Structural and biological properties of vermistatin and two new vermistatin derivatives isolated from the marine-mangrove endophytic fungus Guignardia sp No. 4382

Vermistatin (=(3R)-4,6-dimethoxy-3-{4-oxo-6-[(1E)-prop-1-en-1-yl]-4H-pyran-3-yl}-2-benzofuran-1(3H)-one; 1) and two new vermistatin derivatives, compounds 2 and 3, were isolated from the fungal strain Guignardia sp. No. 4382 obtained from the South-China Sea. Their structures were elucidated by various methods, including circular dichroism (CD), 1D- and 2D-NMR, and HR-EI-MS. The structures of 1 and 2 were unequivocally corroborated by X-ray crystallography, and their absolute configurations were derived by CD spectroscopy based on a literature comparison. The in vitro cytotoxic and antifungal activities of 1 and 2 were tested.