Citrinal B, a new secondary metabolite from endophytic fungus Colletotrichum capsici and structure revision of citrinal A

Citrinal B (2), a new tricyclic compound with a tetrahydro-2H-benzofuro[7-b][1,4]dioxin-9(3H)-one skeleton, together with one known analogue, citrinal A (1), were isolated from the EtOAc extract of the culture of Colletotrichum capsici. Moreover, structure of citrinal A was revised according to the spectroscopic data and single crystal X-ray diffraction analysis with Cu K alpha irradiation. Citrinals A and B (1 and 2) represent a new compound class with a unique skeleton. Both compounds were evaluated for their cytotoxic activities against five human cancer cell lines. (C) 2016 Elsevier Ltd. All rights reserved.