Asperlones A and B, Dinaphthalenone Derivatives from a Mangrove Endophytic Fungus Aspergillus sp. 16-5C

Racemic dinaphthalenone derivatives, (±)-asperlone A (1) and (±)-asperlone B (2), and two new azaphilones, 6′-hydroxy-(R)-mitorubrinic acid (3) and purpurquinone D (4), along with four known compounds, (−)-mitorubrinic acid (5), (−)-mitorubrin (6), purpurquinone A (7) and orsellinic acid (8), were isolated from the cultures of Aspergillus sp. 16-5C. The structures were elucidated using comprehensive spectroscopic methods, including 1D and 2D NMR spectra and the structures of 1 further confirmed by single-crystal X-ray diffraction analysis, while the absolute configuration of 3 and 4 were determined by comparing their optical rotation and CD with those of the literature, respectively. Compounds 1, 2 and 6 exhibited potent inhibitory effects against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with IC50 values of 4.24 ± 0.41, 4.32 ± 0.60 and 3.99 ± 0.34 μM, respectively

Xylanthraquinone, a new anthraquinone from the fungus <i>Xylaria</i> sp. 2508 from the South China Sea

<div><p>Xylanthraquinone (<b>1</b>), a new anthraquinone, along with three known compounds, altersolanol A (<b>2</b>), deoxybostrycin (<b>3</b>) and bostrycin (<b>4</b>) was isolated from the fungus <i>Xylaria</i> sp. 2508 from the South China Sea. The structures of these compounds were identified by NMR experiments, and the absolute configuration of compound <b>1</b> was further confirmed by single-crystal X-ray diffraction with Cu Kα radiation. Compounds <b>1</b>–<b>4</b> did not show inhibitory activities against Mycobacterium tuberculosis protein tyrosine phosphatase B (IC₅₀ values more than 100 μM).</p></div