The comparative toxicity of a reduced, crude comfrey (Symphytum officinale) alkaloid extract and the pure, comfrey‐derived pyrrolizidine alkaloids, lycopsamine and intermedine in chicks (Gallus gallus domesticus). Issue 5 (14th July 2015)

• Record Type: Journal Article
• Authors: Brown, Ammon W.; Stegelmeier, Bryan L.; Colegate, Steven M.; Gardner, Dale R.; Panter, Kip E.; Knoppel, Edward L.; Hall, Jeffery O.
• Is Part Of: Journal of applied toxicology. Volume 36:Issue 5(2016)
• Page Start: 716
• Page End: 725
• Publication Date: 2015-07-14
• Subjects: comfrey -- lycopsamine -- intermedine -- pyrrolizidine alkaloid -- N‐oxide -- tisane; Toxicology -- Periodicals; Industrial toxicology -- Periodicals; Environmentally induced diseases -- Periodicals; Toxicology -- Periodicals; 615.9005
• DOI: 10.1002/jat.3205
• Languages: English
• ISSNs: 0260-437X

Abstract

Abstract: Comfrey ( Symphytum officinale ), a commonly used herb, contains dehydropyrrolizidine alkaloids that, as a group of bioactive metabolites, are potentially hepatotoxic, pneumotoxic, genotoxic and carcinogenic. Consequently, regulatory agencies and international health organizations have recommended comfrey be used for external use only. However, in many locations comfrey continues to be ingested as a tisane or as a leafy vegetable. The objective of this work was to compare the toxicity of a crude, reduced comfrey alkaloid extract to purified lycopsamine and intermedine that are major constituents of S. officinale . Male, California White chicks were orally exposed to daily doses of 0.04, 0.13, 0.26, 0.52 and 1.04 mmol lycopsamine, intermedine or reduced comfrey extract per kg bodyweight (BW) for 10 days. After another 7 days chicks were euthanized. Based on clinical signs of poisoning, serum biochemistry, and histopathological analysis the reduced comfrey extract was more toxic than lycopsamine and intermedine. This work suggests a greater than additive effect of the individual alkaloids and/or a more potent toxicity of the acetylated derivatives in the reduced comfrey extract. It also suggests that safety recommendations based on purified compounds may underestimate the potential toxicity of comfrey. Published 2015. This article has been contributed to by US Government employees and their work is in the public domain in the USA. Abstract : Comfrey ( Symphytum officinale ), a commonly used herb, contains pro‐toxic dehydropyrrolizidine alkaloids, including lycopsamine and intermedine, and has consequently been internationally regulated with respect to its use. To help further define the toxicity of S. officinale, male, California White chicks were used to compare the toxicity of a crude, reduced comfrey alkaloid extract to purified lycopsamine and intermedine. Based on clinical, serum biochemical, tissue adduct concentrations and histopathological analysis, the reduced comfrey extract was more toxic than either pure lycopsamine or intermedine. This suggests a cautionary note when estimates of herbal toxicity are based upon the observed toxicity of isolated toxins.