Ge-Gen-Tang has anti-viral activity against human respiratory syncytial virus in human respiratory tract cell lines

Ethnopharmacological relevance: Ge-Gen-Tang (GGT) has been used against adult respiratory tract infection for thousand years in ancient China. However, GGT is unable to inhibit influenza virus. The effect of GGT to manage respiratory tract viral infection has been questioned. Several ingredients of GGT and their constituents are able to inhibit various viruses. Therefore, GGT might have antiviral activity against other viruses causing respiratory tract illness. Human respiratory syncytial virus (HRSV) is one of the most important airway viruses. However, it is unknown whether GGT is effective against HRSV. Aim of the study: HRSV contributes considerably to respiratory tract illness of the elderly and immuno-compromised adults. There is no effective therapeutic modality for HRSV infection. In order to find a readily available agent to manage HRSV infection, the authors tested the hypothesis that GGT can effectively minimize airway pathology by preventing HRSV-induced'plaque formation in respiratory mucosal cell lines. Materials and methods: Effect of the hot water extract of GGT on HRSV was tested by plaque reduction assay in both human upper (HEp-2) and low (A549) respiratory tract cell lines. Ability of GGT to stimulate anti-viral cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA). Results: GGT dose-dependently inhibited HRSV-induced plaque formation in both cell lines (p<0.0001), especially in A549 cells. GGT was more effective when given before viral infection (p<0.0001). GGT could dose-dependently inhibit viral attachment (p<0.0001) with or without heparin. GGT could further inhibit HRSV internalization time-dependently and dose-dependently (p<0.0001). GGT could stimulate mucosal cells to secrete IFN-beta to counteract viral infection before and after viral inoculation. Conclusions: GGT is effective against HRSV-induced plaque formation in airway epithelium. (C) 2011 Published by Elsevier Ireland Ltd.