1H and 13C NMR assignments for five anthraquinones from the mangrove endophytic fungus Halorosellinia sp (No. 1403)

We report the unambiguous assignments of the H-1 and C-13 NMR spectra of two new natural products, namely, 1,4,5,6,7,9-hexahydroxy-2-methoxy-7-methyl-5 beta,9 beta,8a beta, 6 alpha,10a alpha-hexahydroanthracen-10 (10aH)-one (1) and 1,4,6-trihydroxy-2-methoxy-7-methylanthracene-9, 10-dione (2), together with three known anthraquinones. These compounds were all isolated from the marine endophytic fungus No. 1403 collected from the South China Sea. Compounds 3 and 4 were isolated from the marine fungus for the first time. The structures were elucidated by the spectroscopic methods 1D and 2D NMR including COSY, HMQC, HMBC and NOE, and HREIMS. In our cytotoxicity assays, compound 5 showed cytotoxicity toward KB and KBv-200 cells with IC50 of 1.40 and 2.58 mu g/ml, respectively. In addition, the plausible biogenic relationship of compounds 1, 2, 3 and 4 is discussed. Copyright (c) 2007 John Wiley & Sons, Ltd.