airway inflammation by Illicium verum and trans-anethole

To develop an antiasthmatic agent, Illicium verum and its major components were evaluated for their ability to suppress airway inflammation. Furthermore we have studied the effects of trans-anethole compound on Treg cell-mediated suppression [1]. Asthma was induced in BALB/c mice by systemic sensitization to ovalbumin (OVA) followed by intratracheal, intraperitoneal, and aerosol allergen challenges. Illicium verum and its major components were orally administered for 4 weeks. We investigated their effects on airway hyperresponsiveness, pulmonary eosinophilic infiltration, various immune cell phenotypes, cytokine & cytospin measurements in bronchoalveolar lavage (BAL), Th2 cytokine production, OVA-specific IgE production, Th1/Th2 cytokine production, lung histology and immunofluorescence analysis in this mouse model of asthma [2]. Illicium verum and trans-anethole significantly (p < 0.05) inhibited OVA-induced increases in total cell counts, eosinophil counts, and IL-4, IL-5, and IL-13 levels recovered in bronchoalveolar lavage fluid in OVA-sensitized mice. trans-Anethole further substantially (p < 0.05) reduced the total IgE, eotaxin 2 levels, and CCR3 expression of BAL fluid. trans-Anethole also substantially (p < 0.05) increased the Foxp3 and TGF-b1 mRNA expression of BAL fluid. Histological studies showed that trans-anethole dramatically inhibited eosinophilia, and infiltration of lymphocytes in lung tissues. These results suggest that the anti-inflammatory and anti-asthmatic effects of Illicum verum and trans-anethole are exerted through upregulation of regulatory T cells.

Acknowledgements: This research was supported by a grant from the Korea Institute of Planning and Evalution for Technology of Food, Agriculture, Forestry and Fisheries.

Keywords: Illicium verum, trans-anethole, antiasthmatic, Foxp3, regulatory T cells.

References:

[1] Bettelli E, Dastrange M, Oukka M. Foxp3 interacts with nuclear factor of activated T cells and NF-kappa B to repress cytokine gene expression and effector functions of T helper cells. Proc Natl Acad Sci U S A 2005; 102: 5138 – 5143

[2] Pope SM, Brandt EB, Mishra A, Hogan SP, Zimmermann N, Matthaei KI, Foster PS, Rothenberg ME. IL-13 induces eosinophil recruitment into the lung by an IL-5- and eotaxin-dependent mechanism. J Allergy Clin Immunol 2001; 108: 594 – 601

No conflict of interest has been declared by the author(s).