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>