Pestalotiolide A, a New Antiviral Phthalide Derivative from a Soft Coral-derived FungusPestalotiopsissp.

Chemical investigation of the fermentation broth of a Soft Coral-Derived fungus Pestalotiopsis sp., led to the isolation of a new phthalide derivative, pestalotiolide A (1), three known analogues (2, 3 and 4), along with 5'-O-acetyl uridine (5) first isolated as a natural product. The structure of the new compound (1) was established by comprehensive spectroscopic analysis and chemical methods. Compounds 1 - 4 possessed varying degrees of antiviral activities, which was reported for the first time. Compared to the positive control ribavirin (IC50 = 418.0 µM), pestalotiolide A (1) exhibited significant anti-EV71 activity in vitro, with an IC50 value of 27.7µ M. Furthermore, the preliminary structure-activity relationship of antiviral activities was also discussed.