Antitubercular Activity of Mycelium-Associated GanodermaLanostanoids

In a continuation of our research into antitubercular lanostane triterpenoids from submerged cultures of Ganodermaspecies, three strains, Ganoderma orbiformeBCC 22325, Ganodermasp. BCC 60695, and Ganoderma australeBCC 22314, have been investigated. Fourteen new lanostane triterpenoids, together with 35 known compounds, were isolated. Antitubercular activities of these mycelium-associated Ganodermalanostanoids against Mycobacterium tuberculosisH37Ra were evaluated. Taken together with the assay data of previously isolated compounds, structure–activity relationships of the antitubercular activity are proposed. Most importantly, 3β- and 15α-acetoxy groups were shown to be critical for antimycobacterial activity. The most potent compound was (24E)-3β,15α-diacetoxylanosta-7,9(11),24-trien-26-oic acid (35).