Secondary metabolites of the marine-derived Aspergillus jensenii LW128 and the antibacterial activity

Abstract:

[Objective] To study the secondary metabolites of the Aspergillus jensenii LW128 isolated from the deep-sea sediment of northwest Pacific and the antibacterial activity.[Methods] Based on silica gel column chromatography, Sephadex LH-20 column chromatography, and reversed-phase high-performance liquid chromatography (RP-HPLC), secondary metabolites were isolated from the crude extract of the fermentation broth of strain LW128 and purified. Their structures were elucidated on the basis of nuclear magnetic resonance (NMR) and mass spectrometry (MS) data, and by comparison with the data of literature. The antibacterial activity of secondary metabolites was evaluated by broth microdilution. [Results] Ten known compounds, diorcinol D (1), diorcinol K (2), diorcinol I (3), (+)-(7S)-7-O-methylsydonic acid (4), (+)-sydonic acid (5), pseudaboydin B (6), anthraquinone aversin (7), 6,8-di-O-methylnidurufin (8), 5-methoxysterigmatocystin (9), and sterigmatocystin (10), were isolated and identified. Compounds 1−3 showed inhibitory effect on the growth of several pathogens. [Conclusion] Aspergillus jensenii LW128 can be a potential resource for antibacterial drugs.