Ganoweberianones A and B, Antimalarial Lanostane Dimers from Cultivated Fruiting Bodies of the Basidiomycete Ganoderma weberianum.

Two lanostane dimers, ganoweberianones A (1) and B (2), together with seven previously undescribed lanostanes, ganoweberianic acids A-G (3-9), and three known compounds (10-12), were isolated from the artificially cultivated fruiting bodies of the basidiomycete Ganoderma weberianum. Ganoweberianone A (1) exhibited significant antimalarial activity against Plasmodium falciparum K1 (multidrug-resistant strain) with an IC50 value of 0.050 μM. A method for semisynthesis of 1 by condensation of the corresponding lanostane monomers and acid-catalyzed intramolecular transesterification was demonstrated.