Thioester-Containing Benzoate Derivatives with α-Glucosidase Inhibitory Activity from the Deep-Sea-Derived Fungus Talaromyces indigoticus FS688.

Eurothiocins C-H ( 1 - 6 ), six unusual thioester-containing benzoate derivatives, were isolated from the deep-sea-derived fungus Talaromyces indigoticus FS688 together with a known analogue eurothiocin A ( 7 ). Their structures were elucidated through spectroscopic analysis and the absolute configurations were determined by X-ray diffraction and ECD calculations. In addition, compound 1 exhibited significant inhibitory activity against α-glucosidase with an IC 50 value of 5.4 μM, while compounds 4 and 5 showed moderate effects with IC 50 values of 33.6 and 72.1 μM, respectively. A preliminary structure-activity relationship is discussed and a docking analysis was performed.