Antibacterial anthraquinone derivatives isolated from a mangrove-derived endophytic fungus Aspergillus nidulans by ethanol stress strategy.

Three new natural products, including a new anthraquinone derivative isoversicolorin C (1), a new xanthone analog isosecosterigmatocystin (2), and a new amino acid derivative, glulisine A (3), along with six related metabolites (4-9) were isolated from the culture broth and mycelia extracts of the mangrove-derived endophytic fungus Aspergillus nidulans MA-143 under 0.1% ethanol stress. Their structures were elucidated by detailed analysis of their NMR spectra, ECD spectrum, and X-ray crystallographic experiments. Compounds 1 and 4 showed potent antibacterial activity against some of the tested microbes.