title: Annonacin in Asimina triloba fruit: implication for neurotoxicity.
abstract: BACKGROUND
  The acetogenin, annonacin, from the tropical annonaceous plant Annona muricata, is a lipophilic, mitochondrial complex I inhibitor reported to be more toxic than rotenone to mesencephalic neurons. The temperate annonaceous plant Asimina triloba (pawpaw) is native to the Eastern United States and products are available online. This study determined whether annonacin is in the pawpaw fruit pulp and whether it or the crude ethyl acetate extract is toxic to cortical neurons.
  
  
  METHODS
  Pawpaw extract was prepared by pulp extraction with methanol and liquid-liquid partitioning with ethyl acetate (EtOAc). Annonacin was isolated from the crude EtOAc extract via column chromatography using a gradient solvent system of increasing polarity. Mass spectroscopy, nuclear magnetic resonance and infrared spectroscopy were used to compare isolated material with synthetic annonacin data and a natural annonacin sample. Toxicity of isolated annonacin and the total EtOAc extract was determined in primary rat cortical neurons using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.
  
  
  RESULTS
  The average concentration of annonacin in the fruit pulp was 0.0701±0.0305mg/g. Purified annonacin (30.07μg/ml) and crude EtOAc extract (47.96μg/ml) induced 50% death of cortical neurons 48h post treatment. Annonacin toxicity was enhanced in the presence of crude extract.
  
  
  CONCLUSIONS
  Pawpaw fruit contains a high concentration of annonacin, which is toxic to cortical neurons. Crude fruit extract also induced neurotoxicity, highlighting the need for additional studies to determine the potential risks of neurodegeneration associated with chronic exposure to pawpaw products.
authors: Department of Anatomical Sciences and Neurobiology, University of Louisville, United States.
authors: Lisa F
authors: LF
authors: Potts
authors: Frederick A
authors: FA
authors: Luzzio
authors: Scott C
authors: SC
authors: Smith
authors: Michal
authors: M
authors: Hetman
authors: Pierre
authors: P
authors: Champy
authors: Irene
authors: I
authors: Litvan
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D031042:Asimina / Q000737:chemistry; D002452:Cell Count; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D005638:Fruit / Q000737:chemistry*; D005663:Furans / Q000494:pharmacology*; D007783:Lactones / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009474:Neurons / Q000187:drug effects*; D009498:Neurotoxins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013055:Spectrophotometry, Infrared; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D005663:Furans; D007783:Lactones; D009498:Neurotoxins; D013778:Tetrazolium Salts; D013844:Thiazoles; C053442:annonacin; C022616:thiazolyl blue