New naphthoquinone derivatives from <i>Fusarium napiforme</i> of a mangrove plant

Abstract

Two new naphthoquinone derivatives, 6-hydroxy-astropaquinone B (<b>1</b>) and astropaquinone D (<b>2</b>) as well as the known compound 3-<i>O</i>-methyl-9-<i>O</i>-methylfusarubin (<b>3</b>) were isolated from <i>Fusarium napiforme</i>, an endophytic fungus isolated from the mangrove plant, <i>Rhizophora mucronata</i>. The structures of <b>1</b> and <b>2</b> were determined by 1D and 2D NMR spectroscopic analyses. Compounds <b>1</b>, <b>2</b> and <b>3</b> exhibited moderate antibacterial activity against <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i>. Furthermore, <b>1</b>, <b>2</b> and <b>3</b> were phytotoxic action in lettuce seeding at a concentration of 30 μg · mL^-1.