Suppression of interleukin (IL)-8 and human beta defensin-2 secretion in LPS-and/or IL-1β-stimulated airway epithelial A549 cells by a herbal formulation against respiratory infections (BNO 1030)

Aim of the study: A special ethanolic-aqueous extract from seven traditional medicinal plants (BNO 1030) has been used for several decades to treat recurrent infections of the respiratory tract. Considering the potential role of interleukin-8 (1L-8) and human beta defensin-2 (hBD-2) in inflammation, we investigated the effect of BNO 1030 on lipopolysaccharide (LPS) from Pseudomonas aeruginosa or IL-1 beta-induced inflammatory mediators in A549 human type II alveolar epithelial cells. Materials and methods: A549 cells were stimulated with LPS (100 eta g/ml) or IL-1 beta (50 ng/ml) in the presence of the preparation and the secretion of IL-8 and hBD-2 were measured after 18 h and 24 h in cell free supernatants using enzyme-linked immunosorbent assays (ELISA). Cell viability and cell growth was investigated by propidium iodide uptake and WST-1 assay, respectively. Results: BNO 1030 inhibited the secretion of IL-8 and hBD-2 at non-cytotoxic concentrations (0.1-100 mu g/ml: cell growth inhibitory concentration, 50% (IC50) = 678 +/- 87.6 mu g/m1). Stimulation by IL-10 led to a 7-fold activation of IL-8 secretion, which was reduced by 37.7 +/- 4.1% (p < 0.05) after incubation with 100 mu g/ml BNO 1030. Inducible hBD-2 was suppressed by 91.8 +/- 15.6% (p < 0.01) at the same concentration of BNO 1030 (IC50 = 0.7 +/- 0.1 mu g/ml). The 2-fold increase of IL-8 secretion by LPS-stimulated cells was completely abolished at concentration of 50 mu g/ml BNO 1030 (IC50 = 5.7 +/- 3.6 mu g/ml). Conclusion: BNO 1030 suppressed the secretion of IL-8 and hBD-2 in cultured epithelial A549 cells. These results support its use as a phytotherapeutic product prepared from traditional remedies in inflammatory diseases, especially those affecting the respiratory tract. (C) 2010 Elsevier Ireland Ltd. All rights reserved.