Truncatones A-D, benzo[j]fluoranthenes from Annulohypoxylon species (Xylariaceae, Ascomycota)

From stromata (fruiting bodies) of three xylariaceous fungi belonging to the genus Annulohypoxylon (A. leptascum, A. cE truncatum and an unidentified Annulohypoxylon sp.), truncatone A (1), three unprecedented derivatives named truncatones B-D (2-4) besides the known 4,5,4',5'-tetrahydroxy-1,1'-binaphthyl (BNT, 5), hypoxylonol C (6) and hypoxylonol F (7) were isolated. Planar structures of the new benzo[j]fluoranthene derivatives 2-4 were determined on the basis of NMR and HRESIMS data. While the relative configuration of 4 was demonstrated by ROESY NMR data and H-1,H-1 coupling constants, absolute configurations of 1, 2, 4 were determined by CD spectroscopy. Compounds 1, 3 and 4 exhibited cytotoxicity against the mouse fibroblast cell line L929. (C) 2016 Elsevier Ltd. All rights reserved.