Overview of available toxicity data for calystegines

Abstract

Calystegines are polyhydroxylated nortropane alkaloids that have been found in various solanaceous foods, in particular in potatoes and aubergines. The biological activity and potential toxicity of calystegines are associated with their capacity to inhibit glycosidases and block carbohydrate metabolism inducing lysosomal storage toxicity. The present report summarises the retrieved information on the possible toxicity of calystegines. Only few in vivo short‐term toxicological studies in rodents on individual calystegines or mixtures of calystegines were retrieved. Overall, these studies are insufficient to conclude on the possible chronic toxicity effects of calystegines in humans, in particular considering the short duration of the studies and potential lower sensitivity of rats and mice to glycosidase inhibitors, compared to other species such as goats and guinea pigs. Several studies and case reports were retrieved on the toxic effects induced in livestock or experimental animals following consumption or administration of plants containing calystegines. However, the concurrent presence of other alkaloids, in particular swainsonine, did not allow using these studies to draw conclusions on the toxicity of calystegines. Since no experimental data on genotoxicity of calystegines were retrieved, in silico predicting models were applied to identify possible alert for genotoxicity of five calystegines recently detected in food. In most of the cases, the outcome of the computational predictions indicated no alerts for genotoxicity; however, the low reliability of the results prevents a firm conclusion on the genotoxic potential of the substances. Overall, the available data do not allow drawing conclusions on the possible toxic effects of calystegines in humans or in livestock, and more data in relevant experimental models would be necessary to characterise the toxic profile of this group of substances.

Characterization of the Root-Associated Microbiome Provides Insights into Endemism ofThymusSpecies Growing in the Kazdagi National Park

“…Chaetothyriales are capable of producing swainsonine which is an indolizidine alkaloid that causes severe toxicity in livestock feeding with swainsonine containing plants (38). Also, calystegines produced as a plant secondary metabolite are known to enhance the toxicity of plants with swainsonine which is only produced by endophytic fungi (39,40). Because T. pulvinatus is a local endemic and critically endangered species, Chaetothyriales enrichment in its rhizosphere soil may be due to a protection mechanism.…”

Emerging Issues on Tropane Alkaloid Contamination of Food in Europe

“…On account of their adverse health effects and their regular occurrence in food in Europe, atropine and scopolamine are regarded as undesirable substances in food and feed and for that reason have been subjected to European Union (EU) regulation since 2016 [ 27 , 28 , 29 ]. No known incidents in humans related to calystegines present in food have been reported [ 30 ]. However, it is known that calystegines can inhibit glucosidase activity, the enzymes that break down oligosaccharides into glucose molecules.…”

“…However, it is known that calystegines can inhibit glucosidase activity, the enzymes that break down oligosaccharides into glucose molecules. As mentioned in the EFSA Report of 2019 on calystegines, experimental models for these kind of toxic effects are not available [ 30 ].…”

Metabolomic and transcriptomic analyses identify external conditions and key genes underlying high levels of toxic glycoalkaloids in tubers of stress-sensitive potato cultivars

“…The CAs are commonly divided into three groups (A, B, and C), depending on their degree of hydroxylation. Although concerns have been raised regarding anti-nutritional effects of CAs, mainly due to their action as glycosidase inhibitors, more research is needed to characterize the toxicity of this group of alkaloids, and recommended safe levels or guidelines are presently lacking ( Binaglia et al., 2019 ).…”