title: MAO-A inhibitory activity of quercetin from Calluna vulgaris (L.) Hull.
abstract: OBJECTIVE
  This study investigated MAO-A inhibitory activity of methanol extract of Calluna vulgaris (L.) Hull., which traditionally has been used as a nerve calming remedy.
  
  
  METHODS
  A methanolic extract of Calluna vulgaris was partitioned against heptane, ethyl acetate and water. The three fractions were tested in a photometric peroxidase linked MAO-A bioassay. The ethyl acetate phase showed the highest MAO-A inhibitory activity. Quercetin was isolated by VLC through bioassay-guided fractionation and purified by re-crystallisation. The structure was elucidated by LC-MS and (1)H NMR.
  
  
  RESULTS
  The IC(50)-value for MAO-A inhibition by quercetin was 18+/-0.2 microM in an assay where the IC(50)-value for MAO-A inhibition by clorgylin was 0.2+/-0.02 microM.
  
  
  CONCLUSIONS
  The content of quercetin in Calluna vulgaris might explain the reported nerve calming effect of the plant.
authors.affiliation: Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen O, Denmark. las@farma.ku.dk
authors.forename: Lasse
authors.initials: L
authors.lastname: Saaby
authors.forename: Hasse B
authors.initials: HB
authors.lastname: Rasmussen
authors.forename: Anna K
authors.initials: AK
authors.lastname: Jäger
mesh_terms: D014151:Anti-Anxiety Agents / Q000737:chemistry / Q000494:pharmacology*; D029795:Calluna / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008996:Monoamine Oxidase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D011794:Quercetin / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D014151:Anti-Anxiety Agents; D008996:Monoamine Oxidase Inhibitors; D010936:Plant Extracts; D011794:Quercetin