1H and 13C NMR assignments of three nitrogen containing compounds from the mangrove endophytic fungus (ZZF08)

Anew natural product, named phomopsin A, 1-(meta-hydroxyphenyl)-4-hydroxy-3-isoquinolone (1), together with two known compounds cytochalasin H (2) and glucosylceramide (3), was isolated from the mangrove endophytic fungus Phomopsis sp. (ZZF08) obtained from the South China Sea coast. The structures were elucidated by 1D and 2D NMR experiments including COSY, HMQC, and HMBC. According to NMR and single-crystal X-ray diffraction, it was found that some assignments about H-1 and C-13 NMR data for cytochalasin H (2) were probably uncorrected in the previous reports. In our cytotoxicity assays, compound 1 showed moderate cytotoxicity toward KB cells with IC50 at 28.0 mu g ml(-1) and KBv200 cells with IC50 at 16.8 mu g ml(-1), and compound 2 exhibited strong cytotoxicity toward KB cells and KBv200 cells with IC50 less than 1.25 mu g ml(-1). Copyright (C) 2008 John Wiley & Sons, Ltd.