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ARS Home » Pacific West Area » Logan, Utah » Poisonous Plant Research » Research » Publications at this Location » Publication #392375

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

Location: Poisonous Plant Research

Title: Identification of two death camas chemotypes within a population and evaluation of toxicity

Author
item Stonecipher, Clinton - Clint
item Lee, Stephen
item Welch, Kevin
item Gardner, Dale
item Cook, Daniel

Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2022
Publication Date: 6/2/2022
Citation: Stonecipher, C.A., Lee, S.T., Welch, K.D., Gardner, D.R., Cook, D. 2022. Identification of two death camas chemotypes within a population and evaluation of toxicity. Toxicon. 215:6-10. https://doi.org/10.1016/j.toxicon.2022.05.047.
DOI: https://doi.org/10.1016/j.toxicon.2022.05.047

Interpretive Summary: Foothill death camas (Zigadenus paniculatus) is a native perennial forb found throughout the western U.S. The toxins in death camas are alkaloids. Zygacine is often the most abundant alkaloid in death camas and is believed to be the primary toxic component. A population of death camas with plants consisting of two different chemical profiles (chemotypes) growing within the same location were identified. The objective of this study was to determine the percentage of a death camas population represented by each of the different chemotypes and to determine if there was a difference in toxicity between the two chemotypes. One third of the population sampled consisted of chemotype 1, while two-thirds of the population consisted of chemotype 2. The zygacine concentration of chemotype 1 was three times higher than chemotype 2. However, chemotype 2 contained higher concentrations of a number of other alkaloids than chemotype 1. We hypothesized that chemotype 1, which consisted of higher concentrations of zygacine, would be more toxic than chemotype 2. The acute toxicity of each chemotype was determined in mice and sheep. The acute toxicity of the chemotype 1 was more toxic than the chemotype 2 to mice. However, in the sheep study there were no differences in adverse effects between chemotypes. Based upon the results of this study, caution should be taken when livestock are grazing death camas, as both chemotypes of death camas appear to pose a similar risk to grazing livestock.

Technical Abstract: Foothill death camas (Zigadenus paniculatus) is a native, cool-season, bulbous perennial forb found throughout the western U.S. The toxins in death camas are steroidal alkaloids. Zygacine is often the most abundant alkaloid in death camas and is believed to be the primary toxic component. A population of death camas with plants consisting of two different chemical profiles (chemotypes) growing within the same location were identified. The objective of this study was to determine the percentage of a death camas population represented by each of the different chemotypes and to determine if there was a difference in toxicity between the two chemotypes. One third of the population sampled consisted of chemotype 1, while two-thirds of the population consisted of chemotype 2. The zygacine concentration of chemotype 1 was three times higher than chemotype 2. Chemotype 2 contained higher concentrations of several other steroidal alkaloids than chemotype 1. We hypothesized that chemotype 1, which consisted of higher concentrations of zygacine, would be more toxic than chemotype 2. The acute toxicity of each chemotype was determined in mice and sheep. In the mouse LD50 study, the acute toxicity of the chemotype 1 alkaloids (2.3 mg / kg BW) was different than the chemotype 2 alkaloids (3.2 mg / kg BW). However, in the sheep study there were no differences in the adverse effects between chemotypes. Based upon the results of this study, caution should be taken when livestock are grazing death camas, as both chemotypes of death camas appear to pose a similar risk to grazing livestock.