New Benzofuranoids and Phenylpropanoids from the Mangrove Endophytic Fungus, Aspergillus sp. ZJ-68

Abstract

Three new benzofuranoids, asperfuranoids A-C (<b>1</b>-<b>3</b>), two new phenylpropanoid derivatives (<b>6</b> and <b>7</b>), and nine known analogues (<b>4</b>, <b>5</b>, and <b>8</b>-<b>14</b>) were isolated from the liquid substrate fermentation cultures of the mangrove endopytic fungus <i>Aspergillus</i> sp. ZJ-68. The structures of the new compounds were determined by extensive spectroscopic data interpretation. The absolute configurations of <b>1</b>-<b>3</b> were assigned via the combination of Mosher's method, and experimental and calculated electronic circular dichroism (ECD) data. Compounds <b>4</b> and <b>5</b> were a pair of enantiomers and their absolute configurations were established for the first time on the basis of their ECD spectra aided with ECD calculations. All isolated compounds (<b>1</b>-<b>14</b>) were evaluated for their enzyme inhibitory activity against <i>α</i>-glucosidase and antibacterial activities against four pathogenic bacteria (<i>Staphylococcus aureus</i>, <i>Escherichia coli</i>, <i>Bacillus subtilis</i>, and <i>Pseudomonas aeruginosa</i>). Among them, compound <b>6</b> exhibited potent inhibitory activity against <i>α</i>-glucosidase in a standard in vitro assay, with an IC₅₀ value of 12.4 μM, while compounds <b>8</b> and <b>11</b> showed activities against <i>S. aureus</i>, <i>E. coli</i>, and <i>B. subtilis</i>, with MIC values in the range of 4.15 to 12.5 μg/mL.