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. (C) 2012 Elsevier Ltd. All rights reserved.