Bifurcatriol, a New Antiprotozoal Acyclic Diterpene from the Brown Alga Bifurcaria bifurcata

Mar Drugs. 2017 Aug 2;15(8):245. doi: 10.3390/md15080245.

Abstract

Linear diterpenes that are commonly found in brown algae are of high chemotaxonomic and ecological importance. This study reports bifurcatriol (1), a new linear diterpene featuring two stereogenic centers isolated from the Irish brown alga Bifurcariabifurcata. The gross structure of this new natural product was elucidated based on its spectroscopic data (IR, 1D and 2D-NMR, HRMS). Its absolute configuration was identified by experimental and computational vibrational circular dichroism (VCD) spectroscopy, combined with the calculation of 13C-NMR chemical shielding constants. Bifurcatriol (1) was tested for in vitro antiprotozoal activity towards a small panel of parasites (Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, and Leishmania donovani) and cytotoxicity against mammalian primary cells. The highest activity was exerted against the malaria parasite P. falciparum (IC50 value 0.65 μg/mL) with low cytotoxicity (IC50 value 56.6 μg/mL). To our knowledge, this is the first successful application of VCD and DP4 probability analysis of the calculated 13C-NMR chemical shifts for the simultaneous assignment of the absolute configuration of multiple stereogenic centers in a long-chain acyclic natural product.

Keywords: Bifurcaria bifurcata; VCD; absolute configuration; antiprotozoal; diterpene; marine alga.

MeSH terms

  • Animals
  • Antimalarials / chemistry
  • Antimalarials / isolation & purification*
  • Antimalarials / pharmacology*
  • Antiprotozoal Agents / chemistry
  • Antiprotozoal Agents / isolation & purification*
  • Antiprotozoal Agents / pharmacology*
  • Circular Dichroism
  • Diterpenes / chemistry
  • Diterpenes / isolation & purification*
  • Diterpenes / pharmacology*
  • Inhibitory Concentration 50
  • Ireland
  • Leishmania donovani / drug effects
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Parasitic Sensitivity Tests
  • Phaeophyceae / chemistry*
  • Plasmodium falciparum / drug effects
  • Trypanosoma brucei rhodesiense / drug effects

Substances

  • Antimalarials
  • Antiprotozoal Agents
  • Diterpenes
  • bifurcatriol