Anthraquinone analogues with inhibitory activities against influenza a virus from Polygonatum odoratum

Three anthraquinone analogues (1–3) were isolated by phytochemical work on EtOAc-soluble ingredients extracted from the roots of Polygonatum odoratum. The structures of all isolates were elucidated by NMR, MS and CD experiments, of which 1 (polygodoquinone A) was identified as a new anthraquinone derivative. Specifically, 1 represents an unusual structure composed of a naphthoquinone derivative linked to an anthraquinone via a C-C bond. 1–3 exhibited remarkable influenza A virus inhibitory activity with IC50 values of 11.4, 11.0, and 2.3 μM, respectively, which were better than ribavirin as the positive control.