New 3-Hydroxyquinaldic Acid Derivatives from Cultures of the Marine Derived Actinomycete Streptomyces cyaneofuscatus M-157

Mar Drugs. 2018 Oct 8;16(10):371. doi: 10.3390/md16100371.


Fractionation of the bioactive extract of a culture of the marine derived actinomycete Streptomyces cyaneofuscatus M-157 led to the isolation of the known 3-hydroxyquinaldic acid (4), its amide (5) and three new derivatives (13) containing different amino acid residues. The structures of the new molecules (13), including their absolute configuration, were determined by the analysis of their ESI-TOF MS and one-dimensional (1D) and two-dimensional (2D) NMR spectra and advanced Marfey's analysis of their hydrolyzation products. Compound 3 spontaneously dimerized in solution to give the disulfide derivative 6. Unfortunately, none of the new compounds isolated confirmed the antimicrobial activity found in the bacterial extract, perhaps indicating that such antibacterial activity might be due to presence in the extract at the trace level of larger bioactive 3-hydroxyquinaldic acid derivatives from which compounds 13 are biosynthetic precursors. Cytotoxicity tests confirmed the moderate and weak IC50 values of 15.6 and 51.5 µM for compounds 5 and 1, respectively.

Keywords: 3-hydroxyquinaldic acid; Cantabrian Sea; Streptomyces cyaneofuscatus; deep-sea actinobacteria.

MeSH terms

  • Actinobacteria / chemistry*
  • Anti-Bacterial Agents / chemistry*
  • Aquatic Organisms / chemistry*
  • Kynurenic Acid / analogs & derivatives*
  • Kynurenic Acid / chemistry
  • Magnetic Resonance Spectroscopy / methods
  • Microbial Sensitivity Tests / methods
  • Streptomyces / chemistry*


  • 3-hydroxyquinaldic acid
  • Anti-Bacterial Agents
  • Kynurenic Acid