Non canonical Cyclic Nucleotides Monophosphates in Aphanizomenon flosaquae: nuclear magnetic resonance and mass spectrometry

Aphanizomenon flos-aquae (AFA) cyanobacteria from Klamath Lake (Oregon) are considered a “superfood”, due to their complete nutritional profile that has proved to have health-enhancing properties. AFA metabolome is quite complex. Here, we present a study that, combining multinuclear 1H, 31P and 13C NMR spectroscopy and high-resolution mass spectrometry, allows the detection of rather unusual phosphorylated metabolites in AFA. In this study we focused our attention on AFA phosphorylated metabolites giving 31P NMR signals at 20 ppm, a chemical shift that pointed to phosphonates. They instead revealed to be nucleoside 2’,3’-cyclic monophosphates (cNMPs), that were characterized by multinuclear 1H, 31P and 13C NMR spectroscopy and high-resolution mass spectrometry. Our data are fully consistent with the proposed structures and hence demonstrate the presence of cNMPs in AFA, for the first time. The most studied of these biomolecules is cAMP that activates a protective mechanism in the case of brain tissue injury, whereas it inhibits mitophagy of damaged mitochondria in the kidney. The role of the other cNMPs there is much to be discovered.