Flavonoids from Matteuccia struthiopteris and Their Anti-influenza Virus (H1N1) Activity

Seven new flavonoid glycosides (<b>1</b>–<b>7</b>), matteflavosides A–G, together with 12 known flavonoids (<b>8</b>–<b>19</b>) were isolated from the rhizomes of Matteuccia struthiopteris (L.) Todar. Their structures were established via the analyses of extensive spectroscopic data. All compounds were evaluated for their anti-influenza virus (H1N1) activity using the neuraminidase inhibition assay. The results showed that compound <b>7</b> exhibited significant inhibitory activity against the H1N1 influenza virus neuraminidase with an EC₅₀ value of 6.8 ± 1.1 μM and an SI value of 34.4, and compounds <b>8</b> and <b>17</b> showed moderate inhibitory activity