Immunomodulating effects of herbal cough medication - in vitro screening in a TLR7- and TLR8-mediated inflammatory model.

BACKGROUND

The study was conducted to investigate the immunomodulatory effects of herbal cough medications available on the market that contain either whole plant extracts from ivy, thyme, Pelargonium or the active plant-derived compound cineole on human lung epithelial cells in order to evaluate their potential in the treatment of viral inflammatory processes.

METHODS

Different concentrations of the commercial plant medications (five medications that contained total ivy, thyme or Pelargonium extracts and one plant medication that contains cineole) were analyzed for their cytotoxicity and immunomodulatory potential on the human epithelial lung cancer cell line A549 and the hTERT-immortalized cell line NuLi-1. Viability was tested using WST-1 assays. AnnexinV/PI staining and flow cytometry analysis were used to investigate apoptosis and necrosis. A549 and NuLi-1 cells were stimulated with toll-like receptor (TLR)7- and TLR8-agonists, mimicking viral infection. Cytokine secretion was analyzed using the bead-based LEGENDplex™ assay.

RESULTS

Non-toxic concentrations of the ivy-, thyme- or Pelargonium - containing medications, but not the medication containing cineole, significantly reduced the secretion of inflammatory cytokines and chemokines after the stimulation of TLR7 and TLR8 in A549 and NuLi-1 cells.

CONCLUSION

Medications derived from ivy, thyme and Pelargonium extracts exhibit anti-inflammatory properties in a model mimicking viral infection in human lung epithelial cells.