Comparison of the toxic effects of two duncecap larkspur (Delphinium occidentale) chemotypes in mice and cattle.
ABSTRACT To compare the toxic effects of a Delphinium occidentale chemotype containing N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids and a D occidentale chemotype lacking MSAL-type alkaloids in mice and cattle.
225 male Swiss Webster mice and 11 Black Angus steers.
4 collections of larkspur containing MSAL-type alkaloids and 4 collections of larkspur lacking MSAL-type alkaloids were used. From each collection, total alkaloid extracts (0.05 to 0.20 mL) were administered via tail-vein injection in 27 to 29 mice. Dried, finely ground plant material from 1 collection with and 1 collection without MSAL-type alkaloids (doses equivalent to 37.6 mg of total alkaloids/kg) were each administered to 8 cattle via oral gavage in a crossover experiment; 3 cattle received a single dose equivalent to 150.4 mg of total alkaloids/kg (no MSAL-type alkaloids). In mice, clinical effects were monitored; in cattle, heart rate was monitored before (baseline) and 24 hours after treatment. At the 24-hour time point, cattle were exercised as a measure of muscle weakness.
In mice, mean LD(50) associated with alkaloid extracts prepared from plants that did or did not contain MSAL-type alkaloids was 2.3 and 54.2 mg/kg, respectively. In cattle at 24 hours after treatment, plant material containing MSAL-type alkaloids significantly increased heart rate from baseline and was associated with exercise-induced collapse; plant material lacking MSAL-type alkaloids had no similar effects.
Taxonomic classification of D occidentale alone was not a good indicator of the toxic risk to grazing cattle.
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ABSTRACT: Low larkspurs have different toxic potentials to livestock due to variation in the individual alkaloids present in the plants. Two species, Delphinium nuttallianum and Delphinium andersonii were dosed to 10 Holstein steers at 10mg and 12mg toxic alkaloids/kg, respectively. Blood samples were collected periodically for 96h, analyzed for serum alkaloid concentrations and toxicokinetic parameters calculated for 16-deacetylgeyerline, 14-deacetylnudicauline, methyllycaconitine and geyerline/nudicauline which co-eluted in the serum analysis. The maximum serum alkaloid concentrations and area under the curve values for 16-deacetylgeyerline and geyerline/nudicauline were significantly different between the two groups due to the concentrations of the alkaloids in each larkspur species. The alkaloid elimination half-lives were similar for the two larkspur species. These results suggest the elimination rates of norditerpene alkaloids from different larkspur species in cattle are similar regardless of plant alkaloid composition. The determining factor for larkspur toxicity is the individual alkaloid composition of the plant.Research in Veterinary Science 05/2013; · 1.77 Impact Factor
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ABSTRACT: To determine the toxicokinetics of N-(methylsuccinimido)anthranoyllycoctonine-type low larkspur alkaloids in beef cattle. 5 Black Angus steers and 35 Swiss Webster mice. -Low larkspur (Delphinium andersonii) was collected, dried, ground, and administered to 5 steers via oral gavage to provide a dose of 12 mg of N-(methylsuccinimido)-anthranoyllycoctonine alkaloids/kg. Steers were housed in metabolism crates for 96 hours following larkspur administration; heart rate was monitored continuously, and blood samples were collected periodically for analysis of serum concentrations of 16-deacetylgeyerline, methyllycaconitine, geyerline, and nudicauline and assessment of kinetic parameters. The LD(50) of a total alkaloid extract from D andersonii was determined in Swiss Webster mice. -The alkaloids were quickly absorbed, with a maximum serum concentration achieved within 18 hours after administration. Geyerline and nudicauline coeluted as 1 peak and were considered together for toxicokinetic analysis. Mean ± SD elimination half-life was 18.4 ± 4.4 hours, 15.6 ± 1.5 hours, and 16.5 ± 5.1 hours for 16-deacetylgeyerline, methyllycaconitine, and geyerline and nudicauline, respectively. There were significant differences in maximum serum concentration, amount absorbed, and distribution half-life among the 4 alkaloids. The mouse LD(50) was 9.8 mg/kg. -Results suggested that clinical poisoning was likely to be most severe approximately 18 hours after exposure. Cattle should be closely monitored for at least 36 hours after initial exposure. Additionally, a withdrawal time of approximately 7 days would be required to clear > 99% of the toxic alkaloids from the serum of cattle that have ingested low larkspur.American Journal of Veterinary Research 08/2012; 73(8):1318-24. · 1.35 Impact Factor