HC Deb 19 April 1993 vol 223 cc5-6W
Mr. David Nicholson

To ask the Minister of Agriculture, Fisheries and Food (1) whether he proposes to carry out further research on the toxicological data on comfrey, with a view to determining a level of safe use; and if he will make a statement;

(2) what pyrrolizidine alkaloids are found in comfrey; and if he will indicate which of these is of proven toxicity.

Mr. Sackville

I have been asked to reply.

Common comfrey (symphytum officinale) and Russian comfrey (symphytum X uplandicum) are believed to be the varieties commonly used in herbal food supplements. The following pirrolizidine alkaloids have been identified and reported in the scientific literature as being present in either common or Russian comfrey or in both.

  • Symphytine1
  • Echimidine1
  • Acetyl-echimidine3
  • Lycopsamine1
  • 7-acetyl lycopsamine1
  • Symlandine1
  • Echinatine3
  • Heliosupine3
  • Acetyl-heliosupine3
  • Intermidine1
  • 7-acetyl intermidine1
  • Uplandicine2
  • Viridiflorine1
  • 1 in common comfrey but not in Russian comfrey.
  • 2 in Russian comfrey.
  • 3 in both common and Russian comfrey.

The majority of alkaloids found in comfrey have not been tested for toxicity. The results of studies on symphtine suggest that it may be genotoxic and carcinogenic. There is some evidence to suggest that echimidine and echinatine may be genotoxic. Whilst the toxicity data on the individual alkaloids found in comfrey are limited, there is evidence from studies using laboratory animals that the dried leaves and roots of common comfrey are potentially carcinogenic.

The Government's independent expert advisory committee, the Committee on Toxicity of Food, Consumer Products and the Environment, reviewed data including that on four cases of human liver damage associated with the consumption of comfrey preparations. It considered the data to be of sufficient concern to warrant action in the interests of public safety and recommended that action should be taken to reduce the intake of comfrey and its potentially toxic constituents.

It is for the manufacturers of preparations using comfrey to submit to the Government the results of research into the safety of other products if they so wish. The Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment advised that further toxicological testing would provide results of limited use in toxicological evaluations.

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