Developmental toxicology of potato alkaloids in the frog embryo teratogenesis assay--Xenopus (FETAX).

Potatoes frequently contain growth inhibitors and toxic compounds including digestive enzyme inhibitors, lectins and glycoalkaloids. The literature suggests that Solanum alkaloids have the ability to induce neurological damage such as spina bifida and other malformations. As part of a programme of improvement in the safety of potatoes using molecular plant genetics and parallel food safety evaluation, we evaluated the effect of several potato glycoalkaloids and aglycones in the frog embryo teratogenesis assay--Xenopus (FETAX) with and without metabolic activation by Aroclor 1254-induced rat liver microsomes. The data suggest that the glycoalkaloid alpha-chaconine is teratogenic and more embryotoxic than alpha-solanine, in terms of the median lethal concentration (LC50) after 96 hr of exposure, the concentration inducing gross terata in 50% of the surviving frog embryos (96-hr EC50, malformation), and the minimum concentration needed to inhibit the growth of the embryos. Since these two compounds differ only in the nature of the carbohydrate side chain attached to the 3-OH group of solanidine, the side chain appears to be an important factor in governing teratogenicity. The aglycones demissidine, solanidine and solasodine were less toxic than the glycosides alpha-chaconine and alpha-solanine. The in vitro teratogenesis assay should be useful for: (a) predicting the teratogenic potential of solanaceae alkaloids, glycoalkaloids and related natural products; and (b) facilitating experimental approaches to suppress plant genes and enzymes that control the biosynthesis of the most toxic compounds.