title: Isolation of narciprimine from Cyrtanthus contractus (Amaryllidaceae) and evaluation of its acetylcholinesterase inhibitory activity.
abstract: BACKGROUND
  Plants of the family Amaryllidaceae are used widely in traditional medicine in South Africa. Several of these, including representatives of the genus Cyrtanthus find use in the treatment of mental illness and age-related dementia.
  
  
  OBJECTIVE
  Based on the distribution of central nervous system-activating alkaloidal constituents within the genus Cyrtanthus, Cyrtanthus contractus was here explored for such compounds which could interact with acetylcholinesterase (AChE), of significance in the progression of neurodegeneration associated with Alzheimer's disease.
  
  
  METHODS
  The known phenanthridone alkaloid narciprimine was isolated via column chromatography of the ethanolic extract of bulbs of Cyrtanthus contractus. The structure of the compound was determined by high field 2D NMR and mass spectroscopic techniques. The classical method of Ellman et al. was used in the determination of AChE inhibitory activity.
  
  
  RESULTS
  The isolation of narciprimine from Cyrtanthus contractus is a landmark find since it has previously only been identified in Zephyranthes, Narcissus and Lycoris, genera endemic to the Americas, Europe and Asia, respectively. Narciprimine exhibited micromolar inhibitory activity (IC(50) 78.9) against the enzyme acetylcholinesterase.
  
  
  CONCLUSIONS
  This work represents the first isolation of narciprimine from an African Amaryllidaceae species, which may be of chemotaxonomic significance. The AChE inhibitory activity of narciprimine, taken together with activities of other structurally similar inhibitors within the series affords further insight to the structural details of the lycorine alkaloid acetylcholinesterase inhibitory pharmacophore.
authors.affiliation: Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa.
authors.forename: Jerald J
authors.initials: JJ
authors.lastname: Nair
authors.forename: Adeyemi O
authors.initials: AO
authors.lastname: Aremu
authors.forename: Johannes
authors.initials: J
authors.lastname: van Staden
mesh_terms: D000110:Acetylcholinesterase / Q000302:isolation & purification / Q000378:metabolism*; D047151:Amaryllidaceae Alkaloids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002845:Chromatography; D004524:Eels; D019668:Liliaceae / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010616:Phenanthrenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots; D010946:Plants, Medicinal; D013329:Structure-Activity Relationship
chemical_list: D047151:Amaryllidaceae Alkaloids; D002800:Cholinesterase Inhibitors; D010616:Phenanthrenes; D010936:Plant Extracts; C569972:narciprimine; D000110:Acetylcholinesterase