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ARS Home » Pacific West Area » Logan, Utah » Poisonous Plant Research » Research » Publications at this Location » Publication #332160
Title: New dehydropyrrolizidine alkaloids isolated from a Crotalaria and two Cryptantha species

Author
item Colegate, Steven
item Gardner, Dale
item Davis, Thomas - Zane
item JOY, R - Natural Resources Conservation Service (NRCS, USDA)
item BETZ, J - National Institutes Of Health (NIH)
item Panter, Kip

Submitted to: International Symposium on Poisonous Plants
Publication Type: Proceedings
Publication Acceptance Date: 5/30/2015
Publication Date: 6/5/2015
Citation: Colegate, S.M., Gardner, D.R., Davis, T.Z., Joy, R.J., Betz, J.M., Panter, K.E. 2015. New dehydropyrrolizidine alkaloids isolated from a Crotalaria and two Cryptantha species. International Symposium on Poisonous Plants. 9:212-218.

Interpretive Summary: Several hundred potentially hepato-, pneumo- and geno-toxic dehydropyrrolizidine alkaloid esters (DHPAs) from several species in genera of the Boraginaceae, Asteraceae (Compositae) and Fabaceae (Leguminosae) have been isolated and characterized over the past 5 or 6 decades. While the dehydropyrrolizidine core can vary in its relative C7-C8 stereochemistry and, to a lesser extent, the character of its substituents, the diversity of structure is related in large part to the stereochemical options that are available to the necic acids that esterify the C7 and/or C9 hydroxyl groups. Therefore the range of DHPAs includes regioisomers and diastereoisomers, including epimeric diastereoisomers varying around only one chiral carbon.

Technical Abstract: The advent of HPLC-esi(+)MS and MS/MS techniques for detection of potential DHPAs, and their N-oxides, within complex plant secondary metabolite mixtures is based upon a recognition of characteristic mass fragment ions derived from the even-mass, protonated molecules (Colegate et al. 2005). This ready recognition then allows for a targeted isolation of suspected DHPAs and subsequent structure elucidation using 1D and 2D NMR spectroscopy. So, despite the diversity and wealth of DHPA structures already described, new structures continue to be elucidated for DHPAs that have been overlooked in previous studies or isolated from new plant sources. Herein is described the detection and subsequent isolation and structure elucidation of new DHPAs from an agricultural crop (Colegate et al. 2012) and two rangeland plants.