Seven New Drimane-Type Sesquiterpenoids from a Marine-Derived Fungus Paraconiothyrium sporulosum YK-03

Seven new drimane-type sesquiterpenoids, namely the sporulositols A–D (1–4), 6-hydroxydiaporol (5), seco-sporulositol (6) and sporuloside (7) were isolated from the ethyl acetate extract of fermentation broth for a marine-derived fungus Paraconiothyrium sporulosum YK-03. Their structures were elucidated by analysis of extensive spectroscopic data, and the absolute configurations were established by crystal X-ray diffraction analysis and comparisons of circular dichroism data. Among them, sporulositols A–E (1–4) and seco-sporulositol (6) represent the first five examples of a unique class of drimanic mannitol derivatives, while compounds 6 and 7 may represent two new series of natural drimanes, possessing an aromatic ring with a rare 4,5-secodrimanic skeleton and an unusual CH(3)-15 rearranged drimanic α-D-glucopyranside, respectively. Furthermore, the origin of mannitol moiety was investigated by reliable HPLC and NMR analyses.