title: Dehydropyrrolizidine alkaloids, including monoesters with an unusual esterifying acid, from cultivated Crotalaria juncea (Sunn Hemp cv.'Tropic Sun').
abstract: Cultivation of  Crotalaria juncea  L. (Sunn Hemp cv. 'Tropic Sun') is recommended as a green manure crop in a rotation cycle to improve soil condition, help control erosion, suppress weeds, and reduce soil nematodes. Because C. juncea belongs to a genus that is known for the production of toxic dehydropyrrolizidine alkaloids, extracts of the roots, stems, leaves, and seeds of 'Tropic Sun' were analyzed for their presence using HPLC-ESI/MS. Qualitative analysis identified previously unknown alkaloids as major components along with the expected macrocyclic dehydropyrrolizidine alkaloid diesters, junceine and trichodesmine. The dehydropyrrolizidine alkaloids occurred mainly as the N-oxides in the roots, stems, and, to a lesser extent, leaves, but mainly as the free bases in the seeds. Comprehensive spectrometric and spectroscopic analysis enabled elucidation of the unknown alkaloids as diastereoisomers of isohemijunceine, a monoester of retronecine with an unusual necic acid. The dehydropyrrolizidine alkaloid contents of the roots, stems, and leaves of immature plants were estimated to be 0.05, 0.12, and 0.01% w/w, respectively, whereas seeds were estimated to contain 0.15% w/w.
authors.affiliation: Poisonous Plant Research Laboratory, Agriculture Research Service, US Department of Agriculture, Logan, Utah 84341, United States. steven.colegate@ars.usda.gov
authors.forename: Steven M
authors.initials: SM
authors.lastname: Colegate
authors.forename: Dale R
authors.initials: DR
authors.lastname: Gardner
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Joy
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Betz
authors.forename: Kip E
authors.initials: KE
authors.lastname: Panter
mesh_terms: D000383:Agriculture / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D029864:Crotalaria / Q000737:chemistry*; D004951:Esterification; D007783:Lactones / Q000032:analysis; D016686:Monocrotaline / Q000031:analogs & derivatives / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D011763:Pyrrolizidine Alkaloids / Q000032:analysis*; D012639:Seeds / Q000737:chemistry; D012987:Soil / Q000032:analysis; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D007783:Lactones; D011763:Pyrrolizidine Alkaloids; D012987:Soil; C004250:trichodesmine; D016686:Monocrotaline