title: Combination of bioautography with HPTLC-MS/NMR: a fast identification of acetylcholinesterase inhibitors from galbanum(†).
abstract: BACKGROUND
  In the search for new natural compounds with acetylcholinesterase (AChE) inhibitory activity this study focused on galbanum, the oleo gum-resin from Ferula gummosa Boiss., which had shown AChE inhibitory activity in a screening.
  
  
  OBJECTIVE
  The isolation of bioactive compounds from plant extracts usually is laborious and time consuming. In an approach to accelerate the characterisation of compounds with AChE inhibitory activity, the potential of a combination of HPTLC bioautography with HPTLC-MS/NMR for the fast identification of active compounds in galbanum was studied.
  
  
  METHODS
  Pre-fractionation of the dichloromethane extract was performed by vacuum liquid chromatography. The resulting fractions were separated by HPTLC and active zones determined by bioautography. A TLC-MS interface was used to elute the single zones from the plates directly into a mass spectrometer. The interface was also used to extract the two major active zones from HPTLC plates for off-line one- and two-dimensional NMR and quadrupole time of flight (QTOF) MS.
  
  
  RESULTS
  The isolated compounds were identified as 7-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}-2H-chromen-2-one (auraptene) and 7-{[(1R,4aR,6S,8aS)-6-hydroxy-5,5,8a-trimethyl-2-methylenedecahydronaphthalen-1-yl]methoxy}-2H-chromen-2-one (farnesiferol A). This is the first report of these substances in F. gummosa. Their median inhibitory concentration (IC50 ) values for AChE inhibition were determined as 47 and 17 µg/mL in comparison with physostigmine as a positive control (IC50 : 0.8 µg/mL) and their concentrations in galbanum were quantified by HPLC as 3.5% and 7.9%, respectively.
  
  
  CONCLUSIONS
  The study showed that HPTLC-MS/NMR can be considered as a fast and high-confidence method for dereplication of natural compounds. From the correlation of the concentration of the elucidated compounds and their IC50 values for AChE inhibition it can be concluded that auraptene and farnesiferol A are contributing to this activity of galbanum.
authors: Department of Pharmacognosy, University of Vienna, Vienna, Austria. Hamid-Reza Adhami@univie.ac.at
authors: Hamid-Reza
authors: HR
authors: Adhami
authors: Uta
authors: U
authors: Scherer
authors: Hanspeter
authors: H
authors: Kaehlig
authors: Timm
authors: T
authors: Hettich
authors: Götz
authors: G
authors: Schlotterbeck
authors: Eike
authors: E
authors: Reich
authors: Liselotte
authors: L
authors: Krenn
mesh_terms: D005591:Chemical Fractionation / Q000379:methods; D002800:Cholinesterase Inhibitors / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods; D003374:Coumarins / Q000032:analysis / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005309:Ferula / Q000737:chemistry*; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D012717:Sesquiterpenes / Q000032:analysis / Q000494:pharmacology
chemical_list: D002800:Cholinesterase Inhibitors; D003374:Coumarins; D012717:Sesquiterpenes; C579605:farnesiferol A; C105832:aurapten