Sheng-Ma-Ge-Gen-Tang (Shoma-kakkon-to) inhibited cytopathic effect of human respiratory syncytial virus in cell lines of human respiratory tract

Ethnopharmacological relevanceSheng-Ma-Ge-Gen-Tang (SMGGT; Shoma-kakkon-to) has been used against pediatric viral infection for thousands of year in ancient China. However, it is unknown whether SMGGT is effective against human respiratory syncytial virus (HRSV).Aim of the studyHRSV is a major pediatric viral pathogen of low respiratory tract infection without effective management. This study tested the hypothesis that SMGGT effectively inhibited cytopathy induced by HRSV.Materials and methodsEffect of the crude extract of SMGGT on HRSV was tested by plaque reduction assay in both human upper (HEp-2) and low (A549) respiratory tract cell lines. Ability of SMGGT to stimulate anti-viral cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA).ResultsCrude extract of SMGGT dose-dependently inhibited HRSV-induced plaque formation. The crude extract was more effective when given before viral infection (p < 0.0001). It inhibited viral attachment dose-dependently (p < 0.0001) and could increase heparin effect on viral attachment. Furthermore, it was synergistic with very low-dose heparin on viral attachment. In addition, the crude extract time-dependently and dose-dependently (p < 0.0001) inhibited HRSV internalization into HEp-2 cells. Epithelial cells secrete IFN-β and TNF-α to counteract viral infection. The crude extract could stimulate epithelial cells to secrete these cytokines beforehand and become resistant to viral infection. It also stimulated IFN-β to defense HRSV after viral inoculation.ConclusionsSheng-Ma-Ge-Gen-Tang could be effective to manage HRSV infection in young children.