Clinical and pathological assessment of the calystegines in Ipomoea carnea in a goat model

Authors: Cook, Daniel; Stegelmeier, Bryan; GARDNER, DALE - Retired ARS Employee; RIET-CORREA, FRANKLIN - Federal University Of Campina Grande; Stonecipher, Clinton; Welch, Kevin

Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2026
Publication Date: 5/5/2026
Citation: Cook, D., Stegelmeier, B.L., Gardner, D.R., Riet-Correa, F., Stonecipher, C.A., Welch, K.D. 2026. Clinical and pathological assessment of the calystegines in Ipomoea carnea in a goat model. Toxicon. 279. Article 109132. https://doi.org/10.1016/j.toxicon.2026.109132.
DOI: https://doi.org/10.1016/j.toxicon.2026.109132

Interpretive Summary: The indolizidine alkaloid swainsonine, found in some Ipomoea species, is a potent cellular glycosidase inhibitor that often poisons livestock. Some Ipomoea species also contain similar polyhydroxy alkaloids, calystegines. The toxicity of calystegines is poorly characterized; however, they also inhibit cellular glycosides and are capable of causing cellular glycoside dysfunction. The objective of this study was to directly compare goats dosed with I. carnea containing both swainsonine and calystegines, or I. carnea containing only the calystegines; thus describing the role of the calystegines in the toxicity of I. carnea. Three groups of four goats each were treated with ground alfalfa (control), I. carnea containing both swainsonine and calystegines or I. carnea containing only the calystegines, for 45 days. Animals were observed daily and weekly body weights, serum biochemistries, and serum swainsonine concentrations were determined. On day 45, all animals were euthanized and necropsied. Goats treated with I. carnea containing swainsonine and the calystegines developed clinical disease characterized by mild intention tremors, proprioceptive deficits, and visceral and neurologic lesions. No changes were noted in the goats treated with alfalfa or I. carnea containing only the calystegines. These findings suggest that I. carnea-induced clinical signs and lesions are due to swainsonine and that calystegines do not contribute to toxicity in goats under these conditions.

Technical Abstract: The indolizidine alkaloid swainsonine, found in some Ipomoea species, is a potent cellular glycosidase inhibitor that often poisons livestock. Some Ipomoea species also contain similar polyhydroxy alkaloids, calystegines. The toxicity of calystegines is poorly characterized; however, they also inhibit cellular glycosides and are capable of causing cellular glycoside dysfunction. The objective of this study was to directly compare goats dosed with I. carnea containing both swainsonine and calystegines, or I. carnea containing only the calystegines; thus describing the role of the calystegines in the toxicity of I. carnea. Three groups of four goats each were treated with ground alfalfa (control), I. carnea containing both swainsonine and calystegines or I. carnea containing only the calystegines, for 45 days. Animals were observed daily and weekly body weights, serum biochemistries, and serum swainsonine concentrations were determined. On day 45, all animals were euthanized and necropsied. Goats treated with I. carnea containing swainsonine and the calystegines developed clinical disease characterized by mild intention tremors, proprioceptive deficits, and visceral and neurologic lesions. No changes were noted in the goats treated with alfalfa or I. carnea containing only the calystegines. These findings suggest that I. carnea-induced clinical signs and lesions are due to swainsonine and that calystegines do not contribute to toxicity in goats under these conditions.