Antibacterial Metabolites of Endophytic Aspergillus sp. HU0206 Isolated from Spinifex littoreus

Abstract:

In order to explore the antibacterial metabolites of endophytic Aspergillus sp. HU0206, seven compounds were obtained from the corn fermentation of endophytic Aspergillus sp. HU0206 isolated from Spinifex littoreus using chromatographic separation method. On the basis of spectral data, they were identified as six methylphenol derivatives, such as sydowiol F (1), 5-methoxy-3,5'-dimethyl-2,3'-oxybiphenyl-1,1',2'-triol (2), corynesidone A (3), pyrolin (4), 3-hydroxylpyrolin (5), 4-ethoxy-3-hydroxymethylphenol (6), and a methylcy-clohexanone, epoxydine A (7). Compound 1 was a new compound. At the dose of 40 μg, compounds 1, 2 and 4 showed obvious antibacterial effects on Staphylococcus aureus, methicillin-resistant S. aureus, Pectobacterium atroseptica, and Ralstonia solanacearum with radius of inhibition zone ≥ 2 mm, and minimum inhibitory concentrations (MICs) was 50 or 100 μg/mL. The radius of inhibition zone of compound 3 was 1-2 mm for above bacteria with MIC higher than 400 μg/mL. However, all compounds did not inhibit the growth of Escherichia coli.

Key words:Endophytic Aspergillus;Metabolite;Methylphenol;Methylcyclohexanone;Antibacterial activity