Pyramidamycins A-D and 3-hydroxyquinoline-2-carboxamide; Cytotoxic benzamides from Streptomyces sp. DGC1

Khaled A. Shaaban, Micah D. Shepherd, Tamer A. Ahmed, S. Eric Nybo, Markos Leggas, Jürgen Rohr

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Four new benzamides, pyramidamycins A-D (2-5) along with the new natural 3-hydroxyquinoline-2-carboxamide (6) were isolated from the crude extract of Streptomyces sp. DGC1. Additionally, five other known compounds, namely 2-aminobenzamide (anthranilamide) (1), 4′,7-dihydroxyisoflavanone (7), 2′-deoxy-thymidine, 2′-deoxy-uridine and adenosine were also isolated and identified. The structures of the new compounds 2-6 were elucidated by 1D and 2D NMR studies along with HR MS analyses. The isolated compounds 1-6 contained the same amide side chain. The isolated compounds 1-7 were biologically evaluated in comparison with landomycin A against a prostate cancer cell line (PC3) and non-small cell lung cancer cell line (H460) for 48 h and against several bacterial strains. Pyramidamycin C (4) was the most active compound against both PC3 and H460 cell lines (GI 50 =2.473 and 7.339 μM, respectively). Benzamides (1-3) demonstrated inhibitory activity against Kocuria rosea B-1106 (a diameter halo of 13±2 mm for 1; 10±2 mm for 2 and 3). Compound 6 was slightly active against both Escherichia coli DH5 and Micrococcus luteus NRRL B-2618 (diameter halos 8±2 and 9±2 mm, respectively). Taxonomically, the amplified 500-bp 16 S rRNA fragment of the Streptomyces sp. DGC1 had 99% identity (BLAST search) to the 16S rRNA gene of Streptomyces atrovirens strain NRRL B-16357.

Original languageEnglish
Pages (from-to)615-622
Number of pages8
JournalJournal of Antibiotics
Issue number12
StatePublished - Dec 2012

Bibliographical note

Funding Information:
We thank Dr Jack Goodman (University of Kentucky) for the ESI MS measurements. We thank the Mass Spectrometry Facility, University of Wisconsin Biotechnology Center for the HR MS data. This work was supported by grants CA102102 and CA 091901 from the US National Institutes of Health to JR.


  • antibacterial
  • anticancer agents
  • benzamides
  • cytotoxicity
  • streptomycetes
  • taxonomy

ASJC Scopus subject areas

  • Pharmacology
  • Drug Discovery


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