Novel beta-methoxyacrylates of the 9-methoxystrobilurin and oudesmansin classes produced by the basidiomycete Favolaschia pustulosa.

Submerged liquid cultures of the basidiomycete Favolaschia pustulosa (Xenova culture collection no. X27732) afforded the novel 9-methoxystrobilurin derivatives, 9-methoxystrobilurin L (1) and 9-methoxystrobilurin E (2), and the related oudemansin derivative, oudemansin L (3). Their structures were established by 2D NMR experiments. Compounds 1 and 3 possess a novel arrangement of two isoprenoid units fused to the aromatic nucleus. Both 1 and 2 have the EEE-configuration in the pentadienyl side chain as reported previously for 9-methoxystrobilurins. Compound 1 was cytotoxic to cells of the human B lymphoblastoid cell line (Jijoye), with an IC50 of 1.8 nM. This cytotoxicity was observed in a 5- day assay only and was not apparent after 2 days. Compound 1 showed some antibacterial activity against Bacillus subtilis (MIC = 0.9 microM) and antifungal activity against Candida albicans (MIC = 6 microM).