Vibralactone Z₄, the first chain-like vibralactone derivative from cultures of the basidiomycete <i>Boreostereum vibrans</i>

The first chain-Like vibralactone derivative, vibralactone Z4 (1), together with three known ones (2–4), were isolated from cultures of the basidiomycete Boreostereum vibrans. Vibralactone Z4 (1) is likely to be a key intermediate from 3 to 4 in their biosynthetic pathway. It showed a weak cytotoxicity to human cancer cell line SW480 (IC50 29.2 ± 1.38 μM).