Isolation and synthesis of acmellonate, a new unsaturated long chain 2-ketol ester from Spilanthes acmella

Nat Prod Res. 2006 Jul 20;20(9):798-804. doi: 10.1080/14786410500246733.

Abstract

Paracress (Spilanthes acmella) is commonly used as a spice, e.g., in Madagascar. To get more information about the taste active compounds, Jambu oleoresin produced from Spilanthes acmella and extracts prepared directly from the plant were fractionated and the fractions were analysed and evaluated by tasting. In addition to the long known tingling compounds (2E,6Z,8E)-deca-2,6,8-trienoic acid N-isobutyl amide (spilanthol) and (2E,6Z,8E)-deca-2,6,8-trienoic acid N-(2-methylbutyl) amide, as a minor constituent also the new 2-ketol ester (7Z,9E)-2-oxo-undeca-7,9-dienyl 3-methylbut-2-enoate (acmellonate) was isolated. The structure of the latter compound was verified by total synthesis of the ketol ester via the reaction of tris(trimethylsilyloxy)ethene and (6Z,8E)-deca-6,8-dienoic acid chloride and subsequent classical esterification. Acmellonate shows a weak tingling and numbing effect on the tongue and contributes only to a small extend to the overall flavour of Jambu.

MeSH terms

  • Asteraceae / chemistry*
  • Caproates / chemistry
  • Esters / chemical synthesis
  • Esters / chemistry
  • Esters / isolation & purification*
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Ketones / chemical synthesis
  • Ketones / chemistry
  • Ketones / isolation & purification*
  • Magnetic Resonance Spectroscopy
  • Organophosphorus Compounds / chemistry
  • Plant Extracts / chemistry
  • Spectrometry, Mass, Electrospray Ionization
  • Spices
  • Taste

Substances

  • Caproates
  • Esters
  • Ketones
  • Organophosphorus Compounds
  • Plant Extracts
  • oleoresins
  • triphenylphosphine