Anti-MRSA and cytotoxic activity of a new diamide compound isolated from <i>Aspergillus</i> sp. H30

A new aromatic diamide compound, aspergillusin A (<b>1</b>), together with three known compounds, globosterol (<b>2</b>), ergosterol (<b>3</b>), and cladosporide A (<b>4</b>), was isolated from the crude extract of the endophytic fungi <i>Aspergillus</i> sp. H30. The structures were elucidated using NMR and MS data, finally, the biosynthetic pathway of compound <b>1</b> was hypothesised. Compounds <b>1</b>–<b>4</b> were tested for their antibacterial activities on six pathogenic bacteria and compound <b>1</b> was also evaluated against human non-small cell lung cancer H1299. Among them, compound <b>1</b> exhibited weak antibacterial activity against MRSA and a strong effect against the human bronchial epithelial cell line, BEAS-2B, with an IC₅₀ value of 12.32 ± 0.37 <i>μ</i>M.