Isochromanones and Isobenzofuranone from Arctic Fungus Gyoerffyella sp. CPCC 401434

A new isochromanone, (3R,4R)-3,6,8-trihydroxy-3,4,5-trimethylisochroman-1-one (1), together with six known isochromanones (2-7) and one known isobenzofuranone (8), were obtained from the Arctic fungus <i>Gyoerffyella</i> sp. CPCC 401434. The chemical structures were determined on the basis of extensive NMR and MS data analyses. All the compounds were first reported from the genus <i>Gyoerffyella</i>. Compounds 6 and 7 showed significant cytotoxic activities. Compounds 2, 3, 5, 8, 9, and 11 displayed significant anti-IAV (H1N1) activities, similar to that of ribavirin.