New dimeric and monomeric chromanones, gonytolides D–G, isolated from the fungus Gonytrichum sp.

In the course of the screening of innate immune regulators from natural resources, we isolated new dimeric and monomeric chromanones, gonytolides D–G (4–7), from Gonytrichum sp. along with a known innate immune promoter, gonytolide A (1). The structures of these compounds were determined by spectral analysis, chemical conversion, and biogenetic consideration. The compounds 4–7 were evaluated on the innate immune response, indicating that the 8,8′-linked bischromanone rings were crucial for innate immune-promoting activity.