British Medicines and Healthcare Products Regulatory
Agency Issues Recall of St. John’s Wort Tablets
On February 8, 2016, the Medicines and Healthcare Products Regulatory
Agency (MHRA) in the United Kingdom (UK) issued a precautionary recall of six
batches of tablets containing a dry extract of St. John’s wort (Hypericum perforatum, Hypericaceae). The tablets were
recalled after laboratory analyses found a pyrrolizidine alkaloid (PA) at levels above the threshold recommended by the Committee
on Herbal Medicinal Products (HMPC). The HMPC currently recommends limiting the ingestion
of toxic 1,2-dehydropyrrolizidine alkaloids (unsaturated PAs) to less than 0.35
μg per day for adults.1 Overall, more than 90,000 St. John’s wort
tablets were recalled.
Comment: This
regulatory action may have far-reaching implications for suppliers and
manufacturers of herbal teas and dietary supplements. The finding of a PA in
St. John’s wort is thought to be due to accidental contamination of the harvest
by weeds such as common ragwort (Jacobaea vulgaris
syn. Senecio jacobaea, Asteraceae), common
groundsel (Senecio vulgaris, Asteraceae), and other
Senecio species, which have been rapidly
expanding in some parts of Europe.2 These weeds have high
concentrations of toxic PAs, so a small number of weeds growing in a field of
medicinal plants can be sufficient to bring PA levels above the recommended HMPC
limit. While many suppliers have increased their efforts to reduce the levels
of PAs in herbal raw materials, Barbara Steinhoff, PhD, of the German Medicines
Manufacturers’ Association (Bundesverband der
Arzneimittel-Hersteller [BAH]), cautions that “the origin of the
causes, the worldwide occurrence, and the cyclic harvesting process of
medicinal plants make it impossible to reduce PA-contamination on a large-scale
in the short term.”3 Subsequent to this action, the MHRA reviewed the information from German
regulatory officials (BfArM) and, based upon expert
advice, concluded that a maximum threshold of 1.0 µg PAs daily could be
accepted in the UK as a transitional limit until clear guidance to minimize
contamination can be put in place.4
References
1. European
Medicines Agency Committee on Herbal Medicinal Products (HMPC). Public statement on the use of herbal medicinal products containing
toxic, unsaturated pyrrolizidine alkaloids (PAs). London, UK: European Medicines
Agency; 2014. Available at: http://www.ema.europa.eu/docs/en_GB/document_library/Public_statement/2014/12/WC500179559.pdf. Accessed
May 10, 2016.
2. Lattrell
B. PA-haltige Pflanzen auf nicht landwirtschaftlich genutzten Flächen. Presented at: 16. BfR-Forum
Verbraucherschutz: Pyrrolizidinalkaloide – Herausforderungen an Landwirtschaft
und Verbraucherschutz; December 3, 2015; Berlin, Germany. Available at: http://www.bfr.bund.de/cm/343/pa-haltige-pflanzen-auf-nicht-landwirtschaftlich-genutzten-flaechen.pdf. Accessed May 10, 2016.
3. Steinhoff
B. Maßnahmen zur Vermeidung und Verringerung von Kontaminationen pflanzlicher
Arzneimittel mit PA: gemeinsames Projekt der Verbände BAH und BPI. Presented at: 16. BfR-Forum
Verbraucherschutz: Pyrrolizidinalkaloide – Herausforderungen an Landwirtschaft
und Verbraucherschutz; December 4, 2015; Berlin, Germany. Available at: http://www.bfr.bund.de/cm/343/massnahmen-zur-vermeidung-und-verringerung-von-kontaminationen-pflanzlicher-arzneimittel-mit-pa.pdf. Accessed May 10, 2016.
4. Wilson A.
Pyrrolizidine alkaloids (PAs) in herbal medicinal products. Letter to holders
of a Traditional Herbal Registration (THR). London, UK: Medicines and Healthcare Products Regulatory Agency; April 6, 2016.
