Platycodin D3 is a NF-κB inhibitor, it could as expectorants in diverse inflammatory pulmonary diseases, it can regulate the production and secretion of airway mucin; it can significantly enhance mitogen- and OVA-induced splenocyte proliferation in the OVA-immunized mice. Platycodin D3 also exerts anti-Hepatitis C virus (HCV) activity.

The aim of this study was to evaluate the functional effects of triterpenoid saponins contained in the root extract of Platycodon grandiflorum (PG) on viral enzyme activities and replication in both HCV replicon cells and cell culture grown HCV- (HCVcc-) infected cells. Inhibitory activities of triterpenoid saponins from PG were verified by NS5B RNA-dependent RNA polymerase assay and were further confirmed in the context of HCV replication. Six triterpenoid saponins (platycodin D, platycodin D2, Platycodin D3, deapioplatycodin D, deapioplatycodin D2, and platyconic acid A), PG saponin mixture (PGSM), were identified as active components exerting anti-HCV activity. Importantly, PGSM exerted synergistic anti-HCV activity in combination with either interferon- α± or NS5A inhibitors.