Beetleane A and Epicoane A: Two Carbon Skeletons Produced by Epicoccum nigrum

Two novel natural products, beetleane A (1) and epicoane A (2), were obtained from the metabolites of an endophytic Epicoccum nigrum. Compound 1 has a unique beetlelike structure that is constructed by the fusion and further fold of an unusual [5.5.5.6]trioxafenestrane with a cycloheptane ring. Compound 2 possesses a compact cagelike structure with a unique 6/5/5/5/6/6/5 heptacyclic ring system. Both 1 and 2 showed strong antiliver fibrosis activity in vitro.