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

Autor: Francisco Javier Ortiz-López, Elsa Alcalde, Aida Sarmiento-Vizcaíno, Caridad Díaz, Bastien Cautain, Luis A. García, Gloria Blanco, Fernando Reyes
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Marine Drugs, Vol 16, Iss 10, p 371 (2018)
Druh dokumentu: article
ISSN: 1660-3397
DOI: 10.3390/md16100371
Popis: 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 (1–3) containing different amino acid residues. The structures of the new molecules (1–3), 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 1–3 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.
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