Vibralactone derivatives containing γ, δ, ε-lactone cores from cultures of the basidiomycete Boreostereum vibrans

Five vibralactone derivatives containing gamma, delta, epsilon-lactone cores, namely vibralactones X (1), Y (2), and Z(1)-Z(3) (3-5), together with the known vibralactone, have been isolated from cultures of the basidiomycete Boreosterewn vi-brans. Compounds 3-5 possessed a novel bis-gamma-lactone group which was found in vibralactone derivatives for the first time. Compounds 3 and 5 exhibited moderate cytotoxicities to human cancer cell lines referring to that of cisplatin.