Dechdigliotoxins A–C, Three Novel Disulfide-Bridged Gliotoxin Dimers from Deep-Sea Sediment Derived Fungus Dichotomomyces cejpii

Dechdigliotoxins A–C (1–3), which represented the first examples of gliotoxin dimers with an unprecedented exocyclic disulfide linkage, were obtained from a deep-sea derived fungus Dichotomomyces cejpii FS110. The structures of these compounds were elucidated on the basis of spectroscopic analysis and the absolute configurations were unambiguously determined through quantum chemical calculations, as well as DP4+ probability simulations. The proposed biosynthetic pathway suggested 1–3 were generated from unusual L-Phe and D-Ser. All the isolates were evaluated for their cytotoxicity against four tumor cell lines.