Callicarpa japonica Thunb. ameliorates allergic airway inflammation by suppressing NF-κB activation and upregulating HO-1 expression

Ethnopharmacological relevance: Callicarpa japonica Thunb., as an herbal medicine has been used for the treatment of inflammatory diseases in China and Korea. Materials and methods: Ultra performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometer (UPLC-PDA-QTof MS) was used to detect the major phenylethanoid glycosides in the C. japonica extract. BALB/c mice were intraperitoneally sensitized by ovalbumin (OVA) (on days 0 and 7) and challenged by OVA aerosol (on days 11-13) to induce airway inflammatory response. The mice were also administered with C. japonica Thunb. (CJT) (20 and 40 mg/kg Per oral) on days 9-13. CJT pretreatment was conducted in lipopolysaccharide (LPS)-stimulated RAW264.7 or phorbol 12-myristate 13-acetate (PMA)-stimulated A549 cells. Results: CJT administration significantly reduced the secretion of Th2 cytokines, TNF-alpha, IL-6, immunoglobulin E (IgE) and histamine, and the recruitment of eosinophils in an OVA-exposed mice. In histological analyses, the amelioration of inflammatory cell influx and mucus secretion were observed with CJT. The OVA-induced airway hyperresponsiveness (AHR), iNOS expression and NF-kappa B activation were effectively suppressed by CJT administration. In addition, CJT led to the upregulation of HO-1 expression. In an in vitro study, CJT pretreatment suppressed the LPS-induced TNF-alpha secretion in RAW264.7 cells and attenuated the PMA-induced IL-6, IL-8 and MCP-1 secretion in A549 cells. These effects were accompanied by downregulated NF-kappa B phosphorylation and by upregulated HO-1 expression. Conclusion: These results suggested that CJT has protective activity against OVA-induced airway inflammation via downregulation of NF-kappa B activation and upregulation of HO-1, suggesting that CJT has preventive potential for the development of allergic asthma.