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

A new aromatic diamide compound, aspergillusin A (1), together with three known compounds, globosterol (2), ergosterol (3), and cladosporide A (4), was isolated from the crude extract of the endophytic fungi Aspergillus sp. H30. The structures were elucidated using NMR and MS data, finally, the biosynthetic pathway of compound 1 was hypothesised. Compounds 1-4 were tested for their antibacterial activities on six pathogenic bacteria and compound 1 was also evaluated against human non-small cell lung cancer H1299. Among them, compound 1 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 μM.