Namalides B and C and Spumigins K-N from the Cultured Freshwater Cyanobacterium Sphaerospermopsis torques-reginae

J Nat Prod. 2017 Sep 22;80(9):2492-2501. doi: 10.1021/acs.jnatprod.7b00370. Epub 2017 Sep 6.

Abstract

Chemical investigations of the terrestrial cyanobacterium Sphaerospermopsis torques-reginae ITEP-024 from northern Brazil afforded namalides B (1) and C (2), the first analogues of this anabaenopeptide-like metabolite to be described. Four other related peptides (3-6), termed spumigins K-N, were also identified. Planar structures and absolute configurations for 1, 2, and 3a-6a were deduced by a combination of 2D NMR, HRMS analysis, and Marfey's methodology. Spumigins K-N (3-6) are the first examples of spumigins containing a 2-hydroxy-4-(4-hydroxyphenyl)butanoic acid (Hhpba) in the N-terminal position. Compounds 1 and 2 inhibited carboxypeptidase A with IC50 values of 0.75 and 2.0 μM, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brazil
  • Butyric Acid / chemistry
  • Butyric Acid / pharmacology*
  • Cyanobacteria / chemistry*
  • Fresh Water / microbiology*
  • Inhibitory Concentration 50
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptides, Cyclic / chemistry
  • Peptides, Cyclic / pharmacology*
  • Torque

Substances

  • 2-hydroxy-4-(4-hydroxyphenyl)butanoic acid
  • Peptides, Cyclic
  • namalide
  • namalide B
  • namalide C
  • Butyric Acid