A new cytotoxic indole-3-ethenamide from the halotolerant fungus Aspergillus sclerotiorum PT06-1

A new cytotoxic indole-3-ethenamide (1) and two known compounds, 7-(3-methylbut-2-enyl)-1H-indole-3-carbaldehyde (2) and emodin (3) were isolated and identified from the ethyl acetate extract of Aspergillus sclerotiorum PT06-1 in a hypersaline nutrient-rich medium. On the basis of spectroscopic analysis and amino-acid analysis, the new structure of 1 was determined to be (S,E)-3-methyl-2-(N- methylacetamido)-N-(2-(7-(3-methylbut-2-enyl)-1H-indol-3-yl)vinyl)butanamide within 3:1 ratio of rotamers along the acetamido single bond in DMSO-d(6) at room temperature. Compound 1 showed moderate cytotoxicity against A-549 cells and weak cytotoxicity against HL-60 cells with the IC(50) values of 3.0 and 27?μM, respectively. Compound 2 has been separated as natural product for the first time, and its NMR data were also reported for the first time in this study.