title: Pro-toxic 1,2-Dehydropyrrolizidine Alkaloid Esters, Including Unprecedented 10-Membered Macrocyclic Diesters, in the Medicinally-used Alafia cf. caudata and Amphineurion marginatum (Apocynaceae: Apocynoideae: Nerieae and Apocyneae).
abstract: BACKGROUND
  Within the Apocynoideae (Apocynaceae) pro-toxic dehydropyrrolizidine alkaloids have been reported only in Echiteae. However, attraction of pyrrolizidine alkaloid-pharmacophagous insects suggested their presence in Alafia cf. caudata Stapf (Nerieae: Alafiinae) and Amphineurion marginatum (Roxb.) D.J. Middleton (Apocyneae: Amphineuriinae), both used as medicinal plants.
  
  
  OBJECTIVE
  To confirm the presence of dehydropyrrolizidine alkaloids in Alafia cf. caudata and Amphineurion marginatum and identify their structures.
  
  
  METHODS
  Methanol extracts of air-dried roots, stems and leaves of non-flowering plants were analysed using HPLC-ESI(+)MS and MS/MS or collision-induced dissociation MS in low and/or high resolution modes. Pyrrolizidine alkaloids were tentatively identified based on the mass spectrometry data. Solid phase extraction combined with semi-preparative HPLC were used to isolate major alkaloids. Structures were elucidated using NMR spectroscopy.
  
  
  RESULTS
  Monoesters of retronecine with senecioic, hydroxysenecioic or syringic acids were identified in roots of Alafia cf. caudata. Two unprecedented 10-membered macrocyclic dehydropyrrolizidine alkaloid diesters were isolated from roots of Amphineurion marginatum. Pyrrolizidine alkaloids were detected in root and leaf material of Alafia cf. caudata at 0.34 and 0.01% dry weight (DW), and 0.13, 0.02 and 0.09% DW in root, leaf and stem material of Amphineurion marginatum.
  
  
  CONCLUSIONS
  The presence of pro-toxic dehydropyrrolizidine alkaloids suggests that medical preparations of these plants pose potential health risks to consumers. Dehydropyrrolizidine alkaloids are evidently more widespread in Apocynoideae than previously assumed, and it would seem rewarding to study other members of this family for the presence of pyrrolizidines, dehydropyrrolizidines and dihydropyrrolizines. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: USDA, ARS, Poisonous Plant Research Laboratory, Logan, UT, 84341, USA.|Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, 84322, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Colegate
authors.affiliation: USDA, ARS, Poisonous Plant Research Laboratory, Logan, UT, 84341, USA.
authors.forename: Dale R
authors.initials: DR
authors.lastname: Gardner
authors.affiliation: Office of Dietary Supplements, National Institutes of Health, 6100 Executive Blvd., Room 3B01, Bethesda, MD, 20892, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Betz
authors.affiliation: Forstzoologie und Entomologie, Albert-Ludwigs-Universität, D-79085, Freiburg, Germany.
authors.forename: Ottmar W
authors.initials: OW
authors.lastname: Fischer
authors.affiliation: LS Pflanzensystematik, Universität Bayreuth, D-95440, Bayreuth, Germany.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Liede-Schumann
authors.affiliation: Forstzoologie und Entomologie, Albert-Ludwigs-Universität, D-79085, Freiburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Boppré
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification*; D029062:Apocynaceae / Q000737:chemistry*; D002411:Cation Exchange Resins; D002851:Chromatography, High Pressure Liquid; D004952:Esters; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010946:Plants, Medicinal; D011758:Pyrroles / Q000737:chemistry / Q000302:isolation & purification*; D052616:Solid Phase Extraction
chemical_list: D000470:Alkaloids; D002411:Cation Exchange Resins; D004952:Esters; D011758:Pyrroles
keywords: Amphineurine; health risk; hydroxysenecioylretronecine; isoshimbaine; marginatine; pyrrolizidine alkaloid-pharmacophagous insects; shimbaine