Five new drimane-type sesquiterpenoids were isolated from cultures of the tropical basidiomycetes, Perenniporia centrali-africana (originating from Kenya) and Cerrena sp. nov. (originating from Thailand). A new pereniporin A derivative (1), a new drimane-type sesquiterpene lactam (2), and the new 6,7-Dehydro-isodrimenediol (3) were isolated from P. centrali-africana. In parallel, the two new drimane-type sesquiterpene lactams 5 and 6 were isolated together with known isodrimenediol (4) from Cerrena sp. This is the first report of drimane-type sesquiterpene lactams from basidiomycetes. The structures were elucidated based on 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data, in combination with high-resolution electrospray mass spectrometric (HR-ESIMS) data. The compounds were devoid of significant antimicrobial and cytotoxic activities.
Marasmodrimanes A–R (1–18), eighteen previously undescribed drimane and 15-nordrimane sesquiterpenoids with diverse structures were isolated from cultures of basidiomycete Marasmius guyanensis TBRC-BCC 78466. Marasmodrimanes A (1) and B (2a/2b/2c) are highly oxygenated drimanes with a lactone bridge. Their structures were elucidated on the basis of spectroscopic analyses, X-ray crystallography, and a chemical correlation experiment. Marasmodrimanes F–J (6–10) are nitrogen atom-containing derivatives, while marasmodrimanes H–R (8–18) are B-ring aromatic 15-nor-drimanes.
Seven previously undescribed highly oxygenated lanostanes, ganoboninones J–P (1–7), were isolated from MeOH extract of cultivated fruiting bodies of Ganoderma cf. hochiminhense (strain TBRC-BCC 22084). Five known lanostanes (8–12) and a meroterpenoid, ganomycin I (13), were also isolated. Ganoboninoes J–M (1–4) are highly rearranged 27-nor-lanostanes possessing an unknown cyclopropane-fused carbon skeleton. Among these, ganomycin I (13) showed antioxidant activity in the DPPH radical scavenging assay with an IC value of 33.8 M (11.6 mg/mL), therefore, it was identified as a key antioxidant constituent of the mushroom MeOH extract (IC50 64.5 mg/mL). Ganoboninones K (2) and P (7) exhibited antitubercular activity against Mycobacterium tuberculosis H37Ra (MIC 25 mg/mL). On the other hand, ganoboninone N (5) and ganomycin I showed selective cytotoxicity to NCI-H187 cells (IC50 13.6 and 5.72 mM, respectively)