Anti-asthmatic effect of laurotetanine extracted from Litsea cubeba (Lour.) Pers. root on ovalbumin-induced allergic asthma rats, and elucidation of its mechanism of action
Purpose: To investigate the anti-asthmatic effect of laurotetanine on allergic asthma rat model.
Methods: Laurotetanine was extracted from the roots of Litsea cubeba (Lour.) Pers. Asthma was induced in rats by ovalbumin injection. Laurotetanine (20, 40, or 60 mg/kg) was administered orally to the rats for 21 days. Inflammatory cells and cytokines released by T-cell subsets Th1 and Th2 in the bronchoalveolar lavage fluid were determined. Serum immunoglobulin E (IgE) and histamine, in addition to expression of mucin 5AC (MUC-5AC), nuclear factor-kappa B (NF-κB), and an inhibitor of NF-κB (IκB) in lung tissues were also evaluated.
Results: Laurotetanine treatment (20, 40, 60 mg/kg) significantly reduced inflammatory cells, including eosinophils, neutrophils, lymphocytes, and macrophages in treated rats compared with control animals (p < 0.01). Inflammatory cytokines, viz, interleukin (IL) -4, IL-6, IL-13 were also significantly (p < 0.01) decreased by laurotetanine treatment (20, 40, 60 mg/kg), whereas interferon gamma (IFN-γ) was increased (p < 0.01). Serum IgE and histamine were significantly reduced (p < 0.01) by laurotetanine (20, 40, 60 mg/kg). Furthermore, MUC5AC expression in lung tissues was significantly (p < 0.01) downregulated by laurotetanine (20, 40, and 60 mg/kg, but NF-κB and IκB were significantly (p < 0.01) upregulated by laurotetanine (20, 40, and 60 mg/kg).
Conclusion: Laurotetanine exerts an anti-asthmatic effect in rats by inhibition of IgE, histamine, and inflammatory reactions via down-regulating MUC5AC and NF-κB signaling pathways. This finding justifies the need for further development of laurotetanine as a potential anti-asthmatic drug.
Submission of a manuscript to this journal is a representation that the manuscript has not been published previously and is not under consideration for publication elsewhere.
All authors named in each manuscript would be required to sign a form (to be supplied by the Editor) so that they may retain their copyright in the article but to assign to us (the Publishers) and its licensees in perpetuity, in all forms, formats and media (whether known or created in the future) to (i) publish, reproduce, distribute, display and store the contribution, (ii) translate the contribution into other languages, create adaptations, reprints, include within collections and create summaries, extracts and/or abstracts of the contribution, (iii) create any other derivative works(s) based on the contribution, (iv) to exploit all subsidiary rights in the contribution, (v) the inclusion of electronic links from the contribution to third party material where-ever it may be located, and (vi) license any thrid party to do any or all of the above.