Antimicrobial Activity of Depsidones and Macrocyclic Peptides Isolated from Marine Sponge‐Derived Fungus Aspergillus nidulans M256

Abstract

Chemical study on marine sponge‐derivated fungus Aspergillus nidulans resulted in the isolation of seven depsidones (1–7) and two macrocyclic peptides (8 and 9). Their chemical structures were elucidated by extensive analyses of HRESIMS and NMR spectral data, as well as comparison with the literature. Compound 1 was an undescribed depsidone. All compounds exhibited significant antimicrobial activity (MICs: 2–128 µg/mL) towards at least one of seven microbial strains, including Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, and Candida albicans. Of these, chlorinated depsidones (1–3, and 5) displayed potential antimicrobial activity. Nidulin (2) possessed good activity against tested strains except for S. enterica with MIC values in range of 2–16 µg/mL. Interestingly, undescribed depsidone 1 was selectively bioactive on the Gram‐positive bacteria (MICs: 2‐4 µg/mL) and yeast (MIC: 8 µg/mL) but inactivity on the Gram‐negative bacteria (MICs: >256 µg/mL). Macrocyclic peptides, 8 and 9, displayed modest activity against E. faecalis strain with MIC values of 32 and 128 µg/mL, respectively.

Curdepsidone A Induces Intrinsic Apoptosis and Inhibits Protective Autophagy via the ROS/PI3K/AKT Signaling Pathway in HeLa Cells

“…Depsidones are a class of polyphenolic polyketides formed via the oxidative coupling of esters of two polyketide benzoic acid derivatives [11]. They exhibit a variety of bioactivities such as cytotoxic [12,13], anti-inflammatory [14,15], antimicrobial [13,16,17], antimalarial [18], antioxidant [19], and antidiabetic [20] activities. Curdepsidones A-G, derivatives of depsidone, were first isolated from the secondary metabolites of a marine white croakerassociated fungus Curvularia sp.…”