Diterpene Glycosides and Polyketides from Xylotumulus gibbisporus

Four new tetracyclic diterpene glycosides, namely, sordarins C–F (1–4), and three new γ-lactone polyketides, namely, xylogiblactones A–C (5–7), along with sordarin were isolated from the ethyl acetate extracts of the fermented broths of Xylotumulus gibbisporus YMJ863. The structures of 1–7 were elucidated on the basis of spectroscopic data analyses. The configurations of 1–4 were deduced by NOESY, molecular modeling, and comparison with the literature. The relative configurations of 5–7 were deduced by X-ray crystallographic analysis of 5. Compounds 1–5 and sordarin were evaluated in an antifungal assay using Candida albicans ATCC 18804, C. albicans ATCC MYA-2876, and Saccharomyces cerevisiae ATCC 2345, and only sordarin exhibited significant antifungal activities against these fungal strains, with MIC values of 64.0, 32.0, and 32.0 μg/mL, respectively. The effect of compounds 1–7 and sordarin on the inhibition of NO production in lipopolysaccharide-activated murine macrophages was also evaluated. Compounds 2 and sordarin inhibited NO production with IC50 values of 327.2 ± 46.6 and 157.1 ± 24.1 μM, respectively.