Antibacterial and NF-κB Inhibitory Lumazine Peptides, Aspochalasin, γ-Butyrolactone Derivatives, and Cyclic Peptides from a Hawaiian <i>Aspergillus flavipes</i>

Abstract

Five new lumazine peptides (<b>1</b>-<b>5</b>), a new aspochalasin derivative (<b>6</b>), and a new γ-butyrolactone derivative (<b>7</b>), together with seven known compounds (<b>8</b>-<b>14</b>), were isolated from a Hawaiian fungal strain, <i>Aspergillus flavipes</i> FS888. Compound <b>1</b> is an uncommon natural product containing an isocyano group. The structures of the new compounds <b>1</b>-<b>7</b> were elucidated by NMR spectroscopy, HRESIMS, chemical derivatization, and ECD analysis. Compounds <b>12</b>-<b>14</b> showed significant antibacterial activity against <i>S. aureus</i> when in combination with disulfiram. Additionally, compounds <b>9</b> and <b>13</b> showed NF-κB inhibitory activity with IC₅₀ values of 3.1 ± 1.0 and 10.3 ± 2.0 μM, respectively.