Assignment of Absolute Configurations of Two Promising Anti-<i>Helicobacter pylori</i> Agents from the Marine Sponge-Derived Fungus <i>Aspergillus niger</i> L14

Abstract

A chemical investigation into endozoic fungus Aspergillus niger L14 derived from the marine sponge of Reniera japonica collected off Xinghai Bay (China) resulted in the isolation of two dimeric naphtho-γ-pyrones, fonsecinone A (1) and isoaurasperone A (2). Through a combination of ECD spectra and X-ray diffraction analysis, the chiral axes of compounds 1 and 2 were unambiguously determined as Rα-configurations. Bioassay results indicated that these substances exhibited remarkably inhibitory effects on human pathogens Helicobacter pylori G27 and 159 with MIC values of ≤4 μg/mL, which are similar to those of the positive control, ampicillin sodium. To the best of our knowledge, this is the first report on absolute configuration of 1 and crystallographic data of 2, as well as their potent anti-H. pylori activities.

Keywords

• <i>Aspergillus niger</i>
• endozoic fungus
• fonsecinone A
• aurasperone A
• anti <i>Helicobacter pylori</i>
• chiral axis