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United States Department of Agriculture

Agricultural Research Service

Research Project: Understanding and Mitigating the Adverse Effects of Poisonous Plants on Livestock Production Systems

Location: Poisonous Plant Research

Title: Profiling of dehydropyrrolizidine alkaloids and their N-oxides in herbarium-preserved specimens of Amsinckia species using HPLC-esi(+)MS

Authors
item Colegate, Steven
item Welsh, Stanley -
item Gardner, Dale
item Betz, Joseph -
item Panter, Kip

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 23, 2014
Publication Date: July 30, 2014
Citation: Colegate, S.M., Welsh, S.L., Gardner, D.R., Betz, J.M., Panter, K.E. 2014. Profiling of dehydropyrrolizidine alkaloids and their N-oxides in herbarium-preserved specimens of Amsinckia species using HPLC-esi(+)MS. Journal of Agricultural and Food Chemistry. 62(30):7382-7392.

Interpretive Summary: Species of the Boraginaceae Amsinckia genus are known to produce dehydropyrrolizidine alkaloids that are potentially poisonous leading to liver and lung disease plus the potential to cause cancers. However, identification of Amsinckia species can be very subtle and there seems to be marked differences in toxicity towards grazing livestock. Herbarium specimens (collected in 1899 to 2013) of 10 Amsinckia species and one variety were analyzed for the presence of these potentially toxic alkaloids and/or their N-oxides. The alkaloids were detected in all specimens examined ranging from about one to 4000 'g/g of plant. Usually occurring mainly as their N¬-oxides, the predominant alkaloids were the closely related lycopsamine and intermedine. Within a designated species, an inconsistent profile was often observed that may be due to natural variation or taxonomic misassignment. It was clear that investigation of the herbarium specimens sheds light on the potential for toxicity towards livestock.

Technical Abstract: Species of the Amsinckia genus (Boraginaceae) are known to produce potentially hepato-, pneumo-, and/or genotoxic dehydropyrrolizidine alkaloids. However, the taxonomic differentiation of Amsinckia species can be very subtle and there seems to be marked differences in toxicity toward grazing livestock. Methanol extracts of mass-limited leaf samples from herbarium specimens (collected from 1899 to 2013) of 10 Amsinckia species and one variety were analyzed using HPLC-esi(+)MS and MS/MS for the presence of potentially toxic dehydropyrrolizidine alkaloids and/or their N-oxides. Dehydropyrrolizidine alkaloids were detected in all specimens examined ranging from about 1 to 4000 µg/g of plant. Usually occurring mainly as their N-oxides, the predominant alkaloids were the epimeric lycopsamine and intermedine. Also sometimes observed in higher concentrations were the 3'- and 7-acetyl derivatives of lycopsamine/intermedine and their N-oxides. Within a designated species, an inconsistent profile was often observed that may be due to natural variation, taxonomic misassignment, or nonuniform degradation due to plant collection and storage differences.

Last Modified: 9/23/2014
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