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ARS Home » Pacific West Area » Logan, Utah » Poisonous Plant Research » Research » Publications at this Location » Publication #230141
Title: HPLC/MS analysis of toxic norditerpenoid alkaloids: Refinement of toxicity assessment of low larkspurs (Delphinium spp.)

Author
item Gardner, Dale
item Pfister, James

Submitted to: Phytochemical Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2008
Publication Date: 11/14/2008
Citation: Gardner, D.R., Pfister, J.A. 2008. HPLC/MS Analysis of Toxic Norditerpenoid Alkaloids: Refinement of toxicity assessment of low larkspurs (Delphinium spp.). Phytochemical Analysis 20:104-113.

Interpretive Summary: Low larkspurs (Delphinium nuttallianum and D. andersonii) are toxic to cattle when eaten during spring or summer on foothill and mountain rangelands in the western U.S. To assess the potential toxicity of the plants, methods are needed to identify and quantify the toxic MSAL type alkaloids in the plant. Therefore, the objectives of this chemistry study were to compare normal phase and reverse phase HPLC-MS methods of analysis, and to define the individual alkaloids from several sites. The major toxic alkaloids found in the low larkspurs included methyllycaconitine (MLA), nudicauline, 14-deacetylnudicauline, and geyerline. Total toxic alkaloid concentrations ranged from 0.72 mg/g (dry weight) to 7.02 mg/g. The low larkspurs contain a number of toxic alkaloids in addition to the dominant toxic alkaloid MLA that need to be assessed when considering the toxicity of the plant. Both normal phase and reverse phase HPLC methods are adequate to detect and quantify the alkaloids. The reverse phase separation may be preferred because columns are readily available, solvent use is reduced, and the simplicity of the electrospray ionization source.

Technical Abstract: The low larkspurs (Delphinium nuttallianum and D. andersonii) are two toxic plant species that are often fatally ingested by cattle on western U.S. rangelands. To assess the potential toxicity of the plants, methods are needed to identify and quantify the toxic N-methylsuccinimidoanthranoyllycacontine type alkaloids in the plant. The objective is to compare normal phase and reverse phase HPLC-MS methods of analysis for detection and identification of toxic alkaloids in two species of toxic larkspur plants. Define the toxic alkaloids found in Delphinium nuttallianum and D. andersonii collected from several sites in the western United States. The major toxic alkaloids found in the low larkspurs included methyllycaconitine, nudicauline, 14-deacetylnudicauline, and geyerline. Other toxic alkaloids detected at lower concentrations included 16-deacetylgeyerline, gradiflorine, bearline, 14-acetylbearline, barbinine, 16-demethylnudicauline and three additional isomers of bearline. Total toxic alkaloid concentrations ranged from 0.72 mg/g (d.w.) to 7.02 mg/g determined by reverse phase HPLC-MS. The low larkspurs contain a number of toxic alkaloids in addition to the alkaloid methyllycaconitine that need to be assessed when considering the toxicity of the plant. Both normal phase and reverse phase HPLC methods are adequate to detect and quantify the alkaloids. The reverse phase separation may be preferred due to readily available columns, reduced solvent use and simplicity of the electrospray ionization source.